711
FXUS63 KARX 021830
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
130 PM CDT SUN AUG 2 2026
KEY MESSAGES
- DRY WITH SEASONABLE TEMPERATURES TODAY AND MONDAY WITH HIGHS
IN THE UPPER 70S TO LOWER 80S. TEMPERATURES WILL LIKELY REMAIN
NEAR TO SLIGHTLY BELOW AVERAGE FOR THIS WEEK.
- CHANCES (30-80%) FOR SHOWERS AND STORMS RETURN FOR TUESDAY AND
WEDNESDAY. THERE IS SOME POTENTIAL (10-30%) FOR RAINFALL
AMOUNTS OVER 1" IN NORTHEAST IOWA AND SOUTHWEST WISCONSIN
DURING THIS TIMEFRAME.
DISCUSSION
ISSUED AT 130 PM CDT SUN AUG 2 2026
REST OF TODAY - MONDAY: DRIER & SEASONABLE
UPPER-LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL BE THE NAME OF
THE GAME FOR THE REST OF TODAY AND MONDAY AS CLOUD COVER THIS
MORNING WILL CONTINUE TO CLEAR, RESULTING IN MOSTLY SUNNY
CONDITIONS. OVERALL, HIGH TEMPERATURES WILL GENERALLY REMAIN IN THE
UPPER 70S TO LOWER 80S TODAY WITH A SLIGHT INCREASE IN HIGH
TEMPERATURES FOR MONDAY AS SOUTHERLY SURFACE FLOW DEVELOPS INTO THE
REGION.
TUESDAY - WEDNESDAY: SHOWER AND STORM CHANCES RETURN
AS WE HEAD INTO TUESDAY, THE OVERALL SYNOPTIC PATTERN CHANGES
SLIGHTLY AS AN UPPER-LEVEL SHORTWAVE TROUGH PUSHES NORTH OF THE
REGION WITH AN ATTENDING SURFACE BOUNDARY TRANSLATING THROUGH THE
REGION. CONSEQUENTLY, MEASURABLE PRECIPITATION CHANCES INCREASE (50-
90%) IN THE GRAND ENSEMBLE (GEFS/EC/CANADIAN ENSEMBLE) DURING THIS
PERIOD. OVERALL THIS SETUP DOES NOT LOOK OVERLY CONDUCIVE FOR SEVERE
WEATHER DUE TO THE TIMING OF THE BOUNDARY AND MINIMAL INSTABILITY
(ONLY AROUND 500-750 J/KG OF MUCAPE IN THE GFS) PRESENT DURING THIS
PERIOD. ALTHOUGH, SOME ELONGATION IN HODOGRAPHS DURING THIS
TIMEFRAME DOES SUGGEST SOMEWHAT FAVORABLE SHEAR PROFILES. IN ANY
CASE, FAIRLY RESPECTABLE WARM CLOUD DEPTHS OVER 4KM AND PRECIPITABLE
WATERS APPROACHING 2 INCHES WOULD SUGGEST A FAIRLY FAVORABLE
ENVIRONMENT FOR HEAVY RAINFALL. AS A RESULT, HAVE NOTICED A
SHIFT OF TAILS OF 0 ACROSS PORTIONS OF NORTHEAST IOWA AND
SOUTHWEST WISCONSIN IN THE EC EXTREME FORECAST INDEX. THIS IS
BEING GENERATED IN PART DUE TO SOME PROBABILITIES (10-30%) OF
OVER AN INCH OF RAINFALL PRESENT IN THE GRAND ENSEMBLE
(GEFS/EC/CANADIAN ENSEMBLE). SOME OF THE HIGHEST MEMBERS IN THE
90TH TO 95TH PERCENTILE GRAND ENSEMBLE (GEFS/EC/CANADIAN
ENSEMBLE) WOULD SUGGEST AMOUNTS IN THE 2-3" RANGE CANNOT BE
RULED OUT DURING THIS PERIOD SOUTH OF THE MN STATE LINE. SO
WHILE THE THREAT FOR SEVERE POTENTIAL IS QUITE LOW CONFIDENCE
DURING THIS PERIOD, WILL HAVE TO WATCH TO SEE IF WE CAN
OVERACHIEVE ON RAINFALL AMOUNTS.
