505
FXUS63 KARX 232350
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
650 PM CDT THU APR 23 2026
KEY MESSAGES
- SHOWERS AND STORMS CURRENTLY OVER WESTERN MINNESOTA AND IOWA
MOVE INTO OUR AREA THIS AFTERNOON AND OVERNIGHT. SOME STORMS
COULD BE STRONG TO SEVERE. RAINFALL AMOUNTS OF 0.5 TO 1 INCH
ARE EXPECTED, LOCALLY UP TO 2 INCHES.
- TEMPERATURES COOL TO NEAR NORMAL FRIDAY THROUGH EARLY NEXT
WEEK. HIGHS IN THE 60S AND LOWS IN THE 40S ARE EXPECTED.
- ANOTHER ROUND OF SHOWERS AND STORMS LOOKS LIKELY (70-90%)
SUNDAY NIGHT THROUGH MONDAY.
DISCUSSION
ISSUED AT 115 PM CDT THU APR 23 2026
TONIGHT - FRIDAY MORNING: SHOWERS AND STORMS
SHOWERS AND STORMS CURRENTLY OVER WESTERN MINNESOTA AND IOWA
SHIFT EASTWARD THROUGH THE REGION THIS EVENING AND OVERNIGHT
ALONG A COLD FRONT. AHEAD OF THE FRONT, ISOLATED STORMS ARE
POSSIBLE ACROSS OUR AREA THROUGH THE AFTERNOON HOURS ALONG A
RIBBON OF 850HPA MOISTURE TRANSPORT. THERE'S SOME UNCERTAINTY
WHETHER THESE STORMS CAN DEVELOP AT ALL AS HRRR/RAP SOUNDINGS
DEPICT WARM AIR IN THE MID-LEVELS RESULTING IN CAPPING
INVERSION. HOWEVER, THE MOISTURE TRANSPORT IS ABLE TO SATURATE
THIS LAYER, THUNDERSTORM DEVELOPMENT IS FAVORED. STORMS THAT
DEVELOP WOULD POSE A THREAT FOR HAIL UP TO 1 INCH OWING TO STEEP
MID-LEVEL LAPSE RATES OF 7-8C/KM AND SBCAPE OF 1500-2000 J/KG
PER THE 23.13Z RAP ALTHOUGH STORMS IN THIS ENVIRONMENT WILL BE
SHORT LIVED AS 0-6KM BULK SHEAR IS WEAK AT BEST, SO VERY LITTLE
RESIDENCE TIME WILL OCCUR FOR HAIL TO GROW BIGGER THAN THIS.
AS THE FRONT MOVES THROUGH THE REGION, THE ONGOING CONVECTION
IS EXPECTED TO MAINTAIN ITSELF OWING TO FORCING FROM THE FRONT
AS WELL AS MUCAPE OF 1000-1500 J/KG. THE LINEAR TO QUASI-LINEAR
MODE WILL CONTINUE AS 0-6KM SHEAR REMAINS WEAK, MOSTLY LOCKED UP
IN THE LOWER LEVELS. BECAUSE OF THIS, DAMAGING WINDS ARE THE
PRIMARY THREAT ALONG THIS LINE, ALTHOUGH IF ANY BOWING SEGMENTS
DEVELOP AND ARE ABLE TO ORIENT PERPENDICULAR TO THE 0-3KM SHEAR
VECTOR, THEY RUN THE RISK OF A WEAK TORNADO DEVELOPING GIVEN
CURVATURE IN THE 0-1KM LAYER PER MODEL HODOGRAPHS.
APART FROM THE STRONG/SEVERE STORM THREAT, HEAVY RAINFALL IS
EXPECTED ACROSS THE REGION AS THE STORMS MOVE THROUGH THE
REGION. PWATS OF 1.2-1.3 INCHES CONTINUE TO BE DEPICTED IN HIGH-
RESOLUTION GUIDANCE, WELL ABOVE THE 90TH PERCENTILE OF
CLIMATOLOGY. DECENT PROBABILITIES FOR RAINFALL AMOUNTS OVER 1
INCH REMAIN IN THE 23.12Z HREF, SITTING AROUND 30-60% WITH SOME
SIGNAL FOR UP TO 2 INCHES. OVERALL EXPECTATIONS ARE FOR AMOUNTS
GENERALLY 0.5-1 INCHES WITH LOCALIZED AREAS UP TO 2 INCHES,
MOST FAVORABLE OVER NORTHEAST IOWA AND NORTH-CENTRAL WISCONSIN
PER THE 23.12Z HREF 24HR LPMM. WIDESPREAD FLOODING IS NOT A
CONCERN AT THIS POINT, BUT PONDING IS EXPECTED IN LOW-LYING
AREAS AND RISES ON RIVERS IN SMALLER BASINS WHERE THE HEAVIEST
RAINFALL OCCURS.
OVERALL, ALL SEVERE HAZARDS ARE ON THE TABLE THIS AFTERNOON AND
EVENING THROUGH TWO ROUNDS OF STORMS, ALTHOUGH SIGNIFICANT
SEVERE POTENTIAL IS NOT EXPECTED GIVEN THE MESSY STORM MODE.
SEVERE POTENTIAL IS HIGHEST WEST OF THE MISSISSIPPI RIVER WITH
THE INITIAL ONSET AND WANES WITH EASTWARD EXTENT OVERNIGHT AS
INSTABILITY DECREASES. THE FRONT AND SHOWERS/STORMS MOVE EAST
OF OUR AREA AROUND 3AM FRIDAY.
