185
FXUS63 KARX 142346
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
646 PM CDT THU MAY 14 2026
KEY MESSAGES
- SHOWERS LIKELY (40-70% CHANCE) LATE THIS AFTERNOON AND INTO
THE OVERNIGHT WITH RAINFALL AMOUNTS GENERALLY AROUND A TENTH
OF AN INCH OR LESS. ADDITIONAL STORMS LIKELY (40-80% CHANCE)
IN SOUTHWEST WI AND NORTHEAST IA WITH SOME POTENTIALLY BEING
STRONG WITH HAIL AND GUSTY WINDS LATE FRIDAY EVENING AND
OVERNIGHT.
- WARMER TEMPERATURES BEGINNING FRIDAY AND CONTINUING INTO EARLY
NEXT WEEK WITH HIGHS IN THE UPPER 70S TO 80S. THERE IS A SMALL
CHANCE (10% CHANCE) TEMPERATURES MAY WARM INTO THE UPPER 80S
TO NEAR 90 ON FRIDAY, MAINLY IN RIVER VALLEY LOCATIONS.
- MORE ACTIVE WEATHER PATTERN THIS WEEKEND THROUGH TUESDAY WITH
PERIODIC CHANCES FOR SHOWERS AND STORMS. THERE IS POTENTIAL
FOR STRONG TO SEVERE STORMS THROUGHOUT THIS PERIOD WITH SUNDAY
AND MONDAY CURRENTLY POSING THE GREATEST RISK.
DISCUSSION
ISSUED AT 147 PM CDT THU MAY 14 2026
REST OF TODAY - SATURDAY: WARMER ON FRIDAY WITH PERIODIC
SHOWERS/STORM
UPPER-LEVEL RIDGING PUSHES EASTWARD TODAY USHERING IN ZONAL FLOW
INTO THE OVERNIGHT AND FOR THE DAY ON FRIDAY. AS THE UPPER-LEVEL
RIDGE THAT WAS SITUATED OVER OUR REGION PUSHES EASTWARD, A SHORTWAVE
ON THE EASTERN PERIPHERY OF THE ZONAL FLOW REGIME WILL PUSH INTO THE
LOCAL AREA WITH SOME ACCOMPANYING WARM AIR ADVECTION IN THE LOW-
LEVELS. CONSEQUENTLY, MUCH OF THE CAMS PUSH AN AXIS OF SHOWERS
THROUGH THE LOCAL AREA LATE THIS AFTERNOON AND INTO THE OVERNIGHT,
EXITING EAST BY SUNRISE. OVERALL, PROBABILITIES FOR RAINFALL AMOUNTS
OVER 0.2" IN THE RECENT HREF ARE NOT OVERLY HIGH (UNDER 40% CHANCE),
SO NOT EXPECTING OVERLY ROBUST RAINFALL AMOUNTS.
AS WE HEAD INTO THE DAYTIME HOURS ON FRIDAY, TEMPERATURES WILL BE
NOTICEABLY WARMER IN LIGHT OF THIS WARM AIR ADVECTION WITH HIGHS
REACHING INTO THE 80S FOR MANY SPOTS ON FRIDAY. GIVEN THE FAIRLY
PRONOUNCED MIXING SHOWN IN THE RAP/HRRR SOUNDINGS, WOULD NOT BE
SHOCKED IF TEMPERATURES OVERACHIEVE SLIGHTLY, POTENTIALLY GETTING
CLOSE TO THE 90 DEGREE MARK IN SOME SPOTS (10% CHANCE). HOWEVER,
THIS IS CONTINGENT ON EXACTLY HOW DEEP WE MIX, OF WHICH THE HRRR/RAP
ARE THE MOST AGGRESSIVE. OTHERWISE, A STATIONARY BOUNDARY WILL SET
UP ACROSS THE AREA WITH THIS WARMER AIRMASS IN PLACE WITH DEWPOINTS
PUSHING INTO THE LOW TO MID 50S. MUCAPE VALUES RESPOND ACCORDINGLY
IN THE RAP WITH VALUES OF AROUND 1000 J/KG ACROSS THE AREA. WHILE
THERE IS FAIRLY STEEP LOW-LEVEL LAPSE RATES RESULTING IN A
PRONOUNCED LOW-LEVEL DRY LAYER, WILL NEED TO WATCH IF ANY SURFACE
PARCELS CAN OVERCOME THIS LAYER AND CONVECTIVE ALONG AND SOUTH OF
THIS BOUNDARY DURING THE EVENING HOURS ON FRIDAY. IF A STRONGER OR
SEVERE STORM CAN DEVELOP IN THE WARM SECTOR SOUTH OF THIS STATIONARY
BOUNDARY (GENERALLY ALONG AND SOUTH OF I-90), FAIRLY ELONGATED
HODOGRAPHS ACROSS GUIDANCE WOULD SUGGEST A SUPERCELLULAR MODE COULD
MANIFEST WITH THE POTENTIAL FOR LARGE HAIL (UP TO GOLF BALL SIZED)
AND STRONG WIND GUSTS.
