871
FXUS63 KARX 151051
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
551 AM CDT WED APR 15 2026
KEY MESSAGES
- ANOTHER ROUND OF STRONG TO SEVERE STORMS POSSIBLE TODAY AND
TONIGHT, PRIMARILY AFFECTING NORTHEAST IOWA INTO SOUTHWEST
WISCONSIN WITH POTENTIALLY DAMAGING WIND AND LARGE HAIL.
ISOLATED TORNADO THREAT CANNOT BE RULED OUT.
- BREAK IN STORMS AND RAINFALL EXPECTED THURSDAY WITH A LINE OF
SEVERE STORMS POSSIBLE FRIDAY AFTERNOON AND NIGHT. WHILE IT
REMAINS TOO FAR OUT TO NAIL DOWN DETAILS, ALL HAZARDS LOOK
POSSIBLE WITH ENHANCED FORCING AND TAPPING INTO THE UNSTABLE
AIRMASS.
UPDATE
ISSUED AT 420 AM CDT WED APR 15 2026
A LOWER CONFIDENCE DENSE FOG ADVISORY HAS BEEN ISSUED FOR PARTS
OF CENTRAL WISCONSIN AS FOG HAS BEEN SLOWLY SPREADING SOUTHWARD
FROM NORTHERN WISCONSIN THROUGHOUT THE NIGHT ACROSS ALREADY
SATURATED GROUND. ONGOING ELEVATED CONVECTION AND AN EXPANSIVE
ANVIL SHIELD HAVE RESULTED IN VISIBILITIES BOUNCING AROUND QUITE
A BIT AT THE AUTOMATED SITES, BUT THERE LOOKS TO BE ENOUGH OF A
BREAK IN THE STORMS TO HAVE AT LEAST AREAS OF DENSE FOG THROUGH
THE EARLY MORNING.
DISCUSSION
ISSUED AT 1217 AM CDT WED APR 15 2026
ONGOING EARLY MORNING STORMS:
TUESDAY'S LOW LEVEL TROUGH ABANDONED 1" PWATS (GOES DERIVED) ACROSS
THE SOUTHEASTERN 3/4 OF THE FORECAST AREA, PERMITTING THE
OVERNIGHT STORM THREAT TO LIE JUST SOUTH OF THE FORECAST AREA,
DUE TO ENHANCED FORCING. OVERNIGHT STORM INITIATION OBSERVED ON
DMX/OAX RADAR IS EVIDENT OF THE LINGERING BOUNDARY AS DMX VWP
LIGHT NORTH WINDS OPPOSES TOP/ICT/EAX 925MB WINDS OF 35+ KTS.
FORTUNATELY, AS THE STORMS PROGRESS NORTH TOWARDS THE FORECAST
AREA, A DRIER, COLDER AIRMASS WILL LIMIT OVERALL STRENGTH.
UNFORTUNATELY, AREAS THAT RECEIVED HEAVY RAINFALL TUESDAY NIGHT
WILL LIKELY SEE ONGOING STORM POTENTIAL THROUGH THE EARLY
MORNING HOURS POTENTIALLY CAUSING FLOODING IN SPOTS WHERE
STRONGEST STORMS WERE REALIZED AND CAUSED HEAVIEST RAINFALL.
