Area Forecast Discussion 22:56:50.8178390

.DISCUSSION...
805 PM CDT

NO LARGE SCALE CHANGES NEEDED TO GOING FORECASTS FOR TONIGHT.

SHORT TERM ADJUSTMENTS FOR CONTINUED W TO E CLEARING OF
STRATOCUMULUS WITH BACK EDGE MOVING OVER THE LAKE SHORE BETWEEN
9 AND 930 PM CDT. ALSO ADJUSTED TEMPERATURES FOR REST OF THE
EVENING AS CLEAR SKIES AND DRY CALM AIR WITH THE SURFACE RIDGE
SITTING RIGHT OVER THE LOCAL FORECAST AREA ALLOWED TEMPERATURES
TO NOSEDIVE INTO THE 30S AFTER SUNSET W AND S PORTIONS OF AREA.

TRS

//PREV DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANTI-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 04Z...

* GUSTY SOUTHERLY WINDS TUESDAY. CMS

//DISCUSSION...UPDATED 04Z...

WITH MAINLY CLEAR SKIES AND LIGHT/CALM WINDS...TEMPS HAVE QUICKLY
DROPPED DOWN TO THE DEWPOINTS WITH VISIBILITIES STARTING TO DROP
DOWN INTO THE 6-8SM RANGE. STILL NOT ANTICIPATING ANY WIDESPREAD
FOG PROBLEMS...BUT HAVE INCLUDED PREVAILING LIGHT FOG AT RFD/DPA.
WITH THE POSSIBILITY OF MVFR VIS AT TIMES...LIKELY FROM SHALLOW
GROUND FOG. CMS

PREVIOUS 00Z DISCUSSION...

SOUTHERN END OF A LARGE AREA OF 3-4KFT CIGS STEADILY MOVING EAST
ACROSS NORTHERN IL EARLY THIS EVENING. A FEW LOCATIONS...MAINLY IN
WI REPORTING HIGH MVFR CIGS. EXPECT THE BACK EDGE OF THIS DECK OF
CLOUDS TO BE EAST OF ORD/MDW BY 02Z OR SO...THOUGH COULD STILL BE
A FEW HRS OF FEW/SCT CLOUDS AND WILL NEED TO MONITOR TRENDS WITH
THE EVENING UPDATES. OTHERWISE ONLY HIGH/MID CLOUDS EXPECTED FOR
THE REMAINDER OF THE PERIOD. COULD BE SOME PATCHY FOG AROUND
OVERNIGHT THROUGH SUNRISE BUT DOESN/T APPEAR AS FAVORABLE AS IT
WAS THIS MORNING AND NOT PLANNING ANY MENTION AT THIS TIME.

A LARGE RIDGE OF HIGH PRESSURE JUST TO THE EAST WILL CONTINUE TO
SLOWLY DRIFT EAST TONIGHT. WEST/SOUTHWEST WINDS UNDER 10KTS SHOULD
TURN MORE SOUTHERLY THROUGH THE NIGHT WITH SPEEDS 5KTS OR LESS. BY
MORNING...A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS WILL BE
SLOWLY SHIFTING EAST...TIGHTENING THE GRADIENT BETWEEN THE
DEPARTING RIDGE. AS THE LOW LEVELS BEGIN TO MIX IN THE MID/LATE
MORNING HRS...EXPECT GUSTS IN THE 20KT RANGE FOR MOST OF THE
AFTERNOON...DIMINISHING SOME WITH SUNSET TUESDAY. CMS

//ORD AND MDW CONFIDENCE...UPDATED 04Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS TUESDAY. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...COLD FRONT/WIND SHIFT TO THE NORTH LATE AFTERNOON/EARLY
EVENING. SHOWERS DEVELOPING LATE AFTERNOON/EARLY EVENING. MVFR CIGS
DEVELOPING IN THE EVENING.
THURSDAY...MVFR CIGS/SHOWERS IN THE MORNING...VFR IN THE AFTERNOON.
FRIDAY...VFR.
SATURDAY AND SUNDAY...SLIGHT CHANCE OF SHOWERS.

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM TUESDAY TO 10 PM TUESDAY.

&&

$$

Zone Forecast 22:05:55.7875945

.REST OF TONIGHT...MOSTLY CLEAR. LOWS IN THE MID 30S. LIGHT AND
VARIABLE WINDS BECOMING SOUTH 5 TO 10 MPH OVERNIGHT.
.TUESDAY...MOSTLY SUNNY. HIGHS IN THE MID 60S. SOUTH WINDS 10 TO
15 MPH.
.TUESDAY NIGHT...PARTLY CLOUDY. LOWS IN THE UPPER 40S. SOUTH
WINDS 10 TO 15 MPH.
.WEDNESDAY...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE LOWER 60S. SOUTHWEST WINDS 10 TO 15 MPH.
.WEDNESDAY NIGHT...SHOWERS. LOWS IN THE UPPER 30S. NORTH WINDS
10 TO 20 MPH. CHANCE OF PRECIPITATION 80 PERCENT.
.THURSDAY...MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 40S.
.THURSDAY NIGHT...PARTLY CLOUDY. LOWS IN THE MID 30S.
.FRIDAY...MOSTLY SUNNY. HIGHS IN THE LOWER 50S.
.FRIDAY NIGHT...PARTLY CLOUDY. LOWS AROUND 40.
.SATURDAY...PARTLY SUNNY WITH A 20 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE MID 50S.
.SATURDAY NIGHT...PARTLY CLOUDY WITH A 30 PERCENT CHANCE OF
SHOWERS. LOWS IN THE LOWER 40S.
.SUNDAY THROUGH MONDAY...MOSTLY CLEAR. HIGHS IN THE LOWER 50S.
LOWS IN THE LOWER 30S.

Area Forecast Discussion 21:03:00.7502220

.DISCUSSION...
805 PM CDT

NO LARGE SCALE CHANGES NEEDED TO GOING FORECASTS FOR TONIGHT.

SHORT TERM ADJUSTMENTS FOR CONTINUED W TO E CLEARING OF
STRATOCUMULUS WITH BACK EDGE MOVING OVER THE LAKE SHORE BETWEEN
9 AND 930 PM CDT. ALSO ADJUSTED TEMPERATURES FOR REST OF THE
EVENING AS CLEAR SKIES AND DRY CALM AIR WITH THE SURFACE RIDGE
SITTING RIGHT OVER THE LOCAL FORECAST AREA ALLOWED TEMPERATURES
TO NOSEDIVE INTO THE 30S AFTER SUNSET W AND S PORTIONS OF AREA.

TRS

//PREV DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANTI-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 02Z...

* GUSTY SOUTHERLY WINDS TUESDAY. CMS

//DISCUSSION...UPDATED 00Z...

SOUTHERN END OF A LARGE AREA OF 3-4KFT CIGS STEADILY MOVING EAST
ACROSS NORTHERN IL EARLY THIS EVENING. A FEW LOCATIONS...MAINLY IN
WI REPORTING HIGH MVFR CIGS. EXPECT THE BACK EDGE OF THIS DECK OF
CLOUDS TO BE EAST OF ORD/MDW BY 02Z OR SO...THOUGH COULD STILL BE
A FEW HRS OF FEW/SCT CLOUDS AND WILL NEED TO MONITOR TRENDS WITH
THE EVENING UPDATES. OTHERWISE ONLY HIGH/MID CLOUDS EXPECTED FOR
THE REMAINDER OF THE PERIOD. COULD BE SOME PATCHY FOG AROUND
OVERNIGHT THROUGH SUNRISE BUT DOESN/T APPEAR AS FAVORABLE AS IT
WAS THIS MORNING AND NOT PLANNING ANY MENTION AT THIS TIME.

A LARGE RIDGE OF HIGH PRESSURE JUST TO THE EAST WILL CONTINUE TO
SLOWLY DRIFT EAST TONIGHT. WEST/SOUTHWEST WINDS UNDER 10KTS SHOULD
TURN MORE SOUTHERLY THROUGH THE NIGHT WITH SPEEDS 5KTS OR LESS. BY
MORNING...A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS WILL BE
SLOWLY SHIFTING EAST...TIGHTENING THE GRADIENT BETWEEN THE
DEPARTING RIDGE. AS THE LOW LEVELS BEGIN TO MIX IN THE MID/LATE
MORNING HRS...EXPECT GUSTS IN THE 20KT RANGE FOR MOST OF THE
AFTERNOON...DIMINISHING SOME WITH SUNSET TUESDAY. CMS

//ORD AND MDW CONFIDENCE...UPDATED 02Z...

* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS TUESDAY. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...COLD FRONT/WIND SHIFT TO THE NORTH LATE AFTERNOON/EARLY
EVENING. SHOWERS DEVELOPING LATE AFTERNOON/EARLY EVENING. MVFR CIGS
DEVELOPING IN THE EVENING.
THURSDAY...MVFR CIGS/SHOWERS IN THE MORNING...VFR IN THE AFTERNOON.
FRIDAY...VFR.
SATURDAY AND SUNDAY...SLIGHT CHANCE OF SHOWERS.

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...10 AM TUESDAY TO 10 PM TUESDAY.

&&

$$

Area Forecast Discussion 20:07:52.7174728

.DISCUSSION...UPDATE FOR REST OF TONIGHT...
805 PM CDT

NO LARGE SCALE CHANGES NEEDED TO GOING FORECASTS FOR TONIGHT.