SATURDAY FEATURES CONTINUED ZONAL FLOW ALOFT WHICH WILL KEEP
TEMPERATURES WARMER WITH HIGHS REMAINING IN THE UPPER 70S TO 80S.
SOME WEAK SHORTWAVE PERTURBATIONS CAN BE NOTED IN ENSEMBLE MEMBERS
WHICH MAY RESULT IN SOME SHOWER POTENTIAL FOR THE AFTERNOON, MOST
NOTABLY THE RRFS WHICH TRIES TO BRING AN AXIS OF CONVECTION THROUGH
THE REGION DURING THE LATE MORNING HOURS. AN AXIS OF CONVECTION THEN
WILL LIFT INTO THE REGION DURING THE EVENING HOURS ON SATURDAY AND
INTO SUNDAY MORNING AS WELL. ONCE AGAIN HODOGRAPHS LOOK FAIRLY
ELONGATED IN THE GFS/NAM LATE SATURDAY AFTERNOON AND EVENING WHICH
WOULD SUGGEST THE POTENTIAL FOR SOME SUPERCELLULAR STRUCTURES
INITIALLY ACROSS NORTHEAST IA AND SOUTHWEST WI. WITH MUCAPE VALUES
OF AROUND 1000-1500 J/KG AND MID-LEVEL LAPSE RATES OF AROUND 7-7.5
C/KM, WOULD THINK THAT LARGE HAIL WOULD BE THE MAIN CONCERN WITH ANY
STRONG TO SEVERE STORMS. DEEP LAYER SHEAR EVENTUALLY WANES LATER
INTO THE EVENING, SO WOULD EXPECT STORM ORGANIZATION TO BECOME
MORE MESSY WITH TIME INTO THE OVERNIGHT HOURS.
SUNDAY - TUESDAY: ACTIVE PATTERN WITH ADDITIONAL SHOWER/STORM
CHANCES, POTENTIAL FOR SEVERE STORMS ON SUNDAY & MONDAY
THE PATTERN TURNS MUCH MORE ACTIVE BEGINNING ON SUNDAY AS AN UPPER-
LEVEL TROUGH SITUATED OVER THE ROCKIES ATTEMPTS TO PUSH EASTWARD,
LEAVING OUR AREA IN A SOUTHWESTERLY FLOW PATTERN. AS THIS OCCURS, A
VERY PROFOUND AXIS OF 850MB MOISTURE TRANSPORT PUSHES NORTH INTO THE
UPPER-MISSISSIPPI RIVER VALLEY ON SUNDAY AFTERNOON AND EVENING,
BRINGING DEWPOINTS INTO THE 60S FOR A SIZABLE PORTION OF THE AREA.
AS A RESULT, THE GRAND ENSEMBLE (GEFS/EC/CANADIAN ENSEMBLE) HAS HIGH
PROBABILITIES (50-80%) FOR SBCAPE OVER 1000 J/KG DURING THIS TIME
PERIOD. OVERALL, WITH THE SHARP WARMER AND MOISTURE ADVECTION REGIME
MOVING INTO THE REGION, SOUNDINGS IN THE DETERMINISTIC GFS AND GRAND
ENSEMBLE (GEFS/EC/CANADIAN ENSEMBLE) WOULD SUGGEST A MORE ELEVATED
STORM ENVIRONMENT ON SUNDAY WITH A WARM NOSE PRESENT. ADDITIONALLY,
SHEAR PROFILES ARE SOMEWHAT QUESTIONABLE WITH AN INTER-QUARTILE
RANGE FOR EFFECTIVE SHEAR IN THE GRAND ENSEMBLE (GEFS/EC/CANADIAN
ENSEMBLE) RANGING FROM 20 TO 30 KTS, LIKELY MORE OF A HAIL
ENVIRONMENT WITH UPDRAFTS THAT DO NOT SUSTAIN AS WELL.
