292
FXUS63 KARX 310837
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
337 AM CDT TUE MAR 31 2026
KEY MESSAGES
- LOW STORM CHANCES (20 TO 40%) WITH A LARGE HAIL THREAT WILL
BE POSSIBLE THIS MORNING MOSTLY SOUTH OF I-90.
- A STRONG WEATHER SYSTEM IMPACTS THE AREA WEDNESDAY INTO
THURSDAY NIGHT WITH PROBABILITIES FOR WINTRY IMPACTS
INCREASING, ESPECIALLY FOR THURSDAY MORNING. AFTER A PERIOD OF
WINTRY MIX WEDNESDAY INTO EARLY THURSDAY MORNING,
PRECIPITATION IS EXPECTED TO SWITCH OVER TO RAIN FOR MOST
LOCATIONS SOUTH OF I-94 BY MID MORNING THURSDAY.
- THERE IS ALSO QUITE A BIT OF RAIN WITH THIS SYSTEM AS RAIN
TOTALS RANGE FROM 1 TO 2 INCHES SOUTH OF I-90 WITH THE HIGHEST
PROBABILITIES (20 TO 40%) FOR 2+ INCHES IN SOUTHWEST
WISCONSIN AND PORTIONS OF NORTHEAST IOWA.
DISCUSSION
ISSUED AT 337 AM CDT TUE MAR 31 2026
THIS MORNING STORM CHANCES:
STORM CHANCES CONTINUE OVERNIGHT SLIGHTLY FARTHER NORTH AS THE
NOCTURNAL LOW LEVEL JET PERSISTS. EVENTUALLY THE COLD FRONTAL
BOUNDARY, DRAPED SOUTHWEST TO NORTHEAST FROM SOUTHWEST THROUGH EAST-
CENTRAL MINNESOTA, DRAGS EAST-SOUTHEAST ACROSS THE FORECAST AREA
INTO THE MORNING HOURS. EXACT TIMING AND OVERLAP WITH DIURNAL
HEATING WILL DETERMINE MORNING STORM THREAT LOCALLY. RECENT HRRR
FORECAST MODEL RUNS SUGGEST POSSIBLE STORM INITIATION WITHIN THE
WARM SECTOR OVER THE EASTERN HALF OF THE FORECAST AREA FROM WESTERN
INTO CENTRAL WISCONSIN NEAR 31.12Z. WHILE MID LEVEL LAPSE RATES WILL
BE STEEP ENOUGH TO SUPPORT ELEVATED INSTABILITY AND STRONG TO SEVERE
STORMS, SLIGHT MODERATION IS EXPECTED THROUGH THE OVERNIGHT FROM
CURRENT 8.5C/KM IN RAP MESOANALYSIS. THEREFORE, LARGE HAIL AND
DAMAGING WIND POTENTIAL REMAINS THROUGH EARLY THIS MORNING.
COLDER TODAY, WINTER WEATHER SETUP WEDNESDAY:
AS THE COLD FRONT SAGS SOUTH ACROSS THE FORECAST AREA THROUGH TODAY,
DAYTIME HIGH TEMPERATURES IN THE 50S EXPECTED. SOUTHERN EXTENT OF
LOW LEVEL BAROCLINIC BOUNDARY RELATIVE TO FORECAST AREA WILL
DETERMINE SUBSEQUENT WINTER STORM PROBABILITIES WEDNESDAY THROUGH
THURSDAY. CURRENT FORECASTS SUGGEST THE LOW LEVEL BAROCLINIC
BOUNDARY AND ACCOMPANYING SHARP TROUGH LYING ACROSS THE FORECAST
AREA, SHIFTING SLIGHTLY SOUTH OF THE FORECAST AREA TONIGHT. EXACT
LOCATION WILL DETERMINE INITIAL LOCATION OF CYCLOGENESIS LEE OF THE
ROCKIES WEDNESDAY, ACCOMPANYING PRECIPITATION TYPES WEDNESDAY, AS
WELL AS SUBSEQUENT PROGRESSION AND INTENSITY OF CYCLOGENESIS THROUGH
THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY INTO FRIDAY.
INITIAL PRECIPITATION CHANCES WEDNESDAY AFTERNOON WILL BE TIED TO
LOW LEVEL FRONTOGENESIS ALONG THE LOW LEVEL WARM FRONTAL BOUNDARY,
STREWN QUASI-ZONALLY NEAR THE FORECAST AREA. HIGH RESOLUTION
FORECAST SOUNDINGS HAVE JUST BEGUN TO PEER INTO THIS FORECAST
WINDOW, INCREASING WINTER WEATHER SIGNAL WITH SNOW SOUNDINGS FOR
AREAS ALONG AND NORTH OF I-94 AND FREEZING RAIN/SLEET SOUNDINGS FOR
AREAS ALONG THE I-90 CORRIDOR. NOW THERE HAS BEEN A RECENT TREND IN
THE MODELS TO SHIFT THE COOLER TEMPERATURES NORTHWARD AS THE CENTER
OF THE LOW PASSES SOMEWHERE OVER OUR FORECAST AREA. THE LOCATIONS
FOR WHERE THE MODELS PUT THE CENTER OF THE LOW AT DIFFER FROM NEAR
THE IA, WI, MN STATE LINE TO AREAS CLOSER TO THE I-35 CORRIDOR IN
SOUTHERN MN. THIS SHIFT NORTHWARD FOLLOWS WHAT THE SOUNDINGS HAVE
SHOWN WHERE SNOW IS NOW FAVORED NORTH OF I-94 AND A WINTRY MIX IS
BETWEEN I-90 AND I-94.