SHORT TERM ADJUSTMENTS FOR CONTINUED W TO E CLEARING OF
STRATOCUMULUS WITH BACK EDGE MOVING OVER THE LAKE SHORE BETWEEN
9 AND 930 PM CDT. ALSO ADJUSTED TEMPERATURES FOR REST OF THE
EVENING AS CLEAR SKIES AND DRY CALM AIR WITH THE SURFACE RIDGE
SITTING RIGHT OVER THE LOCAL FORECAST AREA ALLOWED TEMPERATURES
TO NOSEDIVE INTO THE 30S AFTER SUNSET W AND S PORTIONS OF AREA.

TRS

&&

.PREV DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANTI-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* LOW END VFR CIGS EARLY THIS EVENING.
* GUSTY SOUTHERLY WINDS TUESDAY. CMS

//DISCUSSION...UPDATED 00Z...

SOUTHERN END OF A LARGE AREA OF 3-4KFT CIGS STEADILY MOVING EAST
ACROSS NORTHERN IL EARLY THIS EVENING. A FEW LOCATIONS...MAINLY IN
WI REPORTING HIGH MVFR CIGS. EXPECT THE BACK EDGE OF THIS DECK OF
CLOUDS TO BE EAST OF ORD/MDW BY 02Z OR SO...THOUGH COULD STILL BE
A FEW HRS OF FEW/SCT CLOUDS AND WILL NEED TO MONITOR TRENDS WITH
THE EVENING UPDATES. OTHERWISE ONLY HIGH/MID CLOUDS EXPECTED FOR
THE REMAINDER OF THE PERIOD. COULD BE SOME PATCHY FOG AROUND
OVERNIGHT THROUGH SUNRISE BUT DOESN/T APPEAR AS FAVORABLE AS IT
WAS THIS MORNING AND NOT PLANNING ANY MENTION AT THIS TIME.

A LARGE RIDGE OF HIGH PRESSURE JUST TO THE EAST WILL CONTINUE TO
SLOWLY DRIFT EAST TONIGHT. WEST/SOUTHWEST WINDS UNDER 10KTS SHOULD
TURN MORE SOUTHERLY THROUGH THE NIGHT WITH SPEEDS 5KTS OR LESS. BY
MORNING...A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS WILL BE
SLOWLY SHIFTING EAST...TIGHTENING THE GRADIENT BETWEEN THE
DEPARTING RIDGE. AS THE LOW LEVELS BEGIN TO MIX IN THE MID/LATE
MORNING HRS...EXPECT GUSTS IN THE 20KT RANGE FOR MOST OF THE
AFTERNOON...DIMINISHING SOME WITH SUNSET TUESDAY. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM CONFIDENCE REGARDING CLOUD TRENDS THIS EVENING.
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS TUESDAY. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...COLD FRONT/WIND SHIFT TO THE NORTH LATE AFTERNOON/EARLY
EVENING. SHOWERS DEVELOPING LATE AFTERNOON/EARLY EVENING. MVFR CIGS
DEVELOPING IN THE EVENING.
THURSDAY...MVFR CIGS/SHOWERS IN THE MORNING...VFR IN THE AFTERNOON.
FRIDAY...VFR.
SATURDAY AND SUNDAY...SLIGHT CHANCE OF SHOWERS.

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Zone Forecast 19:53:54.7091766

.REST OF TONIGHT...PARTLY CLOUDY TIL LATE EVENING THEN
CLEARING. LOWS IN THE MID 30S. LIGHT AND VARIABLE WINDS IN THE
EVENING BECOMING SOUTH AROUND 10 MPH AFTER MIDNIGHT.
.TUESDAY...MOSTLY SUNNY. HIGHS IN THE MID 60S. SOUTH WINDS 10 TO
15 MPH.
.TUESDAY NIGHT...PARTLY CLOUDY. LOWS IN THE UPPER 40S. SOUTH
WINDS 10 TO 15 MPH.
.WEDNESDAY...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE LOWER 60S. SOUTHWEST WINDS 10 TO 15 MPH.
.WEDNESDAY NIGHT...SHOWERS. LOWS IN THE UPPER 30S. NORTH WINDS
10 TO 20 MPH. CHANCE OF PRECIPITATION 80 PERCENT.
.THURSDAY...MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 40S.
.THURSDAY NIGHT...PARTLY CLOUDY. LOWS IN THE MID 30S.
.FRIDAY...MOSTLY SUNNY. HIGHS IN THE LOWER 50S.
.FRIDAY NIGHT...PARTLY CLOUDY. LOWS AROUND 40.
.SATURDAY...PARTLY SUNNY WITH A 20 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE MID 50S.
.SATURDAY NIGHT...PARTLY CLOUDY WITH A 30 PERCENT CHANCE OF
SHOWERS. LOWS IN THE LOWER 40S.
.SUNDAY THROUGH MONDAY...MOSTLY CLEAR. HIGHS IN THE LOWER 50S.
LOWS IN THE LOWER 30S.

Area Forecast Discussion 18:33:06.6611814

.DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANIT-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* LOW END VFR CIGS EARLY THIS EVENING.
* GUSTY SOUTHERLY WINDS TUESDAY. CMS

//DISCUSSION...UPDATED 00Z...

SOUTHERN END OF A LARGE AREA OF 3-4KFT CIGS STEADILY MOVING EAST
ACROSS NORTHERN IL EARLY THIS EVENING. A FEW LOCATIONS...MAINLY IN
WI REPORTING HIGH MVFR CIGS. EXPECT THE BACK EDGE OF THIS DECK OF
CLOUDS TO BE EAST OF ORD/MDW BY 02Z OR SO...THOUGH COULD STILL BE
A FEW HRS OF FEW/SCT CLOUDS AND WILL NEED TO MONITOR TRENDS WITH
THE EVENING UPDATES. OTHERWISE ONLY HIGH/MID CLOUDS EXPECTED FOR
THE REMAINDER OF THE PERIOD. COULD BE SOME PATCHY FOG AROUND
OVERNIGHT THROUGH SUNRISE BUT DOESN/T APPEAR AS FAVORABLE AS IT
WAS THIS MORNING AND NOT PLANNING ANY MENTION AT THIS TIME.

A LARGE RIDGE OF HIGH PRESSURE JUST TO THE EAST WILL CONTINUE TO
SLOWLY DRIFT EAST TONIGHT. WEST/SOUTHWEST WINDS UNDER 10KTS SHOULD
TURN MORE SOUTHERLY THROUGH THE NIGHT WITH SPEEDS 5KTS OR LESS. BY
MORNING...A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS WILL BE
SLOWLY SHIFTING EAST...TIGHTENING THE GRADIENT BETWEEN THE
DEPARTING RIDGE. AS THE LOW LEVELS BEGIN TO MIX IN THE MID/LATE
MORNING HRS...EXPECT GUSTS IN THE 20KT RANGE FOR MOST OF THE
AFTERNOON...DIMINISHING SOME WITH SUNSET TUESDAY. CMS

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM CONFIDENCE REGARDING CLOUD TRENDS THIS EVENING.
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS TUESDAY. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

WEDNESDAY...COLD FRONT/WIND SHIFT TO THE NORTH LATE AFTERNOON/EARLY
EVENING. SHOWERS DEVELOPING LATE AFTERNOON/EARLY EVENING. MVFR CIGS
DEVELOPING IN THE EVENING.
THURSDAY...MVFR CIGS/SHOWERS IN THE MORNING...VFR IN THE AFTERNOON.
FRIDAY...VFR.
SATURDAY AND SUNDAY...SLIGHT CHANCE OF SHOWERS.

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.

&&

$$

Area Forecast Discussion 17:08:37.6109982

.DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANIT-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* LOW END VFR CIGS THROUGH EARLY EVENING. CMS

//DISCUSSION...UPDATED 18Z...

SOUTHWEST FLOW PERSISTING AT LOW LEVELS THROUGH TUESDAY. A WEAK
UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA WILL HELP TO
PRODUCE SOME MVFR/VFR CEILINGS ACROSS NORTHERN IL AND NORTHWEST
DURING THE AFTERNOON HOURS. TONIGHT WE SHOULD HAVE A BIT MORE WIND
THAN LAST NIGHT...SO NOT EXPECTING A REPEAT OF THE FOG TUESDAY
MORNING.

PAW

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.

&&

$$

Hazardous Weather Outlook 16:25:02.5851098

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

Hazardous Weather Outlook 16:16:54.5802786

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST
ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

Area Forecast Discussion 15:05:28.5378471

.DISCUSSION...
301 PM CDT

VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW CONSIDERABLE CLOUDS
ACROSS NORTHERN ILLINOIS STRETCHING NORTH THROUGH WISCONSIN. FURTHER
UPSTREAM ACROSS IOWA/MINNESOTA DIFFLUENT FLOW ALOFT HAS ALLOWED DRY
AIR TO ENTRAIN INTO THE NEAR SFC ENVIRONMENT...AND ERODE MOST OF THE
CLOUDS WITH FULL SUNSHINE. LLVL ANIT-CYCLONIC FLOW REMAINS CENTERED
OVER THE TENNESSEE VALLEY AND BEGINNING TO DRIFT EAST AS THE MID-LVL
TROUGH AXIS PIVOTS EAST AS WELL.

