044
FXUS63 KLOT 170521
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
1121 PM CST FRI JAN 16 2026
KEY MESSAGES
- TWO CLIPPER SYSTEMS WILL BRING A CHANCE FOR ACCUMULATING SNOW
WITH MINOR IMPACTS DURING THE AFTERNOON AND EARLY EVENING
HOURS OF BOTH SATURDAY AND SUNDAY.
- BITTERLY COLD CONDITIONS ARE EXPECTED SUNDAY NIGHT THROUGH
TUESDAY MORNING WITH WIND CHILLS 15 BELOW TO 25 BELOW ZERO
POSSIBLE MONDAY MORNING.
DISCUSSION
ISSUED AT 253 PM CST FRI JAN 16 2026
PERIODS OF SNOW FROM MULTIPLE DISTURBANCES IN OVERALL NORTHWEST
FLOW WILL BE THE MAIN STORY THROUGH EARLY NEXT WEEK, WITH
INCREASINGLY COLDER CONDITIONS BEHIND EACH SYSTEM. WHILE SNOW
SHOWERS WILL BE POSSIBLE AT ANY TIME THROUGH AT LEAST SUNDAY
NIGHT, THE POTENTIAL FOR ACCUMULATING SNOW WITH MINOR IMPACTS
WILL BE CONFINED TO THE MID AFTERNOON TO EARLY EVENING EACH DAY.
SNOW SHOWER ACTIVITY IS CURRENTLY AT A LULL EARLY THIS
AFTERNOON IN THE WAKE OF THIS MORNING'S TROUGH. LOW-LEVEL WARM
ADVECTION AND SOME BREAKS IN CLOUDS HAVE PUSHED TEMPS WELL INTO
THE 30S AND WETBULB TEMPS ABOVE FREEZING. MEANWHILE, GRADUAL CAA
ALOFT WILL WEAKEN AN EXISTING INVERSION AND DEEPEN THE SURFACE-
BASED LAYER OF STEEPER LAPSE RATES. THE COMBINATION OF MOISTURE
ADVECTION INTO THE SOUTHWEST CWA AND A SHEARED-OUT REMNANT MID-
LEVEL TROUGH HAS RECENTLY INTERACTED WITH DIURNAL INFLUENCES TO
GENERATE CONVECTIVE SHOWERS OVER WEST-CENTRAL ILLINOIS. GIVEN
THEIR CONVECTIVE NATURE, PRECIP TYPE SHOULD FALL AS ALL SNOW
WITH THE HEAVIEST CORES, BUT LIGHTER SHOWERS MAY EXHIBIT A MIX
OF RAIN AND SNOW OVER THE NEXT FEW HOURS SOUTH OF THE I-80
CORRIDOR. SHARP REDUCTIONS IN VISIBILITY CAN BE EXPECTED WITH A
QUICK SLUSHY ACCUMULATIONS OF A FEW TENTHS OF AN INCH POSSIBLE
IN THE HEAVIEST SHOWERS.
FARTHER NORTH AND WEST, A MORE PROMINENT MID-LEVEL WAVE WILL
DRIFT SOUTHEASTWARD TONIGHT. MODEST LOW-LEVEL MOISTURE WITH SOME
DIURNAL ENHANCEMENT HAS SUPPORTED THE DEVELOPMENT OF WEAKER
SNOW SHOWERS AS FAR EAST AS THE MISSISSIPPI RIVER NORTH OF THE
QUAD CITIES. THESE SHOWERS SHOULD INCREASE IN COVERAGE THROUGH
EARLY EVENING, RESULTING IN SCATTERED TO NUMEROUS SHOWERS ACROSS
NORTHERN ILLINOIS VERY LATE THIS AFTERNOON AND INTO THE
EVENING. LASTLY, A COLD FRONT OVER EASTERN IOWA WILL PROVIDE
ADDITIONAL SUPPORT FOR SHOWER INTENSITY AND COVERAGE THIS
EVENING. MARGINAL LOW-LEVEL TEMPS AHEAD OF THE FRONT SHOULD
LIMIT OVERALL IMPACTS EARLY THIS EVENING, BUT ISOLATED BURSTS OF
SNOW, ESPECIALLY ON THE COLD FRONT, MAY PRODUCE NARROW SWATHS
OF UP TO ONE INCH OF ACCUMULATION, WINDS GUSTING TO 30 MPH, AND
FALLING TEMPS. NOT EXPECTING THESE SHOWERS TO MEET SNOW SQUALL
CRITERIA (MAINLY DUE TO TEMPS NEAR/ABOVE FREEZING), BUT WILL
NEED TO MONITOR UPSTREAM TRENDS FOR MORE IMPACTFUL SHOWERS IF
COVERAGE/INTENSITY INCREASE MORE THAN EXPECTED OR TEMPS BEGIN TO
FALL EARLIER.
THE WAVE TO THE NORTHWEST WILL DRIFT ACROSS ILLINOIS THROUGH
THE DAY SATURDAY AND INTO THE EVENING. WITH REMAINING MID-LEVEL
MOISTURE, EXISTING FORCING, AND RELATIVELY COLD TEMPS ALOFT, WE
SHOULD SEE AN ASSOCIATED BAND OF LIGHT SNOW (UP TO ONE INCH)
GRADUALLY SHIFT SOUTHEASTWARD ACROSS THE CWA LATE MORNING INTO
EARLY EVENING.
