852
FXUS63 KARX 160015
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
715 PM 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 AN UNSTABLE AIRMASS IN
PLACE.
DISCUSSION
ISSUED AT 121 PM CDT WED APR 15 2026
SEVERE STORMS POSSIBLE AGAIN TODAY
ANOTHER DAY, ANOTHER CHANCE FOR SEVERE WEATHER TO IMPACT THE
DRIFTLESS REGION. EARLY THIS AFTERNOON AN ELEVATED SUPERCELL WAS
MOVING ACROSS WESTERN AND CENTRAL IOWA, RIDING A QUASI-STATIONARY
BOUNDARY NORTH AND EAST ALONG A GRADIENT OF MLCAPE. AS IT'S
GENERALLY ON THE COOL SIDE OF THE FRONT, THIS IS EXPECTED TO
CONTINUE TO POSE MORE OF A LARGE HAIL THREAT GIVEN STEEP MID LEVEL
LAPSE RATES AND SUFFICIENT CAPE IN THE HAIL GROWTH ZONE. FURTHER
EAST ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN, LINGERING CLOUD
COVER AND LIGHT SHOWERS HAVE ALLOWED THE AREA TO REMAIN SUFFICIENTLY
CAPPED AND OVERALL STABLE. AS THESE FINALLY START TO MOVE TO THE
EAST/NORTHEAST, WE MAY SEE A SMALL WINDOW OF DESTABILIZATION.
LATEST MESOANALYSIS TRENDS SHOW MEAGER DESTABILIZATION BEFORE
STORMS REALLY START TO FIRE LATER THIS AFTERNOON AS ASCENT FROM
AN EJECTING UPPER TROUGH ACROSS THE CENTRAL PLAINS INCREASES
ACROSS THE AREA AND INTERACTS WITH THE SURFACE BOUNDARY.
MODERATELY STRONG MID LEVEL LAPSE RATES SHOULD STILL PROMOTE
BETWEEN 500-1500 J/KG OF MLCAPE, EVEN WITH THE CONTINUED CLOUD
COVER. THE MAIN THREAT WITH ANY STORMS WOULD BE LARGE TO
POTENTIALLY VERY LARGE HAIL. THERE'S ALSO POTENTIAL FOR
SPLITTING SUPERCELLS GIVEN THE SIGNIFICANTLY ELONGATED STRAIGHT
HODOGRAPHS EXPECTED WITH THIS ACTIVITY. THE MAIN QUESTION WILL
BE HOW LONG STORMS CAN STAY SEMI-DISCRETE BEFORE EITHER LIFTING
NORTH OF THE BOUNDARY OR GROWING UPSCALE INTO A CLUSTER AS
EFFECTIVE BULK SHEAR BETWEEN 30-50 KTS WILL PROMOTE UPSCALE
GROWTH. THESE STORMS WILL ALSO BE EFFECTIVE RAINFALL PRODUCERS
AS PWATS CONTINUE TO INCREASE WITH 850 MB MOISTURE TRANSPORT
INTO THE REGION. ANOTHER 0.5-1.5 INCHES OF PRECIPITATION IS
EXPECTED WITH ACROSS PORTIONS OF SW AND CENTRAL WISCONSIN, AREAS
THAT HAVE ALREADY SEEN AMPLE RAINFALL AND FLOODING OVER THE
PAST COUPLE OF DAYS. HAVE ISSUED A FLOOD WATCH FOR THIS AREA
STARTING AT 4 PM AND CONTINUING THROUGH 7 AM TOMORROW MORNING AS
AREAL FLOODING MAY FORM WITH EXACERBATION TO ALREADY ONGOING
AREAL/RIVER FLOODING EXPECTED.
EVEN MORE SEVERE WEATHER FRIDAY
AFTER A BRIEF REPRIEVE FROM SEVERE STORMS THURSDAY, WE RE-ENTER
THE SEVERE WEATHER FRAY ON FRIDAY. A DEEP TROUGH OVER THE
ROCKIES IS EXPECTED TO START SLIDING EAST WITH ASCENT OUT AHEAD
OF IT INCREASING ACROSS THE SOUTHWESTERLY FLOW ALOFT. AT THE
SURFACE A FAMILY OF LOWS WILL STRETCH SOUTH FROM THE DAKOTAS
INTO THE CENTRAL PLAINS AND COLORADO ROCKIES WITH A COLD FRONT
CONNECTING THEM. A BROAD WARM SECTOR WILL DEVELOP ACROSS THE
MISSISSIPPI VALLEY AHEAD OF THIS COLD FRONT WHICH WILL ALLOW FOR
CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON AS ASCENT ALOFT
INCREASES LOCALLY AND INTERACTS WITH THE EASTWARD MOVING COLD
FRONT. A HIGHLY UNSTABLE AIR MASS SHOULD BE IN PLACE WITH
FORECAST INSTABILITY IN THE 2000-3000 J/KG RANGE. EFFECTIVE
SHEAR WILL BE AMPLE ENOUGH TO SUPPORT INITIAL SUPERCELLULAR
DEVELOPMENT BEFORE UPSCALE GROWTH OCCURS AND FORMS A MORE LINEAR
STRUCTURE. A 40-60 KT JET IN THE 850-700 MB LAYER WILL ALSO
HELP TO PROMOTE LOW/MID LEVEL HODOGRAPH CURVATURE AND STRENGTH,
INCREASING THE POTENTIAL FOR TORNADOES WITH THE SUPERCELLS. THE
MAIN QUESTION WILL BE HOW FAR NORTH CAN THE MOISTURE AND MORE
AMPLE INSTABILITY MAKE IT AHEAD OF STORM INITIATION WITH GREATER
UNCERTAINTY IN NORTHWARD EXTENT. FAR SOUTHERN PORTIONS OF NE
IOWA ARE CURRENTLY IN A DAY 3 ENHANCED RISK (LEVEL 3/5) WITH THE
REST OF THE LOCAL AREA IN A LEVEL 2 SLIGHT RISK.