OVERNIGHT INTO TUE AS TROUGH AXIS DEPARTS THE REGION...SEMI-ZONAL
FLOW SETS UP AT 500MB. DOWNSTREAM RIDGE WILL SLOW DOWN AND BECOME
POSITIONED OVER THE MID-ATLANTIC/NEW ENGLAND REGIONS THROUGH WED.
ACROSS THE UPPER MIDWEST GUIDANCE CONTINUES TO INDICATE A FRONTAL
BOUNDARY WILL SAG SOUTH. THE CHALLENGE HAS CONTINUED TO BE ON THE
FORWARD SPEED AND PRECIP TIMING WITH THIS BOUNDARY.

TEMPERATURES OVERNIGHT WITH DEPARTING CLOUDS WILL STEADILY RADIATE
INTO THE 30S AWAY FROM LAKE MICHIGAN...POSSIBLY TOUCHING THE
FREEZING POINT. CLOSER TO LAKE MICHIGAN TEMPERATURES WILL HOVER IN
THE UPPER 30S TO ARND 40 DEG.

TUESDAY WILL BE MUCH WARMER WITH A SOUTHERLY FLOW DEVELOPING IN THE
LLVLS. 850MB THERMAL RIDGE OF 6 TO 8 DEG C WILL ADVECT OVERHEAD AND
WITH MINIMAL SOLAR SHIELDING WILL PROVIDE AN OPPORTUNITY FOR SFC
TEMPS TO WARM INTO THE 60S.

WEDNESDAY...
GUIDANCE CONTINUES TO DEMONSTRATE NOISE AMONGST OPERATIONAL MODELS.
LATEST NAM/GFS ARE SHOWING SOME MODEL CORRECTIONS ARE TAKING PLACE
WITH A SLIGHTLY FASTER REGIME IN BRINGING THE FRONTAL BOUNDARY
ACROSS THE REGION EARLIER IN THE DAY WED. CONFIDENCE REMAINS HIGH
THAT PRECIP WILL REMAIN WEST OF THE CWFA THROUGH MOST OF WED...WITH
A STEADY MOISTURE ADVECTION INTO THE REGION BY WED EVENING. THIS
COUPLED WITH A THERMAL RIDGE ALOFT REMAINING IN PLACE TO PROVIDE SFC
TEMPS IN THE MID 60S. SOME LOCATIONS ALONG AND SOUTH OF LA SALLE TO
KANKAKEE COUNTY LINE COULD PUSH THE UPPER 60S.

THURSDAY...
STUBBORN FRONTAL BOUNDARY ARRIVES EARLY THUR AND SLOWLY PUSHES
THROUGH THE CWFA TONIGHT. 850MB THERMAL TROUGH OF -2 TO 0 DEG C
ARRIVES OVERHEAD AS SFC ANTI-CYCLONIC FLOW BUILDS IN FROM THE
CENTRAL PLAINS INTO THE WESTERN GREAT LAKES. THIS SHOULD BRING AN
END TO THE PRECIP BY THUR EVENING...WITH DRY AIR TO CLOSE OUT THE
WEEK. TEMPERATURES THUR WILL STRUGGLE TO WARM BEYOND THE UPPER 40S
TO LOWER 50S.

FRIDAY THROUGH SUNDAY...
ENSEMBLES HAVE MAINTAINED SOME LEVEL OF CONSISTENCY WITH RESPECT TO
MINIMAL SPREAD IN THE 500MB WAVE PATTERN AS A RIDGE PUSHES EAST
ACROSS THE GREAT LAKES REGION FRI/SAT. THIS SHOULD KEEP DRY AIR IN
PLACE THROUGH AT LEAST FRI...WITH JUST SLIGHT CHANCE OF PRECIP FOR
SAT AFTN AS OPERATIONAL MODELS CONTINUE TO ADVERTISE A POTENT
SHORTWAVE DEVELOPING OVER THE SOUTHERN PLAINS AND RAPIDLY
STRENGTHENING AND LIFTING NORTHEAST. THE TREND HAS BEEN FOR A
FURTHER NORTHWEST PATH OF THIS SYSTEM...WHICH MAY END UP PREVENTING
PRECIP FROM ARRIVING SAT AFTN AND PUSHING IT INTO SUN. THIS SCENARIO
IS GROWING IN CONFIDENCE AS THE DOWNSTREAM RIDGE MAY BE SLIGHTLY
STRONGER THAN OPERATIONAL SOLUTIONS ARE ANTICIPATING. TEMPERATURES
THROUGH THE EXTENDED PERIODS ARE EXPECTED TO BE MAINLY IN THE
50S...POSSIBLY REACHING 60 DEG ON SAT. OVERNIGHT LOWS WILL MAINLY BE
IN THE 30S TO A FEW NIGHTS IN THE LOWER 40S.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* VFR-LEVEL CEILINGS SCATTERING OUT THIS EVENING.

PAW

//DISCUSSION...UPDATED 18Z...

SOUTHWEST FLOW PERSISTING AT LOW LEVELS THROUGH TUESDAY. A WEAK
UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA WILL HELP TO
PRODUCE SOME MVFR/VFR CEILINGS ACROSS NORTHERN IL AND NORTHWEST
DURING THE AFTERNOON HOURS. TONIGHT WE SHOULD HAVE A BIT MORE WIND
THAN LAST NIGHT...SO NOT EXPECTING A REPEAT OF THE FOG TUESDAY
MORNING.

PAW

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Radar Outage Notification 14:57:52.5333327

NOUS63 KLOT 311957
FTMLOT
Message Date: Oct 31 2011 19:57:07KLOT is Dual Pol radar is back online.

Area Forecast Discussion 14:40:27.5229873

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* VFR-LEVEL CEILINGS SCATTERING OUT THIS EVENING.

PAW

//DISCUSSION...UPDATED 18Z...

SOUTHWEST FLOW PERSISTING AT LOW LEVELS THROUGH TUESDAY. A WEAK
UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA WILL HELP TO
PRODUCE SOME MVFR/VFR CEILINGS ACROSS NORTHERN IL AND NORTHWEST
DURING THE AFTERNOON HOURS. TONIGHT WE SHOULD HAVE A BIT MORE WIND
THAN LAST NIGHT...SO NOT EXPECTING A REPEAT OF THE FOG TUESDAY
MORNING.

PAW

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 14:22:08.5121072

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* VFR-LEVEL CEILINGS DEVELOPING BY MID AFTERNOON.

PAW

//DISCUSSION...UPDATED 18Z...

SOUTHWEST FLOW PERSISTING AT LOW LEVELS THROUGH TUESDAY. A WEAK
UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA WILL HELP TO
PRODUCE SOME MVFR/VFR CEILINGS ACROSS NORTHERN IL AND NORTHWEST
DURING THE AFTERNOON HOURS. TONIGHT WE SHOULD HAVE A BIT MORE WIND
THAN LAST NIGHT...SO NOT EXPECTING A REPEAT OF THE FOG TUESDAY
MORNING.

PAW

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH PCONFIDENCE IN ALL FORECAST ELEMENTS.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
221 PM CDT

SOUTHERLY WINDS WILL BE ON THE INCREASE TONIGHT INTO TUESDAY AS AN
AREA OF LOW PRESSURE MOVES ACROSS SOUTHERN CANADA. THIS LOW WILL
PUSH A COLD FRONT FROM THE NORTHERN PLAINS ACROSS THE UPPER
MISSISSIPPI VALLEY BY TUESDAY. THIS COLD FRONT WILL CONTINUE
EASTWARD ACROSS LAKE MICHIGAN LATE WEDNESDAY AND WEDNESDAY NIGHT. AT
THE SAME TIME...AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG
THIS FRONT ACROSS THE SOUTHERN PLAINS. THIS LOW WILL THEN TRACK
EASTWARD ACROSS MISSOURI AND ILLINOIS WEDNESDAY NIGHT AND THURSDAY.

IT APPEARS THAT THE COMBINATION OF THE COLD AIR MOVING OVER THE LAKE
BEHIND THE FRONT...COMBINED WITH A STRENGTHENING PRESSURE GRADIENT
ASSOCIATED WITH THE DEVELOPING SURFACE LOW...WILL PRODUCE A
PERIOD OF STRONG NORTH TO NORTHEASTERLY WINDS ACROSS LAKE MICHIGAN
WEDNESDAY INTO THURSDAY. SOME GALE FORCE WINDS ARE POSSIBLE DURING
THIS PERIOD...ESPECIALLY OVER THE SOUTH HALF OF THE LAKE.
HOWEVER...DUE TO ABOVE AVERAGE UNCERTAINTY ON THE EXACT TIMING AND
TRACK OF THE SURFACE LOW...I AM NOT CONFIDENT ENOUGH TO INCLUDE
WINDS OF THIS MAGNITUDE AT THIS TIME.

FOLLOWING THIS STORM...A SURFACE HIGH WILL BUILD IN ACROSS THE GREAT
LAKES ON THURSDAY NIGHT AND FRIDAY. THIS WILL PRODUCE A PERIOD OF
LIGHTER WINDS BEFORE SOUTHERLY WINDS INCREASE AGAIN INTO NEXT
WEEKEND AHEAD OF A POTENT STORM SYSTEM EXPECTED DEVELOP ACROSS THE
CENTRAL ROCKIES BEFORE LIFTING NORTH NORTHEAST WARD ACROSS THE UPPER
MISSISSIPPI VALLEY.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 12:30:26.4457574

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* VFR-LEVEL CEILINGS DEVELOPING BY MID AFTERNOON.