IN ANY CASE, WITH THE PRECIPITATION CHANCES, A FRONTAL PASSAGE AND
ZONAL FLOW ALOFT DURING THIS PERIOD, TEMPERATURES WILL LIKELY REMAIN
ON THE COOLER SIDE OF NORMAL FOR THIS TIME OF YEAR WITH MEDIAN HIGH
TEMPERATURES IN THE NBM REMAINING GENERALLY IN THE 70S TO LOWER 80S
FOR TUESDAY AND WEDNESDAY. GIVEN THAT MUCH OF THE LOCAL AREA WILL BE
ON THE COOL SIDE OF THE FRONTAL PASSAGE COME WEDNESDAY, WOULD NOT BE
OVERLY SURPRISING FOR MUCH OF THE LOCAL AREA TO STRUGGLE TO REACH 80
DEGREES.
THURSDAY - SATURDAY: STAYING SEASONABLE WITH SHOWER AND STORM CHANCES
TEMPERATURES WILL BEGIN TO WARM SLIGHTLY AGAIN AS SURFACE HIGH
PRESSURE BEHIND THE AFOREMENTIONED FRONTAL PASSAGE WILL AID IN
WARMING SURFACE TEMPERATURES. HOWEVER, GIVEN ZONAL TO
NORTHWESTERLY FLOW ALOFT LATE THIS WEEK, WOULD NOT EXPECT
TEMPERATURES TO RECOVER ALL THAT MUCH WITH THE NBM KEEPING
TEMPERATURES NEAR NORMAL. BY FRIDAY AND SATURDAY, PREDICTABILITY
IN THE MIDDLE AND UPPER-LEVEL FLOW PATTERN BECOMES LOWER AS THE
SYNOPTIC PATTERN FAVORS ZONAL TO NORTHWESTERLY FLOW WITH
EMBEDDED SHORTWAVE PERTURBATIONS. AS A RESULT, THINKING THERE
REMAINS SOME CHANCES FOR SHOWERS AND STORMS AT THIS POINT IN THE
FORECAST PERIOD, HOWEVER CONFIDENCE IS VERY LOW IN DETAILS AT
THIS JUNCTURE AS THE LOCATION OF THE THERMAL RIDGE, WHICH MAY
PROMOTE CAPPING ALOFT, WILL NEED TO BE RESOLVED AS WELL.
CONSEQUENTLY, FEEL THE LOW PRECIPITATION CHANCES (10-40%) IN
THE NBM FOR FRIDAY AND SATURDAY ARE APPROPRIATE AT THIS
JUNCTURE.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1231 PM CDT SUN AUG 2 2026
HIGH PRESSURE DRIFTING OVERHEAD WILL SET THE STAGE FOR
POTENTIALLY MORE BR AND LOW CEILINGS TOWARD DAYBREAK MONDAY.
LIGHT EAST TO NORTHEAST WINDS THIS AFTERNOON WILL BECOME
SOUTHERLY TONIGHT. FOG IS EXPECTED IN THE WISCONSIN AND
KICKAPOO RIVER VALLEYS, LIKELY SPILLING INTO THE MISSISSIPPI
RIVER VALLEY BELOW LA CROSSE AND SURROUNDING TRIBUTARIES ALSO.
THE MAIN QUESTION IS WHETHER A LIGHT WIND LAYER JUST ABOVE THE
SURFACE WILL BE DEEP ENOUGH FOR BR TO EXTEND INTO LSE AND RST.
RIGHT NOW THERE IS A LOW CHANCE (20%) BUT THE SETUP SEEMS
FAVORABLE ENOUGH SO HAVE INTRODUCED MVFR VISIBILITY IN THE
TAFS. THAT SHOULD BURN OFF BY 15Z WITH SOUTHERLY WINDS
INCREASING TOWARD MIDDAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...KURZ
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