765
FXUS63 KARX 312337
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
637 PM CDT TUE MAR 31 2026
KEY MESSAGES
- WINTRY IMPACTS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY,
ESPECIALLY NEAR AND NORTH OF I-94. CONFIDENCE IS INCREASING
THERE, WITH SNOW AND SLEET (1-3 INCHES), AND ICE UP TO ONE-
QUARTER INCH IN THE FORECAST. FURTHER SOUTH SOME MINOR ICING
ACCUMULATIONS COULD OCCUR TO I-90, BUT WARMER TEMPERATURES
HAVE PUSHED ICE ACCUMULATIONS NORTH. RAINFALL OF 1-2" IS
EXPECTED WITH RIVER RISES. SOME SEVERE STORMS MAY BE POSSIBLE
THURSDAY AFTERNOON AS THE AREA WARMS.
- LATE WEEK, ANOTHER SYSTEM IS MOVING THROUGH THE AREA BRINGING
ADDITIONAL RAINFALL AND MORE WINTRY WEATHER POSSIBLY. SOME
WINTRY PRECIPITATION COULD OCCUR IN THE NORTHERN AREAS. RIVERS
WILL BE ON THE RISE AND THIS SYSTEM COULD CAUSE FURTHER RISES,
INCREASING FLOODING THREATS.
DISCUSSION
ISSUED AT 150 PM CDT TUE MAR 31 2026
MIDWEEK SYSTEM BRINGS MOST IMPACTS NORTH OF I-94
A COMPLEX STORM MOVES INTO THE AREA LATER WEDNESDAY AFTERNOON
LASTING INTO THURSDAY. THIS BRINGS WINTRY WEATHER ON THE FRONT END,
TRANSITIONING TO RAIN, AND SEVERE THUNDERSTORM POTENTIAL BY THURSDAY
AFTERNOON FOR SOME. SINCE YESTERDAY, THE STORM HAS TRENDED FURTHER
NORTHWEST WITH THE TRACK, PLACING THE AREA IN A WARMER TEMPERATURE
REGIME. THE ECMWF ENSEMBLES FOR THE PAST FEW RUNS HAVE BECOME
MORE CLUSTERED IN A LOW TRACK NEAR OR WEST OF LA CROSSE AND MORE
TIGHTLY CLUSTERED THAN THE GEFS. THE 31.06Z GEFS LOW PRESSURE
CENTERS TRACK (MOSTLY) NEAR OR EAST OF LA CROSSE WHICH IS A
COLDER SOLUTION. THE PROBABILITIES FOR ICING HAVE LIKEWISE
SHIFTED NORTH OF THE I-90 CORRIDOR, WITH RAIN FALLING UNDER
WARMER TEMPERATURES.
THE FORECAST PROBLEM FOR ICING IS REALLY ABOUT SURFACE TEMPERATURES
AS THE WARM LAYER ALOFT IS RATHER LARGE WITH A MAXT OF 5-10C. WET-
BULB TEMPERATURE BECOMES A KEY INGREDIENT TO ICE ACCUMULATION
AND WITH THE SURFACE RIDGE BUILDING IN OVERNIGHT AND EASTERLY
FLOW WEDNESDAY, NORTH-CENTRAL WI HAS THE LOWEST DEWPOINTS AND
WETBULB TEMPERATURES (IN THE 20S) AT FREEZING RAIN ONSET. THUS,
THE MAIN THREAT AREA FOR ICING IS STILL MORE APPARENT AND OF
HIGHER CONFIDENCE NORTHEAST OF I-94. THE 31.00Z GEFS AND GEPS
PROBABILITIES FOR 1/4 INCH PLUS OF ICE ARE IN THE 40-50% RANGE
THERE, INCREASING EASTWARD. THESE ARE ALSO ABOUT A COUNTY NORTH
SINCE YESTERDAY. THE ECMWF ENS HAS A SUBSTANTIAL PERIOD OF
FREEZING RAIN DOMINANT IN THE MEMBERSHIP AS WELL WED NIGHT
THROUGH ABOUT NOON THU. THAT AREA WILL SEE SOME FRONT END
SNOW/SLEET (1-2" IN THE LATEST FORECAST) BEFORE TRANSITIONING TO
FREEZING RAIN AFTER THU 12 AM. DURING THAT PERIOD, MODEL MEAN
LIQUID EQUIVALENT PRECIPITATION IS AROUND 1 INCH. THUS, A WINTER
STORM WATCH FOR CLARK AND TAYLOR COUNTIES HAS BEEN ISSUED FOR
THE POTENTIAL OF 0.25" OF ICE. SOMETIMES IN APRIL, GROUND WARMTH
CAN CAUSE GREATER DAMAGE TO TREES - LIMBS AWAY FROM THAT
WARM SOURCE.