CONFIDENCE FOR HOW THE SEVERE POTENTIAL WILL EVOLVE DIMINISHES
SOMEWHAT AS WE START THE UPCOMING WORK WEEK AS THE MAIN DRIVER WILL
BE TIED A SYNOPTIC COLD FRONT THAT WILL PROGRESS THROUGH THE REGION
EARLY NEXT WEEK. OVERALL, CONFIDENCE IS VERY HIGH THAT THERE WILL BE
AMPLE MOISTURE IN PLACE DURING THIS PERIOD AS THE GRAND ENSEMBLE
(GEFS/EC/CANADIAN ENSEMBLE) HAS VERY HIGH PROBABILITIES (80-100%)
FOR DEWPOINTS OVER 65 DEGREES DURING THE DAY ON MONDAY. THE KEY
QUESTIONS THAT REMAIN FOR HOW MONDAY (OR POSSIBLY TUESDAY?) WILL BE
RELATED TO THE EXACT TIMING OF THE AFOREMENTIONED FRONT AND HOW THE
FEATURES ALOFT DEVELOP AS THIS OCCURS. CURRENTLY, THE DETERMINISTIC
GFS AND EC DEPICT VASTLY DIFFERENT SCENARIOS. IN THE GFS SCENARIO,
THIS WOULD HAVE THE TROUGH OVER THE ROCKIES TRANSLATE INTO THE GREAT
PLAINS AND QUICKLY BECOME NEGATIVELY-TILTED AS IT PUSHES INTO THE
MIDWEST ON MONDAY EVENING. THIS WOULD COINCIDE WITH THE FRONTAL
PASSAGE WHICH WOULD ALLOW FOR FAVORABLE EXIT REGION DYNAMICS
RESULTING IN A STRONGLY FORCED ENVIRONMENT FOR ORGANIZED CONVECTION
WITH ALL HAZARDS POSSIBLE LATE MONDAY AFTERNOON AND EVENING. THE EC
HAS EFFECTIVELY A 24 HOUR SHIFT FROM THE GFS WHERE IT DOES NOT BRING
THE COLD FRONTAL PASSAGE INTO REGION UNTIL TUESDAY WHICH IN TURN
WOULD MAKE MONDAY'S FORECAST MUCH MORE CHALLENGING AS ANY CONVECTION
WOULD BE RELATED TO ANY SHORTWAVE PERTURBATIONS IN SOUTHWESTERLY
FLOW WITH WEAK FLOW ALOFT POTENTIALLY HINDERING ORGANIZED STORM
DEVELOPMENT AND THUS MAKING SEVERE POTENTIAL MORE UNCERTAIN.
WITH MULTIPLE ROUNDS OF STORMS SEEMING LIKELY, THERE IS SOME SIGNAL
FOR HEAVY RAINFALL AS WELL WITH THE NBM HAVING RELATIVELY HIGH
PROBABILITIES (40-80%) FOR RAINFALL AMOUNTS OVER 1" DURING THIS
PERIOD. THE NBM EVEN HAS SOME MEDIUM PROBABILITIES (20-60%) FOR 2"
OR MORE AS WELL. OVERALL THOUGH, GIVEN THE SYNOPTIC UNCERTAINTIES
PREVIOUSLY DISCUSSED, SEEING LOW CONFIDENCE IN ENSEMBLE DATASETS
SUCH AS THE 14.00Z EC EXTREME FORECAST INDEX FOR QPF WHICH HAS A
BROAD BRUSHED SHIFT OF TAILS OF 0 BUT NO TANGIBLE PROBABILITIES.
THIS WOULD SUGGEST THAT THERE ARE MEMBERS THAT CONTAIN ANOMALOUSLY
HIGH RAINFALL TOTALS, BUT CONFIDENCE IS LOW ON WHERE THIS WILL OCCUR
AND EXACT TIMING.
IN ANY CASE, MAIN TAKEAWAYS FROM THIS FORECAST IS CONFIDENCE IS VERY
HIGH (OVER 80%) THAT WE WILL SEE PERIODS OF STORMS OVER THE NEXT FEW
DAYS, SOME OF WHICH HAVING THE POTENTIAL TO BECOME SEVERE. HOWEVER,
MUCH OF THE SEVERE POTENTIAL ON SUNDAY AND PARTICULARLY ON MONDAY
WILL BE DICTATED ON HOW UPPER-LEVEL FEATURES RESOLVE WHICH
DETERMINISTIC AND ENSEMBLE GUIDANCE IS HAVING DISAGREEMENTS AT THIS
JUNCTURE. REGARDLESS, THIS WILL CERTAINLY BE A PERIOD OF TIME TO
MONITOR AS FORECAST DETAILS WILL LIKELY CHANGE REGARDING SUNDAY AND
MONDAY.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 645 PM CDT THU MAY 14 2026
VFR CONDITIONS PREVAIL THROUGH THE TAF PERIOD. A BAND OF SHOWERS
AND STORMS IS CURRENTLY MAKING ITS WAY INTO SOUTHEAST MINNESOTA
AND NORTHEAST IOWA, AROUND THE I-35 CORRIDOR. THIS BAND WILL
SHIFT EAST THROUGHOUT THE EVENING AND INTO THE EARLY MORNING
HOURS. CIGS DO LOWER WHILE IT IS RAINING, HOWEVER THEY REMAIN IN
THE 5KFT TO 7KFT RANGE. THESE CIGS STICK AROUND FOR A FEW HOURS
AFTER THE RAIN HAS ENDED AND BY MID-MORNING ON FRIDAY, ALL
LOCATIONS WILL SEE MOSTLY CLEAR SKIES FOR THE REST OF THE DAY.
SOUTHEAST WINDS SUSTAINED AT 15 TO 20 MPH SHIFT TO THE SOUTHWEST
FOR FRIDAY DURING THE MID TO LATE MORNING.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...CECAVA
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