427
FXUS63 KARX 010627
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
127 AM CDT WED JUL 1 2026
KEY MESSAGES
- SEVERAL ROUNDS OF SEVERE STORMS FOR THE REMAINDER OF THE WEEK,
BRINGING THE RISK FOR MAINLY DAMAGING WINDS AND HEAVY RAIN.
THE MAIN TIME PERIODS FOR SEVERE WEATHER IN THE NEXT 24 HOURS
ARE EARLY THIS MORNING AND AGAIN LATER THIS AFTERNOON AND
EVENING.
- WARM AND MUGGY CONDITIONS PERSIST FOR THE REMAINDER OF THE
WEEK, BUT HEAT INDICES WILL BE SLIGHTLY COOLER THAN THE START
OF THE WEEK AND SHIFTING TO THE SOUTH.
- MORE SEASONABLE TEMPERATURES FOR THE HOLIDAY WEEKEND, THOUGH
SHOWER/STORM CHANCES EXIST (40-60%).
DISCUSSION
ISSUED AT 1200 AM CDT WED JUL 1 2026
EARLY THIS MORNING: FIRST ROUND OF STORMS
ANOTHER CONVECTIVE COMPLEX IS PROGGED TO DEVELOP ON THE NOSE OF
A 30-40 KT LLJ IN NORTHERN IOWA AFTER 06-09Z AND TRANSLATE NE
THROUGH THE MORNING HOURS. DAMAGING WINDS WILL BE THE MAIN
CONCERN WITH THESE STORMS QUICKLY BECOMING OUTFLOW DOMINANT AND
NOT LAST TOO LONG GIVEN THE COMPACT/COMPLEX HODOGRAPHS BUT AMPLE
MUCAPE VALUES OF 1500-2000 J/KG. THE RECENT CAMS ARE ALL
DEPICTING THIS FEATURE IN SOME WAY SHAPE AND FORM WITH THE
EXPLICIT GUSTS FROM THE HRRR HITTING 50-60 KTS IN SMALL POCKETS
FROM SOUTH-CENTRAL MN INTO WEST-CENTRAL WI. THE OTHER AREA OF
FOCUS WITH THESE MORNING STORMS IS IF/WHERE THEY LAY OUT AN
OUTFLOW BOUNDARY THAT COULD MODULATE THE THREATS AND AREA OF
CONCERN FOR STORMS LATER IN THE DAY.
THIS AFTERNOON/EVENING: ROUND 2 OF SEVERE STORMS
CONFIDENCE IS INCREASING THAT THE MORNING CONVECTION WILL LAY
OUT A DIFFERENTIAL HEATING BOUNDARY FROM SOUTH-CENTRAL MINNESOTA
INTO WEST-CENTRAL WISCONSIN, BUT THE DEVIL IS IN THE DETAILS AS
TO ITS STRENGTH AND POSITION, WHICH WILL FEED INTO THE BEHAVIOR
OF STORMS LATER IN THE AFTERNOON. THE 01.00Z HREF GUIDANCE IS
TARGETING THIS BOUNDARY FOR CONVECTIVE INITIATION AROUND 19-21Z,
THOUGH IN WHAT FORM REMAINS LESS CERTAIN. THE ARW/NMM CORES
HAVE THE LENGTH OF THE LINE INITIATING IN UNISON AND GROWING
UPSCALE, WHILE THE HRRR HOLDS THE CAP LONGER AND RIDES MORE
DISCRETE CONVECTION ALONG THE BOUNDARY--A SCENARIO THAT WOULD
INCREASE THE TORNADO AND HAIL RISK. THIS ASPECT OF THE FORECAST
REMAINS FLUID AND LIKELY WILL REMAIN AS SUCH UNTIL THE MIDDAY
HOURS WHEN WE CAN BETTER ASSESS THE ENVIRONMENT BEHIND THE
MORNING CONVECTION.
NO MATTER HOW STORMS FORM, THEY WILL BE FEEDING ON A FAVORABLE
THERMODYNAMIC AND KINEMATIC PROFILE WITH MLCAPE VALUES OF
2000-2500 J/KG AND SOMEWHAT ELONGATED HODOGRAPHS THAT WOULD
SUPPORT ORGANIZED CELL STRUCTURES. UPSCALE GROWTH INTO A BOWING
LINE SEGMENT IS ANTICIPATED, BUT TIMING OF THIS TRANSITION
REMAINS LESS CERTAIN. THE TORNADO THREAT LOOKS TO CONTINUE WITH
THIS UPSCALE TRANSITION IF BOWING LINE SEGMENTS CAN REORIENT
THEMSELVES WITH THE 0-3-KM SHEAR VECTOR, THOUGH WE'LL HAVE TO
SEE IF THERE IS LOCALIZED BACKING OF THE 0-1-KM WIND FIELD TO
FURTHER ENHANCE THIS TORNADO THREAT.