PAW

//DISCUSSION...UPDATED 18Z...

SOUTHWEST FLOW PERSISTING AT LOW LEVELS THROUGH TUESDAY. A WEAK
UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA WILL HELP TO
PRODUCE SOME MVFR/VFR CEILINGS ACROSS NORTHERN IL AND NORTHWEST
DURING THE AFTERNOON HOURS. TONIGHT WE SHOULD HAVE A BIT MORE WIND
THAN LAST NIGHT...SO NOT EXPECTING A REPEAT OF THE FOG TUESDAY
MORNING.

PAW

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH PCONFIDENCE IN ALL FORECAST ELEMENTS.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Radar Outage Notification 11:37:22.4142357

NOUS63 KLOT 311637
FTMLOT
Message Date: Oct 31 2011 16:37:10KLOT is Dual Pol radar will be down awhile for general maintenance check.

Zone Forecast 10:54:13.3886047

.REST OF TODAY...PARTLY CLOUDY. HIGHS IN THE LOWER 50S. WEST
WINDS AROUND 10 MPH IN THE LATE MORNING AND EARLY AFTERNOON
BECOMING LIGHT AND VARIABLE LATE IN THE AFTERNOON.
.TONIGHT...MOSTLY CLEAR. LOWS IN THE MID 30S. LIGHT AND VARIABLE
WINDS UNTIL EARLY MORNING BECOMING SOUTH AROUND 10 MPH DURING THE
PREDAWN HOURS.
.TUESDAY...MOSTLY SUNNY. HIGHS IN THE LOWER 60S. SOUTH WINDS
10 TO 15 MPH.
.TUESDAY NIGHT...PARTLY CLOUDY. LOWS IN THE MID 40S. SOUTH WINDS
AROUND 10 MPH.
.WEDNESDAY...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 50S. SOUTHWEST WINDS 10 TO 15 MPH.
.WEDNESDAY NIGHT...SHOWERS LIKELY. LOWS IN THE LOWER 40S. CHANCE
OF PRECIPITATION 70 PERCENT.
.THURSDAY...MOSTLY CLOUDY WITH A 50 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 40S.
.THURSDAY NIGHT...PARTLY CLOUDY. LOWS IN THE UPPER 30S.
.FRIDAY AND FRIDAY NIGHT...PARTLY CLOUDY. HIGHS IN THE LOWER 50S.
LOWS IN THE LOWER 40S.
.SATURDAY...PARTLY SUNNY WITH A 20 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 50S.
.SATURDAY NIGHT...PARTLY CLOUDY WITH A 30 PERCENT CHANCE OF
SHOWERS. LOWS IN THE LOWER 40S.
.SUNDAY...MOSTLY SUNNY. HIGHS AROUND 50.

Area Forecast Discussion 09:01:24.3215915

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* VFR-LEVEL CEILINGS MOVING INTO THE AREA BY 16Z.

PAW

//DISCUSSION...UPDATED 12Z...

WITH AN UPPER LEVEL SYSTEM SLOWLY PROGRESSING THROUGH THE REGION
THIS MORNING...VFR CLOUD COVER REMAINS ACROSS MUCH OF THE AREA.
ALTHOUGH...THIS CLOUD COVER CURRENTLY IS SCATTERED ACROSS THE AREA
WITH THE TERMINALS CLEAR AT THIS TIME. EXPECT THIS CLOUD COVER TO
MOVE BACK OVER THE TERMINALS THROUGH MID MORNING...BUT WITH
CEILINGS TO REMAIN VFR. WITH THIS SYSTEM EXITING TONIGHT...OUTSIDE
OF SOME HIGH LEVEL CIRRUS DONT EXPECT MUCH IN TERMS OF CLOUD COVER
THROUGH THE REMAINDER OF THE FORECAST PERIOD. WITH CLEARING SKIES
THIS MORNING...PATCHY FOG HAS DEVELOPED IN AND AROUND THE
TERMINALS WITH SOME LOWER VIS OF 3-5SM OBSERVED. THIS FOG SHOULD
CONTINUE TO SCATTER/LIFT OVER THE NEXT COUPLE OF HOURS BUT WITH A
POSSIBILITY OF THIS LOWER VIS TO MOVE OVERHEAD.

LIGHT AND VARIABLE WINDS ACROSS THE AREA WILL SLOWLY INCREASE OUT
OF THE WEST/SOUTHWEST TODAY...BUT WITH GUSTS NOT MUCH OF AN ISSUE.
WINDS WILL THEN DIMINISH THIS EVENING BEFORE REALLY PICKING UP OUT
OF THE SOUTH ON TUESDAY.

RODRIGUEZ

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* MEDIUM CONFIDENCE IN VFR-LEVEL CEILINGS.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 07:04:45.2523015

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* FOG EARLY THIS MORNING...WITH POSSIBLE VIS AROUND 5SM AT TIMES.

* VFR CEILINGS TO MOVE BACK OVERHEAD BY MID MORNING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

WITH AN UPPER LEVEL SYSTEM SLOWLY PROGRESSING THROUGH THE REGION
THIS MORNING...VFR CLOUD COVER REMAINS ACROSS MUCH OF THE AREA.
ALTHOUGH...THIS CLOUD COVER CURRENTLY IS SCATTERED ACROSS THE AREA
WITH THE TERMINALS CLEAR AT THIS TIME. EXPECT THIS CLOUD COVER TO
MOVE BACK OVER THE TERMINALS THROUGH MID MORNING...BUT WITH
CEILINGS TO REMAIN VFR. WITH THIS SYSTEM EXITING TONIGHT...OUTSIDE
OF SOME HIGH LEVEL CIRRUS DONT EXPECT MUCH IN TERMS OF CLOUD COVER
THROUGH THE REMAINDER OF THE FORECAST PERIOD. WITH CLEARING SKIES
THIS MORNING...PATCHY FOG HAS DEVELOPED IN AND AROUND THE
TERMINALS WITH SOME LOWER VIS OF 3-5SM OBSERVED. THIS FOG SHOULD
CONTINUE TO SCATTER/LIFT OVER THE NEXT COUPLE OF HOURS BUT WITH A
POSSIBILITY OF THIS LOWER VIS TO MOVE OVERHEAD.

LIGHT AND VARIABLE WINDS ACROSS THE AREA WILL SLOWLY INCREASE OUT
OF THE WEST/SOUTHWEST TODAY...BUT WITH GUSTS NOT MUCH OF AN ISSUE.
WINDS WILL THEN DIMINISH THIS EVENING BEFORE REALLY PICKING UP OUT
OF THE SOUTH ON TUESDAY.

RODRIGUEZ

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE OF FOG THIS MORNING...WITH MEDIUM CONFIDENCE AT
THE POSSIBILITY OF LOWER VIS.

* MEDIUM CONFIDENCE WITH CEILING TRENDS TODAY.

* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...VFR.

WEDNESDAY...CHANCE OF SHRA LATE...OTHERWISE VFR.

THURSDAY...CHANCE OF SHRA...OTHERWISE VFR.

FRIDAY...VFR.

SATURDAY...CHANCE OF SHRA...OTHERWISE VFR.

SUNDAY...VFR.

RODRIGUEZ

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 05:25:26.1933073

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 10Z...

* DEVELOPING FOG WITH POSSIBLE VIS OF 3-5SM OVER THE NEXT COUPLE
OF HOURS.

* VFR CEILINGS TO MOVE BACK OVER THE TERMINALS LATER THIS MORNING.

RODRIGUEZ

//DISCUSSION...UPDATED 06Z...

WEAKENING LOW PRESSURE CONTINUES TO MOVE NORTHEASTWARD TOWARD
NORTHERN LAKE MICHIGAN TONIGHT WITH A FRONTAL BOUNDARY APPROACHING
FROM THE WEST. SOUTH WINDS WILL TURN WEST YET TONIGHT AND INCREASE
SLIGHTLY LATER MONDAY MORNING. MAIN ISSUE WILL BE CIGS. VFR CIGS
ARE STARTING TO SCATTER FROM THE WEST BUT AN EXPANSIVE AREA OF VFR
CIGS IS SPREADING EASTWARD FROM IOWA AND IS EXPECTED TO MOVE
OVERHEAD OVERNIGHT. MAIN QUESTION WILL BE WHETHER THESE CLOUDS
REMAIN IN PLACE THROUGH DAYBREAK AND LOWER OR IF NEW STRATOCU
DEVELOPMENT WILL OCCUR DURING THE LATE MORNING...FOLLOWING
SCATTERING OF THE OVERNIGHT DECK...WITH BASES AROUND 3000 FT THEN
LIFT INTO THE AFTERNOON. WEST TO SOUTHWEST WINDS WILL TURN
SOUTHERLY MONDAY EVENING WITH ONLY SOME HIGH CIRRUS EXPECTED.

ONE OTHER POTENTIAL ISSUE IS FOG DEVELOPMENT TONIGHT THANKS TO HE
RAIN THAT FELL EARLIER. INDICATED PATCHY/SHALLOW FOG AT DPA/RFD
BUT CANNOT COMPLETELY RULE OUT AT THE REMAINING SITES BUT
RETURNING CLOUD COVER MAY MITIGATE THIS.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 10Z...

