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 08Z...
* NO CONCERNS IN THE NEAR TERM.
* SOUTHERLY WINDS PICKING UP BY MID MORNING WITH GUSTS UP TO 20KT
POSSIBLE THROUGH THE AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
WITH HIGH PRESSURE STRETCHED ACROSS THE REGION...QUIET WEATHER
ONGOING ACROSS THE TERMINALS. OUTSIDE OF SOME SCATTERED HIGH
LEVEL CIRRUS TODAY...NO REAL CLOUD COVER EXPECTED. THEN A
DEVELOPING SYSTEM TO THE WEST WILL SLOWLY SHIFT EAST WITH TIME
CLOSER TO THE END OF THE FORECAST PERIOD...WITH AN INCREASE IN
HIGH LEVEL CIRRUS AND MID LEVEL MOISTURE BUT WITH ANY PRECIP
STAYING WELL WEST OF THE TERMINALS.
LIGHT SOUTHERLY WINDS WILL GRADUALLY PICK UP BY MID MORNING WITH
GUSTS UP TO 20KT POSSIBLE THROUGH THE AFTERNOON...BEFORE
DIMINISHING BY THE EVENING. ALTHOUGH AS THE SYSTEM TO THE WEST
SLOWLY SHIFTS EAST...WINDS ALOFT WILL REMAIN ON THE INCREASE. THIS
COULD KEEP SOUTH/SOUTHWEST WINDS AROUND THE 10KT RANGE TOWARDS
THE END OF THE FORECAST PERIOD.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN VFR CONDITIONS.
* HIGH CONFIDENCE IN WIND SPEED AND DIRECTION.
RODRIGUEZ
//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...
259 AM CDT
A COLD FRONT THAT SPANS THE NORTHERN PLAINS WILL SLOWLY PUSH EAST
ACROSS THE NORTHERN MISSISSIPPI VALLEY TODAY...WHILE RIDGING
OVER THE EASTERN CONUS MOVES EAST. THE PRESSURE GRADIENT WILL
TIGHTEN THROUGH THE DAY AND WINDS WILL INCREASE CONSIDERABLY. NOT
EXPECTING WINDS TO REACH GALE LEVELS FOR THE OPEN WATERS...BUT
REMAIN AT OR AROUND 30 KT LATER THIS AFTERNOON AND INTO THE
EVENING HOURS. DID HOIST A SMALL CRAFT ADVISORY FOR LATER THIS
MORNING THAT WILL BE IN EFFECT INTO THE EVENING. CONDITIONS WILL
BE MARGINAL FOR MOST LOCATIONS...THOUGH CANT COMPLETELY RULE OUT
THE OCCASIONAL GUST AOA CRITERIA. WINDS WILL THEN FLIP TO THE
NORTH AS THE FRONT SLIDES BY AND THE STRONGER CASE FOR AN ADVISORY
WILL CREEP UP OVERNIGHT WEDNESDAY AS WAVES WILL INCREASE ABOVE
CRITERIA. WINDS WILL ALSO PICK UP OUT OF THE NORTH AND REACH 30 KT
FROM THE OPEN WATERS TO ALL COASTAL LOCATIONS. HIGH PRESSURE WILL
THEN WORK ACROSS THE LAKES BY THE END OF THE WEEK ALLOWING THE
STRONG NORTHERLY WINDS TO ABATE FOR A SHORT TIME. ANOTHER CENTRAL
PLAINS STORM SYSTEM WILL MOVE ACROSS LAKE SUPERIOR AND INTO CANADA
THIS WEEKEND...BRINGING WINDY SOUTHERLY CONDITIONS ACROSS THE
ENTIRE SPAN OF THE LAKE.
SHEA
&&
.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.
&&
$$
