534
FXUS63 KARX 211726
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1126 AM CST SUN DEC 21 2025
KEY MESSAGES
- A WINTRY MIX OF SNOW AND VERY LIGHT FREEZING RAIN IS LOOKING
MORE PROBABLE ALONG AND NORTH OF INTERSTATE 90 TONIGHT FROM
12-6 AM. A LIGHT GLAZE OF ICE IS POSSIBLE WITH THE HIGHEST
PROBABILITIES TARGETING A LINE FROM WABASHA-JACKSON COUNTY
(40-70%) - LOWERING SOUTH TO I-90. MAINLY SNOW IS EXPECTED
NORTH OF I-94, LASTING INTO MID-MONDAY MORNING, WHERE TOTALS
WILL BE UP TO 1 INCH.
- MUCH OF THIS WEEK LOOKS TO BE WARMER THAN NORMAL AS BROAD
RIDGE OF HIGH PRESSURE COVERS MUCH OF THE CONUS.
UPDATE
ISSUED AT 1125 AM CST SUN DEC 21 2025
AFTER REVIEW OF THE LATEST MODEL GUIDANCE AND 21.12Z CAMS,
DECIDED TO REINTRODUCE MORE FREEZING RAIN POTENTIAL LATER
TONIGHT. PROBABILITIES FOR FREEZING RAIN, POSSIBLY MIXED WITH
SLEET AND SNOW, START TO INCREASE AROUND I-90 MOVING NORTH, WITH
THE HIGHEST PROBABILITIES OF 40-70% FROM WABASHA EAST TO
JACKSON COUNTY WI.
THE 21.12Z CAMS ARE ALL MORE ROBUST WITH A 5-8KFT CLOUD BASED
PRECIPITATION AREA (AND MODEL SIMULATED REFLECTIVITY) IN STRONG
WARM AIR ADVECTION AND A WEAK 700 MB SHORTWAVE TROUGH. THERE IS
A SUB-CLOUD BASE DRY LAYER THAT WILL COMPLICATE THINGS, BUT THE
ROBUST WARM LAYER WOULD CAUSE ANY HYDROMETEORS THAT MAKE IT
THROUGH THAT LAYER WITHOUT SUBLIMING/EVAPORATING TO BE IN THE
FORM OF LIQUID. WITH SURFACE TEMPS IN THE 29-31F RANGE, LIGHT
ICING COULD OCCUR. NORTH OF I-94, SNOW IS THE MORE DOMINANT TYPE
WITH LIGHT ACCUMULATIONS. THE MAIN WINDOW FOR AREAS WEST/SW OF
I-94 IS 12-5AM, 3AM-9AM I-94 AND NORTH.
WILL BE INCREASING OUR MESSAGING FOR THE VERY LIGHT ICING (A
GLAZE)THREAT OVERNIGHT. CONFIDENCE HAS INCREASED, BUT THE DRY
LAYER STILL CAUSING SOME PAUSE ON HOW AGGRESSIVE TO GET WITH
THE THE GLAZING (ADVISORY NEEDED?). WE WILL KEEP ASSESSING.
DISCUSSION
ISSUED AT 136 AM CST SUN DEC 21 2025
TONIGHT INTO MONDAY
AS AN UPPER LEVEL RIDGE IN THE SOUTHERN STREAM BUILDS NORTH AND
NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT, 925
AND 850 MB WARM AIR ADVECTION WILL RESULT IN PRECIPITATION
DEVELOPING ALONG AND NORTH OF INTERSTATE 90. SOUNDINGS INDICATE
THAT DRY AIR BELOW 700 MB WILL INITIALLY SLOW THE DEVELOPMENT OF
THIS PRECIPITATION. THE PRECIPITATION SHOULD INITIALLY START
OUT AS SNOW AND BY THE TIME THE WARM NOSE DEVELOPS ENOUGH FOR
LIQUID PRECIPITATION, THE SURFACE TEMPERATURES SHOULD HAVE
WARMED SUFFICIENTLY THAT IT WILL BE RAIN OR DRIZZLE. THIS LIQUID
PRECIPITATION SHOULD OCCUR AT THE END OF THE EVENT. SNOW TOTALS
WILL BE UP TO 1 INCH NORTH OF INTERSTATE 94. HIGH TEMPERATURES
WILL BE IN THE 30S ON MONDAY.
TUESDAY THROUGH SATURDAY
THROUGH MUCH OF THIS PERIOD, A SOUTHERN STREAM UPPER LEVEL RIDGE
OF HIGH PRESSURE WILL PRODUCE WARMER THAN NORMAL TEMPERATURES
ACROSS MUCH OF THE CONUS INCLUDING THE UPPER MISSISSIPPI RIVER
VALLEY. WITH 850 MB TEMPERATURES 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL JUST SOUTH AND SOUTHWEST OF THE FORECAST AREA FROM
TUESDAY INTO CHRISTMAS EVE, THERE WILL LIKELY BE NUMEROUS
RECORD HIGHS AND WARM LOWS. LOCALLY, TEMPERATURES WILL RANGE
FROM THE MID-30S TO LOWER 40S ON CHRISTMAS EVE, FROM THE MID-30S
TO MID-40S ON CHRISTMAS DAY (WHICH IS SLIGHTLY COOLER THAN THE
PAST COUPLE OF DAYS), AND FROM THE UPPER 20S TO UPPER 30S ON
BOXING DAY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1125 AM CST SUN DEC 21 2025
VFR CONDITIONS ARE EXPECTED BUT LLWS AND CHANCES FOR FZRA DO
ACCOMPANY THOSE CONDITIONS.
LLWS...OVERNIGHT THE LOW-LEVEL WIND FIELD INCREASES OFF THE
SURFACE TO ABOUT 2KFT TO CAUSE A PERIOD OF LLWS ACROSS MUCH OF
THE AREA. THE WIND SHEAR IS 32-35 KTS WITHIN THAT LAYER BASED ON
LITTLE MECHANICAL MIXING AND A STRONG INVERSION IN PLACE.
A PERIOD OF FZRA/SN WILL TRAVERSE THE AREA FROM SOUTHWEST TO
NORTHEAST INCREASING IN INTENSITY AS IT SHIFTS NORTHEAST. WITH
WARM TEMPERATURES ALOFT AND BELOW FREEZING NEAR AT THE SURFACE,
SOME FREEZING RAIN IS POSSIBLE NORTH OF I-90 IN THE 06-12Z
WINDOW. SOME ICE PELLETS OR SNOW MAY ALSO MIX IN. A LIGHT GLAZE
OF ICE IS POSSIBLE BY SUNRISE MONDAY - WITH PROBABILITIES
INCREASING NORTH OF I-90 (40-70% KRGK-KBCK). HAVE INCLUDED A
PROB30 FOR THAT WINTRY MIX FOR THE KRST/KLSE TAFS WHICH ARE
LOCATED ON THE SOUTHERN EDGE OF THE PROBABILITIES. SNOW IS
EXPECTED NORTH OF I-94.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
UPDATE...BAUMGARDT
DISCUSSION...BOYNE
AVIATION...BAUMGARDT
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