314
FXUS63 KARX 291840
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
140 PM CDT MON JUN 29 2026
KEY MESSAGES
- DANGEROUS HEAT PERSISTS THROUGH AT LEAST WEDNESDAY, BUT
OPPRESSIVE TEMPERATURES/HUMIDITY LINGER THROUGH LATE WEEK. AN
EXCESSIVE HEAT WARNING REMAINS IN EFFECT FOR MOST OF THE
REGION WHILE A HEAT ADVISORY REMAINS IN EFFECT FOR TAYLOR
COUNTY IN WISCONSIN.
- PERIODIC STORMS ARE POSSIBLE THIS WEEK (20-40%), BUT
TIMING/LOCATION REMAINS UNCERTAIN. STORMS THAT DEVELOP COULD
BECOME STRONG TO SEVERE.
DISCUSSION
ISSUED AT 139 PM CDT MON JUN 29 2026
THIS AFTERNOON - TUESDAY: DANGEROUS HEAT AND STORM POTENTIAL
DANGEROUS HEAT IS EXPECTED AREAWIDE OVER THE NEXT 24-36 HOURS.
A VERY MOIST AIRMASS REMAINS IN PLACE THIS AFTERNOON WITH
DEWPOINTS IN THE MID TO UPPER 70S ACROSS MUCH OF THE AREA WHICH
IS EXPECTED TO REMAIN IN PLACE THROUGHOUT THE DAY TUESDAY. OVERALL
EXPECTATIONS ARE FOR TEMPERATURES TO CLIMB INTO THE LOW TO MID
90S GIVEN 850HPA TEMPERATURES OF 20-22C, RESULTING IN HEAT
INDICES AROUND 75F TONIGHT AND IN THE UPPER 90S TO MID 100S
DURING THE DAY TUESDAY.
THERE IS SOME CONCERN FOR STRONG/SEVERE STORMS TONIGHT, MAINLY
NORTHWEST OF A LINE FROM CHARLES CITY, IA TO WAUSAU, WI
(10-30%) THOUGH EXPECTATIONS ARE FOR MOST OF (IF NOT ALL OF)
THESE STORMS TO MISS OUR AREA DUE TO STRONG CAPPING IN PLACE
GIVEN 700HPA TEMPERATURES OF 12+C. HOWEVER, THERE ARE SOME CAM
SOLUTIONS SUGGESTING A LINE OF CONVECTION MOVES WEST-EAST
THROUGH THE REGION AFTER MIDNIGHT ON THE NOSE OF AN
STRENGTHENING NOCTURNAL LOW LEVEL JET AND 850HPA MOISTURE
TRANSPORT. CONFIDENCE IS LOW IN WHICH SCENARIO WILL WIN OUT, BUT
CURRENTLY LEANING TOWARDS MOST STORM ACTIVITY REMAINING OUT OF
OUR AREA AS THIS HAS THE GREATEST CONSENSUS AMONGST MODEL
GUIDANCE. REGARDLESS, IF STORMS DO AFFECT THE AREA TONIGHT, THE
PRIMARY HAZARD WILL BE DAMAGING WINDS.
ADDITIONAL CONCERN FOR STRONG/SEVERE STORMS COMES TUESDAY
AFTERNOON, MAINLY NORTH OF I-94 (20-30%). THE EXPECTED HEAT AND
HUMIDITY TUESDAY WILL CONTINUE TO SUPPORT THE VOLATILE
ATMOSPHERE IN PLACE WITH MUCAPE VALUES EXCEEDING 3000 J/KG IN
MOST MODEL SOLUTIONS ALONG WITH EFFECTIVE BULK SHEAR OF
30-35KTS. WITHIN THIS ENVIRONMENT, A SURFACE BOUNDARY ASSOCIATED
WITH THE SURFACE LOW OVER SOUTHERN CANADA LAYS OUT AND STALLS
FROM NORTHEAST TO SOUTHWEST FROM NORTHERN WISCONSIN TO NORTHERN
IOWA WITH THE FAVORABLE ATMOSPHERE IN PLACE AHEAD OF IT. ABOVE
THE SURFACE FEATURES, A RIBBON OF 700HPA POSITIVE VORTICITY AND
DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A NEARBY
JET CORE COULD SUPPORT STORM DEVELOPMENT, ALTHOUGH THE OVERALL
QG FORCING IS FAIRLY WEAK AND NEBULOUS.
