107
FXUS63 KLOT 312357
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
557 PM CST WED DEC 31 2025
KEY MESSAGES
- ACCUMULATING SNOW THROUGH EARLY TO MID EVENING WILL LIKELY
RESULT IN HAZARDOUS TRAVEL CONDITIONS, PARTICULARLY IN THE 5
TO 9 PM WINDOW AS TEMPERATURES QUICKLY FALL AND NORTH WINDS
GUST TO 30 MPH.
- TURNING SHARPLY COLDER TONIGHT AND THURSDAY, MODERATING BACK
TO NEAR AVERAGE FOR THE WEEKEND AND POSSIBLY SOMEWHAT ABOVE
AVERAGE EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 239 PM CST WED DEC 31 2025
THROUGH THURSDAY NIGHT:
SNOW IS QUICKLY DEVELOPING ACROSS SOUTHERN WISCONSIN AND INTO
NORTHERN ILLINOIS THIS AFTERNOON IN RESPONSE TO A STRENGTHENING
130- 140 KNOT UPPER JET STREAK TRACKING SOUTHEASTWARD OVER
EASTERN MINNESOTA AND WESTERN WISCONSIN. OVERALL EXPECTATIONS
THROUGH THIS EVENING REMAIN MOSTLY UNCHANGED, ALBEIT AN HOUR OR
SO LATER WITH TIMING THAN PREVIOUSLY EXPECTED.
OVER THE NEXT FEW HOURS (THROUGH ABOUT 5PM), SNOW ON MOST
TRAVELED SURFACES MAY STRUGGLE TO ACCUMULATE AS AIR TEMPS HAVE
SETTLED IN THE MID 30S FOR MOST LOCATIONS. TRAVEL IMPACTS MAY
QUICKLY INCREASE AFTER 5PM AS A SURGING COLD FRONT UNDERCUTS THE
PRECIP WITH RAPIDLY FALLING TEMPS AND WNW WINDS SHIFTING NNW
AND GUSTING TO 30 MPH. SNOW SHOULD THEN QUICKLY END FROM NORTH
TO SOUTH MID TO LATE EVENING. WHILE WE LIKELY WILL NOT MEET SNOW
SQUALL CRITERIA EARLY THIS EVENING (6-8PM), SHALLOW STEEP LOW-
LEVEL LAPSE RATES, BRIEFLY HIGHER SNOWFALL RATES, GUSTY WINDS
AND FALLING TEMPS WITH THE COLD FRONT ALL POINT TO A BRIEF
PERIOD OF HAZARDOUS TRAVEL CONDITIONS OVER NORTHEAST ILLINOIS
AND NORTHWEST INDIANA. WILL CONTINUE TO HIGHLIGHT THIS PERIOD,
PARTICULARLY WITH ANY INCREASED EVENING TRAVEL NYE. OVERALL
ACCUMULATIONS LOOK TO BE AROUND ONE INCH FOR NORTHEAST ILLINOIS
AND NORTHWEST INDIANA WITH GRADUALLY DECREASING AMOUNTS TOWARD
WESTERN AND CENTRAL ILLINOIS. WOULD NOT BE SURPRISED TO SEE A
NARROW CORRIDOR OF 2" TOTALS OVER NORTHEAST ILLINOIS EMBEDDED
WITHIN THE BROADER SNOW SHIELD.
TEMPS WILL CONTINUE TO PLUMMET AFTER THE SNOW ENDS, WITH WIND
CHILL VALUES FALLING INTO THE -5 TO 5F RANGE BY MIDNIGHT AND
THROUGH THE OVERNIGHT PERIOD. THURSDAY WILL BE THE COLDEST DAY
THROUGH EARLY NEXT WEEK AS HIGHS STRUGGLE TO RISE MUCH INTO THE
20S. ANOTHER 140 KNOT UPPER JET STREAK WILL TRACK FARTHER
NORTHEAST THAN TODAY'S SYSTEM, BUT STILL MAY PRODUCE ENOUGH TOP-
DOWN SATURATION TO RESULT IN A PERIOD OF LIGHT SNOW OVER FAR
NORTHEAST ILLINOIS DURING THE AFTERNOON AND EARLY EVENING.
KLUBER
FRIDAY THROUGH WEDNESDAY:
ANOTHER MID LEVEL TROUGH CURRENTLY ANALYZED OFF THE SAN DIEGO
COAST WILL WEAKEN AND LIFT NORTHWARD OVER THE CALIFORNIA CENTRAL
VALLEY THROUGH THURSDAY. MODELS ARE SUGGESTING A SHORTWAVE TO
EJECT FROM THIS TROUGH THURSDAY NIGHT AND TRAVEL EASTWARD OVER
KANSAS INTO FRIDAY MORNING. THIS WAVE IS PROJECTED TO PHASE WITH
ANOTHER WEAK, BROAD, MOISTURE STARVED WAVE COMING OUT OF THE
DAKOTAS. AS SURFACE CYCLOGENESIS DEVELOPS OVER THE OZARKS AND
PROVIDES PRECIPITATION FOR SOUTHERN ILLINOIS, WINDS LOCALLY WILL
SWITCH TO THE SOUTHEAST AND ALLOW FOR SOME, RELATIVELY
SPEAKING, WARMER AIR TO LIFT NORTHWARD IN THE MORNING PROVIDING
MODERATE TEMPERATURES, BEFORE WINDS SWITCH TO THE NORTHEAST IN
THE LATE AFTERNOON.
