374
FXUS63 KARX 210511
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1211 AM CDT TUE APR 21 2026
KEY MESSAGES
- WARMER TEMPERATURES TODAY THROUGH THURSDAY WITH HIGHS WELL
INTO THE 70S FOR MOST. TEMPERATURES WILL COOL BACK DOWN ON
FRIDAY AND INTO THE WEEKEND WITH HIGHS GENERALLY IN THE UPPER
50S TO 60S.
- SHOWERS AND STORMS LIKELY (70-90% CHANCE) FOR THURSDAY EVENING
AND OVERNIGHT. A FEW STRONG TO SEVERE STORMS CANNOT BE RULED
OUT.
DISCUSSION
ISSUED AT 1153 PM CDT MON APR 20 2026
TODAY - WEDNESDAY: DRIER AND MUCH WARMER
UPPER-LEVEL RIDGING WILL BE THE NAME OF THE GAME OVER THE NEXT
COUPLE OF DAYS ALLOWING FOR FAIRLY ROBUST WARM AIR ADVECTION TO MOVE
INTO THE REGION BRINGING MUCH WARMER TEMPERATURES. AS A RESULT, THE
NBM INTER-QUARTILE RANGE FOR HIGH TEMPERATURES RANGES FROM THE LOWER
70S TO LOWER 80S FROM TODAY THROUGH THURSDAY. A QUICK MOVING
SHORTWAVE TROUGH DOES PUSH THROUGH THE LOCAL AREA DURING THE MORNING
AND INTO THE EARLY AFTERNOON, HOWEVER LIKELY WOULD NOT SEE MUCH
PRECIPITATION POTENTIAL WITH THIS AS THE STRONGER FORCING WOULD
REMAIN SOUTHEAST OF THE AREA AS PEAK HEATING ARRIVES. AS A RESULT,
NOT SEEING MUCH PRECIPITATION CHANCES IN THE MOST RECENT HREF WITH
THE BULK THE HIGHER PROBABILITIES WELL TO OUR SOUTH IN THE IL/IN
REGION. OTHERWISE, SUBSIDENCE UNDER THIS AFOREMENTIONED RIDGE SHOULD
KEEP PRECIPITATION POTENTIAL AT A MINIMUM THROUGH WEDNESDAY.
THURSDAY: SHOWERS AND STORMS LIKELY
THE PATTERN CHANGES SLIGHTLY INTO THURSDAY AS A UPPER-LEVEL TROUGH
PIVOTS INTO THE NORTHERN PLAINS AND CLOSES OFF WITH A RAPIDLY
DEVELOPING SURFACE LOW ALONG WITH IT. AS THIS SURFACE LOW DEEPENS
AND PULLS NORTHWARD, A TRAILING COLD FRONT PUSHES EAST TOWARDS THE
LOCAL AREA DURING THE EVENING AND OVERNIGHT HOURS ON THURSDAY.
DEFINITELY WOULD HAVE THE FORCING ALONG THE FRONT FOR PRECIPITATION,
MAIN QUESTION WOULD REALLY BE ANY SEVERE POTENTIAL. CURRENTLY, THE
NAM/GFS GENERALLY AGREE ON KEEPING THE STRONGER UPPER-LEVEL JET
STREAK FURTHER WEST OF THE LOCAL AREA, AS A RESULT SHEAR ALOFT IS
GENERALLY FAIRLY ABSENT AS NOTED WITH ONLY 20-30 KTS OF 0-6KM SHEAR
IN THE NAM/GFS THAT WOULD BE PARALLEL TO THE FRONT, SUGGESTING A
LINEAR MODE. AS A RESULT, WITH RESPECTABLE PROBABILITIES (40-70%)
FOR MUCAPE OVER 1000 J/KG IN THE EC ENSEMBLE WEST OF THE MISSISSIPPI
RIVER, WOULD EXPECT STORMS TO FORM ALONG THE COLD FRONT, BUT
INDIVIDUAL UPDRAFTS WOULD LIKELY NOT MAINTAIN VERY WELL. SHEAR
PROFILES GENERALLY SEEM TO BE FAVORED IN THE LOW-LEVELS WHICH DRAWS
INTO ANOTHER QUESTION HOW MUCH THOSE COULD BE UTILIZED WITH A DECENT
EML PRESENT IN THE GFS/NAM RESULTING IN SOME CAPPING ACROSS THE
LOCAL AREA. IF NO CAP IS PRESENT, THEN WOULD THINK A WIND AND WEAK
SPIN-UP RISK WOULD BE A POSSIBILITY. HOWEVER, CONFIDENCE IN HOW ANY
SEVERE POTENTIAL WOULD MANIFEST IS FAIRLY LOW AT THIS POINT AS
MARGINAL MID-LEVEL LAPSE RATES (6.5-7.5 C/KM) AND RELATIVELY
UNIMPRESSIVE MUCAPE VALUES WOULD SUGGEST NOT AN OVERLY
IMPRESSIVE HAIL THREAT ASSUMING A CAPPED ATMOSPHERE.