THE BIGGEST QUESTION IS IF CONVECTIVE INITIATION CAN EVEN OCCUR
IN THIS ENVIRONMENT. 700HPA TEMPERATURES REMAINING AROUND 12C
MAY MAKE IT CHALLENGING FOR CONVECTION TO DEVELOP, ESPECIALLY
GIVEN THE NEBULOUS FORCING. MANY CAM SOLUTIONS DO SUGGEST THE
BULK OF DEVELOPMENT REMAINS ACROSS NORTHERN WISCONSIN. THERE IS
ALSO THE ISSUE OF HOW THE STORMS OVERNIGHT EVOLVE AND THEIR
INFLUENCE ON WHERE MESOSCALE BOUNDARIES SET-UP WHICH WOULD ALSO
INFLUENCE CONVECTIVE INITIATION. ALL OF THIS SAID, IF
CONVECTION IS ABLE TO DEVELOP, EXPECTATIONS ARE FOR DAMAGING
WINDS TO BE THE PRIMARY THREAT. THE AFOREMENTIONED WARM
TEMPERATURES ALOFT MAKE LARGE HAIL UNFAVORABLE AS WBZ HEIGHTS
ARE FORECAST TO BE ABOVE 10KFT, BUT CERTAINLY CAN'T RULE OUT
SOME SMALLER STONES UP TO 1 INCH GIVEN THE AMPLE INSTABILITY.
WEDNESDAY - FRIDAY: HOT/HUMID CONDITIONS CONTINUE AND STORM CHANCES
WEDNESDAY MORNING BRINGS ADDITIONAL STRONG/SEVERE STORM
POTENTIAL (50-70%) ALONG THE AFOREMENTIONED STATIONARY BOUNDARY
AS IT LAYS OUT WEST-EAST ACROSS THE REGION. A SUBTLE SHORTWAVE
LIFTS NORTHWARD ATOP THIS FEATURE WITH AMPLE MOISTURE REMAINING
IN PLACE. MUCAPE OF 2500+ J/KG WILL EXIST ALONG THE BOUNDARY
WITH 30-35KTS OF EFFECTIVE BULK SHEAR. DAMAGING WINDS AND HAIL
UP TO 1 INCH AGAIN SEEM POSSIBLE WITH STORMS THAT DEVELOP DURING
THIS PERIOD.
SLIGHTLY COOLER TEMPERATURES ARE DEPICTED IN ENSEMBLE SUITES
WEDNESDAY THROUGH FRIDAY AS THE UPPER RIDGE BEGINS TO SHIFT EVER
SLOWLY EASTWARD ALTHOUGH TEMPERATURES STILL REMAIN IN THE UPPER
80S TO LOW 90S. THE EVOLUTION OF ANY POSSIBLE CONVECTION MAY
ALSO ACT TO FURTHER TEMPER AFTERNOON HIGHS. HOWEVER, DEWPOINTS
REMAIN IN THE LOW TO MID 70S AND WITH LITTLE TEMPERATURE RELIEF
OVERNIGHT, CONFIDENCE IS HIGH IN HEAT IMPACTS LINGERING THROUGH
AT LEAST WEDNESDAY.
HOLIDAY WEEKEND - EARLY NEXT WEEK: SEASONABLE, ADDITIONAL SHOWERS
AND STORMS
AS WE HEAD INTO THE HOLIDAY WEEKEND, THE UPPER LEVEL PATTERN
BECOMES MORE ZONAL AS COMPARED TO TODAY/TUESDAY ALLOWING VARIOUS
SHORTWAVES TO TRAVERSE THE MEAN 500HPA FLOW. THESE SHORTWAVES
WILL TEND TO KNOCK DOWN TEMPERATURES ALOFT AS WELL AS AT THE
SURFACE WITH AN OVERALL COOLING TREND NOTED IN THE 29.00Z LREF.
SURFACE HIGHS FALL INTO THE LOW TO MID 80S, NEAR NORMAL FOR THIS
TIME OF YEAR, ALTHOUGH THERE IS A FAIR DEGREE OF UNCERTAINTY IN
EXACT TEMPERATURE VALUES AS THE 25TH-75TH PERCENTILE SPREAD IS
AROUND 5-10 DEGREES WITH SOME OUTLIERS STILL SUGGESTING THE 90S
COULD BE IN PLAY. ADDITIONAL SHOWER AND STORM CHANCES ALSO EXIST
OVER THE HOLIDAY WEEKEND WITH THE 29.13Z NBM CURRENTLY
SUGGESTING 30-60% PROBABILITIES FOR MEASURABLE RAINFALL, BUT
THERE IS STILL PLENTY OF VARIATION TO WORK OUT OVER THE COMING
DAYS.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1231 PM CDT MON JUN 29 2026
GUSTY SOUTHERLY WINDS WILL PERSIST THROUGH THE TAF PERIOD WITH
VFR CONDITIONS EXPECTED. AS A LOW PRESSURE SYSTEM SLIDES ACROSS
THE UPPER MIDWEST, THERE IS A LOW CHANCE (20%) FOR PASSING
SHOWERS AFTER MIDNIGHT TONIGHT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...EXTREME HEAT WARNING UNTIL 9 PM CDT TUESDAY FOR WIZ029-032>034-
041>044-053>055-061.
HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR WIZ017.
MN...EXTREME HEAT WARNING UNTIL 9 PM CDT TUESDAY FOR MNZ079-086>088-
094>096.
IA...EXTREME HEAT WARNING UNTIL 9 PM CDT TUESDAY FOR IAZ008>011-018-
019-029-030.
DISCUSSION...FALKINHAM
AVIATION...JAW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page