054
FXUS63 KARX 231048
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
548 AM CDT THU APR 23 2026
KEY MESSAGES
- SHOWERS AND STORMS (80-95%) THIS EVENING AND OVERNIGHT. A FEW
STRONG TO SEVERE STORMS CANNOT BE RULED OUT. WIDESPREAD
RAINFALL AMOUNTS OF 0.75" TO 1.25" ARE LIKELY WITH LOCALIZED
AMOUNTS OF UP TO AROUND 2" POSSIBLE.
- WARM TEMPERATURES TODAY WITH HIGHS IN THE 70S TO LOWER 80S
GIVE WAY TO MORE SEASONABLE TEMPERATURES FOR FRIDAY AND INTO
THE WEEKEND WITH HIGHS IN THE 60S FOR MOST.
- ADDITIONAL PRECIPITATION LIKELY (60-80%) FOR SUNDAY NIGHT AND
INTO MONDAY.
DISCUSSION
ISSUED AT 1159 PM CDT WED APR 22 2026
THIS EVENING & OVERNIGHT: SHOWERS AND STORMS LIKELY, A FEW STRONG TO
SEVERE POSSIBLE
A CLOSED UPPER-LEVEL LOW SITTING NEAR THE BORDER OF MONTANA AND
SASKATCHEWAN WILL CONTINUE TO MEANDER THROUGH SOUTHERN CANADA OVER
THE COMING DAYS, WHILE THIS OCCURS A SHORTWAVE TROUGH IS PIVOTS IN
THE NORTHERN PLAINS AROUND THIS FEATURE THIS AFTERNOON AND INTO THE
OVERNIGHT. WITH THIS SHORTWAVE PASSAGE TO OUR WEST, AN ATTENDING
SURFACE LOW OCCLUDES INTO MANITOBA AND PUSHES A SURFACE COLD FRONT
TOWARDS THE LOCAL AREA. A COUPLE DIFFERENT FORCING MECHANISMS SEEM
APPARENT FOR STORMS TODAY, THE FIRST OF WHICH BEING A RIBBON OF
THETA-E ADVECTION DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
AND A SECOND BEING THE AFOREMENTIONED COLD FRONTAL PASSAGE LATER
INTO THE EVENING AND OVERNIGHT. OVERALL, THE ENVIRONMENT IS FAIRLY
QUESTIONABLE AS DEEP-LAYER SHEAR IS RELATIVELY ABSENT WITH MESSY
MIDDLE AND UPPER-LEVEL HODOGRAPHS DUE TO THE UPPER-LEVEL JET STREAK
LAGGING BEHIND THE FRONTAL PASSAGE. AS A RESULT, SHEAR PROFILES ARE
RELATIVELY LOW-LEVEL DOMINATED WITH SOME LOW-LEVEL HODOGRAPH
CURVATURE PRESENT IN THE RAP/HRRR ACROSS THE REGION. CONSEQUENTLY,
WOULD EXPECT STORM MODE TO BE QUASI-LINEAR WITH PULSE-LIKE UPDRAFTS
ALONG THE VARIOUS FORCING MECHANISMS AS DEPICTED IN MUCH OF THE
CAMS. WOULD THINK AT LEAST SOME HAIL UP TO QUARTER SIZED CANNOT BE
RULED OUT WITH SOME STRONGER CORES AND MID-LEVEL LAPSE RATES OF
AROUND 7 C/KM, HOWEVER THESE WOULD LIKELY NOT BE LONG LIVED.
ADDITIONALLY, WITH THE AFOREMENTIONED LOW-LEVEL HODOGRAPH CURVATURE
AND 0-3KM SHEAR MAGNITUDES OF AROUND 30 KTS AT TIMES, CANNOT RULE
OUT A WEAK SPIN UP OR TWO. IN ANY CASE, SIGNIFICANT SEVERE POTENTIAL
SEEMS PREDOMINANTLY OFF THE TABLE AS ANY SEVERE THREATS THAT
MANIFEST WOULD BE HAIL TO AROUND QUARTER SIZED, MARGINALLY
SEVERE WIND GUSTS (UP TO AROUND 60 MPH) OR PERHAPS A WEAK
TORNADO.
COULD SEE SOME FAIRLY IMPRESSIVE RAINFALL WITH THESE STORMS THOUGH
AS THE RECENT HREF HAS SOME RESPECTABLE PROBABILITIES (20-60%) FOR
RAINFALL AMOUNTS OVER 1 INCH ACROSS THE LOCAL AREA WITH 90TH
PERCENTILE VALUES APPROACHING 2 INCHES IN SOME SPOTS. SO WIDESPREAD
AMOUNTS OF 0.75" TO 1" SEEM PLAUSIBLE WITH UPWARDS OF 2 INCHES WHERE
STORMS REPEAT OVER THE SAME LOCATIONS. WOULD NOT EXPECT ANY
WIDESPREAD FLOODING CONCERNS WITH THIS BUT COULD SEE SOME PONDING IN
LOW-LYING AREAS OR RISES ON RIVERS IN SMALLER BASINS THAT RECEIVE
MULTIPLE ROUNDS OF RAIN.
