880
FXUS63 KLOT 211133
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
533 AM CST WED JAN 21 2026
KEY MESSAGES
- A STRONG ARCTIC FRONT WILL BRING A 1-2 HOUR PERIOD OF GUSTY
SNOW SHOWERS (GREATEST COVERAGE NORTH OF I-80). WINDS GUSTING
TO 40+ MPH MAY LEAD TO PATCHY BLOWING AND DRIFTING SNOW
THROUGH TONIGHT WHERE SNOW FALLS.
- A SECOND ARCTIC FRONT WILL USHER IN AN EXTENDED PERIOD OF
DANGEROUS COLD THURSDAY NIGHT THROUGH EARLY NEXT WEEK.
- AN EXTREME COLD WATCH HAS BEEN ISSUED FOR LATE THURSDAY NIGHT
INTO FRIDAY MORNING FOR AREAS NEAR AND NORTH OF INTERSTATE-55
WHERE WIND CHILLS MAY DROP BELOW -30F.
DISCUSSION
ISSUED AT 340 AM CST WED JAN 21 2026
AFTER A BURST OF HEAVIER SNOW ACROSS FAR NORTHERN ILLINOIS AND
EVEN IN PARTS OF NORTHWEST INDIANA, SNOW HAS MOSTLY STRUGGLED TO
FILL IN OVER MUCH OF THE AREA EARLY THIS MORNING. STILL CAN'T
RULE OUT THE DEVELOPMENT OF A SECONDARY SOUTHERLY BAND RESULTING
IN AN ADDITIONAL DUSTING NEAR AND EAST OF INTERSTATE-55, BUT
GIVEN IMPACTS ARE NOT ANTICIPATED TO BE AT THE LEVEL OF A WINTER
WEATHER ADVISORY, HAVE ACCORDINGLY CANCELLED IT EARLY. STILL
CAN'T RULE OUT SOME SLICK SPOTS INTO THE FIRST PART OF THE AM
COMMUTE WHERE ROADS ARE STILL PARTIALLY SNOW COVERED AND WHERE
ANY ADDITIONAL SNOW FALLS THROUGH MID MORNING.
WITH LESS SNOW HAVING FALLEN OVERNIGHT, TEMPERATURES TODAY ARE
ANTICIPATED TO WARM INTO THE 30S NEAR AND SOUTH OF I-88 (MID-
UPPER 20S NORTH). IN FACT, SOME AREAS WELL SOUTH OF I-80 COULD
TOUCH 40 BY THIS AFTERNOON. WINDS WILL BECOME BREEZY OUT OF THE
WEST SOUTHEAST BY THIS AFTERNOON WITH GUSTS TO 20-25 MPH.
ATTENTION WILL QUICKLY TURN TO THIS EVENING WHEN A STRONG
ARCTIC FRONT IS EXPECTED TO PUSH ACROSS THE AREA. THIS FEATURE
IN QUESTION IS CURRENTLY PROGRESSING ACROSS NORTHERN NORTH
DAKOTA EARLY THIS MORNING AND IS EXPECTED TO RACE SOUTHEAST
WITH TIME TOWARD THE AREA THROUGH THE DAY. WHILE CONFIDENCE IN A
SHORT PERIOD OF SNOW SHOWERS AND GUSTY WINDS DEVELOPING IS HIGH
FOR THIS PERIOD, THERE REMAINS UNCERTAINTY WITH THEIR
INTENSITY. STEEPENING LOW-LEVEL LAPSE RATES COULD SUPPORT A
SHORT 1-2 HOUR BURST OF SNOW (AND QUICK ACCUMULATIONS TO 1")
FOLLOWED BY A PERIOD OF WIND GUSTS TO 40+ MPH THROUGH THE
EVENING. THIS COULD BE PAIRED WITH BLOWING AND DRIFTING SNOW
WHERE SNOW DOES ACCUMULATE. HAVE ELECTED TO HOLD OFF ON EITHER
A WIND ADVISORY OR WINTER WEATHER ADVISORY ISSUANCE ON THIS
SHIFT AND WILL LET THE DAY SHIFT GET ONE FINAL LOOK AT THINGS TO
DETERMINE WHICH PRODUCT BEST FITS THE MESSAGE BASED ON UPSTREAM
TRENDS (AND IF WARRANTED).
