091
FXUS63 KARX 230547
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1247 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 /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1247 AM CDT THU APR 23 2026
VFR CONDITIONS FOR THE EARLY OVERNIGHT HOURS TRANSITION TO MVFR
CONDITIONS AS LOW LEVEL CIGS BETWEEN 1500 AND 2500FT MOVE INTO
NORTHEAST IOWA, SOUTHEAST MINNESOTA, AND PORTIONS OF WESTERN
WISCONSIN BY 12Z. THE MID MORNING THROUGH MUCH OF THE AFTERNOON
WILL PROVIDE A BREAK IN THE MVFR FLIGHT CONDITIONS ACROSS MUCH
OF WESTERN WISCONSIN UNTIL MORE MVFR CIGS MOVE IN FOR THE
EVENING AND EARLY OVERNIGHT. THERE IS ALSO A 15 TO 30% CHANCE
THAT IFR CIGS OCCUR DURING THIS TIME. SCATTERED SHOWERS AND
STORMS BEGIN TO FORM DURING THE EARLY TO MID AFTERNOON ACROSS
MUCH OF THE AREA. ANOTHER LINE OF STORMS FORMS IN SOUTHERN
MINNESOTA AND NORTHERN IOWA AND SHIFTS EASTWARD THROUGH THE
REGION DURING THE EVENING AND OVERNIGHT HOURS EXITING INTO
CENTRAL WISCONSIN BETWEEN 08 AND 10Z. SOUTHERLY WINDS INCREASE
LATER THIS MORNING AND THROUGH THE AFTERNOON WITH SUSTAINED
WINDS OF 15 TO 25 MPH AND GUSTS OF 25 TO 35 MPH. WINDS DIMINISH
HEADING INTO THE EVENING AND SHIFT TO THE NORTHWEST AS A COLD
FRONT BEGINS TO MOVE INTO SOUTHEAST MINNESOTA TOWARDS THE END OF
THE TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...NAYLOR
AVIATION...CECAVA
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