320
FXUS63 KARX 240000
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
700 PM CDT SAT MAY 23 2026
KEY MESSAGES
- SHOWERS MOVE THROUGH WESTERN WISCONSIN THIS AFTERNOON BEFORE
EXITING TO THE EAST THIS EVENING.
- ADDITIONAL SHOWERS AND STORMS POSSIBLE SUNDAY NIGHT (20-50% CHANCE)
AND MONDAY AFTERNOON/EVENING (15-25% CHANCE). IF STORMS DO
DEVELOP ON MONDAY AFTERNOON/EVENING THEY MAY BECOME STRONG
WITH STRONG WIND GUSTS AND SMALL HAIL.
- MUCH WARMER AND DRIER FOR TUESDAY THROUGH FRIDAY WITH HIGH
TEMPERATURES IN THE 80S AREAWIDE.
DISCUSSION
ISSUED AT 155 PM CDT SAT MAY 23 2026
REST OF TODAY - SUNDAY NIGHT: WARMING TREND, SHOWER/STORM CHANCES
GOES-19 WATER VAPOR IMAGERY AND 23.15Z RAP 500MB HEIGHTS DEPICT A
FAIRLY PRONOUNCED TROUGH SITUATED OVER THE GREAT PLAINS WITH A LOW
ATTEMPTING TO CLOSE OFF ACROSS SOUTHERN CANADA. IN GENERAL THIS
FEATURE IS EXPECTED TO MOVE EASTWARD WITH TIME AS OUR AREA GETS
SUBJECTED INTO ZONAL FLOW INTO SUNDAY. HOWEVER, PRIOR TO THIS
OCCURRING, A WEAK FRONTAL PASSAGE COMBINED WITH VERY WEAK INSTABILITY
HAS RESULTED IN SOME SHOWERS THIS AFTERNOON ALONG AND EAST OF
THE MISSISSIPPI RIVER AS HIGHLIGHTED IN MUCH OF THE CAMS. GIVEN
FAIRLY WEAK INSTABILITY (AROUND 250 J/KG) THINK THAT THESE CELLS
ALONG THE FRONT IN WESTERN WI WILL NOT BE OVERLY ROBUST OF
WHICH THE CAMS GENERALLY AGREE.
AS WE HEAD INTO SUNDAY, ZONAL TO SLIGHTLY NORTHWESTERLY FLOW IS
ANTICIPATED FOR THE DAYTIME HOURS, HOWEVER WITH SOUTHWESTERLY FLOW
IN THE LOW-LEVELS PUSH INTO THE AREA WITH AN INCREASING AXIS OF 850MB
MOISTURE TRANSPORT, WARM ADVECTION GETS PUSHED INTO THE REGION WITH
THE INTER-QUARTILE RANGE FOR HIGH TEMPERATURES IN THE NBM RANGING
FROM THE UPPER 70S TO LOWER 80S ACROSS THE LOCAL AREA. BY THE TIME
THE EVENING AND OVERNIGHT ROLLS AROUND, THIS 850MB MOISTURE
TRANSPORT AXIS BECOMES MORE ROBUST OVERNIGHT AND INTO THE EARLY
MORNING HOURS ON MONDAY AS IT INTERACTS WITH THE NOCTURNAL LOW-LEVEL
JET. AS A RESULT, CAMS GENERALLY AGREE ON SOME CONVECTIVE
DEVELOPMENT ACROSS SOUTHERN MN THAT PUSHES EAST/NORTHEAST THROUGH
THE OVERNIGHT AND INTO THE EARLY MORNING HOURS ON MONDAY. OVERALL,
WHILE INSTABILITY DURING THE OVERNIGHT REACHES AROUND 1500-2000
J/KG OF MUCAPE IN THE RECENT RAP, SHEAR PROFILES ARE NOT ALL
THAT IMPRESSIVE WITH LOTS OF LOOPING IN THE 0-6KM HODOGRAPHS
WHICH WOULD NOT FAVOR ORGANIZED STORM STRUCTURES. ADDITIONALLY,
A FAIRLY PRONOUNCED NOCTURNAL CAPPING INVERSION WOULD BE IN
PLACE AS WELL. CONSEQUENTLY, ANY SEVERE POTENTIAL SEEMS UNLIKELY
DURING THIS OVERNIGHT PERIOD WITH ANY STORMS THAT PUSH INTO OUR
AREA.
MONDAY: WARMER, OUTSIDE CHANCE FOR STORM ON MONDAY AFTERNOON &
EVENING
BY THE TIME MONDAY ROLLS AROUND, CONTINUED LOW-LEVEL SOUTH TO
SOUTHWESTERLY FLOW WILL ALLOW OUR TEMPERATURES TO CONTINUE TO WARM
FURTHER AS AN UPPER-LEVEL RIDGE BEGINS TO PUSH INTO THE GREAT
PLAINS. AS A RESULT, THE INTER-QUARTILE RANGE FOR HIGH TEMPERATURES
IN THE GRAND ENSEMBLE (GEFS/EC/CANADIAN ENSEMBLE) RANGING FROM THE
UPPER 70S TO LOWER 80S. GRANTED WITH FAIRLY PRONOUNCED INVERTED-V
SOUNDINGS AND THE RIDGE OVER THE AREA, TEMPERATURES WILL LIKELY
OVERACHIEVE THIS.