MUCH COOLER THIS WEEKEND, SNOW CHANCES??
BEHIND THIS COLD FRONT, COLD AIR ADVECTION WILL BE RATHER STRONG
GIVEN THE TIGHT PRESSURE GRADIENT BEHIND THE DEPARTING SURFACE LOW
(MOVING NORTHEAST INTO ONTARIO). WITH THE STRONG COOLING EXPECTED IN
THE WAKE OF THE FRONT, ANY POST FRONTAL PRECIPITATION MAY
POTENTIALLY TURN TO A RAIN SNOW MIX FRIDAY NIGHT INTO SATURDAY AS
LOWS DROP INTO THE LOW TO MID 30S. NO ACCUMULATIONS ARE EXPECTED AS
SURFACE TEMPERATURES WILL REMAIN QUITE WARM AFTER THE STRETCH OF 70+
DEGREE TEMPERATURES WE'VE SEEN AS OF LATE. ANY SNOW SHOULD MELT ON
CONTACT PRETTY QUICKLY. PRECIPITATION WILL GRADUALLY COME TO AN
END THROUGH THE DAY WITH HIGH TEMPERATURES IN THE 40S, 20-30+
DEGREES COOLER FROM FRIDAY. BEYOND SATURDAY, IT LOOKS LIKE A DRY
FORECAST WITH TEMPERATURES WARMING BACK INTO THE 50S AND 60S BY
MID WEEK - A MUCH WELCOMED RELIEF AFTER AN ACTIVE WEEK OF
SEVERE WEATHER!
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 639 PM CDT WED APR 15 2026
MORE WIDESPREAD STORM CHANCES SEEN SHIFTING EAST THROUGH THE
SOUTHERN HALF OF THE FORECAST AREA AFFECTING SMALLER AIRPORTS
FROM NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN AT
16.00Z TAF ISSUANCE. WHILE THIS AREA IS EXPECTED TO CONTINUE
EXITING EAST, THE UPSTREAM LOW CENTER RAISES CONCERNS FOR
ADDITIONAL SCATTERED STORMS SOMEWHERE ACROSS THE FORECAST AREA,
POTENTIALLY FARTHER NORTH AFFECTING LOCAL TAF SITES (KLSE/KRST).
THEREFORE, HAVE INCLUDED PROB30 TS AT KLSE GIVEN CURRENT
CONFIDENCE IN LOCATION BUT WILL REQUIRE FURTHER INVESTIGATION AS
STORMS CONTINUE DEVELOPING THROUGH CENTRAL IOWA.
SIMILAR TO PREVIOUS OVERNIGHTS, EXPECT VFR-LIFR SHALLOW FOG TO
DEVELOP IN SPOTS AFFECTING SELECT SITES WHERE IT THICKENS. VFR
EXPECTED THROUGH
HYDROLOGY
ISSUED AT 121 PM CDT WED APR 15 2026
A FLOOD WATCH HAS BEEN ISSUED FOR SOUTHWESTERN WISCONSIN AND
PORTIONS OF WEST CENTRAL WISCONSIN AS YET ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS IS SET TO IMPACT THE REGION. WITH ADDITIONAL .5-
1.5 INCHES OF QPF EXPECTED FROM THIS ACTIVITY, AREAL AND RIVER
FLOODING IS EXPECTED TO WORSEN. THE MAIN BASINS OF CONCERN LOOK
TO BE THE KICKAPOO, THE YELLOW (WI), LEMONWEIR, AND WISCONSIN
RIVERS AS THESE AREAS HAVE ALREADY BEEN HIT HARD OVER THIS PAST
WEEK. MAJOR FLOODING IS EITHER ALREADY OCCURRING OR EXPECTED TO
OCCUR FOR THE YELLOW RIVER AT NECEDAH, CASTLE ROCK DAM ON THE
WISCONSIN RIVER, AND THE LEMONWEIR RIVER IN NEW LISBON.
FLOODING ALONG THE LEMONWEIR HAS ALREADY LEAD TO SOME ROAD
CLOSURES IN PORTIONS OF JUNEAU AND MONROE COUNTIES WITH
ADDITIONAL RAIN LIKELY TO EXACERBATE ONGOING PROBLEMS.
ADDITIONAL RAINFALL IS ALSO EXPECTED FRIDAY AS A LINE OF STORMS
MOVES THROUGH THE ENTIRE AREA, AGAIN IMPACTING PORTIONS OF SW
AND WC WISCONSIN. QPF TOTALS WITH THAT SYSTEM REMAIN A BIT MORE
UNCERTAIN - THOUGH ANOTHER 0.5 -1.5 INCHES CERTAINLY LOOKS
POSSIBLE.
ARX WATCHES/WARNINGS/ADVISORIES
WI...FLOOD WATCH THROUGH THURSDAY MORNING FOR WIZ042>044-053>055-
061.
MN...NONE.
IA...NONE.
DISCUSSION...BARENDSE
AVIATION...JAR
HYDROLOGY...BARENDSE
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