383
FXUS63 KARX 192342
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
642 PM CDT WED AUG 19 2026
KEY MESSAGES
- DRY AND PLEASANT TODAY.
- THUNDERSTORM POTENTIAL RETURNS THURSDAY EVENING INTO FRIDAY
MORNING WITH THE MAIN HAZARD BEING LIGHTNING.
- SEASONAL TEMPERATURES IN THE 70S TO LOWER 80S ARE FORECAST EACH
AFTERNOON OVER THE NEXT WEEK.
DISCUSSION
ISSUED AT 1240 PM CDT WED AUG 19 2026
THIS AFTERNOON TO THURSDAY MORNING: DRY AND PLEASANT CONDITIONS
A COOLER, DRIER AIRMASS WILL REMAIN IN PLACE THROUGH THE REST OF
TODAY INTO THURSDAY MORNING OVER THE UPPER MIDWEST. PLEASANT
CONDITIONS ARE FORECAST DURING THIS TIME FRAME WITH LIGHT WINDS
AND MOSTLY CLEAR SKIES. LIGHT WINDS AND CLEAR SKIES TONIGHT MAY
SUPPORT THE FORMATION OF SOME PATCHY FOG, ESPECIALLY IN THE
RIVER VALLEYS OF FAR SOUTHWESTERN WISCONSIN. OTHERWISE, THURSDAY
WILL BE A FEW DEGREES WARMER WITH INCREASING CLOUD COVER OUT
AHEAD OF THE NEXT WEATHER SYSTEM.
THURSDAY AFTERNOON THROUGH FRIDAY: THUNDERSTORM POTENTIAL
A SHORTWAVE TROUGH, ORIGINATING OUT OF THE CANADIAN PRAIRIE
PROVINCES, IS FORECAST TO MOVE SOUTHEAST TOWARDS THE GREAT LAKES
REGION THURSDAY INTO FRIDAY. OUT AHEAD OF THIS SYSTEM, MID LEVEL
MOISTURE WILL INCREASE WHICH WILL RESULT IN THE FORMATION OF SHOWERS
AND THUNDERSTORMS FROM THE NORTHERN PLAINS DOWN THROUGH THE UPPER
MIDWEST. ALTHOUGH IT IS POSSIBLE A STORM MAY BE STRONG TO MARGINALLY
SEVERE AS THEY MOVE INTO THE WESTERN CWA ON THURSDAY EVENING,
CONFIDENCE IN THAT SCENARIO IS LOW SINCE CIN IS RAPIDLY INCREASING
AS STORMS APPROACH THE AREA. FLOODING IS NOT REALLY A CONCERN WITH
THE STORMS EITHER, AS PWAT VALUES ARE ONLY NEAR THE 75TH PERCENTILE
(BASED ON SOUNDING CLIMATOLOGY FROM KMPX) AND THE STORMS SHOULD BE
MOVING RELATIVELY QUICKLY. THE BULK OF THE PRECIPITATION SHOULD BE
EAST OF THE AREA BY SUNRISE ON FRIDAY. CLOUD COVER SHOULD CLEAR OUT
THROUGHOUT THE DAY AS DRIER AIR MAKES ITS WAY OVER THE AREA ONCE
AGAIN AND TEMPERATURES SHOULD BE ABLE TO RISE UP INTO THE UPPER 70S
TO LOWER 80S DURING THE AFTERNOON.
THIS WEEKEND INTO NEXT WEEK: SEASONAL AND MOSTLY DRY CONDITIONS
FORECAST GUIDANCE REMAINS CONSISTENT IN BUILDING A RIDGE OF HIGH
PRESSURE ACROSS THE WESTERN AND CENTRAL US WITH A TROUGH ACROSS THE
EASTERN US THIS WEEKEND INTO THE NEXT WORK WEEK. THIS PATTERN WOULD
PLACE THE UPPER MISSISSIPPI RIVER VALLEY IN BETWEEN THESE SYSTEMS,
WHICH DOES LEAD TO UNCERTAINTY REGARDING THE EXACT DETAILS OF THE
FORECAST THROUGHOUT THIS TIME FRAME. IN GENERAL, THIS PATTERN FAVORS
SEASONAL TEMPERATURES AND MOSTLY DRY CONDITIONS. ENSEMBLE FORECAST
GUIDANCE HINTS AT THE POTENTIAL FOR SOME LIGHT RAINFALL EARLY NEXT
WEEK, HOWEVER THAT WILL HIGHLY DEPEND UPON MOISTURE REMAINING OVER
THE AREA AS WELL AS THE PRECISE TRACK OF UPPER LEVEL DISTURBANCES.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 642 PM CDT WED AUG 19 2026
LIGHT AND VARIABLE WINDS OVERNIGHT TRANSITIONING TO
SOUTHWESTERLY WINDS AT 10 TO 15 MPH FOR THE LATER MORNING INTO
THE EARLY EVENING ON THURSDAY. PREDOMINANTLY VFR CONDITIONS FOR
MANY LOCATIONS ACROSS THE REGION. THE EXCEPTION TO THIS IS
PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN THAT MAY
SEE SOME FOG EARLY THURSDAY MORNING. THERE IS A LOWER POTENTIAL
FOR FOG FOR RIVER VALLEYS NORTH OF THE WISCONSIN RIVER DUE TO
THE LIGHT WIND LAYER AND NO CLOUD COVER. THE ONE CAVEAT TO THIS
IS THAT DRIER AIR WILL MOVE IN OVERNIGHT LOWERING DEWPOINTS. AS
A RESULT, THE DEWPOINT DEPRESSION MAY BE TOO HIGH FOR FOG TO
FORM. CURRENTLY GIVE THIS A 20 TO 30% OF OCCURRING. WILL
CONTINUE TO MONITOR THIS POTENTIAL TO SEE IF FOG NEEDS TO BE
ADDED TO KLSE.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...MUSCHA
AVIATION...CECAVA
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