216
FXUS63 KILX 210344
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
944 PM CST TUE JAN 20 2026
KEY MESSAGES
- A PAIR OF CLIPPER SYSTEM WILL PASS THROUGH NORTHERN ILLINOIS
TONIGHT AND AGAIN WEDNESDAY EVENING. GUSTY WINDS ARE EXPECTED
AT TIMES AND LIGHT SNOW IS POSSIBLE, MAINLY FROM I-74
NORTHWARD.
- AN ARCTIC AIR MASS WILL BRING A RETURN OF BITTERLY COLD
TEMPERATURES THURSDAY NIGHT THROUGH THE WEEKEND. SINGLE DIGIT
HIGHS AND SUB-ZERO LOWS WILL BE POSSIBLE FOR PORTIONS OF
CENTRAL ILLINOIS.
- A WINTER STORM SYSTEM WILL PASS THROUGH THE SOUTHERN STATES
FRIDAY THROUGH THE WEEKEND, AND COULD SPREAD SNOW INTO PARTS OF
CENTRAL AND SOUTHEAST IL. THERE IS AROUND A 60 PERCENT CHANCE OF
EXCEEDING AN INCH OF SNOW SOUTH OF I-70 AND A 20 PERCENT CHANCE
OF EXCEEDING 3 INCHES.
DISCUSSION
ISSUED AT 111 PM CST TUE JAN 20 2026
A LARGE-SCALE TROUGH REMAINS ANCHORED OVER THE CENTRAL US, WITH A
SUBTLE SHORTWAVE RIDGE EMBEDDED IN THE BASE OF THE TROUGH ALONG
WITH HIGH PRESSURE OVER THE SOUTHEAST US BRINGING A RESPITE FROM
THE COLD AIR MASS AS SOUTHERLY FLOW DEVELOPS IN THE REGION. THIS
SHOULD BRING HIGHS IN THE UPPER 20S TO LOWER 30S TODAY, FOLLOWED
BY MID 30S TO LOWER 40S WEDNESDAY. LOWS TONIGHT SHOULD FALL ONLY
TO THE LOWER OR MID 20S AIDED BY MIXING FROM BREEZY SOUTHWESTERLY
WINDS. MEANWHILE, A COUPLE OF CLIPPER-TYPE SYSTEMS EMBEDDED IN
THE NORTHWEST FLOW ALOFT WILL MOVE THROUGH NORTHERN IL, TONIGHT
AND WEDNESDAY EVENING, RESPECTIVELY. WHILE THESE WILL AFFECT
PRIMARILY NORTHERN IL, LIGHT PRECIPITATION COULD EXTEND INTO PARTS
OF CENTRAL IL, ESPECIALLY NORTH OF I-74. DESPITE SOME LOW LEVEL
DRY AIR, FORECAST SOUNDINGS GENERALLY INDICATE THIS WILL SATURATE
AT LEAST BRIEFLY, WITH LIFT AND SATURATION THROUGH THE DENDRITIC
GROWTH ZONE, SO HAVE INCREASED POPS WITH BOTH FEATURES, AND HAVE
AT LEAST A SLIGHT CHANCE FOR MUCH OF THE FORECAST AREA NORTH OF
I-70. PRECIPITATION TYPE LOOKS TO BE SNOW WITH BOTH, DESPITE THE
MILD HIGHS ON WEDNESDAY, AS THEY AVOID THE WARMEST PART OF THE
AFTERNOON. AMOUNTS LOOK TO BE LIGHT, WITH MOST AREAS SEEING ONLY A
VERY LIGHT DUSTING AT MOST, HOWEVER FROM AROUND GALESBURG TO
PEORIA TO BLOOMINGTON NORTHWARD THERE COULD REASONABLY BE A
SIGNIFICANT PORTION OF AN INCH FROM THE FIRST DISTURBANCE (5
PERCENT CHANCE OF EXCEEDING AN INCH).
THE NEXT FEATURE OF NOTE IS AN ARCTIC COLD FRONT THAT SHOULD
ARRIVE THURSDAY AND BRING VERY COLD AIR INTO THE AREA FOR FRIDAY
THROUGH THE WEEKEND. HIGHS SHOULD BE SINGLE DIGITS AND TEENS
FRIDAY AND SATURDAY, FOLLOWED BY TEENS AND LOWER 20S SUNDAY AND
MONDAY. WIND CHILLS AS LOW AS 10 TO 25 BELOW ZERO LOOK ON TRACK
FOR FRIDAY AND SATURDAY, AND MAINTAINING SOME SUB-ZERO VALUES
SUNDAY AND MONDAY.
A MAJOR WINTER STORM WILL TRAVERSE THE SOUTHERN STATES LATE THIS
WEEK THROUGH THE WEEKEND, INTERACTING WITH ANOMALOUSLY COLD AIR
ASSOCIATED WITH THE FRONT THAT PREVIOUSLY TRAVERSED CENTRAL IL.
THIS SHOULD BRING AREAS OF HEAVY SNOW AND FREEZING RAIN, WITH AT
LEAST SLIGHT POTENTIAL FOR MODERATE SNOWFALL INTO PARTS OF CENTRAL
AND SOUTHEAST IL. THE STORM TRACK REMAINS SOMEWHAT VARIABLE,
HOWEVER PRECIPITATION TYPE AT THIS TIME APPEARS VERY LIKELY TO BE
ALL SNOW THIS FAR NORTH. PROBABILITIES FOR RECEIVING OVER A
QUARTER INCH OF LIQUID EQUIVALENT OF PRECIPITATION (~ 3+ INCHES)
RANGE FROM 10 TO 30 PERCENT FROM I-70 SOUTHWARD IN SOUTHEAST IL
SATURDAY MORNING INTO SUNDAY, WITH VERY LOW PROBABILITIES (<10%)
OF RECEIVING SUCH AMOUNTS TO THE NORTH. ENSEMBLE PROBABILITIES FOR
UNDER AN INCH RANGE FROM AROUND 40 PERCENT SOUTH OF I-70 TO 75
PERCENT NORTH OF PEORIA SUGGESTING A MOST LIKELY OUTCOME OF LIGHT
SNOW FOR THIS AREA.
37
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 944 PM CST TUE JAN 20 2026
A CLIPPER LOW PRESSURE SYSTEM WILL PASS NORTH OF THE CENTRAL IL
TERMINALS TONIGHT, BRINGING AROUND A 30% PROBABILITY OF -SN AND
MVFR CIG/VIS TO KPIA-KBMI. OTHERWISE THIS SYSTEM WILL PRODUCE
WIDESPREAD MID LEVEL CLOUDS (5-7K FT BASES) AND 10-15 KT SOUTH
WINDS, OCCASIONALLY GUSTING NEAR 20 KT. A PERIOD OF LLWS IS
FORECAST FOR ALL TERMINALS FROM 06-12Z. A TRAILING COLD FRONT WILL
CROSS THE REGION WED MORNING, VEERING WINDS WSW AND INCREASING
GUSTS TO NEAR 25 KT. ANOTHER DRY FRONT WILL PASS THROUGH WED
EVENING, VEERING WINDS WEST, GUSTING 25-30 KT.
25
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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