STRONG TO SEVERE STORM THREAT TODAY & TONIGHT:
STRONG TO SEVERE STORM THREAT INCREASES ACROSS THE SOUTHERN
HALF OF THE FORECAST AREA THIS AFTERNOON AND EVENING AS A
POTENTIALLY DEEPENING LOW PUSHES NORTHEAST THROUGH THE CENTRAL
PLAINS TOWARDS THE MISSISSIPPI RIVER VALLEY. SIMILAR TO BOTH
MONDAY AND TUESDAY, MERIDIONAL ADVECTION OF THE WARMER, MOISTER
AIRMASS THROUGH THE LATE MORNING HOURS INCREASES MEAGER INITIAL
STORM CHANCES BEFORE THE UNSTABLE AIRMASS TAKES SHAPE THROUGH
THE AFTERNOON. A FEEDBACK LOOP BETWEEN THE DEEPENING CYCLONE
AND THE FRONTAL BOUNDARY RAISES QUESTIONS OF DURATION AND
NORTHERN EXTENT OF STORMS. THEREFORE, OVERALL CONFIDENCE REMAINS
LOW DUE TO DIFFERING SOLUTIONS IN STRENGTH OF MESO CYCLOGENESIS
LIFTING THROUGH NORTHEAST IOWA INTO SOUTHWEST WISCONSIN THROUGH
THE AFTERNOON. ONGOING LATE MORNING OBSERVATIONS OF SURFACE
WINDS AND PROGRESSION OF SYNOPTIC FORCING WILL IRON OUT FURTHER
DETAILS HOWEVER.
THE MOST LOCALLY WIDESPREAD AND POTENTIALLY STRONG SOLUTION
(HRRR/RAP) KEEPS AN OPEN, ALBEIT TIGHTENING WAVE AS IT NEARS THE
FORECAST AREA, SUFFICIENTLY STRENGTHENING TO ABATE THE DRIER AIR
ATTEMPTING TO PUSH FROM NORTHWEST TO SOUTHEAST. THIS SOLUTION
PERPETUATES LOCAL STORM CHANCES ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA THROUGH THE AFTERNOON, EVENING, TONIGHT, AND EARLY
THURSDAY MORNING. FORTUNATELY, ASSOCIATED TEMPERATURE SOUNDING
PROFILES SHOW MOSTLY ELEVATED STORMS, LIMITING TORNADO RISK WITH
VERY LONG, STRAIGHT, HODOGRAPHS RAISING WIND THREAT CONCERNS
WITH SECONDARY HAZARD OF LARGE HAIL. ALTHOUGH, AN ISOLATED
TORNADO CANNOT BE RULED OUT GIVEN STRETCHING OF VORTICITY ALONG
THE NEAR SURFACE FRONTAL BOUNDARY. FURTHERMORE, THIS SOLUTION
SUGGESTS AN INITIALLY CONGEALED STORM MODE THROUGH THE DAY
BECOMING LINEAR AS THE DRY PUNCH PUSHES THROUGH TONIGHT AS THE
MESO LOW PROVIDES ADDITIONAL FORCING FOR STORMS THROUGH THURSDAY
MORNING. THIS IS AN OUTLIER SOLUTION AT THE CURRENT JUNCTURE
AND GIVEN THE PROCLIVITY FOR THE HRRR TO JOG NORTH/SOUTH IN ITS
SOLUTIONS DEPENDING ON INITIALIZATION TIME, BEARS AWARENESS
RATHER THAN RAW BELIEF.
HIGHER CONFIDENCE SITUATION IN STORMS GRAZING OUR SOUTHERN
PERIPHERY THIS AFTERNOON AND EVENTUALLY EXITING EAST THROUGH THE
EVENING HOURS AS THE DRIER AIR QUICKLY PUSHES THREATS SOUTH AND
EAST OF THE FORECAST AREA. REGARDLESS, ALL WILL DEPEND ON
PREVIOUS STORMS WHICH IN TURN DEPEND ON ONGOING STORMS EARLY
THIS MORNING SEEN STREWN ACROSS CENTRAL IOWA.
STORM CHANCES RETURN FRIDAY AFTERNOON & NIGHT:
A BREAK IN STORM CHANCES ON THURSDAY IS EXPECTED AS SHORTWAVE
RIDGING ALLOWS TODAY'S DRIER AIR TO THE NORTHWEST TO ADVECT
SOUTHEAST THROUGH THE LOCAL FORECAST AREA. SUBSEQUENT LONGWAVE
TROUGHING, SEEN IN GOES WV IMAGERY OVER THE PACIFIC NORTHWEST IS
EXPECTED TO PHASE THROUGH THE CENTRAL PLAINS THURSDAY, ENHANCING
LOW LEVEL MOISTURE TRANSPORT INTO THE NORTHERN PLAINS FRIDAY.
