468
FXUS63 KLOT 121804
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
104 PM CDT MON OCT 12 2026
KEY MESSAGES
- RECORD WARMTH IS LIKELY TODAY, ALONG WITH BREEZY/GUSTY
SOUTHWESTERLY WINDS.
- SHOWERS LIKELY AND SOME EMBEDDED THUNDERSTORMS TUESDAY NIGHT
INTO WEDNESDAY MORNING, AND AGAIN ON THURSDAY.
- TURNING MUCH COOLER INTO NEXT WEEKEND.
DISCUSSION
ISSUED AT 206 AM CDT MON OCT 12 2026
FOG HAS DEVELOPED ACROSS PARTS OF NORTHERN IN, MAINLY JUST EAST
OF THE CWA BORDER AND OTHER THEN SOME VERY SHALLOW PATCHY FOG
AND MAINLY ACROSS NORTHWEST IN EARLY THIS MORNING, NOT EXPECTING
ANY WIDESPREAD FOG CONCERNS.
AN UPPER RIDGE WILL BUILD ACROSS THE REGION TODAY BRINGING HIGH
TEMPS IN THE MID 80S NORTH TO UPPER 80S SOUTH AND MADE NO
CHANGES TO THE PREVIOUS FORECAST. CURRENT CLOUD COVER IS
EXPECTED TO THIN BY MIDDAY AND IF MOSTLY SUNNY SKIES MATERIALIZE,
ITS POSSIBLE HIGH TEMPS MAY BE A DEGREE OR TWO WARMER THEN
CURRENTLY FORECAST. AS THE LOW LEVELS MIX AND LOW LEVEL WINDS
INCREASE, SOUTHWEST WINDS MAY GUST INTO THE 25-30 MPH RANGE THIS
AFTERNOON AND THESE GUSTS MAY CONTINUE INTO THIS EVENING AND
PERIODICALLY OVERNIGHT AS STRONG LOW LEVEL WINDS ARE EXPECTED
TONIGHT. AND WHILE TEMPS ARE EXPECTED TO QUICKLY DROP THROUGH
THE 70S EARLY THIS EVENING, TEMPS WILL LEVEL OFF IN THE UPPER
60S TO NEAR 70 FOR LOWS BY TUESDAY MORNING.
A WEAK TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA TUESDAY
MORNING, SHIFTING WINDS WESTERLY BUT WITH LITTLE CHANGE TO THE
AIRMASS, HIGH TEMPS ON TUESDAY ARE LIKELY TO BE NEARLY THE SAME
AS TODAY, RANGING FROM LOWER 80S ACROSS NORTHERN IL, MID 80S FOR
MUCH OF THE CHICAGO METRO AND UPPER 80S FOR AREAS SOUTH OF
I-80. WITH DEWPOINTS CREEPING INTO THE MID 60S ON TUESDAY, HEAT
INDEX VALUES SOUTH OF I-80 MAY CLIMB INTO THE LOWER 90S TUESDAY
AFTERNOON.
PRECIP CHANCES FOR TODAY AND TONIGHT, WHILE ALREADY LOW, NOW
APPEAR TOO LOW FOR ANY MENTION AND WILL HAVE A DRY FORECAST
THROUGH TUESDAY AFTERNOON. IF ANY ISOLATED SHOWERS WERE TO
DEVELOP, THE BEST TIME WINDOW APPEARS TO BE AROUND/JUST AFTER
DAYBREAK TUESDAY MORNING.
A COLD FRONT WILL MOVE SOUTH INTO THE AREA LATE TUESDAY
AFTERNOON AND SLOWLY MOVE SOUTH ACROSS THE AREA TUESDAY NIGHT.
THIS WILL BE THE TIME PERIOD WHEN SHOWERS AND SCATTERED
THUNDERSTORMS ARE POSSIBLE. PRECIPITABLE WATER VALUES RANGE
BETWEEN 1.5 AND 2 INCHES TUESDAY NIGHT INTO WEDNESDAY MORNING
WITH HEAVY RAIN POSSIBLE, BUT THERE IS STILL QUITE A BIT OF
UNCERTAINTY FOR COVERAGE AND CURRENTLY, AREAS SOUTH OF I-80 ARE
MORE FAVORED FOR HIGHER COVERAGE. THE SPC DAY2 OUTLOOK ALSO HAS
A LEVEL 1 FOR SEVERE THUNDERSTORMS INTO THE FAR WESTERN PART OF
THE AREA. THIS POTENTIAL MAY ALSO BE DEPENDENT ON THE LOCATION
OF THE PRECIPITATION AND IF CONVECTION ENDS UP FURTHER SOUTH.
