749
FXUS63 KLOT 170930
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
330 AM CST SAT JAN 17 2026
KEY MESSAGES
- TWO CLIPPER SYSTEMS WILL BRING ACCUMULATING SNOW WITH MINOR
IMPACTS THIS AFTERNOON/EVENING AND AGAIN SUNDAY AFTERNOON/
EVENING.
- 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 227 AM CST SAT JAN 17 2026
AS THE MAIN UPPER LEVEL LOW SLOWLY LIFTS NORTHEAST AND OPENS
TODAY, ANOTHER UPPER LOW IS FORECAST TO MOVE ACROSS ACROSS THE
AREA THIS AFTERNOON INTO THIS EVENING, WHEN IT TOO BEGINS TO
WEAKEN. MODELS ARE IN GENERAL AGREEMENT WITH A PERIOD OF LIGHT
SNOW SPREADING AND DEVELOPING ACROSS THE AREA THIS AFTERNOON,
CONTINUING THROUGH MID EVENING AND THEN DISSIPATING BY LATE
EVENING. NOT MUCH MOISTURE TO WORK WITH IN THIS DRY AIRMASS, BUT
THESE LOW QPF EVENTS CAN STILL BE IMPACTFUL, ESPECIALLY WITH
THE COLD TEMPS IN THE UPPER TEENS/LOWER 20S EXPECTED TODAY AND
ACCUMULATION ON UNTREATED SURFACES. HAVE INCREASED POPS INTO THE
70-80% RANGE FOR AREAS ALONG/NORTH OF I-80. SNOW AMOUNTS WILL
LIKELY BE UNDER AN INCH WITH JUST A DUSTING FURTHER SOUTH.
NEXT SYSTEM ARRIVES SUNDAY AFTERNOON AHEAD OF A BLAST OF ARCTIC
AIR AND SIMILAR TO TODAY'S SYSTEM, SHOULD BE A HIGH POP/LOW QPF
EVENT. BOOSTED POPS TO LIKELY FOR THE NORTHERN HALF OR SO THE
CWA FOR SUNDAY AFTERNOON/EVENING. SNOWFALL WITH THIS SYSTEM
COULD BE IN THE ONE INCH RANGE, PERHAPS 1-2 INCHES ACROSS FAR
NORTHEAST IL, TO A DUSTING ACROSS THE SOUTH. SIMILAR TEMPS IN
THE UPPER TEENS/NEAR 20 WILL LIKELY ALLOW FOR ACCUMULATION ON
UNTREATED SURFACES. WINDS BEGIN TO INCREASE AS THE SNOW ENDS
SUNDAY EVENING. WITH GUSTS POSSIBLY INTO THE 30 MPH RANGE, SOME
BLOWING SNOW WILL LIKELY RESULT EVEN AFTER THE FALLING SNOW HAS
ENDED.
TEMPERATURES WILL BE DIVING SUNDAY NIGHT INTO MONDAY MORNING AND
LOWS AROUND ZERO IN THE NORTHWEST TO LOW SINGLE DIGITS ABOVE
ZERO ELSEWHERE LOOK ON TRACK. THE STRONG WINDS WILL PUSH WIND
CHILLS AS LOW AS 25 BELOW ZERO ACROSS THE NORTHWEST TO 20 BELOW
TO 15 BELOW ZERO FOR THE REST OF THE AREA. TOO EARLY FOR ANY
COLD WEATHER ADVISORIES, BUT IF THESE TRENDS CONTINUE, WILL NEED
TO CONSIDER ONE FOR THE NORTHWEST CWA MONDAY MORNING. HIGHS
BARELY REBOUND IN THE UPPER SINGLE DIGITS/LOW TEENS MONDAY WITH
LOWS BACK IN THE LOW SINGLE DIGITS TUESDAY MORNING, POSSIBLY
JUST BELOW ZERO ACROSS THE NORTHWEST. WINDS WILL HAVE DIMINISHED
QUITE A BIT BY TUESDAY MORNING, BUT POSSIBLY STILL IN THE 10
MPH RANGE WITH WIND CHILLS 5 BELOW TO 15 BELOW ZERO POSSIBLE.
RATHER GOOD CONSISTENCY IN THE MODELS AND THEIR ENSEMBLES FOR A
BRIEF MODERATION OF TEMPS TUESDAY INTO WEDNESDAY AHEAD OF A
CLIPPER SYSTEM MOVING ACROSS THE GREAT LAKES REGION. HIGH TEMPS
ON TUESDAY BACK IN THE 20S AND POSSIBLY UPPER 20S/LOWER 30S ON
WEDNESDAY. STILL SOME UNCERTAINTY FOR PRECIP CHANCES ACROSS THE
LOCAL AREA TUESDAY NIGHT INTO WEDNESDAY MORNING WITH THIS
CLIPPER. BLENDED GUIDANCE NOW HAS CHANCE POPS FOR THE NORTHERN
HALF OR SO OF THE AREA AND THAT SEEMS REASONABLE FOR NOW.
THERE REMAINS QUITE A BIT OF UNCERTAINTY FOR THE END OF NEXT
WEEK INTO NEXT WEEKEND WITH THE POTENTIAL FOR AN ACTIVE PATTERN
FOR OR NEAR THE LOCAL AREA. WHILE THE ENSEMBLES STILL SHOW A
DECENT SPREAD IN POSSIBILITIES, THIS TIME PERIOD HAS LOOKED
ACTIVE FOR THE PAST WEEK. REGARDLESS OF WHETHER PRECIP DEVELOPS
FOR THE LOCAL AREA, CURRENT TRENDS FAVOR A CONTINUED COLD/VERY
COLD PATTERN. CMS
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
MARINE
ISSUED AT 330 AM CST SAT JAN 17 2026
A GALE WATCH IS IN EFFECT LATE SUNDAY NIGHT THROUGH MONDAY
AFTERNOON FOR THE IL AND IN NEARSHORE WATERS.
AN ARCTIC COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY NIGHT
BRINGING MUCH COLDER TEMPERATURES AND STRONG WINDS TO THE
REGION, WITH A PERIOD OF GALES EXPECTED LATE SUNDAY NIGHT
THROUGH AT LEAST MIDDAY MONDAY. FREEZING SPRAY IS ALSO EXPECTED,
ESPECIALLY FOR THE IN NEARSHORE WATERS. CMS
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 9 PM CST THIS EVENING FOR WINTHROP
HARBOR IL TO GARY IN.
GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING 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.
GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON FOR
GARY TO BURNS HARBOR IN-BURNS HARBOR TO MICHIGAN CITY IN.
VISIT US AT WEATHER.GOV/CHICAGO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page