WINDS WILL EASE GRADUALLY AFTER MIDNIGHT THROUGH DAYBREAK
THURSDAY, REMAINING BREEZY. FORECAST HIGHS ON THURSDAY ARE IN
THE 20S FOR MOST OF THE AREA WITH UPPER TEENS TOWARD THE
WISCONSIN STATE LINE. A SECOND ARCTIC FRONT THEN PUSHES ACROSS
THE AREA LATER IN THE DAY ON THURSDAY. THIS COULD ALSO BE PAIRED
WITH SOME GUSTY SNOW SHOWERS, ALBEIT WITH LESS COVERAGE THAN
THIS EVENING. DID INTRODUCE A FORMAL MENTION OF SNOW SHOWERS IN
THE FORECAST WITH THIS UPDATE TO ACCOUNT FOR THIS.
TEMPERATURES ARE EXPECTED TO PLUMMET IN THE WAKE OF THE FRONT
THURSDAY NIGHT, POTENTIALLY WELL BELOW ZERO ACROSS INTERIOR
NORTHERN ILLINOIS. WINDS COULD STILL BE IN THE 15-25 MPH RANGE
OUT OF THE NORTHWEST THROUGH THE MORNING ON FRIDAY. BECAUSE OF
THIS, WIND CHILLS WILL HAVE THE POTENTIAL TO DROP BELOW -30F FOR
PORTIONS OF THE AREA. ACCORDINGLY, HAVE ISSUE AN EXTREME COLD
WATCH FOR AREAS GENERALLY NEAR AND NORTH OF INTERSTATE-55. CAN'T
RULE OUT COUNTIES ON THE SOUTHEAST PERIPHERY OF THE WATCH BEING
CONVERTED TO A COLD WEATHER ADVISORY INSTEAD OF A WARNING WITH
LATER UPDATES IF TEMPERATURES TREND A BIT WARMER THAN CURRENTLY
FORECAST, BUT THE MESSAGE FOR DANGEROUS COLD WILL REMAIN
UNCHANGED FOR EARLY FRIDAY MORNING! WHILE NOT AS EXTREME AS
EARLY FRIDAY AM, WIND CHILLS MAY REMAIN COLDER THAN -15F
THROUGH SATURDAY MORNING ACROSS THE REGION. BE SURE TO CHECK ON
FAMILY MEMBERS AND NEIGHBORS REGULARLY DURING THIS STRETCH OF
VERY COLD AIR. BUNDLE UP IN SEVERAL LAYERS IF YOU MUST HEAD
OUTDOORS.
LAKE EFFECT SNOW MAY OCCUR INTO PARTS OF NORTHWEST INDIANA IN
THE WAKE OF THURSDAY'S FRONT AT TIMES THROUGH SATURDAY.
CONFIDENCE IN THE DETAILS AT THIS DISTANCE REMAIN LOW, BUT
SOMETHING TO MONITOR FOR THOSE IN NORTHERN PORTER COUNTY.
A MAJOR WINTER STORM IS EXPECTED TO TAKE SHAPE TO OUR SOUTH
LATE WEEK. THERE REMAINS SOME UNCERTAINTY WITH THE HANDLING OF
A TRAILING WAVE DIVING OUT OF CANADA AND HOW IT INTERACTS/PHASES
WITH THE SOUTHERN SYSTEM. THIS COULD LEAD TO ACCUMULATING SNOW
LIFTING AS FAR NORTH AS THE LOCAL AREA SATURDAY NIGHT INTO
SUNDAY (CURRENTLY 30-40% CHANCE). THE EPS REMAINS THE MOST
CONSISTENT WITH THIS SIGNAL AND WILL BE SOMETHING TO MONITOR
CLOSELY OVER THE COMING DAYS.
PETR
AVIATION /12Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 533 AM CST WED JAN 21 2026
FORECAST CONCERNS INCLUDE...
SCATTERED SNOW SHOWERS THIS EVENING, POSSIBLY WITH BLOWING SNOW.
GUSTY WESTERLY WINDS TODAY.
STRONG/GUSTY WESTERLY WINDS TONIGHT.
THERE WILL BE A CHANCE OF FLURRIES THROUGH MID MORNING WITH A
10-20% PERCENT CHANCE OF A BRIEF PERIOD OF MVFR VIS WITH LIGHT
SNOW BUT ONLY HAVE FLURRIES MENTIONED IN THIS FORECAST.
A STRONG COLD FRONT WILL MOVE ACROSS THE AREA THIS EVENING WITH
SCATTERED SNOW SHOWERS EXPECTED ALONG/AHEAD OF THIS FRONT. ONLY
MEDIUM CONFIDENCE FOR COVERAGE AND CURRENT PROB MENTION HAS THIS
POTENTIAL HANDLED WELL FOR NOW. WHERE ANY SNOW SHOWERS OCCUR,
THERE MAY BE A SHORT BURST OF HEAVY SNOW WITH VIS UNDER 1SM.
