356
FXUS63 KARX 171846
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
146 PM CDT TUE MAR 17 2026
KEY MESSAGES
- A QUICK HITTING CLIPPER SYSTEM WILL BRING LIGHT SNOW TO MUCH
OF THE AREA LATE THIS AFTERNOON AND INTO TONIGHT. WIDESPREAD
SNOWFALL AMOUNTS OF 1-2" ARE EXPECTED. A BRIEF PERIOD OF
FREEZING DRIZZLE CANNOT BE RULED OUT (UNDER 20% CHANCE) AS
PRECIPITATION ENDS.
- MUCH WARMER TEMPERATURES BY THE END OF THE WORK WEEK AND INTO
SATURDAY. HIGHS WILL REACH INTO THE 50S AND 60S FOR MANY ON
SATURDAY.
DISCUSSION
ISSUED AT 146 PM CDT TUE MAR 17 2026
THIS AFTERNOON - TONIGHT: CLIPPER BRINGS LIGHT SNOW
CLOUD COVER WILL INCREASE TODAY AHEAD OF OUR NEXT CLIPPER SYSTEM
THAT WILL DIVE SOUTH INTO THE LOCAL AREA FROM MANITOBA/SASKATCHEWAN,
CANADA LATER THIS EVENING AND INTO THE OVERNIGHT. CURRENTLY, FORCING
WITH THIS CLIPPER SYSTEM IS NOT OVERLY ROBUST WITH THE MAIN FORCING
MECHANISM DRIVING THIS CLIPPER BEING A WEAK RIBBON OF 600-800MB
FRONTOGENESIS AS DISPLAYED IN THE 17.15Z RAP. OVERALL, THE
ACCOMPANYING SHORTWAVE WITH THIS CLIPPER IS RELATIVELY WEAK.
CONSEQUENTLY, MUCH OF THE CAMS HAVE A BAND OF LIGHT SNOW MOVING
THROUGH DURING THE LATE EVENING AND INTO THE OVERNIGHT THAT
QUICK TRANSLATES EASTWARD. ADDITIONALLY, WITH A FAIRLY DRY SUB-
CLOUD LAYER INITIALLY PRESENT IN THE HRRR/RAP SOUNDINGS, HAVE
OPTED TO DELAY THE ONSET TIMING OF SNOW SLIGHTLY AS THIS DRY AIR
WILL NEED TO SATURATE. OVERALL, NBM PROBABILITIES ARE NOT
OVERLY IMPRESSIVE WITH THE PROBABILITIES FOR OVER 2" BEING
AROUND 20-50% ACROSS THE AREA, EVEN LOWER FOR OVER 3" (10-30%).
AS A RESULT, IMPACTS FROM THIS SHOULD BE FAIRLY MINIMAL
ESPECIALLY CONSIDERING THAT IT WILL LIKELY TAKE THE FORM OF A
DRIER SNOW AT ONSET WITH SOUNDINGS HAVING DECENT DGZ RESIDENCY,
HOWEVER SNOW TO LIQUID RATIOS WILL GENERALLY DROP AS WARM AIR
ADVECTION BEGINS TO WORK IN LATER INTO THE OVERNIGHT. ONE LAST
CONSIDERATION FOR THIS SYSTEM WILL BE THE LOSS OF SATURATION IN
THE DENDRITIC GROWTH ZONE FOR BRIEF PERIOD AS PRECIPITATION
EXITS. AS A RESULT, CANNOT RULE OUT A 1-2 HOUR PERIOD OF
FREEZING DRIZZLE TONIGHT AT THE VERY END OF THE SNOW NEAR AND
EAST OF THE MISSISSIPPI RIVER. HOWEVER, GIVEN THIS WILL BE
FALLING ONTO ALREADY ACCUMULATED SNOWFALL, ANY FREEZING DRIZZLE
THAT DOES OCCUR LIKELY WOULD RESULT IN MINIMAL IMPACTS ON MOST
SURFACES.