CONFIDENCE & WINTER PRECIPTIATION TYPES MIDWEEK:
VARIATION IN PRECIPTIATION TYPES INHERENTLY TIED TO SURFACE
TEMPERATURES, DEPENDENT ON TEMPERATURE GRADIENT AND STRENGTH OF EAST
WINDS NORTH OF THE FRONT SOLIDIFYING THE COLD SECTOR THROUGH THE
UPPER MISSISSIPPI RIVER VALLEY. THEREFORE, REGARDLESS OF DIFFERENCES
EXACT PRECIPITATION TYPES AND LOCATIONS, ALL HIGH RESOLUTION MODELS
SHOW A STOUT WARM NOSE PROVIDING SOME DEGREE OF OFF-SURFACE MELTING.
FURTHERMORE, THE HIGH APRIL SUN ANGLE WILL LIMIT INITIAL FROZEN
PRECIPITATION ACCUMULATION ON ROADWAYS GIVEN THE ABOVE FREEZING SOIL
TEMPERATURES. THEREFORE, DAYTIME FREEZING PRECIPITATION IMPACTS MAY
BE LIMITED TO ELEVATED SURFACES AND GRASSY SURFACES ONLY TO RETURN
OVERNIGHT WITH LACK OF DIURNAL HEATING. SIMILAR FOR SNOW
ACCUMULATION, POTENTIALLY LIMITED TO ELEVATED SURFACES UNTIL THE
OVERNIGHT WHEN LOW LEVEL FRONTOGENESIS EXPANDS IN COVERAGE. WITH THE
NORTHWARD SHIFT, PRECIPITATION TYPE SWITCHES TO ALL RAIN FOR MOST
LOCATIONS BY THURSDAY AFTERNOON WHEREAS PREVIOUS FORECASTS AND MODEL
RUNS HAD WINTRY MIX BEING POSSIBLE INTO THURSDAY NIGHT. THE TRACK OF
THIS STORM WILL BE VERY IMPORTANT TO WATCH AS THIS WILL HAVE
IMPLICATIONS ON AMOUNTS, PRECIPITATION TYPES, AND TRANSITION OF
DIFFERENT PRECIPITATION TYPES.
HEAVY RAIN INTO THE WEEKEND:
AS THE EXTRATROPICAL LOW LIFTS NORTHEAST OF THE UPPER MISSISSIPPI
RIVER VALLEY THROUGH THE END OF THE WEEK, ADDITIONAL SUBSEQUENT
CYCLOGENESIS THROUGH THE NORTHERN PLAINS RETURNS PRECIPITATION
CHANCES ACROSS THE UPPER MIDWEST FRIDAY AND THROUGH THE WEEKEND.
WHILE CURRENT CONFIDENCE FOR HEAVY RAIN WILL BE THE MAIN CONCERN
THROUGH THE EARLY WEEKEND, MIXED PRECIPITATION AS THE LOW EXITS EAST
WILL BRING ANOTHER THREAT OF WINTER IMPACTS. CURRENT CONFIDENCE FOR
1" OF QPF IN LONG TERM GLOBAL ENSEMBLES RAISES CONCERNS FOR RIVER
FLOODING ON FLASHIER RIVERS.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1229 AM CDT TUE MAR 31 2026
MID AND HIGH CLOUDS WILL PERSIST ACROSS MUCH OF THE AREA
OVERNIGHT. STILL PLENTY OF UNCERTAINTY ON WHETHER ANY SHOWERS OR
STORMS WILL DEVELOP NORTH OF CLAYTON AND GRANT COUNTIES
OVERNIGHT, SO KEPT THE TAFS DRY AND GOT RID OF THE MVFR CEILINGS
ON TUESDAY MORNING.
HYDROLOGY
ISSUED AT 142 PM CDT MON MAR 30 2026
RAIN AMOUNTS WEDNESDAY NIGHT AND THURSDAY COULD APPROACH 2
INCHES IN SOUTHWEST WISCONSIN. SHOULD THIS OCCUR, AND THE
PRECIPITATION TYPE REMAIN AS ALL RAIN, STREAM AND RIVER RISES
ARE POSSIBLE ON THE KICKAPOO RIVER LATE IN THE WEEK.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...CECAVA/JAR
AVIATION...BOYNE
HYDROLOGY...BAUMGARDT
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