327
FXUS63 KARX 211103
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
603 AM CDT TUE JUL 21 2026
KEY MESSAGES
- DRY CONDITIONS AND COOLER TEMPERATURES ARE EXPECTED THROUGH
FRIDAY WITH DAYTIME HIGHS FROM THE 70S TO LOW 80S.
- THUNDERSTORM CHANCES RETURN ALONG WITH MORE SUMMER-LIKE HEAT THIS
WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 244 AM CDT TUE JUL 21 2026
TUESDAY THROUGH FRIDAY: BELOW AVERAGE TEMPERATURES AND DRY CONDITIONS
A 500MB TROUGH WILL BE IN PLACE OVER THE NORTHEAST WITH THE
CENTER OF HIGH PRESSURE REMAINING OVER THE SOUTHERN HIGH PLAINS
THROUGH THURSDAY-FRIDAY. THIS PATTERN LEADS TO NORTHWEST FLOW
OVER THE UPPER MISSISSIPPI RIVER VALLEY RESULTING IN A COOLER
AIR MASS IN PLACE LOCALLY. THIS COOLER AIR MASS WILL INITIALLY
BE NOTICEABLE TODAY BEHIND A COLD FRONTAL PASSAGE OVERNIGHT.
BELOW AVERAGE TEMPERATURES, IN THE 70S TO LOWER 80S, ARE
EXPECTED THROUGH THE WORK WEEK AS THE COOLER AIR MASS REMAINS
IN PLACE. THERE IS STRONG ENSEMBLE AGREEMENT IN THIS SCENARIO
PANNING OUT WITH 25TH TO 75TH PERCENTILE TEMPERATURE DIFFERENCES
ONLY UPWARDS OF 5 DEGREES THROUGH SATURDAY. NEGATIVE THETA-E
ADVECTION IS FORECAST DURING THE REST OF THE WEEK WHICH WILL NOT
BE FAVORABLE FOR THE DEVELOPMENT OF SHOWERS OR STORMS.
THIS WEEKEND INTO NEXT WEEK: THUNDERSTORM CHANCES RETURN
THE AFOREMENTIONED UPPER LEVEL CENTER OF HIGH PRESSURE IS
EXPECTED TO MOVE OVER THE INTERMOUNTAIN WEST OVER CO/NM THIS
WEEKEND WITH A JET STREAM ROUNDING THE TOP OF THE RIDGE FROM THE
CANADIAN PRAIRIES INTO THE MIDWEST DURING THIS TIME FRAME. MID
LEVEL MOISTURE SHOULD RETURN TO THE REGION AND WITH EMBEDDED
H300 SHORTWAVES PROGRESSING THROUGH THE NORTHWEST FLOW OVER THE
CWA, SHOWER AND THUNDERSTORM CHANCES ARE LIKELY TO RETURN.
DETAILS ARE UNCERTAIN AND WILL CHANGE AS WE GET CLOSER TO THE
WEEKEND, BUT THERE IS THE POTENTIAL FOR SEVERE THUNDERSTORMS ON
SUNDAY AS INSTABILITY INCREASES OVER THE AREA. IN ADDITION TO
THE STORM CHANCES, WAA SHOULD LEAD TO TEMPERATURES INCREASING
BACK INTO THE 80S TO LOW 90S SATURDAY THROUGH MONDAY.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 600 AM CDT TUE JUL 21 2026
BESIDES INCREASING CLOUD COVER BRINGING POTENTIAL FOR TEMPORARY
MVFR CEILINGS LATER THIS MORNING INTO THE EARLY AFTERNOON, VFR
EXPECTED ACROSS MOST OF THE LOCAL FORECAST AREA THROUGH THE
21.12Z TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...MUSCHA
AVIATION...JAR
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