FURTHER SOUTH OF CLARK AND TAYLOR COUNTIES, ROUGHLY TO ABOUT THE I-
90 CORRIDOR, TEMPERATURES NEAR THE SURFACE ARE FORECAST TO BE RIGHT
NEAR OR ABOVE FREEZING. RIVER VALLEYS SHOULD HAVE LITTLE TO NO ICE
ACCUMULATION WITH ABOVE FREEZING TEMPERATURES. BUT, SOME LIGHT ICE
ACCUMULATION COULD OCCUR WEDNESDAY NIGHT PRIOR TO THE WARMING
ESPECIALLY HEADING NORTH AWAY FROM I-90 AND ON HIGHER TERRAIN
(WHERE IT IS COLDER). BY NOON THURSDAY, EVEN AREAS NORTH OF
I-94 CONVERT TO RAIN. THIS WILL LESSEN THE OVERALL IMPACTS OF
PROLONGED ICE...ANY ICING FROM WED NIGHT AND THU MORNING SHOULD
MELT THURSDAY.
OVERALL, THE GRAND ENSEMBLE HAS SHIFTED THE MAX PRECIP BAND
NORTHWEST FROM CENTRAL AND SOUTHWEST WI TO NOW THROUGH THE CENTER OF
THE LOCAL AREA: WATERLOO IA TO WAUSAU WI, WITH 30-40%
PROBABILITIES OF OVER 1.50" TOTALS IN THE MAX BAND. THIS
INCOMING AIR MASS IS IMPRESSIVE WITH NEAR CLIMATOLOGY MAXES FOR
THE PRECIPITABLE WATER INFLOW. STRONG FORCING SIGNALS ARE SEEN
IN THIS NEGATIVELY TILED SYSTEM WITH MODERATELY STRONG 850 MB
MOISTURE TRANSPORT CONVERGENCE SURGES WED NIGHT AND THURSDAY.
MANY OF THE RIVER BASINS SHOULD BE ABLE TO TOLERATE 2" OF RAIN.
SEE THE HYDROLOGY SECTION FOR MORE.
THE WARM SECTOR SURGE INTO NORTHEAST IA THROUGH CENTRAL WI AND SOUTH
THURSDAY AFTERNOON SEEMS TO INDICATE, PER MODEL SOUNDINGS, THE
POTENTIAL FOR POSSIBLY SEVERE THUNDERSTORMS SOUTHWEST THOUGH
EAST OF LA CROSSE. ML CAPE IS ON THE ORDER OF 500-1000 J/KG IN
THE WARM SECTOR IN A SMALL REGION FEEDING INTO THE LOW CENTER
APPROXIMATELY NEAR LA CROSSE 4 PM THURSDAY. THESE STORMS COULD
BE SURFACE-BASED AND WOULD HAVE AMPLE WIND SHEAR. HOWEVER, THE
LOW-LEVEL CURVATURE IS IN QUESTION AS IT SEEMS ONCE PARCELS
BECOME SURFACE-BASED, SOME SURFACE WIND BACKING OCCURS CREATING
MORE OF A STRAIGHT-LINE HODOGRAPH. WILL HAVE TO CONTINUE TO
MONITOR THIS TRICKY LOWER CAPE, HIGHER WIND SHEAR SITUATION FOR
POSSIBLE DISCRETE, ROTATING STORMS IN THE WARM SECTOR.