ENSEMBLE MODELS CONTINUE TO PROJECT THAT THE UPPER LEVEL LOW
OVER ONTARIO/QUEBEC WILL WEAKEN AND GRADUALLY MOVE EAST, HOWEVER
THERE IS STILL SOME DISAGREEMENT AMONG MEMBERS IN HOW MUCH OF
IT WILL WEAKEN AND MOVE EAST. AN UPPER LEVEL RIDGE DEVELOPS OVER
THE GREAT PLAINS, THERE IS A CHANCE THAT BROAD NORTHWEST FLOW
REMAINS OVER THE REGION. AS ANOTHER SHORT WAVE TROUGH DEVELOPS
OVER THE WEEKEND, THE SMALL ADJUSTMENTS IN THE CANADIAN LOW IS
KEEPING ANY IMPACTS FROM THE WAVE OVER WISCONSIN. PERHAPS A WEAK
SNOW SHOWER GRAZES THE WISCONSIN STATELINE, BUT CONFIDENCE
REMAINS LOW AT THIS DISTANCE.
TEMPERATURES SHOULD MODERATE NICELY THROUGH THE WEEKEND. AS
THAT RIDGE CONTINUES TO BUILD EARLY NEXT WEEK, HIGH PRESSURE
WILL SPREAD OVER THE REGION AND HIGH TEMPERATURES WILL CONTINUE
TO GRADUALLY CLIMB AND BECOME MORE MILD WITH THE CHANCE THAT
AREAS SOUTH OF I-80 COULD SEE THE 40S EARLY NEXT WEEK. AS HIGH
PRESSURE DOMINATES, WE COULD BE IN FOR A QUIETER STRETCH IN
TERMS OF PRECIPITATION CHANCES.
DK
AVIATION /00Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 544 PM CST WED DEC 31 2025
MAIN CONCERNS FOR THE AVIATION COMMUNITY:
- NARROW, QUICK HITTING BAND OF SNOWFALL WITH POTENTIAL ICE
PELLETS DIVING SOUTHWARD THROUGH THE METRO TERMINALS.
- WINDS QUICKLY SHIFT FROM WESTERLY TO NORTHERLY, WITH GUSTS
REMAINING IN THE 20-25KT RANGE THROUGH MOST OF THE NIGHT.
- POSSIBLE SNOW FLURRIES THURSDAY MIDDAY INTO THE EARLY
AFTERNOON, HOWEVER CONFIDENCE LOW SO LEFT OUT AT THIS TIME.
A NARROW BAND OF SNOWFALL WITH LOCALIZED REPORTS OF EMBEDDED
ICE PELLETS IS TRAVERSING SOUTHWARD THROUGH THE METRO TERMINALS,
CURRENTLY IMPACTING ORD. THIS IS EXPECTED TO CONTINUE TRACKING
SOUTH INTO MDW NEAR 0030Z, AND THEN INTO NORTHERN INDIANA
SHORTLY BEFORE 01Z. THIS BAND SHOULD EXIT QUICKLY, WITH 30-45
MINUTES OF IMPACT. SOME ADDITIONAL SNOW FLURRIES ARE OCCURRING
AROUND MKE AND ARE ANTICIPATED TO TRACK SOUTH ALONG THE LAKE
FRONT TERMINALS THROUGH THE EVENING.
WESTERLY WINDS WILL QUICKLY SHIFT NORTHERLY BEHIND THE FRONTAL
PUSH, WITH GUSTS CONTINUING IN THE 20-25KT RANGE BEFORE
DIMINISHING AFTER MIDNIGHT (06Z). WINDS DECREASE THURSDAY
MORNING, TURNING BACK WESTERLY, BELOW 10KTS AROUND THE REGION.
SOME MODELS INDICATE THE POSSIBILITY OF SNOW FLURRIES THURSDAY
MIDDAY INTO THE EARLY AFTERNOON, HOWEVER AT THIS TIME CONFIDENCE
IS TOO LOW TO INCLUDE MENTION.
BAKER / RATZER
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 AM CST THURSDAY FOR THE IL
NEARSHORE WATERS.
SMALL CRAFT ADVISORY UNTIL 10 AM CST THURSDAY FOR CALUMET
HARBOR IL TO BURNS HARBOR IN.
SMALL CRAFT ADVISORY UNTIL 3 PM CST THURSDAY FOR BURNS HARBOR
TO MICHIGAN CITY IN.
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