* HIGH CONFIDENCE OF OBSERVING FOG WITH MEDIUM CONFIDENCE OF VIS
TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS MOVING BACK OVER THE TERMINALS
WITH MEDIUM CONFIDENCE AS TO THE EXACT TIMING.

* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR.

WEDNESDAY...VFR WITH SHRA ARRIVING WEDNESDAY NIGHT WITH MVFR
POSSIBLE.

THURSDAY...SHRA WITH MVFR POSSIBLE.

FRIDAY...VFR.

SATURDAY...VFR...CHANCE OF SHRA.

MDB

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Short Term Weather 05:07:54.1828925

.NOW...
SKIES HAVE CLEARED TEMPORARILY OVER PORTIONS OF NORTHEAST
ILLINOIS...WHICH COMBINED WITH LIGHT WINDS AND MOIST GROUND FROM
YESTERDAYS RAIN HAS LED TO THE DEVELOPMENT OF PATCHY FOG. FOG MAY
BE LOCALLY DENSE FOR A BRIEF TIME EARLY THIS MORNING...WITH
VISIBILITY LESS THAN A HALF MILE IN A FEW SPOTS. HOWEVER...CLOUDS
ACROSS NORTHWEST AND NORTH CENTRAL ILLINOIS WILL SPREAD OVERHEAD
PRIOR TO SUNRISE. THIS WILL CAUSE TEMPERATURES TO RISE SLIGHTLY
AND SHOULD ALLOW VISIBILITY TO IMPROVE. UNTIL THEN...IF VENTURING
OUT EARLY ON YOUR MORNING COMMUTE...BE ALERT FOR PATCHY DENSE FOG
AND REDUCED VISIBILITY.

Hazardous Weather Outlook 04:10:01.1485098

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

Zone Forecast 04:00:17.1427282

.TODAY...PARTLY SUNNY. HIGHS IN THE LOWER 50S. WEST WINDS AROUND
10 MPH UNTIL LATE AFTERNOON BECOMING LIGHT AND VARIABLE LATE IN
THE AFTERNOON.
.TONIGHT...MOSTLY CLEAR. LOWS IN THE MID 30S. LIGHT AND VARIABLE
WINDS UNTIL EARLY MORNING BECOMING SOUTH AROUND 10 MPH DURING THE
PREDAWN HOURS.
.TUESDAY...MOSTLY SUNNY. HIGHS IN THE LOWER 60S. SOUTH WINDS
10 TO 15 MPH.
.TUESDAY NIGHT...PARTLY CLOUDY. LOWS IN THE MID 40S. SOUTH WINDS
AROUND 10 MPH.
.WEDNESDAY...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 50S. SOUTHWEST WINDS 10 TO 15 MPH.
.WEDNESDAY NIGHT...SHOWERS LIKELY. LOWS IN THE LOWER 40S. CHANCE
OF PRECIPITATION 70 PERCENT.
.THURSDAY...MOSTLY CLOUDY WITH A 50 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 40S.
.THURSDAY NIGHT...PARTLY CLOUDY. LOWS IN THE UPPER 30S.
.FRIDAY AND FRIDAY NIGHT...PARTLY CLOUDY. HIGHS IN THE LOWER 50S.
LOWS IN THE LOWER 40S.
.SATURDAY...PARTLY SUNNY WITH A 20 PERCENT CHANCE OF SHOWERS.
HIGHS IN THE UPPER 50S.
.SATURDAY NIGHT...PARTLY CLOUDY WITH A 30 PERCENT CHANCE OF
SHOWERS. LOWS IN THE LOWER 40S.
.SUNDAY...MOSTLY SUNNY. HIGHS AROUND 50.

Area Forecast Discussion 03:42:42.1322838

.DISCUSSION...
340 AM CDT

WEAKENING SURFACE LOW PRESSURE WAS LIFTING NORTH ACROSS NORTHEAST
WISCONSIN EARLY THIS MORNING...WITH TRAILING OCCLUDED COLD FRONT
ABOUT TO PUSH EAST OF THE CWA. LINGERING LIGHT SHOWERS WITH FRONT
SHOULD EXIT BY 12Z. PATCHY FOG HAS DEVELOPED IN SOME SPOTS WHERE
SKIES HAVE CLEARED OVER MOIST GROUND...HOWEVER CLOUDS MOVING BACK
INTO WESTERN ILLINOIS WILL LIKELY KEEP FOG FROM BECOMING TOO
WIDESPREAD THIS MORNING. SUBSIDENCE WILL INCREASE LATER THIS MORNING
AS UPPER TROUGH MOVES OFF...AND RIDGING BUILDS IN TO THE AREA THIS
AFTERNOON. THIS SHOULD ALLOW DECREASING CLOUD COVER BY THIS
AFTERNOON.

SOUTHERLY FLOW DEVELOPS LATER TONIGHT AFTER WEAK SURFACE HIGH
PRESSURE RIDGE PASSES ACROSS THE FORECAST AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. WARM ADVECTION DEVELOPS IN EARNEST BY
EARLY TUESDAY...AHEAD OF POSITIVE TILT UPPER TROUGH DEVELOPING
ACROSS THE NORTHERN CONUS. DRY AIR AND LOW LEVEL THERMAL RIDGE
SHOULD HELP TO PUSH TEMPS INTO THE LOWER AND MIDDLE 60S
TUESDAY...MORE ALONG THE LINES OF THE WARMER MET GUIDANCE.

UPPER TROUGH DIGS ACROSS THE CENTRAL CONUS TUESDAY NIGHT AND
WEDNESDAY. NORTHERN STREAM SHORT WAVE PASSING NORTH OF THE GREAT
LAKES TRAILS A SLOW MOVING COLD FRONT ACROSS WISCONSIN AND EASTERN
IOWA TUESDAY NIGHT...AND ACROSS LAKE MICHIGAN AND ILLINOIS ON
WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT IN DEVELOPING PRECIP ON THE
COOL SIDE OF THE BAROCLINIC BOUNDARY...THOUGH VARIOUS MODELS ARE A
LITTLE DIFFERENT IN HOW FAR THE FRONT PUSHES INTO THE WFO LOT CWA.
THE GREATER CHANCE OF PRECIPITATION WILL BE ACROSS THE NORTHWEST
PART OF THE FORECAST AREA WEDNESDAY...AND HAVE BASED POPS MORE ALONG
SLOWER ECMWF/WRF SOLUTIONS AT THIS POINT.

SHORT WAVE MOVING INTO THE SOUTHERN PART OF THE TROUGH IS PROGGED
TO DEVELOP A CLOSED UPPER LOW ACROSS KANSAS AND MISSOURI WEDNESDAY
NIGHT...WITH RAIN SPREADING ACROSS THE REMAINDER OF THE CWA AS
BAROCLINIC ZONE NORTH OF SURFACE FRONT BECOMES FOCUS FOR DEVELOPING
DEFORMATION ZONE INTO THURSDAY. SURFACE LOW QUICKLY OCCLUDES AND
MOVES INTO THE LOWER OHIO VALLEY THURSDAY NIGHT...WITH PRECIP
DIMINISHING FROM NORTHWEST TO SOUTHEAST ACROSS THE CWA.

HIGH PRESSURE THEN SPREADS ACROSS THE GREAT LAKES REGION FRIDAY AS
UPPER RIDGE DEVELOPS ALOFT...AND DEEP TROUGH TAKES SHAPE OVER THE
WESTERN CONUS IN A CONTINUATION OF HIGH AMPLIFIED UPPER AIR PATTERN.
GFS/ECMWF IN PRETTY GOOD AGREEMENT IN A NEGATIVE TILT SHORT WAVE AND
ASSOCIATED DEEP SURFACE LOW LIFTING NORTHEAST ACROSS THE PLAINS AND
INTO WESTERN MINNESOTA ON SATURDAY. THIS IS EXPECTED TO RESULT IN
GUSTY SOUTH WINDS...WITH ANOTHER SHOT OF STRONG WARM ADVECTION. HAVE
BUMPED MAX TEMPS A BIT FOR SATURDAY...IN LINE WITH 00Z MEX GUIDANCE
WHICH IS AT THE HIGH END OF THE ENSEMBLE ENVELOPE. MAY EVENTUALLY
NEED TO RAISE TEMPS MORE...AS LOCATION OF THERMAL RIDGE AND DIURNAL
TIMING COME INTO BETTER FOCUS. OCCLUDED COLD FRONT PUSHES THROUGH
THE FORECAST AREA SATURDAY NIGHT AND SUNDAY...WITH RELATIVELY LOW
CHANCE ATTENDANT POPS. NO REAL PUSH OF REALLY COLD AIR SEEN AT THIS
DISTANCE INTO EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 08Z...

* VFR CEILINGS TO MOVE BACK OVER THE TERMINALS LATER THIS MORNING.

RODRIGUEZ

//DISCUSSION...UPDATED 06Z...

