304 PM CDT
ANTI-CYCLONIC FLOW REMAINS CENTERED ACROSS THE TENNESSEE VALLEY
INFLUENCING WEATHER ACROSS NORTHERN IL/NORTHWEST THIS AFTERNOON.
PRESSURE GRADIENT HAS STEADILY TIGHTENED ACROSS THE WESTERN GREAT
LAKES...COUPLED WITH FULL SUNSHINE AND SFC WINDS HAVE INCREASED INTO
THE LOW/MID TEENS. AFTN TEMPS HAVE FINALLY WARMED INTO THE 60S
ACROSS CWFA WITH A FEW 70 DEG ACROSS THE SOUTHERN TIER INTO CENTRAL
IL.
QUASI-STATIONARY FRONTAL BOUNDARY WAS DRAPPED ACROSS LAKE SUPERIOR
AND EXTENDS WEST THROUGH THE CENTRAL ROCKIES. RETURN FLOW MOISTURE
WILL CREEP NORTHWEST INTO THE SOUTHERN PLAINS AS A 500MB TROUGH AXIS
PIVOTS EAST THROUGH THE ROCKIES. THIS WILL ALLOW A SHORTWAVE TO
DEVELOP ON THE LEE-SIDE OF THE ROCKES OVERNIGHT. SKIES WILL REMAIN
MOSTLY CLEAR THROUGH THE OVERNIGHT PERIOD...WITH JUST SOME CIRRUS
BEGINNING TO ADVECT EAST EARLY WED MORNING. WITH DRY SFC CONDS IN
PLACE AND NOT ANTICIPATING WINDS TO FALL OFF SUBSTANTIALLY...TEMPS
SHOULD NOT RADIATE AS EFFICIENTLY AS IN PREVIOUS NIGHTS.
ANTICIPATING
A RATHER MILD NIGHT WITH TEMPS IN THE LOW/MID 40S OR UPPER 40S
CLOSER TO LAKE MICHIGAN.
WEDNESDAY THROUGH THURSDAY...
500MB TROUGH AXIS CONTINUES TO SLOWLY PIVOT EAST ACROSS THE CENTRAL
PLAINS DURING THE DAY WED AS THE SFC SHORTWAVE IS EXPECTED TO REMAIN
RELATIVELY IN PHASE WITH THE UPPER LEVEL SUPPORT. PRIMARILY THIS IS
DUE TO A POTENT DOWNSTREAM RIDGE ACROSS THE MIDDLE ATLANTIC AND AN
ANTI-CYCLONIC FLOW PUSHING INTO THE SOUTHERN ROCKIES. EXPECT THIS TO
SLOWLY BRING THE FRONTAL BOUNDARY SOUTH ACROSS THE CWFA...HOWEVER
SOLUTIONS CONTINUE TO STRUGGLE WITH ARRIVAL OF PRECIP WED. BOUNDARY
LAYER SHOULD REMAIN RELATIVELY DRY THROUGH MUCH OF THE DAY
WED...HOWEVER A STEADY POOLING OF MOISTURE FROM THE NORTHWEST
THROUGHOUT THE AFTERNOON AND EVENING HOURS IS EXPECTED. THE SREF
CONTINUES TO DEMONSTRATE NOISE WITH PRECIP ONSET...SO CONFIDENCE IS
A STRUGGLE. NONETHELESS IT STILL APPEARS PRECIP SHOULD BE OVERHEAD
BY WED EVENING. THE NEXT CHALLENGE WILL BE QPF TOTALS. MODELS DIFFER
ON THE TOTALS...THUS HAVE OPTED TO LEAN HEAVILY TOWARDS SREF QPF
PRECIP FOR THE WED/THUR PERIOD.
SFC ANTI-CYCLONIC FLOW ACROSS THE CENTRAL PLAINS CONTINUES TO ADVECT
EAST FROM THE CENTRAL PLAINS ELONGATING NORTH ACROSS THE WESTERN
GREAT LAKES. THIS MAY ALLOW A SHARP CUTOFF OF PRECIP OVER THE
CWFA...BRINGING AN END TO THE PRECIP BY MIDDAY THUR. ENOUGH DRY AIR
WILL EVENTUALLY FILTER INTO THE REGION AND ALLOW SKIE TO BECOME
PARTLY CLOUDY. TEMPS ALOFT DO NOT APPEAR TO BE TOO COOL...HOWEVER
WITH CONSIDERABLE FILTERING OF THE SUN THUR EXPECT HIGHS TO STRUGGLE
TO PUSH BEYOND THE MID/UPR 40S POSSIBLY 50 DEG IN SOME LOCATIONS.
FRIDAY THROUGH MONDAY...
ACTIVE PATTER CONTINUES TO BE ADVERTISED BY ENSEMBLES THROUGH THE
WEEKEND. 500MB WAVE PATTERN HAS A RIDGE PUSHING 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.
WITH A LARGE ANOMALOUS TROUGH PUSHING INTO THE WETERN CONUS...THIS
SETS THE STAGE FOR POTENTIAL CONVECTION EARLY NEXT WEEK. AIDING TO
THE CONFIDENCE OF SUCH A POTENTIAL SCENARIO IS A STRENGTHENING LLVL
JET AS 850MB WINDS FROM THE SOUTH/SOUTHWEST 3 SIGMA ABOVE NORMAL
WITH MINIMAL SPREAD AMONGST ENSEMBLES.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WINDS GUSTING UP TO 20 KT THIS AFTERNOON.