FRIDAY - SUNDAY: SEASONABLE TEMPERATURES
AS WE HEAD INTO FRIDAY AND THE WEEKEND, ZONAL FLOW BEHIND THE COLD
AIR ADVECTION REGIME WITH THE AFOREMENTIONED COLD FRONT WILL USHER
IN MORE SEASONABLE TEMPERATURES FOR FRIDAY AND INTO THE WEEKEND WITH
HIGHS LIKELY IN THE 60S FOR MUCH OF THE AREA. WITH SKIES CLEARING
DUE TO SOME WEAK HIGH PRESSURE OVERHEAD AND LIGHTER SURFACE WINDS ON
SATURDAY MORNING, CANNOT RULE OUT SOME POTENTIAL FOR PATCHY
FROST IN NORTH-CENTRAL WI WITH LOWS FALLING INTO THE MIDDLE TO
UPPER 30S.
SUNDAY NIGHT - EARLY NEXT WEEK: PRECIPITATION CHANCES RETURN
BY SUNDAY NIGHT AND INTO MONDAY, OUR NEXT FEATURE COMES IN THE FORM
OF A FAIRLY PRONOUNCED SHORTWAVE TROUGH PUSHING TOWARDS THE LOCAL
AREA IN SOUTHWESTERLY 500MB FLOW. AS THIS PUSHES TOWARDS THE REGION,
A FAIRLY PRONOUNCED SURFACE LOW EJECTS TOWARDS THE UPPER MISSISSIPPI
RIVER VALLEY ACROSS DETERMINISTIC GUIDANCE. OVERALL, CONFIDENCE
IS VERY HIGH FOR MEASURABLE RAINFALL DURING THIS PERIOD WITH
HIGH PROBABILITIES (80-95%) IN THE GRAND ENSEMBLE
(GEFS/EC/CANADIAN ENSEMBLE). THERE IS EVEN ALREADY SOME MEDIUM
PROBABILITIES (50-70%) FOR RAINFALL AMOUNTS OF OVER 0.5" DURING
THIS PERIOD AS WELL WITHIN THE GRAND ENSEMBLE (GEFS/EC/CANADIAN
ENSEMBLE). THE MAIN POINT OF UNCERTAINTY THAT REMAINS IS WHERE
THE SURFACE LOW TRACKS, A FURTHER NORTH TRAJECTORY MAY INTRODUCE
SOME INSTABILITY INTO THE REGION WHICH COULD BE MORE FAVORED
FOR CONVECTION, AS OPPOSED TO A SOUTHERLY TRACK WHICH WOULD
FAVOR MORE OF A STRATIFORM RAIN SETUP. OVERALL, THE GRAND
ENSEMBLE (GEFS/EC/CANADIAN ENSEMBLE) HAS SOME LOW PROBABILITIES
(10-30%) FOR 100 J/KG SBCAPE. SO IF A NORTHERN TRACK OCCURS,
COULD INTRODUCE SOME CONVECTION WITH A LOWER-END SEVERE RISK.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 547 AM CDT THU APR 23 2026
MVFR CIGS BETWEEN 1500 AND 2500FT WILL BE MOVING INTO SOUTHEAST
MINNESOTA AND NORTHEAST IOWA OVER THE NEXT FEW HOURS. WHILE
LOWERED CIGS BETWEEN 3000 AND 5000FT MOVE INTO AREAS ALONG AND
EAST OF THE MISSISSIPPI RIVER LATER THIS MORNING, THESE MVFR
CIGS WILL GRADUALLY MOVE INTO WESTERN WISCONSIN BY THE MID
AFTERNOON TO EARLY EVENING. PERIODIC SHOWERS AND STORMS EXPECTED
FOR TODAY AND INTO TONIGHT BEGINNING LATER THIS MORNING AND
EARLY AFTERNOON IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THESE
STORMS MOVE INTO WESTERN WISCONSIN BY THE MID TO LATE
AFTERNOON. MVFR TO IFR VISIBILITIES WILL BE POSSIBLE UNDER
HEAVIER RAIN. SOUTHERLY WINDS INCREASE THIS MORNING AND CONTINUE
THROUGH THE AFTERNOON WITH SUSTAINED WINDS OF 15 TO 25 MPH AND
GUSTS OF 25 TO 35 MPH. THESE SOUTHERLY WINDS SHIFT TO THE
NORTHWEST AS A COLD FRONT MOVES ACROSS THE REGION BETWEEN 06 AND
12Z.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...CECAVA
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