327 AM CDT
THE MOTS /MORE OF THE SAME/ PHILOSOPHY WILL SLOWLY BE COMING TO AN
END THIS WEEK AS FALL MAKES A TRIUMPHANT RETURN...BRINGING CHILLY
AND WET WEATHER WITH IT. LEADING UP TO THE MIDDLE OF THE
WEEK...THE REGION WILL STILL BE ABLE TO ENJOY THE UNSEASONABLY
WARM AND CLIMATOLOGICALLY DRY CONDITIONS.
LARGE RIDGE OVER THE EASTERN OHIO VALLEY IS SLOWLY WEAKENING BUT
CONTINUING TO DOMINATE OUR WEATHER FOR THE NEAR TERM AND THE
SUNDAY WEATHER PICTURE WILL AGAIN BE PRIMARILY UNCHANGED.
SHORTWAVE DIGGING THROUGH WESTERN TEXAS WILL BEGIN ROTATE AROUND
THE BASE OF AN UPPER LEVEL TROUGH THAT SPANS MUCH OF THE
ROCKIES...AND EVENTUALLY LIFT NORTH THROUGH THE PLAINS...SPAWNING
ANOTHER WEAK SURFACE LOW THAT WILL MOVE IN A SIMILAR MOTION TO THE
DECAYING LOW ACROSS WESTERN NEBRASKA THIS MORNING. PRESSURE
GRADIENT WILL ORIENT THIS AFTERNOON TO ALLOW SOUTHERLY WINDS TO
TURN A LITTLE MORE SOUTHEASTERLY...IMPACTING TEMPERATURES ACROSS
COASTAL LOCATIONS. STILL FEEL THAT THE LAKEFRONT CHICAGO METRO
WILL REACH THE MID TO UPPER 70S BEFORE THE SOUTHEAST INFLUENCE
INCREASES. THE SAME TREND WILL BE NOTED NORTH ACROSS LAKE COUNTY
AS WELL. OTHERWISE WITH MID LEVELS ONLY COOLING SLIGHTLY...LOWER TO
MID 80S ACROSS THE REGION WILL BE EXPECTED AGAIN. FORECAST
SOUNDINGS INDICATE EFFICIENT MIXING UP TO OR SLIGHTLY ABOVE 900
HPA THIS AFTERNOON...AND WE SHOULD SEE THE DRY AIR ALOFT...TRANSLATE
DOWN TO THE SURFACE AGAIN. SIMILAR TO THE PREVIOUS FEW DAYS...DEWPOINTS
WILL FALL INTO THE AFTERNOON HOURS INTO THE UPPER 40S WITH
HUMIDITIES HAVING A SIMILAR RESPONSE INTO THE 30 PCT RANGE FOR
AREAS GENERALLY SOUTH OF I-80.
THE RIDGE WILL BEGIN TO BREAK DOWN EARLY IN THE WORK WEEK...BRINGING
AN END TO THE UNSEASONABLY WARM AND DRY WEATHER. MODELS ARE STILL IN
PRETTY GOOD AGREEMENT THE OVERALL EVOLUTION AND TIMING OF A COLD
FRONT SWINGING THROUGH THE AREA ON WEDNESDAY. BEGAN TO INTRODUCE THE
MENTION OF SHOWERS OVERNIGHT TUESDAY FOR AREAS WEST OF I-39...WITH
THE ENTIRE CWA BEING UNDER THE GUN BY WEDNESDAY. CONVERGENCE ALONG
THE FRONT IS MARGINAL AND INSTABILITY IS RATHER ANEMIC...AND THE BEST
DYNAMICS REMAINING ACROSS SOUTHERN ILLINOIS. FORECAST SOUNDINGS ARE
SHOWING SLIGHT ELEVATED INSTABILITY INTO THE OVERNIGHT HOURS OF
WEDNESDAY WITH MID LEVEL LAPSE RATES APPROACHING 7.5 DEG/C AS A
WEAK S/WV ROTATES THROUGH...AND WILL MAINTAIN THE MENTION OF
ISOLATED THUNDER THROUGH THAT TIME...THOUGH IT WILL LIKELY BE RAIN
WITH A FEW RUMBLES.