THERE IS STILL SOME UNCERTAINTY SEEN IN THE ENSEMBLES ON THE
TRACK, BUT OVERALL WE FEEL THIS IS STABILIZING A BIT.
WEEKEND STORM COULD BRING MORE IMPACTS
CLOSED UPPER LEVEL LOW TRACKS ACROSS THE NORTHERN PLAINS AND GREAT
LAKES REGION MAINLY FRIDAY EVENING INTO THE WEEKEND. MUCH OF THE
AREA WILL SEE RAIN...WITH A FEW STORMS FRIDAY EVENING. WITH COOLER
TEMPS OVER THE AREA FRIDAY NIGHT...THE NORTHERN PARTS OF THE
FORECAST AREA COULD SEE A WINTRY MIX. SOME SNOW COULD ALSO MIX IN
FOR THE REST OF THE AREA ON SATURDAY AS COLDER AIR FILTERS IN ON THE
BACKSIDE OF THE UPPER LEVEL CLOSED LOW. TOTAL PRECIPITATION AMOUNTS
AT THIS TIME LOOK TO BE UP TO AN INCH IN A FEW LOCATIONS WITH THIS
SYSTEM. ANOTHER POSSIBILITY (20-30 PERCENT) OF RAIN OR SNOW IS
EXPECTED EARLY NEXT WEEK AS A WEAK SHORTWAVE EMBEDDED IN THE
NORTHWESTERLY FLOW ALOFT MOVES OVER THE GREAT LAKES REGION.
TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL THROUGH THE
FORECAST PERIOD.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 627 PM CDT TUE MAR 31 2026
MAINLY HIGH CLOUDS ARE EXPECTED THROUGH WEDNESDAY MORNING AND
THEN THE CLOUDS WILL LOWER AS A LOW PRESSURE SYSTEM APPROACHES
THE REGION FROM THE CENTRAL PLAINS. IN ADDITION TO THE CLOUDS
LOWERING, A WINTRY MIX WILL MOVE INTO THE REGION DURING THE
AFTERNOON.
HYDROLOGY
ISSUED AT 150 PM CDT TUE MAR 31 2026
PROBABILITIES INDICATE MUCH OF THE AREA WILL SEE 1-2 INCHES OF RAIN
WITH THE WED NIGHT AND THU SYSTEM. MANY OF THE RIVER BASINS SHOULD
BE ABLE TO TOLERATE 2" OF RAIN WITH WITHIN BANK RISES PER THE RIVER
FORECAST CENTER RIVER ENSEMBLE OUTPUT. HOWEVER, SHOULD MORE THAN
2 INCHES OF RAINFALL (15-25% CHANCE), MINOR FLOOD STAGE COULD
BE REACHED ON MULTIPLE RIVER SYSTEMS INCLUDING THE KICKAPOO,
TREMPEALEAU, AND YELLOW. 3 INCH RAIN TOTALS WOULD BRING FLOODING
TO THE TURKEY RIVER...BUT THESE 3 INCH PROBABILITIES ARE NEAR
0%.
THE SECOND STORM ON FRIDAY NIGHT AND SATURDAY COULD BRING MORE
FLOODING HOWEVER WITH RISING RIVER LEVELS AFTER THE FIRST STORM.
WE DONT HAVE DETAILS BUT THAT FAR YET, BUT WILL BE ABLE TO GET
A BETTER HANDLE ON THE FLOODING POTENTIAL FOR THE WEEKEND ON
THURSDAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...WINTER STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR WIZ017-029.
MN...NONE.
IA...NONE.
DISCUSSION...BAUMGARDT/CECAVA/JAR
AVIATION...BOYNE
HYDROLOGY...BAUMGARDT
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