051
FXUS63 KIWX 070621
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
121 AM EST SUN DEC 7 2025
KEY MESSAGES
- SNOW ACCUMULATIONS OF 1 TO 3 INCHES TONIGHT INTO SUNDAY AFTERNOON,
WITH THE HIGHEST TOTALS NEAR LAKE MICHIGAN. IF TRAVELLING,
EXPECT PERIODS OF LOW VISIBILITY AND SLICK ROADS.
- HIGHS IN THE 30S THROUGH WEDNESDAY EXCEPT BRIEFLY COLDER
MONDAY AND AGAIN NEXT FRIDAY AND SATURDAY WITH HIGHS ONLY IN
THE LOWER 20S. MORNING LOWS ON MONDAY, TUESDAY, AND NEXT
SATURDAY WILL AGAIN DIP DOWN INTO THE SINGLE DIGITS.
- SEVERAL SYSTEMS WILL BRING SNOW MIXED WITH RAIN AT TIMES
THROUGH THIS UPCOMING WEEK. IMPACTS WILL BE LIMITED.
DISCUSSION
ISSUED AT 223 PM EST SAT DEC 6 2025
TONIGHT, CHANCES FOR SNOW SHOWERS AND LIGHT SNOW WILL INCREASE
THROUGH THE EVENING WITH A WEAK CLIPPER TYPE SYSTEM PUSHING IN
FROM THE WEST. THIS WILL CONTINUE AND SPREAD EASTWARD THROUGH
LATE TONIGHT AND TOMORROW MORNING. BY SUNDAY AFTERNOON WE WILL
SEE THE SNOWFALL FOR MOST AREAS DIMINISHING HOWEVER THERE WILL
STILL BE A CHANCE FOR LAKE EFFECT SNOW SHOWERS THROUGH SUNDAY
NIGHT. GENERALLY 1 TO 2 INCHES OF SNOWFALL ACCUMULATIONS ARE
EXPECTED WITH THIS SYSTEM. A FEW LOCATIONS COULD SEE UP TO 3
INCHES TOTAL. SOME LIGHT DRIZZLE/FREEZING DRIZZLE MAINLY AS THE
ONSET FOR PRECIPITATION OCCURS THIS EVENING WOULD BE POSSIBLE
BUT WOULD BE VERY SHORT LIVED BEFORE CHANGING OVER TO FLURRIES
AND SNOW SHOWERS. THE LARGER SNOWFALL AMOUNTS WILL BE FOR THE
NORTHWESTERN PORTIONS OF THE CWA AND AREAS NEAR LAKE MICHIGAN.
AT THIS TIME MESSAGING OF ANY HAZARDS SUCH AS SLICK ROADS WOULD
MOST LIKELY BE BEST DISSEMINATED THROUGH AN SPS PRODUCT LATER
THIS EVENING.
COLD AIR WILL USHER IN BEHIND THIS SYSTEM BEGINNING SUNDAY
AFTERNOON AND EVENING AND DROP TEMPERATURES QUICKLY. OVERNIGHT
LOW TEMPERATURES ON MONDAY MORNING WILL DIP DOWN INTO THE SINGLE
DIGITS NEAR ZERO. WITH RELATIVELY LIGHT WINDS THE WIND CHILLS
WILL MAKE IT FEEL LIKE 0 TO -5 DEGREES. HIGHS ON MONDAY WILL
ONLY GET INTO THE LOW 20S WITH SLIGHTLY WARMER TEMPERATURES
ALONG THE LAKE MICHIGAN SHORELINE. TUESDAY MORNING WILL ONCE
AGAIN GET DOWN INTO THE SINGLE DIGITS HOWEVER JUST SLIGHTLY
WARMER THAN THE NIGHT BEFORE WITH LOWS JUST UNDER THE 10
DEGREE MARK.
