466
FXUS63 KARX 221801
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
101 PM CDT WED APR 22 2026
KEY MESSAGES
- SHOWERS AND STORMS ARE VERY LIKELY (75-95%) THURSDAY EVENING
INTO THE OVERNIGHT HOURS. A FEW STRONG TO SEVERE STORMS CAN'T
BE RULED OUT.
- TEMPERATURES COOL TO NEAR NORMAL FRIDAY THROUGH EARLY NEXT
WEEK. HIGHS IN THE 60S AND LOWS IN THE 40S ARE EXPECTED.
- ANOTHER ROUND OF PRECIPITATION IS LIKELY (60-80%) SUNDAY NIGHT
INTO MONDAY.
DISCUSSION
ISSUED AT 101 PM CDT WED APR 22 2026
THURSDAY EVENING - FRIDAY: SHOWERS AND STORMS
A 500HPA LONGWAVE TROUGH CURRENTLY SITUATED OVER THE
INTERMOUNTAIN WEST WILL EJECT EASTWARD INTO THE NORTHERN GREAT
PLAINS LATE TONIGHT, DEEPENING A SURFACE LOW OVER THE DAKOTAS.
THE LOW AND ASSOCIATED FRONTS SHIFT EASTWARD DURING THE DAY
THURSDAY WITH THE COLD FRONT EXPECTED TO MOVE THROUGH OUR AREA
LATE THURSDAY INTO THE OVERNIGHT HOURS.
AHEAD OF THE MAIN FRONT, CAMS DEPICT A PERIOD OF SHOWERS/STORMS
DEVELOPING AS MOISTURE TRANSPORT AND WARM ADVECTION INCREASE,
COINCIDING WITH MUCAPE UPWARDS OF 1500-1750 J/KG. WHILE 0-6KM
SHEAR IS PRACTICALLY NIL IN THIS ENVIRONMENT, 700-500HPA LAPSE
RATES OF 7-8 C/KM ARE DEPICTED IN 22.09Z RAP SOUNDINGS OWING TO
THE PRESENCE OF AN EML OVER THE UPPER MISSISSIPPI RIVER VALLEY.
IF STORMS ARE ABLE TO DEVELOP DURING THIS PERIOD, SOME SMALL
HAIL DEVELOPMENT CAN'T BE RULED OUT GIVEN AMPLE INSTABILITY AND
FAVORABLE LAPSE RATES. THERE IS SOME UNCERTAINTY WHETHER
CONVECTIVE INITIATION CAN OCCUR DURING THIS PERIOD THOUGH,
ESPECIALLY SOUTH OF I-90, OWING TO THE PRESENCE OF A WARM NOSE
IN RAP/HRRR/RRFS SOUNDINGS. IT WILL LARGELY COME DOWN TO IF THE
850HPA MOISTURE TRANSPORT/WARM AIR ADVECTION WILL BE ENOUGH TO
OVERCOME ANY CAPPING PRESENT.
AS WE HEAD INTO THE EVENING HOURS THURSDAY, CONFIDENCE IS HIGH
THAT SHOWERS AND STORMS ALONG THE COLD FRONT WILL MOVE EASTWARD
INTO OUR AREA (75-95%). A FAIRLY MESSY STORM MODE IS EXPECTED AS
WIND SHEAR IS GENERALLY CONFINED TO THE LOWEST 3KM. 0-3KM SHEAR
SITS AROUND 25-35KTS WITH LITTLE TO NO INCREASE IN THE 3-6KM
LAYER. INSTABILITY ON THE ORDER OF 1000-1500 J/KG WILL SUPPORT
THUNDERSTORMS AS THEY MOVE THROUGH THE REGION AND POSSIBLY SOME
STRONGER UPDRAFTS, ALTHOUGH THESE WILL LIKELY NOT BE ABLE TO
SUSTAIN THEMSELVES FOR LONG GIVEN THE LACK OF DEEP LAYER SHEAR.