THEREFORE, AMPLE FORCING AND INSTABILITY PROGRESSES EAST CAUSING
LINEAR STORM MODE ACROSS THE FORECAST AREA FRIDAY.
UNFORTUNATELY, MACHINE LEARNING SEVERE WEATHER FORECAST MODELS
HAVE DRASTICALLY INCREASED LOCAL PROBABILITIES NEARING 50% FOR
THE SOUTHERN HALF OF THE FORECAST AREA. CURRENT CONFIDENCE IS
LIMITED DUE TO INFLUENCE OF DIURNAL HEATING TO POTENTIAL TIMING
OF FRONTAL PASSAGE LOCALLY. WILL REQUIRE CLOSE MONITORING IN
COMING FORECASTS.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 550 AM CDT WED APR 15 2026
A BAND OF IFR TO LIFR CEILINGS AND VISIBILITIES EAST OF AN OLZ
TO RCX LINE GRADUALLY CLEAR OUT THIS MORNING WITH MVFR CUMULUS
DECK DEVELOPING ROUGHLY ALONG AND SOUTHEAST OF A CCY TO MDZ LINE
LATER THIS MORNING THROUGH THE AFTERNOON. THUNDERSTORMS ARE
EXPECTED AT TIMES IN THIS SAME CORRIDOR DURING THE AFTERNOON,
SOME OF WHICH COULD PRODUCE LARGE HAIL. FOG MAY DEVELOP LATER
TONIGHT AREAWIDE, BUT THE COVERAGE AND INTENSITY OF THE FOG
REMAINS IN QUESTION. WINDS WILL BE LIGHT FROM THE NORTH TO
NORTHEAST AT 5-10 KTS FOR THE TAF PERIOD.
HYDROLOGY
ISSUED AT 1217 AM CDT WED APR 15 2026
FORTUNATELY, HEAVIEST RAINFALL TUESDAY REMAINED SOUTH OF
MONDAY'S HEAVIEST RAINFALL, EASING OVERALL FLOODING CONCERNS.
THEREFORE, NO CHANGES IN RIVER FLOOD HEADLINES COMPARED TO
PREVIOUS FORECASTS. TUESDAY'S RAINFALL UNFORTUNATELY SLIGHTLY
AFFECTED UPSTREAM OF MORE LOCALLY FLASHIER RIVERS IN NORTHEAST
IOWA (TURKEY RIVER) SOUTHEAST MINNESOTA, AND SOUTHWEST
WISCONSIN (KICKAPOO RIVER). WHILE INITIAL RESPONSES ON THESE
RIVERS HAVEN'T BEEN OVERLY CONCERNING OVERNIGHT, SUBSEQUENT
STORM CHANCES THIS MORNING THROUGH TONIGHT RAISE CONCERN SHOULD
THEY FREQUENT THESE SAME AREAS. SIMILARLY, ONGOING RIVER
FLOODING IN CENTRAL AND WEST-CENTRAL WISCONSIN IS AT RISK SHOULD
STORMS BE REALIZED FARTHER NORTH.
SHORT REPRIEVE IN LOCAL PRECIPITATION CHANCES THURSDAY CEASES
FOR FRIDAY AS THE ANOMALOUSLY MOIST AIRMASS RETURNS FOR STRONG
TO SEVERE STORMS PUSHING SOUTHEAST.
ARX WATCHES/WARNINGS/ADVISORIES
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ043-044-
055.
MN...NONE.
IA...NONE.
UPDATE...SKOW
DISCUSSION...JAR
AVIATION...SKOW
HYDROLOGY...JAR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page