* 40 TO 45 KT FLOW AT 1 TO 2 KFT LATE TONIGHT.
* CIGS DECREASING WEDNESDAY AFTERNOON AHEAD OF APPROACHING FRONTAL
SYSTEM...BUT AT LEAST REMAINING VFR THROUGH CURRENT TAF PERIOD.
BMD/MTF
//DISCUSSION...UPDATED 18Z...
A WARM FRONT WILL LIFT NORTH ACROSS THE REGION TODAY...WITH WINDS
VEERING FROM SSE TO SSW EARLY THIS AFTERNOON. MIXING WILL ALLOW
GUSTS TO AROUND 20 KTS...BEFORE CUTTING OFF AROUND SUNSET THIS
EVENING. DRY LOW AND MID LEVELS WILL KEEP SKIES MOSTLY SUNNY
TODAY...EXCEPT FOR SOME PATCHY CIRRUS. OVERNIGHT...DECOUPLING WILL
ALLOW WINDS TO DIMINISH AT THE SURFACE...BUT JUST ABOVE SURFACE
INVERSION...WINDS QUICKLY INCREASE TO AROUND 40 TO 45 KT. NOT
CONFIDENT ENOUGH THAT WINDS MAY BE INCREASE SHARPLY ENOUGH TO MEET
LLWS CRITERIA...BUT MAY CAUSE BUMPY RIDES OVER THE LOWER COUPLE
THOUSAND FEET.
ON WEDNESDAY...CLOUD COVER WILL INCREASE IN COVERAGE AS TAIL END OF
A COLD FRONT SWINGS THROUGH THE AREA. MODELS INDICATE SOME
PRECIPITATION ALONG WITH THE SURFACE TROUGH...BUT BETTER SIGNAL IS
ALONG AREA OF FRONTOGENESIS/DEFORMATION ZONE BEHIND THE FRONT. WITH
DRY ANTECEDENT CONDITIONS...EXPECT MODELS TO STRUGGLE WITH PRECIP
ONSET TIME...AND HAVE LEANED TOWARDS SLOWER GUIDANCE...WHICH KEEPS
PRECIP JUST BEYOND THE LATEST 30-HR TAF FOR ORD...AND 24-HR TAF FOR
RFD. CLOUDS WILL LOWER THROUGH THE AFTERNOON THOUGH...AND EXPECT
CIGS TO DROP BELOW 050 WEDNESDAY AFTERNOON...WITH ONSET OF
PRECIPITATION HOLDING OFF UNTIL THE EVENING. BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIRECTION AND VFR CONDITIONS THROUGH
THIS EVENING.
* LOW CONFIDENCE IN LLWS CONDS OVERNIGHT.
* MEDIUM CONFIDENCE IN TIMING OF LOWERING CIG TRENDS WEDNESDAY.
BMD/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...SHRA. MVFR WITH POSSIBLE IFR CEILINGS.
THURSDAY...CHANCE OF SHRA. MVFR CEILINGS BECOMING VFR.
FRIDAY...VFR.
SATURDAY...SLIGHT CHANCE OF SHRA LATE...OTHERWISE VFR.
SUNDAY...SLIGHT CHANCE OF SHRA...OTHERWISE VFR.
MONDAY...VFR.
RODRIGUEZ
&&
.MARINE...
207 PM CDT
SOUTHERLY WINDS WILL REMAIN IN THE 20 TO 30 KT RANGE TONIGHT
INTO WEDNESDAY AHEAD OF AN APPROACHING COLD FRONT FROM THE UPPER
MISSISSIPPI VALLEY. THIS COLD FRONT WILL PUSH ACROSS FAR NORTHERN
LAKE MICHIGAN BY EARLY WEDNESDAY MORNING. THE COLD FRONT SHOULD
CLEAR THE ENTIRE LAKE BY WEDNESDAY EVENING. NORTH TO NORTHEASTERLY
WINDS WILL BE THE MAIN STORY BEHIND THIS FRONT AS THEY INCREASE
WEDNESDAY NIGHT. A SURFACE RIDGE OF HIGH PRESSURE EXTENDING FROM
THE PLAINS NORTHWARD ACROSS THE UPPER MIDWEST WILL BUILD IN ACROSS
THE NORTHERN PORTIONS OF THE LAKE WEDNESDAY NIGHT AND THURSDAY. AT
THE SAME TIME...A POTENT AREA OF LOW PRESSURE WILL MOVE ACROSS THE
MID MISSISSIPPI VALLEY EARLY THURSDAY. THE PRESSURE GRADIENT
ASSOCIATED WITH THESE TWO PRESSURE SYSTEMS APPEARS TO PRODUCE THE
STRONGEST WINDS...NEAR GALE FORCE...ACROSS THE SOUTHERN HALF OF THE
LAKE WEDNESDAY NIGHT INTO THURSDAY. THE SURFACE HIGH WILL FINALLY
BUILD ACROSS THE LAKE THURSDAY NIGHT INTO FRIDAY...PRODUCING A PERIOD
OF LIGHTER WINDS. HOWEVER...WINDS LOOK TO INCREASE OUT OF THE SOUTH
FRIDAY NIGHT INTO THE WEEKEND AS ANOTHER STRONG STORM SYSTEM
DEVELOPS ACROSS THE CENTRAL ROCKIES AND LIFTS NORTH NORTHEAST WARD
ACROSS THE UPPER MISSISSIPPI VALLEY BY THE END OF THE WEEKEND.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
