104
FXUS63 KARX 041125
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
625 AM CDT FRI SEP 4 2026
KEY MESSAGES
- SHOWERS AND STORMS MAY CONTINUE (20 TO 50%) FOR MUCH OF THE
EARLY MORNING FOR AREAS EAST OF THE MISSISSIPPI RIVER. THERE
IS A HEAVY RAINFALL THREAT WITH SOME AREAS POTENTIALLY
RECEIVING UP TO 4 TO 5 INCHES OF RAIN, HOWEVER THE EXACT
LOCATION OF THE HEAVIEST RAIN IS UNCERTAIN AS IT COULD BE
OUTSIDE OF OUR FORECAST AREA.
- STORM CHANCES RETURN THIS AFTERNOON AND EARLY EVENING (15 TO
30% MAINLY FOR AREAS ALONG AND SOUTH OF I-90.
- SHOWER AND STORM CHANCES PERSIST THROUGH THE HOLIDAY WEEKEND
AND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 1244 AM CDT FRI SEP 4 2026
TODAY: HEAVY RAIN POTENTIAL THIS MORNING AND STORM POTENTIAL FOR THE
AFTERNOON
CURRENT IR SATELLITE VIEW SHOWS AN AREA OF CONVERGENCE FROM JUST
SOUTH OF THE TWIN CITIES METRO OVER TO NEAR THE GREEN BAY METRO.
STORMS HAVE BEGUN TO FIRE NORTH OF I-94 ALONG THIS BOUNDARY.
THIS BOUNDARY SHOULD GRADUALLY SHIFT SOUTH THROUGH THE OVERNIGHT
HOURS. SOUTH OF THIS BOUNDARY THE LOW LEVEL JET CONTINUES TO
PUSH 25 TO 40KTS OF SOUTHWEST FLOW INTO OUR CWA. PWATS REMAIN
QUITE HIGH (1.8 TO 2.1") WITH INSTABILITY VALUES AROUND 1500-
2500 J/KG OF MLCAPE. LIMITING FACTOR IS 75-200 J/KG OF MLCIN
THROUGH THE MORNING. WITH VEERING WINDS ALOFT THROUGH THE
MORNING, IN ADDITION TO THE ABOVE PARAMETERS, TRAINING STORMS
ARE POSSIBLE (20 TO 40%) WHICH COULD LEAD TO LOCALIZED FLOODING,
PARTICULARLY FOR AREAS EAST OF THE MISSISSIPPI RIVER. TOTAL
RAINFALL AMOUNTS COULD BE UPWARDS OF 1 TO 3 INCHES WITH SOME
LOCATIONS POTENTIALLY SEEING 3 TO 5 INCHES AS THE 12Z HREF LPMM
HAS SHOWN FOR AREAS ALONG THE I-90 CORRIDOR IN WISCONSIN. THE
LOCATION OF THE HIGHEST RAINFALL AMOUNTS WILL LIKELY CHANGE AS
SHOWN BY THE 00Z CAM SUITE WHERE THE LOCATION OF HEAVIEST
RAINFALL MAY FALL ALONG THE I-90 CORRIDOR IN WISCONSIN, OR DOES
IT SET UP MORE IN GRB OR MKX'S FORECAST AREA.
CONDITIONS FOR THE MID-MORNING TO EARLY AFTERNOON SHOULD REMAIN
MOSTLY DRY AS THE BOUNDARY FROM THE MORNING CONTINUES TO SHIFT SOUTH
THROUGH THE CWA. ALL CAMS HAVE THIS BOUNDARY ROUGHLY THROUGH THE
MIDDLE OF OUR FORECAST AREA DURING THE EARLY AFTERNOON. DAYTIME
RECOVERY WILL BE ONGOING AS INSTABILITY BUILDS BACK IN, GIVING THE
AREA ANYWHERE FROM 3000 TO 4500 J/KG OF MLCAPE TO WORK WITH. GIVEN
THAT THERE IS A BOUNDARY, HOWEVER WOULD LIKE TO SEE BETTER SURFACE
CONVERGENCE ALONG IT FOR MORE WIDESPREAD DEVELOPMENT, STORMS MAY
INITIATE ALONG THIS BOUNDARY DURING THE AFTERNOON AND EARLY EVENING
AS IT PROGRESSES SOUTHWARD. COMPARED TO THURSDAY, THERE WILL BE
LITTLE TO NO SHEAR (10 TO 25 KTS OF EFFECTIVE SHEAR) AVAILABLE SO
STORMS WILL STRUGGLE TO GET GOING. FOR THE STORMS THAT CAN GET GOING
AND STICK AROUND FOR A LITTLE WHILE, GUSTY WINDS AND HAIL UP TO 1"
WOULD BE THE MAIN THREATS WITH ANY STRONG TO SEVERE STORM THAT
DEVELOPS.
SATURDAY - EARLY NEXT WEEK: CONTINUED SHOWER AND STORM CHANCES WITH
SLIGHTLY ABOVE NORMAL TEMPERATURES
BY THE WEEKEND, RIDGING BUILDS INTO THE CENTRAL US WITH THE MAIN
RIDGE AXIS SETTING UP TO OUR WEST. OUR REGION REMAINS IN NORTHWEST
FLOW ALOFT WITH VARIOUS WAVES MOVING ALONG THE NORTHERN PART OF THE
RIDGE GIVING US A CONTINUED CHANCE (15 TO 40%) OF SEEING SHOWERS AND
STORMS FOR SUNDAY AND MONDAY. THERE IS BETTER AGREEMENT WITHIN THE
LONGER RANGE MODELS DEPICTING A SHORTWAVE TROUGH MOVING THROUGH THE
UPPER MIDWEST MONDAY NIGHT INTO TUESDAY. NBM POPS FOR THAT TIMEFRAME
ARE 40 TO 75%. TEMPERATURES COOL DOWN SLIGHTLY FROM WHAT WE HAVE
SEEN THIS WEEK, BUT REMAIN SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
UPPER 70S TO LOW 80S FOR SUNDAY AND MONDAY WITH A BRIEF WARMUP FOR
MIDWEEK WITH HIGHS BACK INTO MID 80S.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 620 AM CDT FRI SEP 4 2026
CONVECTION AND STRATUS/FOG CONCERNS WILL BE PRESENT OVER THE
NEXT 24 HOURS. AT ISSUANCE TIME, BELT OF SHRA AND TS IS
OCCURRING AROUND A CCY-LSE-Y50 ARC WITH THIS AXIS EXPECTED TO
SHIFT SOUTHEAST OVER THE NEXT FEW HOURS. HAVE INCLUDED A VCTS AT
LSE TO COVER THIS GIVEN THE WIDELY SPACED NATURE OF THE TS.
STRATUS/FOG TO THE NORTH IS ADVANCING SOUTHWARD, CURRENTLY
LOCATED ALONG A MVE-MDZ LINE. EXPECT THAT SURFACE INSOLATION
SHOULD HALT THE ADVANCE OF THIS SOON. HOWEVER, CONTINUED
PRESENCE OF A MOIST AIR MASS SHOULD LEAD TO THIS REDEVELOPING
TONIGHT AND GUIDANCE IS IN GOOD AGREEMENT THIS WILL SPREAD TO
LSE/RST SOMETIME AFTER 06Z. HAVE THEREFORE INCLUDED IFR AT BOTH
SITES LATE IN THE PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS
EVENING FOR WIZ061.
MN...NONE.
IA...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS
EVENING FOR IAZ029-030.
DISCUSSION...CECAVA
AVIATION...FERGUSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page