WEAKENING LOW PRESSURE CONTINUES TO MOVE NORTHEASTWARD TOWARD
NORTHERN LAKE MICHIGAN TONIGHT WITH A FRONTAL BOUNDARY APPROACHING
FROM THE WEST. SOUTH WINDS WILL TURN WEST YET TONIGHT AND INCREASE
SLIGHTLY LATER MONDAY MORNING. MAIN ISSUE WILL BE CIGS. VFR CIGS
ARE STARTING TO SCATTER FROM THE WEST BUT AN EXPANSIVE AREA OF VFR
CIGS IS SPREADING EASTWARD FROM IOWA AND IS EXPECTED TO MOVE
OVERHEAD OVERNIGHT. MAIN QUESTION WILL BE WHETHER THESE CLOUDS
REMAIN IN PLACE THROUGH DAYBREAK AND LOWER OR IF NEW STRATOCU
DEVELOPMENT WILL OCCUR DURING THE LATE MORNING...FOLLOWING
SCATTERING OF THE OVERNIGHT DECK...WITH BASES AROUND 3000 FT THEN
LIFT INTO THE AFTERNOON. WEST TO SOUTHWEST WINDS WILL TURN
SOUTHERLY MONDAY EVENING WITH ONLY SOME HIGH CIRRUS EXPECTED.

ONE OTHER POTENTIAL ISSUE IS FOG DEVELOPMENT TONIGHT THANKS TO HE
RAIN THAT FELL EARLIER. INDICATED PATCHY/SHALLOW FOG AT DPA/RFD
BUT CANNOT COMPLETELY RULE OUT AT THE REMAINING SITES BUT
RETURNING CLOUD COVER MAY MITIGATE THIS.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 08Z...

* HIGH CONFIDENCE WITH VFR CEILINGS MOVING BACK OVER THE TERMINALS
WITH MEDIUM CONFIDENCE AS TO THE EXACT TIMING.

* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR.

WEDNESDAY...VFR WITH SHRA ARRIVING WEDNESDAY NIGHT WITH MVFR
POSSIBLE.

THURSDAY...SHRA WITH MVFR POSSIBLE.

FRIDAY...VFR.

SATURDAY...VFR...CHANCE OF SHRA.

MDB

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 03:16:16.1165824

.DISCUSSION...
756 PM CDT

FORECAST GRIDS AND DERIVED TEXT PRODUCTS UPDATED FOR CURRENT
TRENDS THIS EVENING WITH LITTLE IF ANY CHANGES MADE FOR
OVERNIGHT.

AN UPPER LOW IS OVER CENTRAL WI EARLY THIS EVENING WITH A PAIR OF
COMPACT BUT POTENT SHORT WAVES ROTATING AROUND THE S END OF THE
UPPER TROUGH THAT EXTENDS SW TO MO.

FIRST IMPULSE MOVES ACROSS NORTHERN IL DURING THE AFTERNOON AND
EARLY EVENING AND IS CURRENTLY OVER THE W SHORE OF LAKE MI JUST E
OF THE WI STATE LINE. THE ASSOCIATED AREA OF RAIN HAS SHIFTED OUT
OVER LAKE MI AND ACROSS NW IN FOR THE MOST PART. SOME SMALL
SHOWERS LINGERING OVER SOUTHERN WI AND NORTHERN IL THOUGH BASED ON
00Z KDVN RAOB THE STRONG ADVECTION OF MID LEVEL DRY AIR SHOULD
PREVENT ANY FURTHER DEVELOPMENT.

THE SECOND IMPULSE WAS APPROACHING THE BASE OF THE UPPER TROUGH AS
IS STARTED TURNING FROM MOVING SSE TO MORE SOUTHWESTERLY WHILE
DROPPING ACROSS EASTERN KS AND WESTERN MO. VORTICITY MAX
ASSOCIATED WITH THIS SECOND SHORT WAVE IS PROGGED TO MOVE E
THROUGH THE BASE OF THE UPPER TROUGH MID TO LATE EVENING AND THEN
START LIFTING NE TO CENTRAL IL BY 06Z AND TO W CENTRAL OR NE IN
BY 12Z MON.

SHOWER ACTIVITY...BOTH IN COVERAGE AND INTENSITY...HAVE BEEN
INCREASING OVER CENTRAL IL PER RADAR LOOP. AS THE VORT MAX EJECTS
OUT LATER THIS EVENING AND OVERNIGHT EXPECT THESE SHOWERS TO MOVE
OVER S AND E PORTIONS OF THE FORECAST AREA BEFORE STRONG MID LEVEL
DRYING SHIFTS ANY SIGNIFICANT THREAT OF ADDITIONAL SHOWERS DURING
THE OVERNIGHT HOURS WILL BE E OF THE FORECAST AREA.

TRS

//PREV DISCUSSION...
256 PM CDT

ABUNDANT MID/HIGH LVL CLOUDS CONTINUE TO BLANKET THE WESTERN GREAT
LAKES THIS AFTERNOON. PRECIPITATION HAS REMAINED LIGHT AND SCATTERED
ACROSS NORTHERN IL...EVENTUALLY WORKING INTO NORTHWEST IN LATER THIS
AFTERNOON AND EVENING. PRESSURE GRADIENT REMAINS TIGHT AS WELL WITH
OCCASIONAL GUSTS BETWEEN 20 AND 30 MPH...HOWEVER ACROSS EASTERN IOWA
THE GRADIENT WAS BEGINNING TO WEAKEN. THUS EXPECT THE WINDS TO
DECOUPLE LATER THIS EVENING. DRY AIR WAS ALSO BEGINNING TO PUSH
ACROSS THE IA/IL STATE LINE AS THE MID-LVL TROUGH AXIS ARRIVES.

FRONTAL PASSAGE CONTINUES TO BE PROGGED FOR THIS EVENING AND WILL
ALLOW SOUTHWEST WINDS TO BECOME WESTERLY THROUGH THE OVERNIGHT
PERIOD. TROUGH AXIS WILL QUICKLY PUSH OVERHEAD WITH DIFFLUENT FLOW
AIDING IN CLOUD EROSION EARLY MONDAY. SFC ANTI-CYCLONIC FLOW SHOULD
REMAIN TO THE SOUTH OF THE CWFA...WHICH WILL ALLOW A LIGHT WIND FROM
THE WEST TO PERSIST THROUGH THE DAY MONDAY AS WELL. TEMPS OVERNIGHT
ARE EXPECTED TO HOVER IN THE 40S...THEN DEPENDING ON WHEN CLOUDS
BEGIN TO BREAK UP EARLY MONDAY...TEMPS FALL INTO THE 30S EXCEPT
AROUND 40 CLOSER TO LAKE MICHIGAN. ENOUGH WIND SHOULD INHIBIT ANY
FROST FORMATION...SO WILL NOT MENTION THIS IN THE FORECAST FOR
TONIGHT.

THEN FOR MONDAY WITH PARTLY CLOUDY SKIES DEVELOPING AND AN 850MB
THERMAL TROUGH OF 0 TO -2 DEG C LINGERING...HIGHS WILL ONLY WARM
INTO THE LOWER 50S. POSSIBLY MID 50S ALONG THE SOUTHERN TIER OF THE
CWFA.

MONDAY NIGHT THROUGH TUESDAY...
TROUGH AXIS STEADILY DEPARTS TO THE EAST AS MID-LVL HEIGHTS CONTINUE
TO RISE. THIS WILL CONTINUE TO PROVIDE DIFFLUENT FLOW ALOFT AND KEEP
DRY AIR IN PLACE THROUGH TUESDAY. IT APPEARS POSSIBLY THAT OVERNIGHT
LOWS MON NGT INTO EARLY TUE COULD YET AGAIN APPROACH THE FREEZING
POINT FOR MANY LOCATIONS AWAY FROM LAKE MICHIGAN. TEMPS ALOFT ARE
MARGINALLY WARMER THAN THE PREVIOUS NIGHT...SO IT WILL BE POSSIBLE A
DECENT LOW LEVEL INVERSION WILL SETUP. THIS MAY ALLOW PATCHY GROUND
FOG TO DEVELOP WITH LIGHT WINDS. FOR TUESDAY A STEADY WARMING TREND
WILL BE IN FULL SWING...AS SFC TEMPS MAY CLIMB INTO THE 60S POSSIBLY
MID 60S FOR LOCATIONS SOUTH OF A LA SALLE COUNTY TO KANKAKEE COUNTY
LINE.

WEDNESDAY...
ANTI-CYCLONIC FLOW REMAINS IN CONTROL FOR MUCH OF WED. LATEST
GUIDANCE HAS BACKED OFF ON ARRIVAL OF MOISTURE. THUS IT APPEARS FOR
MUCH OF WED THE DAY WILL REMAIN DRY. SOUTHWEST WINDS AHEAD OF THIS
NEXT FRONTAL BOUNDARY AND TEMPS COULD EASILY STAY AROUND 60 TO THE
LOWER 60S FOR MUCH OF THE AREA. GUIDANCE HAS CONTINUED TO BACK OFF
ON MOISTURE ARRIVAL UNTIL WED EVENING...WHEN SHORTWAVE FINALLY
BEGINS TO ARRIVE FROM THE NORTHWEST. HAVE PUSHED PRECIP ARRIVAL BACK
UNTIL CLOSER TO 00Z THUR.

