755
FXUS63 KIWX 170850
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
350 AM EST WED DEC 17 2025
KEY MESSAGES
- ROLLER COASTER RIDE OF TEMPERATURES IN STORE FOR THE UPCOMING
7 DAYS, WITH MOST OF THE TIME BEING NEAR OR ABOVE NORMAL FOR
MID DECEMBER.
- DRIZZLE, LIGHT RAIN AND FOG MAY ARRIVE LATE TONIGHT WITH A
PERIOD OF LIGHT TO MODERATE RAIN RAPIDLY MOVING EAST ACROSS
THE AREA THURSDAY.
- MUCH COLDER AIR ARRIVES STARTING THURSDAY AFTERNOON WITH A
MORE RAPID DROP IN TEMPERATURES THURSDAY NIGHT (LOWS IN THE
TEENS). ANY RAIN WILL CHANGE TO SNOW (LIGHT ACCUMULATIONS
POSSIBLE IN LOWER MI) ALONG THE POTENTIAL FOR A FLASH FREEZE
LATE THURSDAY EVENING INTO THE EARLY MORNING HOURS OF FRIDAY.
- IT WILL BE BREEZY AT TIMES, ESPECIALLY THURSDAY INTO FRIDAY.
DISCUSSION
ISSUED AT 350 AM EST WED DEC 17 2025
A TROUGH WAS WORKING EAST WITH PLENTY OF MID LEVEL MOISTURE
AHEAD OF IT. FORCING HAS BEEN SUFFICIENT TO ALLOW FOR A BRIEF
PERIOD OF SPRINKLES AT MI CITY AND SOUTH BEND. IN ITS WAKE,
SKIES WILL CLEAR OUT WITH SIMILAR, IF NOT A HAIR WARMER
TEMPERATURES THAN TUESDAY.
A WILD ROLLER COASTER RIDE WILL BEGIN TO TAKE SHAPE TONIGHT AS A
WARM FRONT SURGES NORTH LATE TONIGHT WITH OVERRUNNING LIFT AND
MOISTURE ALLOWING FOR THE DEVELOPMENT OF SOME LIGHT SHOWERS OR
MAYBE MORE OF A DRIZZLE SETUP AFTER 6Z THU (MAYBE CLOSER TO 9Z)
IN THE WEST AND THEN SPREADING EAST. DEWPOINTS WILL ALSO CLIMB
ABOVE FREEZING, WHICH MAY FACILITATE AT LEAST SOME PATCHY FOG AS
IT PASSES OVER THE COLD GROUND. ALTHOUGH WIDESPREAD CATEGORICAL
POPS EXIST FOR THURSDAY, THE STEADY RAIN WILL COME A FEW HOURS
BEFORE THROUGH A FEW HOURS BEHIND A STRONG COLD FRONT. WINDS
WILL PICK UP SOMEWHAT THURSDAY, BUT STRONGEST GUSTS WILL STILL
REMAIN ABOVE THE SURFACE UNTIL NEAR OR JUST BEHIND THE FRONT AS
THE CAA KICKS IN. A PERIOD OF WIDESPREAD FOG IS POSSIBLE AS
DEWPOINTS AND TEMPERATURES CLIMB INTO THE 40S, BUT THE RAIN MAY
HELP KEEP IT AT BAY.
THE MAIN AREA OF PRECIP LOOKS TO EXIT THE WEST NEAR 20Z THU AND
EAST 00Z FRI. TEMPERATURES WILL BEGIN TO FALL IN THE AFTERNOON
WITH HIGHS LIKELY OCCURRING NEAR OR SHORTLY AFTER 18Z. THE
STRONGER ARCTIC BLAST FOLLOWS A FEW HOURS LATER WITH 850 MB
TEMPS DROPPING 10 DEGREES CELSIUS IN 6 HOURS OR SO. AT THE
SURFACE TEMPERATURES WILL FALL BELOW FREEZING IN THE EVENING AND
INTO THE TEENS AND 20S OVERNIGHT. ANY LINGERING PRECIP WOULD END
UP IN THE FORM OF SNOW WITH THE BEST CHANCES RESIDING NEAR/NORTH
OF THE MI STATE LINE THU NIGHT INTO FRIDAY. A THREAT FOR A FLASH
FREEZE DOES EXIST OVERNIGHT THURSDAY INTO FRIDAY MORNING. THIS
COULD BE REDUCED IF THE PRECIP ENDS FAST ENOUGH AND THE STRONG
WINDS HELP DRY SURFACES BEFORE THEY DROP TOO FAR BELOW FREEZING.
COLDEST DAY OF THE NEXT SEVERAL IN STORE FRIDAY WITH HIGHS IN
THE 20S, FOLLOWED BY MODERATION BACK INTO THE 30S AND 40S. A FEW
SMALL CHANCES FOR PRECIP EXIST INTO WED, BUT NONE ARE OVERLY
IMPRESSIVE WITH PTYPE LIKELY TIED TO TIME OF DAY THE PRECIP
OCCURS.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1222 AM EST WED DEC 17 2025
VFR TO MVFR CONDITIONS EXPECTED AT THE TERMINALS THIS PERIOD,
WITH LLWS TO 45 KNOTS THROUGH 8-10Z. WARM AIR ADVECTION EXPECTED
TO CONTINUE THROUGH TODAY, WITH SOUTHWEST WINDS SHIFTING WEST
THEN BACK TO THE SOUTH THROUGH TONIGHT. ISENTROPIC ASCENT
BRINGING POTENTIAL FOR MVFR CEILINGS AT BOTH SITES IN THE
15-18Z, THOUGH DRIER LOW LEVELS SHOULD PRECLUDE ANY
PRECIPITATION FROM DEVELOPING (DESPITE LIGHT REFLECTIVITIES ON
RADAR ATTM). TEMPERATURES RISING TO AROUND 40 DEGREES TODAY
COULD LEAD TO SOME MIST/BR DEVELOPMENT WITH THE SNOWPACK (MORESO
AT KSBN), BUT LEFT OUT FOR NOW GIVEN GREATER LIKELIHOOD FOR
LOWER CEILINGS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR LMZ043-
046.
GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LMZ043-046.
DISCUSSION...FISHER
AVIATION...MCD
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page