FRIDAY - SUNDAY: COOLER TEMPERATURES AND DRY
COLD AIR ADVECTION BEHIND THE FRONT BRINGS TEMPERATURES CLOSER
TO NORMAL FOR THIS TIME OF YEAR, WITH HIGHS IN THE 60S AND LOWS
IN THE 40S. LOWS MAY BE ABLE TO FALL INTO THE 30S NORTH OF I-94
FRIDAY NIGHT INTO SATURDAY MORNING GIVEN CLEAR SKIES AND DRIER
AIR SHIFTING SOUTHEASTWARD WITH THE 23.13Z NBM SUGGESTING AN 20-
40% CHANCE TO FALL BELOW 37F. GIVEN VEGETATION IS BEGINNING TO
GREEN UP ACROSS THE REGION, SOME CONCERN FOR PLANT DAMAGE FROM
FROST EXISTS DURING THIS TIMEFRAME.
A WEAK SHORTWAVE AT 500HPA MOVES ACROSS THE EASTERN
DAKOTAS/WESTERN MINNESOTA EARLY SATURDAY MORNING WITH THE CAMS
BEGINNING TO SUGGEST SOME PRECIPITATION MAY BE OBSERVED WITH THE
FEATURE. WHILE THE SHORTWAVE IS CURRENTLY SHOWN TO STAY WEST OF
OUR AREA, IF IT SHIFTS FURTHER EAST, SOME LIGHT PRECIPITATION
MAY OCCUR FOR THOSE WEST OF THE MISSISSIPPI RIVER, ALTHOUGH DRY
AIR IN THE SUBCLOUD LAYER WOULD ACT TO HINDER PRECIPITATION
FROM REACHING THE SURFACE. OUTSIDE OF THIS OUTLIER PRECIPITATION
POTENTIAL SATURDAY, THE COMING WEEKEND WILL LARGELY BE
CHARACTERIZED BY DRY WEATHER.
SUNDAY NIGHT - MONDAY: ADDITIONAL SHOWERS AND STORMS
THE NEXT EVENT FOR SHOWERS AND STORMS COMES SUNDAY NIGHT INTO
MONDAY AS A 500HPA TROUGH EJECTS INTO THE CENTRAL GREAT PLAINS,
DEVELOPING A SURFACE LOW THAT LIFTS NORTHWARD INTO THE UPPER
MIDWEST ON MONDAY. CONFIDENCE IN RAINFALL IS HIGH AT THIS POINT
WITH THE BULK OF DETERMINISTIC AND ENSEMBLE GUIDANCE IN
AGREEMENT WITH THIS LOW MOVING NORTHWARD INTO OUR AREA. THE
23.00Z LREF PAINTS 70-90% PROBABILITIES FOR MEASURABLE RAINFALL
IN OUR AREA MONDAY AND EVEN HAS A SIGNAL FOR 1 INCH OR GREATER
AT 10-20%. THE 23.13Z NBM DEPICTS A SIMILAR SCENARIO WITH
70-90% PROBABILITIES FOR MEASURABLE PRECIPITATION AND 30-50%
FOR 1 INCH OR GREATER.
THE MAIN UNCERTAINLY REGARDING THE SYSTEM IS THE TRACK OF THE
PARENT SHORTWAVE AND SURFACE, WHICH HAVE SHIFTED CONSIDERABLY
NORTHWARD IN THE LAST 24 HOURS. THIS BRINGS THE LOW MORE
DIRECTLY OVERHEAD THE UPPER MISSISSIPPI RIVER VALLEY, RESULTING
IN THE WARM SECTOR OF THE CYCLONE INTO OUR AREA. AS SUCH,
INSTABILITY HAS INCREASED ACROSS OUR AREA WITH MUCAPE NOW ON THE
ORDER OF 1000-1500 J/KG DEPICTED IN THE DETERMINISTIC GUIDANCE.
THE NEW TRACK ALSO BRINGS THE ATTENDANT 500HPA JET STREAK
OVERTOP OF THE REGION AS WELL, ACTING TO INCREASE 0-6KM BULK
SHEAR, WHICH SITS AT 30-40KTS ASSUMING A SURFACE BASED PARCEL,
ALTHOUGH LITTLE SHEAR EXISTS IN THE 3-6KM LAYER WHICH WOULD LEAD
TO DIFFICULTY SUSTAINING UPDRAFTS, SIMILAR TO TODAY. THIS
CURRENT SET-UP IS FAVORABLE FOR STRONG TO POTENTIALLY SEVERE
STORMS MONDAY, ALTHOUGH PERHAPS NOT IDEAL. THE SPC HIGHLIGHTS
PORTIONS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN IN A 15%
PROBABILITY FOR SEVERE WEATHER ON DAY 5 WHICH IS ALSO SHOWN IN AINWP
CONVECTIVE GUIDANCE. ALL THIS SAID, WHILE DETAILS WILL BE
IRONED OUT OVER THE WEEKEND, THIS WILL BE A PERIOD TO WATCH AS
THE NEW WEEK APPROACHES.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 633 PM CDT THU APR 23 2026
TWO LINES OF THUNDERSTORMS ARE MOVING THROUGH THE REGION THIS
EVENING. THE FIRST IS MOVING FROM SW TO NE THROUGH MUCH OF
WISCONSIN AS ANOTHER IS MOVING IN FROM THE WEST ACROSS SOUTHERN
MINNESOTA. THE FIRST WILL BE OUT OF THE LOCAL AREA AS THE SECOND
LINE MOVES THROUGH FROM WEST TO EAST OVER THE NEXT 6 TO 8 HOURS.
IFR VSBYS ARE POSSIBLE IN HEAVY RAIN AS THESE STORMS MOVE
THROUGH, WITH BRIEF MVFR CEILINGS. A DRY AIRMASS MOVES IN BEHIND
THE FRONT, LEAVING VFR CONDITIONS TO RETURN AFTER THE STORMS
THROUGH FRIDAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FALKINHAM
AVIATION...JAW
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