184
FXUS63 KARX 260504
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1204 AM CDT SUN APR 26 2026
KEY MESSAGES
- A MOSTLY DRY SUNDAY IS EXPECTED BEFORE PRECIPITATION
CHANCES INCREASE SUNDAY NIGHT THROUGH MONDAY MORNING.
- SEVERE STORM POTENTIAL RETURNS FOR MONDAY AFTERNOON AND
EVENING PRIMARILY FOR THE SOUTHERN HALF OF THE FORECAST AREA
FROM NORTHEAST IOWA INTO SOUTHWEST WISCONSIN. IF SEVERE STORMS
DEVELOP, POTENTIAL FOR ALL HAZARDS (HAIL, DAMAGING WIND, AND
TORNADO) WOULD BE PRESENT.
- COLDER, SLIGHTLY BELOW NORMAL TEMPERATURES EXPECTED THROUGH
NEXT WEEK. A FREEZE MAY (35-55%) OCCUR SATURDAY MORNING,
PRIMARILY IN CLARK/TAYLOR COUNTIES.
DISCUSSION
ISSUED AT 1203 AM CDT SUN APR 26 2026
DRY SUNDAY, PRECIP CHANCES INCREASE SUNDAY NIGHT
DISTURBANCE IN SOUTHWESTERLY FLOW ALOFT CURRENTLY OVER THE MISSOURI
RIVER NORTH OF KANSAS CITY SHOULD LEAD TO CONTINUED LIGHT SHOWERS
JUST TO THE NORTHWEST OF THE CWA ACROSS MN OVERNIGHT INTO SUNDAY
MORNING. A FEW MAY (10%) SNEAK INTO PARTS OF SOUTHEAST MN BUT HAVE
LARGELY KEPT THE FORECAST DRY THROUGH THE DAY SUNDAY. TEMPERATURES
AND DEWPOINTS SHOULD BE HIGHER COMPARED TO SATURDAY AS MOIST
ADVECTION FROM THE GULF BECOMES PREDOMINANT EAST OF A LEE CYCLONE
DEVELOPING AROUND WHERE NM/OK/TX/KS MEET.
MOVING AHEAD TO SUNDAY NIGHT, PRECIP WILL BE ON THE INCREASE AT
850MB MOISTURE TRANSPORT RAMPS UP AND A LEAD DISTURBANCE EJECTS
NORTHEAST. THIS STAGE SHOULD SEE MAINLY SHOWERS BUT COULD (20%) HAVE
A FEW RUMBLES OF THUNDER AS MUCAPE LOOKS TO BE NON-ZERO.
SEVERE STORM POTENTIAL MONDAY
AS THE MAIN BODY OF THE UPPER TROUGH APPROACHES MONDAY AFTERNOON,
SEVERE THUNDERSTORMS WILL LIKELY DEVELOP AS CONTINUED SOUTHERLY
MOIST ADVECTION IN THE LOW LEVELS AND COOLING TEMPERATURES ALOFT
WITH SOUTHWESTERLIES AHEAD OF THE UPPER TROUGH LEAD TO LARGE AMOUNTS
OF INSTABILITY (90% CHANCE TO EXCEED 2000 J/KG OF SBCAPE PER 25.12Z
LREF) AND SHEAR (90% CHANCE TO EXCEED 50 KTS OF SFC-500MB SHEAR).