IN ADDITION TO DAMAGING WINDS--WHICH ARE THE MAIN THREAT WITH
THE AFTERNOON CONVECTION--CONCERNS ARE INCREASING ABOUT THE
POSSIBILITY FOR MULTIPLE ROUNDS OF HEAVY RAINFALL IN THE EVENING
AND OVERNIGHT. BOUNDARY-PARALLEL MID-LEVEL FLOW COUPLED WITH
CONTINUED THETA-E ADVECTION INTO THE INITIATING FRONT COULD
RESULT IN TRAINING CELLS BRINGING POCKETS OF 3-6 INCHES OF RAIN
IN SHORT ORDER. IN FACT, ALL OF THE 01.00Z HREF GUIDANCE MEMBERS
HAVE THIS CORRIDOR OF HIGHER QPF, BUT DIFFER IN 150 MILES ON
ITS LOCATION BETWEEN I-90 IN SOUTHERN MINNESOTA AND I-80 IN
CENTRAL IOWA. THANKFULLY, ANTECEDENT CONDITIONS ARE DRY AND WE
ARE ENTERING A PRIME TIME IN WHICH CROPLAND CAN BETTER ABSORB
SUCH RAINS, BUT OBVIOUSLY SUCH RAINS IN URBAN LOCALES AND
STEEPER TOPOGRAPHY COULD RESULT IN FLOODING.
THURSDAY - FRIDAY: SEVERE STORM RISK CONTINUES
THE HITS KEEP COMING FOR THURSDAY AND FRIDAY WITH THE LOWER
TROPOSPHERIC BAROCLINIC ZONE WOBBLING ACROSS THE REGION DURING
THIS TIME, BUT MORE OR LESS STAYING ACROSS THE FORECAST AREA.
THIS WILL SERVE AS THE FOCUS FOR CONVECTIVE INITIATION AS WE GO
LATER IN THE WEEK, BUT LIKE A GAME OF DOMINOES, ONE SMALL
DEVIATION IN STORMS EARLIER IN THE FORECAST CAN TOTALLY TURN THE
FORECAST ON ITS HEAD IN A HURRY. ONE THING TO WATCH FOR
THURSDAY IS HOW LONG STORMS LATER TONIGHT PERSIST, WITH A LONGER
RESIDENCE TIME TOWARDS MORNING POSSIBLY DELAYING OR SHIFTING
THE SEVERE WEATHER THREAT IN THE AFTERNOON. FRIDAY FACES EVEN
MORE UNCERTAINTY IN THE TIMING AND HAZARDS WITH THE CONVECTION,
BUT THE INGREDIENTS ARE ALL THERE, IT IS JUST A MATTER OF HOW
THEY ARE MIXED.
HOLIDAY WEEKEND- EARLY NEXT WEEK: SEASONABLE TEMPERATURES WITH
ADDITIONAL SHOWER/STORM POTENTIAL
AS THE UPPER LEVEL PATTERN BECOMES MORE ZONAL AS WE HEAD INTO
THE HOLIDAY WEEKEND, SEVERAL SHORTWAVE IMPULSES ARE DEPICTED TO
TRAVERSE THE MEAN FLOW BY THE DETERMINISTIC GLOBAL MODELS. THESE
WAVES SHOULD RESULT A REPRIEVE FROM THIS WEEK'S HEAT AS THEY
USHER IN COOLER AIR, SLIGHTLY COOLING TEMPERATURES TOWARDS THE
MID 80S, MORE SEASONABLE FOR THIS TIME OF YEAR. OUTSIDE OF THE
MORE SEASONABLE TEMPERATURES, THERE IS THE POTENTIAL FOR SHOWERS
AND STORMS THROUGHOUT THE WEEKEND (40-60%), THOUGH THESE MAY
SHIFT MORE TO THE SOUTH DEPENDING ON HOW THURSDAY AND FRIDAY'S
STORMS UNFOLD.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1238 AM CDT WED JUL 1 2026
THERE WILL BE SEVERAL ROUNDS OF STORMS THROUGH TONIGHT. USED THE
CAMS TO TRY ADD SOME TIMING TO THEM. THE FIRST ROUND WILL BE
LIKELY AROUND SUNRISE. THEN THERE WILL LIKELY BE SCATTERED
SUPERCELLS THIS AFTERNOON FOLLOWED BY WIDESPREAD CONVECTION FOR
LATE THIS AFTERNOON AND EVENING.
CLIMATE
ISSUED AT 127 AM CDT WED JUL 1 2026
ON JUNE 30, THE LOW TEMPERATURE AT LA CROSSE REGIONAL AIRPORT WAS
81°F. THIS SURPASSED THE PREVIOUS WARM LOW TEMPERATURE RECORD FOR
THE DATE OF 78°F IN 1931.
THIS LOW TEMPERATURE WAS THE WARMEST JUNE LOW TEMPERATURE. THE
PREVIOUS RECORD WAS 80°F ON JUNE 29, 1931 AND JUNE 22, 2025.
IT ALSO TIED THE WARMEST LOW TEMPERATURE EVER RECORDED IN LA CROSSE.
AN 81°F LOW TEMPERATURE HAS OCCURRED 4 TIMES (JULY 21, 1901; JULY
13, 1995; JULY 4, 2012; AND JUNE 30, 2026).
ARX WATCHES/WARNINGS/ADVISORIES
WI...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS
EVENING FOR WIZ041>044-053>055-061.
MN...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS
EVENING FOR MNZ096.
IA...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS
EVENING FOR IAZ008>011-018-019-029-030.
DISCUSSION...FALKINHAM/SKOW
AVIATION...BOYNE
CLIMATE...BOYNE
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