WEDNESDAY - SUNDAY: WARMING UP, SOME RAIN CHANCES
AS WE HEAD INTO THE MIDDLE OF THE WEEK, AN INITIAL ROUND OF WARM AIR
ADVECTION AND SOUTHWESTERLY SURFACE FLOW WILL PUSH INTO THE REGION
FOR WEDNESDAY BRINGING TEMPERATURES CLOSER TO SEASONABLE WITH HIGHS
GENERALLY INTO THE UPPER 30S TO MIDDLE 40S ACROSS THE REGION. BY THE
TIME THE OVERNIGHT ROLLS AROUND, A SECONDARY WEAK SHORTWAVE CLIPPER
SYSTEM WILL PROGRESS FROM THE NORTHWEST INTO THE REGION. HOWEVER,
GIVEN THAT THERMAL PROFILES IN THE RAP/HRRR SOUNDINGS KEEP MUCH OF
THE SATURATED LAYER ABOVE FREEZING, WOULD EXPECT THIS SYSTEM TO BE
PREDOMINANTLY A RAIN SITUATION FOR MUCH OF THE AREA. THAT BEING
SAID, CANNOT FULLY RULE OUT SOME POCKETS OF FREEZING RAIN IN
WEST/NORTH-CENTRAL WI WHERE THE DEEPER SNOWPACK MAY AID IN KEEPING
TEMPERATURES CLOSE TO FREEZING WEDNESDAY NIGHT. REGARDLESS, QPF
PROBABILITIES IN THE NBM FOR OVER 0.1" ARE NOT OVERLY HIGH (20-40%)
EAST OF THE MISSISSIPPI RIVER SO WOULD NOT BE ALL THAT IMPACTFUL
ASIDE FROM AIDING IN MELTING THE SNOW SOMEWHAT.
BEHIND THIS CLIPPER, AN UPPER-LEVEL RIDGE WILL ATTEMPT TO MOVE INTO
THE REGION ALLOWING FOR RETURNING SOUTHERLY FLOW AND WARM AIR
ADVECTION. AS A RESULT, EXPECTING A FAIRLY RESPECTABLE WARM UP INTO
FRIDAY AND SATURDAY WITH TEMPERATURES LIKELY TRENDING ABOVE, PERHAPS
EVEN WELL ABOVE NORMAL. THE MAIN QUESTION WILL BE EXACTLY HOW MUCH
OF THE SNOWPACK FROM THE PAST WEEKEND BLIZZARD WILL BE GONE AS WE
HEAD INTO FRIDAY AND SATURDAY. CURRENTLY, THE NBM INTER-
QUARTILE RANGE HAS HIGHS RANGING FROM THE UPPER 40S TO LOWER 70S
ON SATURDAY, HIGHLIGHTING THE WIDE RANGE IN POSSIBILITIES THAT
MAY BE CONTINGENT ON WHERE SNOWPACK MELTS. IN LOCATIONS WHERE
SNOWPACK FULLY MELTS, WOULD EXPECT HIGHS IN THE 60S AND 70S TO
BE MORE COMMON AS OPPOSED TO AREAS THAT DO NOT. IN ANY CASE, A
SURFACE COLD FRONT WILL SWING THROUGH THE REGION SATURDAY
EVENING AND INTO SUNDAY BOTH COOLING DOWN TEMPERATURES TO
SEASONABLE AND BRINGING SOME RAIN CHANCES TO THE REGION.
HOWEVER, CURRENT PROBABILITIES FOR MEASURABLE PRECIPITATION
DURING THIS PERIOD IN THE GRAND ENSEMBLE (GEFS/EC/CANADIAN
ENSEMBLE) ARE NOT OVERLY HIGH (20-50%) AT THIS POINT.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1217 PM CDT TUE MAR 17 2026
VFR CONDITIONS ARE EXPECTED FOR MUCH OF THE AFTERNOON PRIOR TO A
CLIPPER SYSTEM MOVING INTO THE AREA LATE THIS AFTERNOON AND INTO THE
EVENING. AS SNOW BEGINS TO MOVE INTO THE AREA, CIGS WILL DROP TO
MVFR HEIGHTS WITH VSBY REDUCTIONS TO IFR LEVELS. AS WE HEAD INTO THE
MORNING HOURS ON WEDNESDAY, CIGS WILL LIKELY REMAIN AT MVFR LEVELS
WITH THE HREF HAVING SOME PROBABILITIES (20-40%) ON WEDNESDAY
MORNING. HOWEVER, HAVE OPTED TO LEAVE OUT ANY IFR CIGS MENTION AFTER
SNOW DEPARTS AS CONFIDENCE IN THIS POTENTIAL REMAINS LOW.
ADDITIONALLY, WITH THE LOW-LEVEL MOISTURE REMAINING IN PLACE BUT
WITH A LACK OF SATURATION ALOFT, A PERIOD OF FREEZING DRIZZLE CANNOT
BE RULED OUT (UNDER 20% CHANCE) AS PRECIPITATION EXITS NEAR AND
EAST OF THE MISSISSIPPI RIVER.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...NAYLOR
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