THE BIG QUESTION REMAINS JUST HOW FAR NORTH THIS HIGHLY FAVORABLE
REGIME WILL EXTEND - LUCKILY FOR OUR NECK OF THE WOODS, STARTING TO
SEE BETTER AGREEMENT ACROSS GEFS/ECENS/CMCE THAT THIS COMBINATION OF
HIGH INSTABILITY AND SHEAR WILL BE CENTERED TO OUR SOUTH IN SE IA/NE
MO/W IL, WHERE THOSE EYE POPPING PROBABILITIES MENTIONED ARE
LOCATED. HOWEVER, WHILE NOT AS STRONG, PROBABILITIES FOR SUFFICIENT
INSTABILITY AND SHEAR FOR SEVERE STORMS LOOK TO BE PRESENT IN NE IA
AND SW WI, WHERE JOINT PROBABILITIES FOR AT LEAST 1000 J/KG OF CAPE
AND 30 KNOTS OF DEEP SHEAR ARE 40-60%. PROGGED HODOGRAPHS IN THIS
AREA SUGGEST DISTRIBUTION OF MID AND UPPER LEVEL SHEAR WOULD SUPPORT
THE DEVELOPMENT OF SUPERCELLS WITH LOW LEVEL SHEAR ALSO SUPPORTING A
TORNADO RISK. MODEL SOUNDINGS ALSO REVEAL THE MAIN SOURCE OF
UNCERTAINTY FOR THE SEVERE STORM RISK - A STRUGGLE FOR THE SURFACE
TO DESTABILIZE GIVEN ROUNDS OF WARM ADVECTION SHOWERS AND STORMS
EXPECTED STARTING SUNDAY NIGHT. SHOULD THIS OCCUR, TORNADO RISK
WOULD BE LIMITED AND POTENTIAL FOR PERHAPS A QUARTER SIZE HAIL
REPORT WOULD BE THE PRIMARY CONCERN. FOR NOW, STILL LOOK TO HAVE A
RISK OF ALL HAZARDS, PARTICULARLY IF THE 26.00Z HRRR AND 25.21Z RAP
VERIFY, AS THESE HAVE JUST-IN-TIME SURFACE DESTABILIZATION DURING
THE MID-AFTERNOON.
AS FOR THE RISK FOR HEAVY RAIN AND FLOODING, 26.01Z NBM DOES HAVE AN
DECENT CHANCE (20-35%) FOR PARTS OF THE AREA TO SEE OVER 2" OF RAINFALL.
THE GOOD NEWS IS THAT THIS SHOULD FALL ACROSS MULTIPLE ROUNDS OF
PRECIP WITH STORM MOTIONS THROUGH THE EVENT FAVORED TO BE 30 MPH OR
GREATER, PARTICULARLY WHEN THE MOST INTENSE PEAK RAIN RATES WOULD
OCCUR WITH THUNDERSTORMS MONDAY AFTERNOON. THUS, AM NOT TOO
CONCERNED ABOUT FLASH FLOODING RISK. AS FOR RIVER FLOODING, HEFS
OUTPUT SUGGESTS AROUND A 10-20% CHANCE TO REACH MINOR STAGE IN OUR
RECENT PROBLEM BASINS (BLACK, TREMPEALEAU, WISCONSIN) SO WILL NEED
TO MONITOR WHICH AREAS SEE MULTIPLE ROUNDS OF MODERATE TO HEAVY RAIN
IN CASE THEY FALL IN THESE DRAINAGES.
TURNING COOLER MOST OF NEXT WEEK
UPPER TROUGHING BECOMES PREDOMINANT FROM HUDSON BAY SOUTH TO THE
GREAT LAKES. A TURN TOWARD TEMPERATURES MAINLY IN THE 50S, A BIT
COOLER THAN NORMAL FOR LATE APRIL AND EARLY MAY, IS FAVORED TUESDAY
THROUGH SATURDAY. OPERATIONAL GUIDANCE SUGGESTS A COLD FRONT WILL
MOVE THROUGH SOMETIME ON FRIDAY LEAVING SATURDAY MORNING AS
POTENTIALLY THE COOLEST OF NEXT WEEK - 26.01Z NBM SUGGESTS A GOOD
(35-55%) CHANCE FOR FREEZING TEMPERATURES TO OCCUR EAST OF THE
MISSISSIPPI.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1202 AM CDT SUN APR 26 2026
VFR CONDITIONS ARE EXPECTED THROUGHOUT MUCH OF THE TAF PERIOD WITH
MID-LEVEL CIGS EXPECTED THROUGHOUT MUCH OF THE DAY. WINDS WILL
REMAIN FROM THE SOUTHEAST, INCREASING DURING THE LATE AFTERNOON AND
INTO THE EVENING ON SUNDAY TO AROUND 10-15 KTS. SOME POTENTIAL THAT
SHOWERS BEGIN TO REACH KRST AFTER 02Z SO HAVE OPTED TO INCLUDE A
PROB30 GROUP FOR THIS POTENTIAL. MVFR CIGS AND VSBYS WILL BE
POSSIBLE WITH ANY SHOWERS, HOWEVER THE PREVAILING MVFR TO IFR CIGS
LIKELY DO NOT MOVE INTO THE REGION UNTIL AFTER 06Z MONDAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON
AVIATION...NAYLOR
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