CAA WILL BE MINIMAL ACROSS THE AREA SATURDAY NIGHT AS LOW-LEVEL
FLOW QUICKLY BACKS SOUTHWEST AHEAD OF A STRONGER TROUGH OVER
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY. GUIDANCE HAS
TRENDED STRONGER AND SLIGHTLY FARTHER SOUTH WITH THIS TROUGH,
WHICH, WHEN PAIRED WITH A 110-120 KNOT JET AXIS POINTING ESE
INTO SOUTHERN ILLINOIS, HAS RESULTED IN BETTER FORCING AND TOP-
DOWN SATURATION OVER NORTHERN ILLINOIS AND NORTHWEST INDIANA
DURING THE AFTERNOON. THE LATEST FORECAST OF UP TO ONE INCH IS
SUPPORTED BY A VAST MAJORITY OF ENSEMBLE MEMBERS WITH ONLY A FEW
OUTLIERS WITH OVER ONE INCH.
EXPECT DAYTIME HIGHS THIS WEEKEND TO SETTLE IN THE MID TO UPPER
TEENS AMID GUSTY WNW TO WSW WINDS, RESULTING IN WIND CHILLS
TOPPING OUT ONLY JUST ABOVE ZERO. A NEXT PUSH OF ARCTIC AIR WILL
ARRIVE LATE SUNDAY AFTERNOON AND EVENING, WITH NOTABLY COLDER
CONDITIONS SUNDAY NIGHT INTO TUESDAY. MINIMUM WIND CHILLS MONDAY
MORNING ARE EXPECTED TO BE -20 TO -25 DEGREES, WITH THE
POTENTIAL THAT A COLD WEATHER ADVISORY (-25 DEGREES) IS NEEDED
FOR AT LEAST SOME OF THE AREA. WITH THE COLD START TO THE DAY,
HIGHS MONDAY WILL STRUGGLE TO REACH 10 DEGREES, WITH MAXIMUM
WIND CHILLS REMAINING SOLIDLY BELOW ZERO. WINDS WILL BEGIN TO
DIMINISH MONDAY NIGHT AS A SURFACE HIGH PASSES SOUTH OF THE
AREA, BUT WIND CHILLS AS LOW AS -15 DEGREES CAN BE EXPECTED
TUESDAY MORNING.
BEYOND TUESDAY, STRONG BAROCLINICITY DEVELOPING ACROSS THE
CENTRAL CONUS WILL SUPPORT A MORE ACTIVE PERIOD OF WEATHER OVER
OR NEAR OUR AREA AS EARLY AS TUESDAY NIGHT. STILL A LOT OF
DISCREPANCIES IN THE BROADER MODEL/ENSEMBLE SYSTEMS CHIEFLY DUE
TO UNCERTAINTY AS TO WHERE THE BAROCLINIC ZONE RESIDES WITH
RESPECT TO OUT AREA.
KLUBER
AVIATION /06Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 1121 PM CST FRI JAN 16 2026
KEY MESSAGES:
- ANOTHER PERIOD OF STEADY SNOWFALL WITH ACCOMPANYING MVFR
CEILINGS IS EXPECTED ON SATURDAY.
AN AREA OF SNOW THAT HAS FLARED UP OVER MDW AND GYY LATE THIS
EVENING SHOULD END BY 07Z AT THESE TAF SITES. COULDN'T RULE OUT
SOME FLURRIES DEVELOPING ELSEWHERE OVERNIGHT TONIGHT, BUT NOT
ANTICIPATING ANY FURTHER VISIBILITY REDUCTIONS AT THIS TIME.
ANOTHER UPPER-LEVEL DISTURBANCE WILL PIVOT INTO THE AREA ON
SATURDAY, ALLOWING FOR A RIBBON OF STEADY, FLUFFY SNOW TO SPREAD
OVER THE TERMINALS. WHILE ACCUMULATIONS ARE ONLY EXPECTED TO
RANGE FROM A DUSTING TO AROUND AN INCH, A PROLONGED PERIOD OF
LOW-END MVFR TO IFR VISIBILITIES IS LIKELY DURING THE AFTERNOON
AND EARLY-MID EVENING AT THE CHICAGO METRO TERMINALS (EARLY-MID
MORNING THROUGH THE LATE AFTERNOON/EARLY EVENING AT RFD). WITH
THE ASSOCIATED MVFR STRATUS DECK SITTING SQUARELY WITHIN THE
DENDRITIC GROWTH ZONE, IT IS POSSIBLE THAT FLURRIES THEN
CONTINUE FOR SEVERAL HOURS BEYOND THE END TIME OF THE STEADIER
SNOWFALL, BUT CONFIDENCE IN THIS IS ONLY LOW-MEDIUM AT THIS
TIME.
OTHERWISE, EXPECT WESTERLY WINDS TO PREVAIL THROUGH THE TAF
PERIOD WITH SOMEWHAT REGULAR GUSTS TO 20-25 KTS.
OGOREK
HYDROLOGY
ISSUED AT 253 PM CST FRI JAN 16 2026
THE UPCOMING EXTENDED PERIOD OF VERY COLD TEMPERATURES WILL LIKELY
RESULT IN THE RAPID DEVELOPMENT OF ICE ON AREA RIVERS AND STREAMS
WHICH MAY INCREASE THE CHANCE OF LOCALIZED ICE JAM FLOODING. LAST
WEEK'S HEAVY RAINFALL HAS RESULTED IN INCREASED STREAMFLOW IN
SEVERAL BASINS, INCLUDING THE FOX, DES PLAINS, AND ILLINOIS RIVER
BASINS. THIS HIGHER STREAMFLOW WILL RESULT IN A GREATER POTENTIAL
FOR FREEZE UP ICE JAM FLOODING.
- IZZI
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 AM CST SATURDAY FOR WINTHROP
HARBOR IL TO GARY IN.
SMALL CRAFT ADVISORY UNTIL 3 AM CST SUNDAY FOR GARY TO BURNS
HARBOR IN-BURNS HARBOR TO MICHIGAN CITY IN.
VISIT US AT WEATHER.GOV/CHICAGO
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