REGARDLESS, AI/ML GUIDANCE DOES PAINT SOME HIGHER SEVERE
OUTLOOK PROBABILITIES FOR THE LOCAL AREA WEST OF THE MISSISSIPPI
RIVER SO CERTAINLY THURSDAY EVENING AND OVERNIGHT REMAINS A
PERIOD TO MONITOR. THAT BEING SAID, STILL A LOT OF QUESTIONS ON
HOW THE CONVECTIVE ENVIRONMENT WILL MANIFEST THOUGH.
FRIDAY & THIS WEEKEND: COOLING TREND
IN THE WAKE OF THE AFOREMENTIONED COLD FRONT, A COOLER AIRMASS
PUSHES INTO THE LOCAL AREA FOR FRIDAY AND INTO THE WEEKEND WITH THE
INTER-QUARTILE RANGE FOR HIGH TEMPERATURES IN THE NBM RANGING FROM
MIDDLE 50S TO MIDDLE 60S FOR THE WEEKEND. HOWEVER, GUIDANCE
GENERALLY AGREES ON KEEPING THE AFOREMENTIONED UPPER-LEVEL CLOSED
LOW IN SOUTH-CENTRAL CANADA FOR THE WEEKEND, AS THIS SLOW PULLS
NORTHWARD IT PUSHES ANOTHER SHORTWAVE TROUGH INTO THE REGION FOR
EARLY NEXT WEEK WHICH INCREASES OUR PRECIPITATION CHANCES, HOWEVER
VAST UNCERTAINTY STILL REMAINS ON THE TIMING AND EXACT LOCATION OF
THIS TROUGH AS IT PUSHES THROUGH THE REGION.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1210 AM CDT TUE APR 21 2026
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS AT THE TERMINALS. LLWS
WILL BE POSSIBLE AT BOTH KLSE AND KRST THROUGH THE OVERNIGHT HOURS
GIVEN THE GENERALLY WEAK LOW LEVEL WINDS. SOUTHERLY SURFACE WINDS
WILL CONTINUE TO DECREASE OVER THE COMING HOURS BEFORE SHIFTING TO
THE NORTH BEHIND A WEAK COLD FRONT THAT MOVES THROUGH THE AREA AFTER
12Z. WINDS ARE EXPECTED TO BECOME LIGHT AND VARIABLE AFTER 00Z
TOMORROW EVENING.
HYDROLOGY
ISSUED AT 1153 PM CDT MON APR 20 2026
FLOODING PERSISTS ALONG THE WISCONSIN AND YELLOW RIVER WITH MINOR
FLOODING ONGOING AT BOTH NECEDAH, WI AND MUSCODA, WI. CURRENT
EXPECTATION IS FOR THE RIVER STAGE AT BOTH LOCATIONS TO FALL OVER
THE NEXT FEW DAYS AS NO PRECIPITATION IS EXPECTED TO FALL IN THESE
BASINS THROUGH AT LEAST WEDNESDAY. THE RIVER STAGE AT MUSCODA, WI
WILL LIKELY FALL BELOW FLOOD STAGE LATE THIS MORNING OR THIS
AFTERNOON WITH NECEDAH, WI LIKELY NOT FALLING BELOW FLOOD STAGE
UNTIL WEDNESDAY AFTERNOON.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...BARENDSE
HYDROLOGY...NAYLOR
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