THIS LEADS TO MORE OF A LINEAR STORM MODE THROUGH THE OVERNIGHT
WITH STRONG TO SEVERE WIND GUSTS BEING THE PRIMARY THREAT WITH
ANY STORMS. HOWEVER, GIVEN THERE IS A COMPONENT OF THE 0-3KM
SHEAR VECTOR THAT IS PERPENDICULAR TO THE SURFACE FRONT AS WELL
AS CURVATURE IN THE 0-1KM LAYER PER MODEL HODOGRAPHS, ANY BOWING
SEGMENTS THAT ARE ABLE TO ORIENT FURTHER PERPENDICULAR TO THIS
SHEAR VECTOR COULD SEE A WEAK TORNADO DEVELOP.
RAINFALL SHOULD BE PRETTY EFFICIENT DURING THIS PERIOD AS WELL
GIVEN SKINNY CAPE PROFILES AND PWATS OF 1.2-1.3 INCHES, ABOVE
THE 90TH PERCENTILE OF SPC SOUNDING CLIMATOLOGY. THE MAIN
HINDRANCE IS WARM CLOUD DEPTHS ARE GENERALLY 8-9KFT, UNDER THE
IDEAL VALUES FOR HEAVY RAINFALL. THAT SAID, THE INTERQUARTILE
RANGE OF THE 22.13Z NBM SHOWS AMOUNTS BETWEEN 0.5 AND 1.0
INCHES, AN INCREASE SINCE THIS TIME YESTERDAY. SOME ISOLATED
POCKETS UPWARDS OF 1.5-2 INCHES ARE ALSO POSSIBLE WHERE
THUNDERSTORMS FREQUENT (30-50% PER THE 22.12Z HREF). AS SUCH,
LOW LYING AREAS MAY SEE SOME PONDING OF WATER. FORTUNATELY,
WHILE SOME AREA RIVERS MAY SEE RISES WITH THIS RAINFALL, THESE
AMOUNTS REMAIN BELOW THOSE NEEDED TO RUN THE RISK OF FLOODING.
FRIDAY - SUNDAY: COOLER TEMPERATURES AND DRY
COLD AIR ADVECTION IN THE WAKE OF THE COLD FRONT FRIDAY MORNING
BRINGS TEMPERATURES DOWN CLOSER TO NORMAL FOR THIS TIME OF
YEAR, GENERALLY IN THE UPPER 50S TO LOW 60S. THIS COOLER AIR
LINGERS THROUGH THE WEEKEND AS THE SURFACE LOW CHURNS ACROSS
SOUTHERN SASKATCHEWAN AND MANITOBA. APART FROM THE TEMPERATURES,
DRY CONDITIONS ARE EXPECTED THROUGH MUCH OF THE WEEKEND GIVEN
WEAK 925- 850HPA RIDGING SHIFTING EASTWARD THROUGH THE REGION.
SUNDAY NIGHT - MONDAY: ADDITIONAL SHOWERS AND STORMS
DETERMINISTIC AND ENSEMBLE GUIDANCE DEPICT A RATHER QUICKLY
MOVING SHORTWAVE TROUGH AND ASSOCIATED JET STREAK MOVING THROUGH
THE CENTRAL UNITED STATES SUNDAY. THESE FEATURES ARE PROGGED TO
INVIGORATE SURFACE CYCLOGENESIS ACROSS THE CENTRAL GREAT PLAINS
BEFORE LIFTING NORTHWARD INTO THE UPPER MIDWEST. SOME
VARIABILITY EXISTS AMONGST THE ENSEMBLE SUITE REGARDING
PLACEMENT/TRACK OF THE LOW, ALTHOUGH THERE IS CONSIDERABLY MORE
AGREEMENT AS COMPARED TO 24 HOURS AGO. AS SUCH, PROBABILITIES
FOR MEASURABLE PRECIPITATION DURING THIS PERIOD IS 70-90% IN THE
22.00Z LREF, 60-80% IN THE 22.13Z NBM. INSTABILITY ISN'T OVERLY
IMPRESSIVE AT THIS POINT, BUT THE PRESENCE OF 500-1000 J/KG OF
MUCAPE IN THE 22.00Z EPS ENSEMBLE WOULD SUPPORT SOME STORM
DEVELOPMENT.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1230 PM CDT WED APR 22 2026
MVFR CEILINGS WILL MOVE INTO THE AREA LATE TONIGHT AND THEN
CONTINUE THROUGH MUCH OF THURSDAY MORNING. OTHERWISE, VFR
CONDITIONS ARE EXPECTED.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FALKINHAM
AVIATION...BOYNE
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