TOTAL DURATION AT ANY ONE LOCATION SHOULD ONLY BE 1-2 HOURS, BUT
FLURRIES MAY PERSIST INTO THE EARLY OVERNIGHT HOURS. THE
EXPECTED STRONG WINDS MAY CAUSE BLOWING SNOW AND ADDED MENTION
TO THE PROB.
SOUTH/SOUTHWEST WINDS TO START WILL TURN WESTERLY THIS MORNING
WITH PERIODIC GUSTS INTO THE 15-20KT RANGE. GUSTS WILL INCREASE
THIS AFTERNOON, INTO THE LOWER/MID 20KT RANGE. WINDS AND GUSTS
WILL QUICKLY INCREASE WITH THE COLD FRONT THIS EVENING WITH
GUSTS INTO THE MID/UPPER 30KT RANGE POSSIBLE. THESE MAY ONLY
LAST A FEW HOURS WITH THE HIGHEST GUSTS POSSIBLY ASSOCIATED WITH
THE SNOW SHOWERS. THESE STRONG WINDS/GUSTS WILL SLOWLY DIMINISH
OVERNIGHT WITH GUSTS IN THE 15-20KT RANGE BY DAYBREAK THURSDAY,
THEN CONTINUING MID/LATE THURSDAY MORNING. CMS
MARINE
ISSUED AT 1106 PM CST TUE JAN 20 2026
HAVE ISSUED A GALE WARNING FOR ALL OF OUR NEARSHORE ZONES
WEDNESDAY NIGHT. ANOTHER FORMIDABLE ARCTIC COLD FRONT IS SLATED
TO PUSH THROUGH THE REGION WEDNESDAY EVENING, CAUSING WEST-
SOUTHWESTERLY WINDS TO TURN WESTERLY/WEST-NORTHWESTERLY AND GUST
TO AT LEAST 35 KTS BEHIND THE FRONT. SOME POTENTIAL FOR 40 KT
GALES EXISTS AS WELL, THOUGH CONFIDENCE IN THIS IS ONLY LOW-
MEDIUM AT THIS TIME. GUSTS WILL GRADUALLY SUBSIDE WITH TIME
THURSDAY MORNING AS THE FRONT AND ASSOCIATED LOW PRESSURE CENTER
PROGRESS EASTWARD.
SOME CONSIDERATION MAY NEED TO BE GIVEN TO A HEAVY FREEZING
SPRAY WARNING FOR OUR NEARSHORE ZONES ADJACENT TO PORTER COUNTY,
IN. HOWEVER, AT THIS TIME, IT APPEARS THAT THE MORE SIGNIFICANT
HEAVY FREEZING SPRAY RISK WILL REMAIN OVER THE OPEN WATERS OF
LAKE MICHIGAN.
OGOREK
HYDROLOGY
ISSUED AT 258 PM CST MON JAN 19 2026
AREA HYDROGRAPHS AND ICE SPOTTER REPORTS CONFIRM THAT ICE
CONTINUES TO DEVELOP AND SPREAD ACROSS AREAL RIVERS. LOCALIZED ICE
JAMS ARE ALREADY PRESENT ALONG THE ROCK, DES PLAINES, AND FOX
RIVERS. CONTINUED COLD TEMPERATURES TONIGHT AND TUESDAY WILL
CAUSE ICE TO CONTINUE EXPANDING AND THICKENING.
AFTER A BRIEF WARM-UP IN TEMPERATURES TO ABOVE 20 DEGREES ON
TUESDAY-WEDNESDAY, ANOTHER PUSH OF BITTERLY COLD TEMPERATURES
WILL ARRIVE THURSDAY NIGHT. AS A RESULT, THE THREAT FOR ICE
JAMS INCLUDING LOCALIZED FLOODING WILL INCREASE FURTHER TOWARD
THE END OF THE WEEK AND THROUGH THE WEEKEND.
- NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...EXTREME COLD WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-
ILZ103-ILZ104-ILZ105-ILZ106-ILZ107-ILZ108.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 7 PM CST THIS
EVENING FOR THE IL AND IN NEARSHORE WATERS.
GALE WARNING FROM 7 PM THIS EVENING TO 6 AM CST THURSDAY FOR
THE IL AND IN NEARSHORE WATERS.
HEAVY FREEZING SPRAY WARNING FROM MIDNIGHT TONIGHT TO 10 AM
CST THURSDAY FOR GARY TO BURNS HARBOR IN-BURNS HARBOR TO
MICHIGAN CITY IN.
VISIT US AT WEATHER.GOV/CHICAGO
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