PRECIPITATION MAY END FOR MOST OF THE AREA WEDNESDAY MORNING
WITH THE DAYLIGHT HOURS ON WEDNESDAY MAINLY DRY, ESPECIALLY
NORTH OF I-80. SHOWERS AND SCATTERED THUNDERSTORMS ARE THEN
EXPECTED TO DEVELOP AND SPREAD BACK ACROSS THE AREA LATE
WEDNESDAY NIGHT INTO THURSDAY AHEAD OF STRONG COLD FRONT THAT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT. PRECIPITABLE WATER
VALUES AREA ALSO IN THE 1.5 TO 2 INCH RANGE ON THURSDAY WITH
HEAVY RAIN AGAIN POSSIBLE.
WITH STRONG COLD AIR ADVECTION EXPECTED THURSDAY NIGHT INTO
FRIDAY, NORTHWEST WINDS MAY GUST INTO THE 35-40 MPH RANGE LATE
THURSDAY NIGHT INTO FRIDAY. THERE STILL REMAINS UNCERTAINTY FOR
HOW COLD THE AIRMASS WILL BE BEHIND THE FRONT BUT CONSIDERING
HOW WARM TEMPS WILL BE THROUGH MIDWEEK, IT WILL BE MUCH COLDER
WITH SATURDAY MORNING PERHAPS THE COLDEST WITH LOWS IN THE
LOWER/MID 30S. THE ECMWF HAD BEEN WARMER AND THE GFS SEEMS TO BE
COMING AROUND TO THAT SOLUTION AS HIGH PRESSURE PASSES THE AREA
SUNDAY MORNING AND THEN WINDS TURN SOUTHERLY WITH MODERATING/
WARMER TEMPS BY SUNDAY. CMS
AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 104 PM CDT MON OCT 12 2026
KEY MESSAGES:
- BREEZY SOUTHWESTERLY WINDS ARE EXPECTED THIS AFTERNOON.
- A STRENGHENING LOW-LEVEL JET MAY LEAD TO A PERIOD OF LOW-
LEVEL WIND SHEAR TONIGHT.
BREEZY SOUTHWESTERLY WINDS ARE EXPECTED THIS AFTERNOON WITH
GUSTS GENERALLY IN THE 20-25 KT RANGE. THE GUSTINESS SHOULD
LARGELY CEASE BY THIS EVENING AS THE BOUNDARY LAYER DECOUPLES,
WHICH WILL OPEN THE DOOR FOR A PERIOD OF LOW-LEVEL WIND SHEAR
TONIGHT AS A 45-50 KT LOW-LEVEL JET CENTERED BETWEEN 1500 AND
5000 FT AGL STRENGTHENS OVER THE REGION.
A COLD FRONTAL PASSAGE TOMORROW MORNING WILL CAUSE WINDS TO
ADOPT A WESTERLY TO WEST-NORTHWESTERLY DIRECTION. SUSTAINED
WIND MAGNITUDES ARE GENERALLY FAVORED TO REMAIN NEAR 10 KTS,
THOUGH OCCASIONAL GUSTS TO AROUND 20 KTS MAY BE OBSERVED --
MAINLY IN THE MORNING. WINDS WILL THEN SLACKEN TOWARDS THE END
OF THE 30-HOUR TAF PERIOD AT ORD AND MDW. THIS MAY ALLOW FOR A
LAKE BREEZE TO PUSH INLAND AND RESULT IN AN EASTERLY WIND SHIFT
AT ORD AND/OR MDW, THOUGH THE BEST POTENTIAL FOR THIS APPEARS
THAT IT MAY NOT COME UNTIL AROUND OR JUST AFTER 00Z.
COULD NOT RULE OUT A BRIEF SPRINKLE OR LIGHT SHOWER THIS
EVENING AS ISENTROPIC ASCENT RAMPS UP COMMENSURATELY WITH THE
STRENGTHENING LOW-LEVEL JET. HOWEVER, AT THIS TIME, THE BETTER
CHANCES FOR ANY RAINDROPS TO BE OBSERVED AT GROUND LEVEL APPEAR
TO BE EAST OF THE TERMINALS, SO HAVE KEPT THE TAFS DRY.
OTHERWISE, VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD.
OGOREK
CLIMATE
ISSUED AT 235 PM CDT SUN OCT 11 2026
HERE ARE THE RECORD WARM TEMPERATURES MOST LIKELY TO BE
THREATENED OR BROKEN EARLY THIS WEEK.
MONDAY OCTOBER 12TH RECORD HIGH TEMPS:
CHICAGO'S CURRENT RECORD HIGH: 84F IN 2008
ROCKFORD'S CURRENT RECORD HIGH: 85F IN 2008
TUESDAY OCTOBER 13TH RECORD HIGH MIN TEMPS:
CHICAGO'S CURRENT RECORD HIGH MIN: 67F IN 1920
ROCKFORD'S CURRENT RECORD HIGH MIN: 61F IN 2008
NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT TUESDAY FOR THE IL
NEARSHORE WATERS.
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