LATER INTO THE AFTERNOON AND EVENING, A RIBBON OF THETA-E ADVECTION
PUSHES THROUGH THE AREA WITHIN A WEAK 850MB MOISTURE TRANSPORT
REGIME. AS A RESULT, THE GFS/NAM HAS CORRIDOR OF RELATIVELY ROBUST
MLCAPE OF AROUND 2000-3000 J/KG. THIS COUPLED WITH THE
AFOREMENTIONED INVERTED-V SOUNDINGS WOULD SUGGEST SOME POTENTIAL FOR
A SURFACE-BASED ENVIRONMENT (ALTHOUGH THIS IS HEAVILY DEPENDENT ON
IF WE HEAT ENOUGH TO BREAK THE CAP) THAT COULD SUPPORT STRONG
WIND GUSTS WITH ANY STORMS THAT GET GOING IN ADDITION TO SMALL
HAIL. HOWEVER, THIS IS RELATIVELY CONDITIONAL SCENARIO GIVEN THE
LACK OF SURFACE CONVERGENCE PRESENT IN THIS THETA-E ADVECTION
REGIME SO IT IS QUESTIONABLE IF THE FORCING IS EVEN THERE DURING
THE AFTERNOON AND EARLY EVENING FOR ANYTHING TO GET GOING.
CONSEQUENTLY, HAVE DECIDED TO ADD SOME LOW-END PRECIPITATION
CHANCES (15-20%) DURING THIS PERIOD TO ACCOUNT FOR THIS LOW
CONFIDENCE SCENARIO.
TUESDAY - FRIDAY: STAYING WARM WITH MINIMAL PRECIPITATION CHANCES
AS WE HEAD INTO MID-WEEK, THE UPPER-LEVEL RIDGE AMPLIFIES OVER THE
REGION WITH CONTINUED WEAK SOUTHERLY LOW-LEVEL FLOW INTO THE REGION
ON TUESDAY. AS A RESULT, TUESDAY AND WEDNESDAY APPEAR TO BE OUR
WARMEST PERIOD WITH SOME NOTABLE DIFFERENCES IN GUIDANCE BETWEEN THE
NBM AND GRAND ENSEMBLE (GEFS/EC/CANADIAN). OVERALL, NBM IS RUNNING
AROUND 5-10 DEGREES WARMER THAN OTHER GUIDANCE DUE TO ITS BIAS
CORRECTION AND WHILE IT WOULD SEEM FAIRLY LIKELY THAT WE WILL
OVERACHIEVE ON TEMPERATURES FROM ENSEMBLE GUIDANCE DUE TO THE MORE
FAVORABLE MIXING AND LACK OF SKY COVER UNDER THE RIDGE, IT IS
UNCLEAR IF WE WILL REACH THE LOWER 90S THAT THE NBM PORTRAYS NEAR I-
90 ON TUESDAY.
OTHERWISE, TEMPERATURES WILL REMAIN ON THE WARM SIDE THROUGHOUT THE
REMAINDER OF THE WEEK WITH HIGHS IN THE 80S AS GUIDANCE CONTINUES TO
KEEP THE UPPER-LEVEL RIDGE SITTING NEAR OR JUST WEST OF THE LOCAL
AREA. THE GEFS AND OPERATIONAL GFS TRIES TO BRING SOME STRONGER
UPPER-LEVEL NORTHERLY FLOW INTO THE REGION LATER INTO THE WEEK WHICH
MAY AID IN RETURNING PRECIPITATION CHANCES AND COOLING OUR
TEMPERATURES. HOWEVER, THIS IS NOT REFLECTED IN EITHER THE EC OR
CANADIAN OPERATIONAL RUNS. ADDITIONALLY WITH SURFACE HIGH PRESSURE
SITUATED OVER THE NORTHERN GREAT LAKES, THE GRAND ENSEMBLE
(GEFS/EC/CANADIAN) KEEPS THE BULK OF THE MEASURABLE PRECIPITATION
CHANCES TO OUR SOUTH AND WEST WITH ONLY LOW TO MEDIUM PROBABILITIES
(20-40%) FOR MEASURABLE PRECIPITATION WEDNESDAY THROUGH FRIDAY.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 658 PM CDT SAT MAY 23 2026
VFR EXPECTED FOR MUCH OF THE LOCAL AREA, OUTSIDE OF CENTRAL
WISCONSIN NEAR ISSUANCE, THROUGH THE 24.06Z TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...JAR
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