422
FXUS63 KIWX 190840
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
340 AM EST FRI DEC 19 2025
KEY MESSAGES
- LIGHT SNOW SHOWERS GRADUALLY TAPER OFF THIS MORNING BUT WIND
GUSTS UP TO 40 MPH WILL CONTINUE MOST OF THE DAY.
- 1-3" OF LAKE EFFECT SNOW IS EXPECTED ACROSS SOUTHWEST MICHIGAN
THROUGH EARLY AFTERNOON.
- MUCH MILDER WEATHER IS EXPECTED NEXT WEEK WITH HIGHS NEAR 60
ON CHRISTMAS DAY.
DISCUSSION
ISSUED AT 340 AM EST FRI DEC 19 2025
SHARP, NEGATIVELY-TILITED MID/UPPER TROUGH AXIS NOW SWINGING THROUGH
THE AREA AS 980MB SURFACE LOW LIFTS TOWARD QUEBEC. MOIST, CYCLONIC
FLOW WILL CONTINUE TO SUPPORT LIGHT SNOW SHOWERS ACROSS MUCH OF THE
CWA THROUGH THE EARLY MORNING AS TEMPS DROP INTO THE TEENS. GUSTY
WINDS AND STRONG SURFACE DRY AIR ADVECTION LIKELY HELPED EVAPORATE
MUCH OF THE WATER ON AREA ROADS BEFORE TEMPS DROPPED SUFFICIENTLY
BELOW FREEZING. HOWEVER, SOME SLICK SPOTS REMAIN POSSIBLE,
ESPECIALLY IN LIGHT OF THE DUSTING OF SNOW RECEIVED IN THE LAST FEW
HOURS. THIS ACTIVITY IS EXPECTED TO WANE BY 12-14Z. ATTENTION THEN
TURNS TO LAKE EFFECT SNOW THAT WILL QUICKLY RAMP UP THIS MORNING AS
850MB TEMPS DROP TO -18C. A MODERATE, ALBEIT BRIEF, LAKE RESPONSE IS
EXPECTED ROUGHLY 09-15Z THIS MORNING WITH INVERSION HEIGHTS AROUND 5
KFT AND BULK OF ASCENT FOCUSED IN THE DGZ. STRONG WINDS WILL LIKELY
FRAGMENT DENDRITES BUT STILL DECENT THERMODYNAMICS NOTED. MAIN
LIMITING FACTOR WILL BE A FETCH JUST NORTH OF DUE WESTERLY,
ASSOCIATED MULTIBAND SETUP, AND PLENTY OF SURFACE DRY AIR UPSTREAM
TO INTERFERE WITH LAKE-INDUCED CONVECTION. TIME WINDOW IS ALSO
LIMITED WITH INVERSION HEIGHTS CRASHING AROUND/JUST AFTER 18Z.
SUSPECT MOST LOCATIONS WILL TOP OUT AROUND AN INCH OR TWO BUT CAN'T
RULE OUT SOME LOCALIZED AMOUNTS AROUND 3" BEFORE SNOW ENDS ENTIRELY
18-20Z. OTHER MAIN STORY IS OF COURSE THE WIND. WE HAVE ALREADY SEEN
NUMEROUS 35KT GUSTS AND THAT WILL LIKELY CONTINUE THROUGH THE DAY.
GRADIENT SLOWLY RELAXES THROUGH THE DAY BUT MIXING HEIGHTS ALSO
INCREASE AND WILL KEEP 30-35KT GUSTS GOING FOR MUCH OF THE DAYTIME
HOURS. WE SHOULD REMAIN SAFELY BELOW WIND ADVISORY CRITERIA THOUGH
AS MAX WINDS IN THE BOUNDARY LAYER REMAIN BELOW 40 KTS ALL DAY.
WEATHER QUIETS DOWN BY THIS EVENING AS TEMPS JUST HOLD STEADY AROUND
20 BEFORE SLOWLY CLIMBING IN WAA EARLY SAT MORNING.
REST OF THE FORECAST IS NOT IMPACTFUL WITH ONLY REAL STORY BEING
MUCH MILDER TEMPS. BOOKEND TROUGHS OVER THE NORTH ATLANTIC AND NORTH
PACIFIC WILL ALLOW STRONG RIDGING TO DEVELOP OVER MUCH OF THE
CENTRAL AND EASTERN CONUS, PARTICULARLY BY CHRISTMAS. WE WILL HAVE
ONE MORE MINOR TROUGH/COLD FRONT CROSS THE AREA LATE SAT. THIS
FRONTAL PASSAGE WILL LIKELY REMAIN ENTIRELY DRY FOR OUR AREA GIVEN
WEAK/NORTHWARD DISPLACEMENT OF CVA FORCING AND LACK OF SUBSTANTIVE
MOISTURE RETURN. IT WILL PUSH TEMPS BACK TO AROUND 20 BY EARLY SUN
MORNING THOUGH WITH HIGHS ONLY RECOVERING TO AROUND 30. INCREASINGLY
MILD WEATHER IS THEN EXPECTED FOR MOST OF NEXT WEEK WITH A FEW
CHANCES FOR LIGHT RAIN. THE FIRST ROUND ARRIVES MON NIGHT WITH A
SECOND ROUND CHRISTMAS EVE, EACH SIGNALING AN ASSOCIATED SURGE OF
WARM AIR CULMINATING IN HIGH TEMPS NEAR 60 ON CHRISTMAS DAY, WHICH
IS NEAR RECORD TERRITORY. COLD AIR MAY EVENTUALLY RETURN NEXT
WEEKEND BUT CONFIDENCE IN THE LONGWAVE PATTERN THAT FAR OUT IS
UNUSUALLY LOW.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 103 AM EST FRI DEC 19 2025
MVFR TO IFR CONDITIONS TO START THE PERIOD, EVENTUALLY IMPROVING
TO VFR LATE THIS AFTERNOON INTO THE OVERNIGHT. KFWA MAY BRIEFLY
SEE A DROP TO IFR CEILINGS/VISIBILITIES THE NEXT COUPLE HOURS
WITH EITHER LIGHT FREEZING DRIZZLE/SNOW OR A MIX (PER
SURROUNDING OBS), WITH WESTERLY WINDS PICKING UP ONCE AGAIN.
GUSTS UP TO AROUND 29KTS ARE EXPECTED THROUGH THE NIGHT. AT KSBN
CONDITIONS ARE LIKELY TO REMAIN MVFR PER MOST OF THE GUIDANCE
AND SURROUNDING/UPSTREAM OBSERVATIONS. AS OF THIS WRITING, THE
LAST OBSERVATION RECEIVED WAS AT 2:54Z, SO CANNOT BE CERTAIN IF
CEILINGS ARE SIMILAR TO SURROUNDING OBS. WSW WINDS SHIFT WNW,
WITH POTENTIAL FOR FLURRIES OR LIGHT SNOW THROUGH THIS AFTERNOON
AS A SHORTWAVE MOVES THROUGH. IT'S POSSIBLE THE SNOWFALL REMAINS
FURTHER NORTH, SO KEPT A MORE OPTIMISTIC FORECAST IN TERMS OF
VISIBILITY/CEILINGS (IN ALIGNMENT WITH ALL OF THE GUIDANCE).
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ043-046.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM EST
SATURDAY FOR LMZ043-046.
DISCUSSION...AGD
AVIATION...MCD
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