648
FXUS63 KARX 211418
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
918 AM CDT FRI AUG 21 2026
KEY MESSAGES
- SCATTERED STORMS POSSIBLE IN SOUTHWEST WISCONSIN EARLY THIS
AFTERNOON, SOME OF WHICH MAY BE ON THE STRONGER SIDE.
- SEASONAL TEMPERATURES CONTINUE INTO NEXT WEEK WITH HIGHS IN
THE 70S TO LOWER 80S.
- DRY WEEKEND WITH THE NEXT POTENTIAL ROUND OF STORMS COMING
TUESDAY AND WEDNESDAY OF NEXT WEEK.
DISCUSSION
ISSUED AT 915 AM CDT FRI AUG 21 2026
EARLY THIS AFTERNOON: STORM POTENTIAL
OUR EARLY MORNING CONVECTION IS PUSHING OFF INTO SOUTH-CENTRAL
AND SOUTHEASTERN WISCONSIN BY 9AM, WITH THE FOCUS TURNING TO
THE TIMING AND LOCATION OF SUBSEQUENT CONVECTIVE DEVELOPMENT
EARLY THIS AFTERNOON AHEAD OF A COLD FRONT SWEEPING THROUGH THE
REGION.
BY MIDDAY, THE COLD FRONT (ALREADY MOVING INTO THE FORECAST
AREA FROM THE WEST) WILL LIKELY BE ALONG A LINE FROM NEAR
OELWIEN, IA TO WISCONSIN RAPIDS, WI. FORECAST PROFILES IN THE
PREFRONTAL AIRMASS SHOW AMPLE INSTABILITY ON THE ORDER OF
2000-2500 J/KG OF MLCAPE, BUT THE WIND PROFILES--WHILE LINEAR TO
THE SOUTHEAST--WILL INITIALLY STRUGGLE TO SUPPORT ORGANIZED
CONVECTION GIVEN THAT THE STRONGER MID TO UPPER LEVEL FLOW LOOKS
TO NOT ARRIVE UNTIL 21-00Z. BY THE TIME THE STRONGER FLOW
ARRIVES AND THE HODOGRAPHS ELONGATE, THE FRONT WILL HAVE
PROGRESSED OUT OF THE FORECAST AREA AND TAKEN THE SEVERE WEATHER
THREAT WITH IT. THEREFORE, WHILE ONE CANNOT RULE OUT A PULSE
STORM CAPABLE OF PRODUCING LOWER END SEVERE HAIL IN SOUTHWESTERN
WISCONSIN BETWEEN 18-21Z, THE MAIN SEVERE WEATHER THREAT WINDOW
FOR THE DAY CONTINUES TO LOOK TO BE JUST TO THE SOUTH AND EAST
OF THE FORECAST AREA.
SATURDAY - MIDWEEK: DRY EARLY, STORMS RETURN TUESDAY
NORTHWEST FLOW RETURNS TO THE REGION FOR THE WEEKEND AS A
TROUGH AMPLIFIES TO OUR EAST AND THE RIDGE SETS UP TO OUR WEST.
THIS RIDGE DECAYS AS IT MOVES EASTWARD INTO EARLY NEXT WEEK.
WITH OUR REGION IN BETWEEN THESE TWO FEATURES AND UNDER THE
INFLUENCE OF SURFACE HIGH PRESSURE, WE LOOK TO BE MOSTLY DRY
AND SLIGHTLY COOLER THROUGH THE WEEKEND UNTIL THE RIDGE BREAKS
DOWN ON TUESDAY. HIGH TEMPERATURES STAY IN THE LOW 70S TO LOW
80S FROM SATURDAY THROUGH MONDAY.
IT WILL NOT BE UNTIL TUESDAY AS A SHORTWAVE CRESTS THE
FLATTENING RIDGE THAT THE NEXT RISK FOR STORMS ARRIVES WITH THE
MEDIUM RANGE ENSEMBLES IN GOOD AGREEMENT (60-80%) THAT THERE
WILL BE STORMS DURING THIS PERIOD. THE EXACT TIMING AND
PLACEMENT DETAILS OF THIS RAIN WILL BE HAMMERED OUT AS WE GET
CLOSER TO THE EVENT. BEYOND TUESDAY, THE FORECAST IS LOOKING
RELATIVELY DRY FOR THE MIDDLE TO LATTER PART OF NEXT WEEK AS THE
UPPER LEVEL RIDGE REBUILDS TO OUR WEST.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 555 AM CDT FRI AUG 21 2026
ONGOING LINE OF TS FROM ONA TO ISW WILL CONTINUE TO SLIDE
SOUTHEAST THROUGH THE AREA OVER THE NEXT FEW HOURS. THIS MAY
(30%) LEAD TO AN ADDITIONAL TS REPORT AT OR NEAR LSE THRU 12Z.
MOVING AHEAD TO THE NEW TAF PERIOD, EXPECT THESE STORMS TO
DEPART OVER THE NEXT FEW HOURS AND PROSPECTS FOR ADDITIONAL
STORMS THIS AFTERNOON APPEAR SLIM, SO RST/LSE ARE VFR OVER THE
NEXT 24 HOURS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...FERGUSON
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