BEHIND THE FRONT WILL BRING THE RETURN TO FALL-LIKE WEATHER WITH
TEMPERATURES DWINDLING THROUGH THE WEEK. CONFIDENCE THEN FALLS ON
HOW LONG THE SHOWERS WILL LINGER AS AN UPPER LOW MIGRATES
OVERHEAD...THROUGH THE END OF THE WEEK. EXTENDED CONSENSUS IS STILL
HIGHLIGHTING OFF AN ON CHANCES FOR LIGHT RAIN THROUGH FRIDAY AND
AGREE THAT IT IS REASONABLE. WHILE TEMPERATURES WILL STRUGGLE TO
REACH 60 BY FRIDAY...THERE ARE INDICATIONS THAT WE COULD SEE A
LAST GASP OF SUMMER BY SUNDAY OR MONDAY /WITH HIGHS POPPING 5 TO
10 DEGREES ABOVE NORMAL/...BEFORE ANOTHER FRONT PLOWS THROUGH.
OBVIOUSLY...LONG RANGE FORECASTS FOR LATE NEXT WEEK NEED TO BE
TAKEN WITH A GRAIN OF SALT THOUGH THE TREND IS ENCOURAGING AFTER
THIS RETURN TO FALL.
SHEA
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT AND VARIABLE WINDS TURNING EAST THIS AFTERNOON. SPEEDS
UNDER 10 KT EXPECTED.
JEE
//DISCUSSION...UPDATED 18Z...
BEAUTIFUL BLUE SKIES ARE WITH US FOR ANOTHER DAY AS THE RIDGE
REMAINS OVERHEAD. WINDS REMAIN LIGHT AND VARIABLE...BUT EXPECTING
WINDS TO TURN EAST THIS AFTERNOON AND REMAIN LESS THAN 10 KT.
A LAKE BREEZE HAS DEVELOPED FOR THE ENTIRE LOT
SHORELINE...AND THE BREEZE IS SLOWLY HEADING INLAND. THINKING WINDS
WILL ALREADY BE OUT OF THE EAST AT ORD AND MDW BY THE TIME THE
BREEZE REACHES THE TERMINALS. WINDS MAY PICK UP...BUT WILL STAY
BELOW 10 KT SO NOT EXPECTING A HUGE IMPACT FROM THE LAKE BREEZE
PASSAGE. WINDS WILL DIE DOWN TO BELOW 5 KT AFTER 00Z WHEN THE
SURFACE DECOUPLES. VFR CONDITIONS CONTINUE TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND SPEED...BUT MEDIUM CONFIDENCE IN TIMING
OF WIND DIRECTION CHANGES.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH TUESDAY...VFR.
WEDNESDAY AND THURSDAY...CHC SHRA/SLGT CHC TSRA BRIEF MVFR...
OTHERWISE VFR.
FRIDAY...SLGT CHC SHRA. OTHERWISE VFR.
SATURDAY...VFR.
MDB
&&
.MARINE...
302 PM CDT
HIGH PRESSURE STRECHES ACROSS THE EASTERN HALF OF THE US. THE WEAK
PRESSURE GRADIENT HAS CREATED LIGHT WINDS ACROSS THE AREA...WITH
THE STRONGEST WINDS IN THE NORTHERN HALF OF LAKE MICHIGAN. WEAK
FLOW WILL CONTINUE OVERNIGHT. A LOW PRESSURE SYSTEM WILL PASS TO
OUR WEST TOMORROW...TIGHTENING THE PRESSURE GRADIENT AND CREATING
STRONGER SOUTHEAST WINDS. A NEW AREA OF LOW PRESSURE WILL DEVELOP
OVER THE GREAT PLAINS TUESDAY AND MOVE EAST. THE LOW AND A COLD
FRONT WILL PASS THROUGH LAKE MICHIGAN ON THURSDAY. MODELS
INDICATE A BROAD TROUGH WILL BE CENTERED OVER THE WESTERN GREAT
LAKES ON THURSDAY. WINDS UNDER THE TROUGH AXIS WILL BE RELATIVELY
WEAKER THAN IN SURROUNDING AREAS. BEHIND THE FRONT...COLD AIR WILL
CREATE UNSTABLE CONDITIONS OVER THE LAKE WITH GALES UP TO 35 KT
OVER THE SOUTHERN HALF OF LAKE MICHIGAN...AND WINDS UP TO 30 KT
OVER THE NORTHERN HALF OF LAKE MICHIGAN. WINDS BEGIN TO WEAKEN
FRIDAY NIGHT.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