WITH A QUASI-ZONAL FLOW ALOFT A FEW WEAK SHORTWAVES MAKE THEIR
WAY THROUGH THE REGION BEGINNING ON TUESDAY AND THIS WILL ALLOW
FOR SOME WARM AIR TO ADVECT NORTHWARD AHEAD OF THE DISTURBANCE
BRINGING A QUICK MODERATION IN TEMPERATURES WITH HIGHS ON
TUESDAY GETTING INTO THE MID 30S. THIS WAA MAY PRESENT A FEW
ISSUES FOR THE FORECAST. THE FIRST WOULD BE HOW WILL THE SNOW ON
THE GROUND AFFECT THE TEMPERATURE FORECAST FOR BOTH THE HIGHS
AND LOWS ON TUESDAY AND WEDNESDAY AS THE WARMER AIR MOVING OVER
THE COLD SNOWY GROUND MAY BECOME MODIFIED AT A GREATER RATE THAN
EXPECTED KEEPING TEMPERATURES A TAD LOWER THAN ADVERTISED.
THIS WOULD ALSO LEAD TO LESS RAIN MIXING IN AND MORE OF THE
FROZEN VARIETY, INCLUDING THE INCREASED POTENTIAL FOR SOME FREEZING
RAIN ESPECIALLY IN THE ONSET OF ANY RAINFALL. THE FINAL ISSUE
WOULD BE THE POTENTIAL FOR DEVELOPMENT OF FOG ACROSS THE AREA
TUESDAY THROUGH WEDNESDAY. SO WE WILL NEED TO CONTINUE TO
MONITOR THE FORECAST FOR THOSE POSSIBILITIES AS WE GET CLOSER TO
THE BEGINNING OF THE WEEK.
ANOTHER COUPLE PUNCHES OF COLD ARCTIC AIR WILL PUSH SOUTHWARD
INTO THE REGION WEDNESDAY THROUGH THE END OF THE WEEK INTO THE
WEEKEND. HIGH TEMPERATURES BY THURSDAY AND FRIDAY WILL ONLY GET
INTO THE 20S AND BY SATURDAY ONLY THE TEENS. LOWS ON SATURDAY
MORNING WILL AGAIN DROP INTO THE SINGLE DIGITS.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1252 AM EST SUN DEC 7 2025
INITIALLY MVFR CONDITIONS WILL DETERIORATE TO IFR/LIFR OVERNIGHT
INTO SUNDAY AS A WEAK CLIPPER SYSTEM MOVES THROUGH OUR
AREA/SOUTH OF OUR AREA. THIS LOW WILL DRIFT EASTWARD AND WEAKEN
THROUGH SUNDAY. A STATIONARY FRONT THAT EXTENDS FROM LAKE ERIE
INTO SOUTHERN LAKE MI/IL/IA HAS BROUGHT US PREDOMINANTLY MVFR
CEILINGS AND A FEW AREAS OF BR REPORTED, WITH GENERALLY
LIGHT/VARIABLE WINDS (WITH THE EXCEPTION OF KSBN WHICH IS
SOUTHWEST AT AROUND 8KTS). THE LOW IS CURRENTLY SITUATED OVER MO
WITH WARM AIR ADVECTION/ISENTROPIC ASCENT LEADING TO AREAS OF
MAINLY LIGHT TO MODERATE SNOW IN SW WI/NW IL/IA (SPARSE HEAVY
SNOW REPORTS AND COUPLE OF MIXED PRECIP REPORTS NEAR THE
DEFORMATION ZONE ON NORTH/WEST SIDE). CEILINGS/VISIBILITY WILL
DROP AS SNOW MOVES IN FIRST AT KSBN SOMETIME BETWEEN 6-9Z BEFORE
PROGRESSING TO KFWA CLOSER TO 10-12Z. FOR NOW HAVE THE LOWER
VISIBILITIES AT KSBN GIVEN THE SYSTEM IS STRONGER INITIALLY AND
THE DEFORMATION ZONE WILL BE OVER THE TERMINAL, DROPPING TO
AROUND 3/4SM BETWEEN 10-14Z. CEILINGS MAY DROP BELOW 600 FT, BUT
CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE AT THIS POINT. KFWA
STILL HAVE CEILINGS DROPPING TO AROUND 500FT 12-15Z, WITH
VISIBILITY AROUND 1SM AS THE DEF. BAND MOVES THROUGH-BUT MOST
MODELS SUGGEST IT WEAKENS. I SUSPECT WE COULD SEE A PERIOD OF
VISIBILITY LESS THAN 1SM BUT WILL WAIT UNTIL NEXT ISSUANCE TO
PROVIDE GREATER DETAILS BASED ON RADAR/OB TRENDS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 4 AM EST
MONDAY FOR LMZ043-046.
DISCUSSION...ANDERSEN
AVIATION...MCD
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