THURSDAY THROUGH SATURDAY...
MARGINAL SPREAD AMONGST ENSEMBLES FOR THE START OF THE EXTENDED
PERIOD...WITH RESPECT TO THE HIGH AMPLITUDE RIDGE PROGGED ACROSS THE
INTERIOR WEST. ACROSS THE MID-SECTION OF THE COUNTRY A FRONTAL
BOUNDARY IS POISED TO SLUGGISHLY PUSH EAST...AS A RESULT GUIDANCE
HAS SHOWN CONSIDERABLE NOISE OR LOW CONFIDENCE ON HOW TO RESOLVE
THIS FEATURE. ENSEMBLES CONTINUE TO FAVOR AMONGST MANY MEMBERS A
GRADUAL PROGRESSION OF THE BOUNDARY TO THE EAST AS THE RIDGE BUILDS
IN FRI. IT APPEARS OPERATIONAL SOLUTIONS HAVE BEEN TOO AGGRESSIVE
WITH PUSHING THE SFC RIDGE EAST LATE IN THE WEEK...AND CONTINUE TO
HINT AT A POTENT SHORT WAVE DEVELOPING ACROSS THE SOUTHERN PLAINS
FRI/SAT.

THIS LATE WEEK INTO NEXT WEEKEND SYSTEM REMAINS A FOCAL POINT
AMONGST MANY OPERATIONAL SOLUTIONS...HOWEVER ENSEMBLES HAVE BEEN
SUGGESTING MUCH OF THE OHIO VALLEY/EXTENDING WEST INTO THE MISSOURI
VALLEY WOULD REMAIN UNDER THE INFLUENCE OF ANTI-CYCLONIC FLOW IN THE
MID-LVLS. THIS WOULD FAVOR A DEFLECTION OF THIS SYSTEM TO THE
NORTHWEST ACROSS THE UPPER MIDWEST. SEVERAL DAYS STAND BETWEEN NOW
AND NEXT WEEKEND...HOWEVER THIS SYSTEM WILL CONTINUE TO BE
MONITORED. BEHIND THIS SYSTEM IT APPEARS A STRONG THERMAL TROUGH IS
DEVELOPING AND EXPECTED TO ARRIVE ACROSS THE GREAT LAKES REGION
SOMETIME OVER THE UPCOMING WEEKEND. THIS MAY LIMIT AFTN MAX TEMPS
FOR THE SECOND HALF OF THE WEEKEND IN THE 40S. LOW CONFIDENCE AT
THIS POINT ON TIMING AND INTENSITY. TEMPERATURES IN THE EXTENDED
APPEAR TO HOVER IN THE 50S...POSSIBLY APPROACHING 60 DEGREES SAT.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 08Z...

* VFR CEILINGS TO MOVE BACK OVER THE TERMINALS LATER THIS MORNING.

RODRIGUEZ

//DISCUSSION...UPDATED 06Z...

WEAKENING LOW PRESSURE CONTINUES TO MOVE NORTHEASTWARD TOWARD
NORTHERN LAKE MICHIGAN TONIGHT WITH A FRONTAL BOUNDARY APPROACHING
FROM THE WEST. SOUTH WINDS WILL TURN WEST YET TONIGHT AND INCREASE
SLIGHTLY LATER MONDAY MORNING. MAIN ISSUE WILL BE CIGS. VFR CIGS
ARE STARTING TO SCATTER FROM THE WEST BUT AN EXPANSIVE AREA OF VFR
CIGS IS SPREADING EASTWARD FROM IOWA AND IS EXPECTED TO MOVE
OVERHEAD OVERNIGHT. MAIN QUESTION WILL BE WHETHER THESE CLOUDS
REMAIN IN PLACE THROUGH DAYBREAK AND LOWER OR IF NEW STRATOCU
DEVELOPMENT WILL OCCUR DURING THE LATE MORNING...FOLLOWING
SCATTERING OF THE OVERNIGHT DECK...WITH BASES AROUND 3000 FT THEN
LIFT INTO THE AFTERNOON. WEST TO SOUTHWEST WINDS WILL TURN
SOUTHERLY MONDAY EVENING WITH ONLY SOME HIGH CIRRUS EXPECTED.

ONE OTHER POTENTIAL ISSUE IS FOG DEVELOPMENT TONIGHT THANKS TO HE
RAIN THAT FELL EARLIER. INDICATED PATCHY/SHALLOW FOG AT DPA/RFD
BUT CANNOT COMPLETELY RULE OUT AT THE REMAINING SITES BUT
RETURNING CLOUD COVER MAY MITIGATE THIS.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 08Z...

* HIGH CONFIDENCE WITH VFR CEILINGS MOVING BACK OVER THE TERMINALS
WITH MEDIUM CONFIDENCE AS TO THE EXACT TIMING.

* HIGH CONFIDENCE WITH WIND SPEED AND DIRECTION.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR.

WEDNESDAY...VFR WITH SHRA ARRIVING WEDNESDAY NIGHT WITH MVFR
POSSIBLE.

THURSDAY...SHRA WITH MVFR POSSIBLE.

FRIDAY...VFR.

SATURDAY...VFR...CHANCE OF SHRA.

MDB

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

Area Forecast Discussion 02:58:27.1059993

.DISCUSSION...
756 PM CDT

FORECAST GRIDS AND DERIVED TEXT PRODUCTS UPDATED FOR CURRENT
TRENDS THIS EVENING WITH LITTLE IF ANY CHANGES MADE FOR
OVERNIGHT.

AN UPPER LOW IS OVER CENTRAL WI EARLY THIS EVENING WITH A PAIR OF
COMPACT BUT POTENT SHORT WAVES ROTATING AROUND THE S END OF THE
UPPER TROUGH THAT EXTENDS SW TO MO.

FIRST IMPULSE MOVES ACROSS NORTHERN IL DURING THE AFTERNOON AND
EARLY EVENING AND IS CURRENTLY OVER THE W SHORE OF LAKE MI JUST E
OF THE WI STATE LINE. THE ASSOCIATED AREA OF RAIN HAS SHIFTED OUT
OVER LAKE MI AND ACROSS NW IN FOR THE MOST PART. SOME SMALL
SHOWERS LINGERING OVER SOUTHERN WI AND NORTHERN IL THOUGH BASED ON
00Z KDVN RAOB THE STRONG ADVECTION OF MID LEVEL DRY AIR SHOULD
PREVENT ANY FURTHER DEVELOPMENT.

THE SECOND IMPULSE WAS APPROACHING THE BASE OF THE UPPER TROUGH AS
IS STARTED TURNING FROM MOVING SSE TO MORE SOUTHWESTERLY WHILE
DROPPING ACROSS EASTERN KS AND WESTERN MO. VORTICITY MAX
ASSOCIATED WITH THIS SECOND SHORT WAVE IS PROGGED TO MOVE E
THROUGH THE BASE OF THE UPPER TROUGH MID TO LATE EVENING AND THEN
START LIFTING NE TO CENTRAL IL BY 06Z AND TO W CENTRAL OR NE IN
BY 12Z MON.

SHOWER ACTIVITY...BOTH IN COVERAGE AND INTENSITY...HAVE BEEN
INCREASING OVER CENTRAL IL PER RADAR LOOP. AS THE VORT MAX EJECTS
OUT LATER THIS EVENING AND OVERNIGHT EXPECT THESE SHOWERS TO MOVE
OVER S AND E PORTIONS OF THE FORECAST AREA BEFORE STRONG MID LEVEL
DRYING SHIFTS ANY SIGNIFICANT THREAT OF ADDITIONAL SHOWERS DURING
THE OVERNIGHT HOURS WILL BE E OF THE FORECAST AREA.

TRS

//PREV DISCUSSION...
256 PM CDT

ABUNDANT MID/HIGH LVL CLOUDS CONTINUE TO BLANKET THE WESTERN GREAT
LAKES THIS AFTERNOON. PRECIPITATION HAS REMAINED LIGHT AND SCATTERED
ACROSS NORTHERN IL...EVENTUALLY WORKING INTO NORTHWEST IN LATER THIS
AFTERNOON AND EVENING. PRESSURE GRADIENT REMAINS TIGHT AS WELL WITH
OCCASIONAL GUSTS BETWEEN 20 AND 30 MPH...HOWEVER ACROSS EASTERN IOWA
THE GRADIENT WAS BEGINNING TO WEAKEN. THUS EXPECT THE WINDS TO
DECOUPLE LATER THIS EVENING. DRY AIR WAS ALSO BEGINNING TO PUSH
ACROSS THE IA/IL STATE LINE AS THE MID-LVL TROUGH AXIS ARRIVES.

FRONTAL PASSAGE CONTINUES TO BE PROGGED FOR THIS EVENING AND WILL
ALLOW SOUTHWEST WINDS TO BECOME WESTERLY THROUGH THE OVERNIGHT
PERIOD. TROUGH AXIS WILL QUICKLY PUSH OVERHEAD WITH DIFFLUENT FLOW
AIDING IN CLOUD EROSION EARLY MONDAY. SFC ANTI-CYCLONIC FLOW SHOULD
REMAIN TO THE SOUTH OF THE CWFA...WHICH WILL ALLOW A LIGHT WIND FROM
THE WEST TO PERSIST THROUGH THE DAY MONDAY AS WELL. TEMPS OVERNIGHT
ARE EXPECTED TO HOVER IN THE 40S...THEN DEPENDING ON WHEN CLOUDS
BEGIN TO BREAK UP EARLY MONDAY...TEMPS FALL INTO THE 30S EXCEPT
AROUND 40 CLOSER TO LAKE MICHIGAN. ENOUGH WIND SHOULD INHIBIT ANY
FROST FORMATION...SO WILL NOT MENTION THIS IN THE FORECAST FOR
TONIGHT.

