338
FXUS63 KLOT 222326
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
626 PM CDT WED OCT 22 2025
KEY MESSAGES
- FROST ADVISORY IN EFFECT LATE TONIGHT INTO EARLY THURSDAY FOR
AREAS WEST/SOUTH OF THE CHICAGO METRO.
- A MORE WIDESPREAD FROST IS LIKELY ACROSS MOST OF THE AREA
THURSDAY NIGHT INTO EARLY FRIDAY MORNING.
DISCUSSION
ISSUED AT 215 PM CDT WED OCT 22 2025
NORTHWEST WINDS ARE SLOWLY DIMINISHING THIS AFTERNOON AND THAT
TREND WILL CONTINUE INTO THIS EVENING. THERE WILL LIKELY STILL
BE SOME PERIODIC GUSTS TONIGHT, MAINLY ACROSS NORTHEAST IL AND
NORTHWEST IN WHERE CLOUD COVER IS LIKELY TO PERSIST. THERE IS
SOME CLEARING ACROSS WEST CENTRAL IL THAT IS JUST STARTING TO
GET INTO THE SOUTHWEST CWA. CONFIDENCE IS LOW FOR HOW FAST THE
CLOUDS WILL CLEAR AND HAVE TRENDED A BIT MORE PESSIMISTIC WITH
NORTHEAST IL AND AREAS NEAR THE LAKE POSSIBLY STAYING MOSTLY
CLOUDY THROUGH DAYBREAK THURSDAY MORNING. THERE MAY BE A PASSING
SPRINKLE THIS AFTERNOON ACROSS FAR NORTHEAST IL AND THEN A FEW
SHOWERS ARE POSSIBLE ACROSS NORTHWEST IN TONIGHT INTO THURSDAY
MORNING, MAINLY FOR NORTHEAST PORTER COUNTY.
NO CHANGES TO THE CURRENT FROST ADVISORY FOR OVERNIGHT/EARLY
THURSDAY MORNING. CLOUDS ARE EXPECTED TO CLEAR OUT OF THE
ADVISORY AREA OVERNIGHT WITH LOW TEMPS IN THE LOWER/MID 30S.
WINDS MAY REMAIN IN THE 5 TO 10 MPH RANGE SO THERE REMAINS
UNCERTAINTY FOR HOW WIDESPREAD THE FROST MAY BECOME.
FROST POTENTIAL LOOKS BETTER EARLY FRIDAY MORNING WITH CLEAR
SKIES AND LIGHT, POSSIBLY CALM WINDS. STILL SOME UNCERTAINTY
WHETHER A FREEZE WARNING WILL BE NEEDED, BASED ON HOW COLD THE
LOW TEMPS DROP. BLENDED GUIDANCE HAS BEEN CONSISTENTLY COLDER
THAN JUST ABOUT ALL GUIDANCE AND SEEMS TO BE INFLUENCED BY THE
MUCH COLDER CANADIAN GUIDANCE. HAVE GENERALLY MAINTAINED THE
PREVIOUS FORECAST WITH LOWS IN THE LOWER 30S (AWAY FROM CHICAGO
AND THE LAKE) WITH A FEW POCKETS OF UPPER 20S IN THE USUAL COOL
SPOTS. WILL NOT BE ISSUING ANY HEADLINES FOR THIS TIME PERIOD
THIS AFTERNOON, BUT TEMP TRENDS WILL NEED TO BE MONITORED FOR
THIS TIME PERIOD.
AN UPPER LOW WILL MOVE ACROSS THE PLAINS FRIDAY INTO SATURDAY
AND THE MODELS DIFFER WITH HOW FAR TO THE NORTHEAST THIS FEATURE
MOVES AND HOW MUCH PRECIPITATION MAY REACH THE LOCAL AREA.
APPEARS MUCH OF SUNDAY COULD BE DRY WITH PERHAPS SHOWERS LATE
IN THE DAY OR OVERNIGHT INTO MONDAY, WHICH IS THE GENERAL TREND
OF THE BLENDED POPS. BETTER CONSENSUS FOR A TROUGH TO DIG SOUTH
ACROSS THE MIDWEST AND PLAINS TUESDAY INTO WEDNESDAY, POSSIBLY
BRINGING A BETTER CHANCE FOR SHOWERS TO THE REGION. CMS
AVIATION /00Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 626 PM CDT WED OCT 22 2025
FORECAST CONCERN FOR THE TERMINALS...
- BREEZY NORTHWEST WINDS THIS EVENING AND POSSIBLY AGAIN
THURSDAY AFTERNOON WITH GUSTS AROUND 20 KTS.
A BROAD UPPER LOW CONTINUES TO SPIRAL OVER THE EASTERN GREAT
LAKES AND ONTARIO WHICH HAS MAINTAINED LOW-LEVEL (3000-3500 FT)
CLOUD COVER ACROSS THE TERMINALS. WHILE CLOUDS ARE EXPECTED TO
SCATTER OUT THIS EVENING, CANNOT RULE OUT A FEW 2500-3000 FT
CLOUDS PASSING THROUGH OVERNIGHT AS THEY PIVOT FROM NORTHERN WI
BENEATH THE UPPER LOW. THAT SAID, THE ONGOING BREEZY NORTHWEST
WINDS WILL DIMINISH INTO THE 7-10 KT RANGE OVERNIGHT WHICH IN
COMBINATION WITH THE CLEARING SKIES MAY ALLOW FOR SOME PATCHY
FROST TO DEVELOP. GIVEN THAT WINDS LOOK TO STAY MORE ELEVATED AT
THE CHICAGO TERMINALS DUE TO BETTER MIXING TONIGHT FROST
CHANCES WILL BE LOW HERE, BUT AREAS NEAR RFD AND NORTHWEST IL
LOOK TO HAVE BETTER CHANCES.
OTHERWISE, VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE
PERIOD WITH SOME SCT TO BKN 4000 FT CUMULUS CLOUDS THURSDAY
AFTERNOON. WINDS WILL REMAIN NORTHWEST THROUGH THE PERIOD WITH
SPEEDS INCREASING SLIGHTLY TO AROUND 10-12 KTS THURSDAY. WHILE
AN OCCASIONAL 17-20 KT GUST CANNOT BE RULED OUT DURING THE
AFTERNOON HOURS, IT APPEARS THE GUSTS WILL BE MUCH MORE
INFREQUENT AND THUS HAVE LEFT OUT OF THE TAFS FOR NOW.
YACK
LOT WATCHES/WARNINGS/ADVISORIES
IL...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CDT THURSDAY FOR
ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019-ILZ021-ILZ023-
ILZ032-ILZ033-ILZ039.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR WINTHROP
HARBOR IL TO GARY IN.
SMALL CRAFT ADVISORY UNTIL 10 PM CDT THURSDAY FOR GARY TO
BURNS HARBOR IN-BURNS HARBOR TO MICHIGAN CITY IN.
VISIT US AT WEATHER.GOV/CHICAGO
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