THEN FOR MONDAY WITH PARTLY CLOUDY SKIES DEVELOPING AND AN 850MB
THERMAL TROUGH OF 0 TO -2 DEG C LINGERING...HIGHS WILL ONLY WARM
INTO THE LOWER 50S. POSSIBLY MID 50S ALONG THE SOUTHERN TIER OF THE
CWFA.

MONDAY NIGHT THROUGH TUESDAY...
TROUGH AXIS STEADILY DEPARTS TO THE EAST AS MID-LVL HEIGHTS CONTINUE
TO RISE. THIS WILL CONTINUE TO PROVIDE DIFFLUENT FLOW ALOFT AND KEEP
DRY AIR IN PLACE THROUGH TUESDAY. IT APPEARS POSSIBLY THAT OVERNIGHT
LOWS MON NGT INTO EARLY TUE COULD YET AGAIN APPROACH THE FREEZING
POINT FOR MANY LOCATIONS AWAY FROM LAKE MICHIGAN. TEMPS ALOFT ARE
MARGINALLY WARMER THAN THE PREVIOUS NIGHT...SO IT WILL BE POSSIBLE A
DECENT LOW LEVEL INVERSION WILL SETUP. THIS MAY ALLOW PATCHY GROUND
FOG TO DEVELOP WITH LIGHT WINDS. FOR TUESDAY A STEADY WARMING TREND
WILL BE IN FULL SWING...AS SFC TEMPS MAY CLIMB INTO THE 60S POSSIBLY
MID 60S FOR LOCATIONS SOUTH OF A LA SALLE COUNTY TO KANKAKEE COUNTY
LINE.

WEDNESDAY...
ANTI-CYCLONIC FLOW REMAINS IN CONTROL FOR MUCH OF WED. LATEST
GUIDANCE HAS BACKED OFF ON ARRIVAL OF MOISTURE. THUS IT APPEARS FOR
MUCH OF WED THE DAY WILL REMAIN DRY. SOUTHWEST WINDS AHEAD OF THIS
NEXT FRONTAL BOUNDARY AND TEMPS COULD EASILY STAY AROUND 60 TO THE
LOWER 60S FOR MUCH OF THE AREA. GUIDANCE HAS CONTINUED TO BACK OFF
ON MOISTURE ARRIVAL UNTIL WED EVENING...WHEN SHORTWAVE FINALLY
BEGINS TO ARRIVE FROM THE NORTHWEST. HAVE PUSHED PRECIP ARRIVAL BACK
UNTIL CLOSER TO 00Z THUR.

THURSDAY THROUGH SATURDAY...
MARGINAL SPREAD AMONGST ENSEMBLES FOR THE START OF THE EXTENDED
PERIOD...WITH RESPECT TO THE HIGH AMPLITUDE RIDGE PROGGED ACROSS THE
INTERIOR WEST. ACROSS THE MID-SECTION OF THE COUNTRY A FRONTAL
BOUNDARY IS POISED TO SLUGGISHLY PUSH EAST...AS A RESULT GUIDANCE
HAS SHOWN CONSIDERABLE NOISE OR LOW CONFIDENCE ON HOW TO RESOLVE
THIS FEATURE. ENSEMBLES CONTINUE TO FAVOR AMONGST MANY MEMBERS A
GRADUAL PROGRESSION OF THE BOUNDARY TO THE EAST AS THE RIDGE BUILDS
IN FRI. IT APPEARS OPERATIONAL SOLUTIONS HAVE BEEN TOO AGGRESSIVE
WITH PUSHING THE SFC RIDGE EAST LATE IN THE WEEK...AND CONTINUE TO
HINT AT A POTENT SHORT WAVE DEVELOPING ACROSS THE SOUTHERN PLAINS
FRI/SAT.

THIS LATE WEEK INTO NEXT WEEKEND SYSTEM REMAINS A FOCAL POINT
AMONGST MANY OPERATIONAL SOLUTIONS...HOWEVER ENSEMBLES HAVE BEEN
SUGGESTING MUCH OF THE OHIO VALLEY/EXTENDING WEST INTO THE MISSOURI
VALLEY WOULD REMAIN UNDER THE INFLUENCE OF ANTI-CYCLONIC FLOW IN THE
MID-LVLS. THIS WOULD FAVOR A DEFLECTION OF THIS SYSTEM TO THE
NORTHWEST ACROSS THE UPPER MIDWEST. SEVERAL DAYS STAND BETWEEN NOW
AND NEXT WEEKEND...HOWEVER THIS SYSTEM WILL CONTINUE TO BE
MONITORED. BEHIND THIS SYSTEM IT APPEARS A STRONG THERMAL TROUGH IS
DEVELOPING AND EXPECTED TO ARRIVE ACROSS THE GREAT LAKES REGION
SOMETIME OVER THE UPCOMING WEEKEND. THIS MAY LIMIT AFTN MAX TEMPS
FOR THE SECOND HALF OF THE WEEKEND IN THE 40S. LOW CONFIDENCE AT
THIS POINT ON TIMING AND INTENSITY. TEMPERATURES IN THE EXTENDED
APPEAR TO HOVER IN THE 50S...POSSIBLY APPROACHING 60 DEGREES SAT.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* LOWER END VFR CIGS CONTINUING THROUGH LATE EVENING THEN EXPECTED
TO SCATTER BEFORE RETURNING OVERNIGHT.

* SCT TO POSSIBLY BKN CIGS AROUND 3000 FT DURING MONDAY MORNING
WITH BASES LIFTING INTO THE AFTERNOON.

MDB

//DISCUSSION...UPDATED 06Z...

WEAKENING LOW PRESSURE CONTINUES TO MOVE NORTHEASTWARD TOWARD
NORTHERN LAKE MICHIGAN TONIGHT WITH A FRONTAL BOUNDARY APPROACHING
FROM THE WEST. SOUTH WINDS WILL TURN WEST YET TONIGHT AND INCREASE
SLIGHTLY LATER MONDAY MORNING. MAIN ISSUE WILL BE CIGS. VFR CIGS
ARE STARTING TO SCATTER FROM THE WEST BUT AN EXPANSIVE AREA OF VFR
CIGS IS SPREADING EASTWARD FROM IOWA AND IS EXPECTED TO MOVE
OVERHEAD OVERNIGHT. MAIN QUESTION WILL BE WHETHER THESE CLOUDS
REMAIN IN PLACE THROUGH DAYBREAK AND LOWER OR IF NEW STRATOCU
DEVELOPMENT WILL OCCUR DURING THE LATE MORNING...FOLLOWING
SCATTERING OF THE OVERNIGHT DECK...WITH BASES AROUND 3000 FT THEN
LIFT INTO THE AFTERNOON. WEST TO SOUTHWEST WINDS WILL TURN
SOUTHERLY MONDAY EVENING WITH ONLY SOME HIGH CIRRUS EXPECTED.

ONE OTHER POTENTIAL ISSUE IS FOG DEVELOPMENT TONIGHT THANKS TO HE
RAIN THAT FELL EARLIER. INDICATED PATCHY/SHALLOW FOG AT DPA/RFD
BUT CANNOT COMPLETELY RULE OUT AT THE REMAINING SITES BUT
RETURNING CLOUD COVER MAY MITIGATE THIS.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN CIGS REMAINING VFR WITH SCATTERING OVER THE
NEXT SEVERAL HOURS AND MEDIUM CONFIDENCE BKN-OVC WILL RETURN
OVERNIGHT.

* LOW-MEDIUM CONFIDENCE IN BKN CLOUD COVERAGE OCCURRING MONDAY
MORNING WITH MEDIUM CONFIDENCE THAT BASES WILL BE 3000 FT OR
BETTER...THERE IS SOME POTENTIAL FOR THEM TO BE SLIGHTLY LOWER.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR.

WEDNESDAY...VFR WITH SHRA ARRIVING WEDNESDAY NIGHT WITH MVFR
POSSIBLE.

THURSDAY...SHRA WITH MVFR POSSIBLE.

FRIDAY...VFR.

SATURDAY...VFR...CHANCE OF SHRA.

MDB

&&

.MARINE...
255 AM CDT

LOW PRESSURE ACROSS NORTHEASTERN WISCONSIN WILL MOVE INTO WESTERN
SUPERIOR THIS MORNING...BEFORE WEAKENING INTO AN OPEN TROUGH.
WINDS WILL INCREASE TOMORROW OUT OF THE SOUTH AS THE GRADIENT
TIGHTENS WITH HIGH PRESSURE EXITING TO THE EAST AND A COLD FRONT
ADVANCING FROM THE WEST. WINDS WILL LIKELY INCREASE AND PEAK JUST
BELOW GALES FOR THE OPEN WATERS...AND A SMALL CRAFT ADVISORY MAY
BE NEEDED FOR THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY FOR
THE NEARSHORE WATERS. THE COLD FRONT WILL THEN SWEEP ACROSS THE LAKE
FLIPPING WINDS AROUND TO THE NORTH OVERNIGHT ON WEDNESDAY. A WEAK
SHOT OF COLD AIR ADVECTION WILL BRING UP THE CHANCES FOR NORTHERLY
GALES ACROSS THE SOUTHERN HALF OF THE LAKE AT THAT TIME. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND.

SHEA

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.

&&

$$