421
FXUS63 KARX 172325
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
625 PM CDT FRI JUL 17 2026
KEY MESSAGES
- ISOLATED TO SCATTERED STORMS THIS AFTERNOON AND TONIGHT. MAIN
HAZARDS WILL BE HEAVY DOWNPOURS AND BRIEF GUSTY WINDS.
- AIR QUALITY CONCERNS COULD RETURN SATURDAY NIGHT INTO SUNDAY
AS NORTHERLY WINDS BRING SMOKE BACK INTO THE AREA.
- SEVERE WEATHER POSSIBLE LATE SUNDAY NIGHT/MONDAY MORNING AND
MONDAY AFTERNOON AND EVENING
DISCUSSION
ISSUED AT 151 PM CDT FRI JUL 17 2026
TODAY - TONIGHT: LOW STORM CHANCES
EARLY THIS AFTERNOON, A COLD FRONT WAS PUSHING SOUTH THROUGH
NORTHERN MINNESOTA. WELL TO THE SOUTH ACROSS THE DRIFTLESS REGION, A
HOT AND UNSTABLE AIR MASS REMAINS IN PLACE WITH A CUMULUS FIELD
DEVELOPING ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. SOME WEAK
SHOWERS HAVE ALREADY STARTED TO BUBBLE UP ACROSS SOUTH CENTRAL
WISCONSIN WITH SLIGHTLY MORE AGITATED CUMULUS DEVELOPING ACROSS NE
IOWA AND WESTERN WISCONSIN. ISOLATED ACTIVITY WILL BE POSSIBLE
ACROSS THE AREA TODAY AS THE CAP ERODES WITH CONTINUED AFTERNOON
HEATING PUSHING SBCAPE VALUES WELL OVER 2000+ J/KG. SHEAR WILL
REMAIN A LIMITING FACTOR FOR THIS AFTERNOON ACTIVITY WITH LESS THAN
20 KTS OF EFFECTIVE SHEAR ACROSS MUCH OF THE AREA. SIMILAR TO
YESTERDAY, THE MAIN HAZARD WITH ANY SHOWER/STORM WILL BE HEAVY
RAINFALL AS STORMS WILL BE SLOW MOVING WITH LITTLE TO NO STEERING
FLOW AND PRECIPITABLE WATER VALUES STILL AROUND 1.4-1.7 INCHES. ANY
SHOWERS AND STORMS ALONG AND NORTH OF THE I-90 CORRIDOR COULD ALSO
SEE SOME GUSTY WINDS WITH ANY COLLAPSING CORES AS DCAPE VALUES MAX
OUT AROUND 1200 J/KG THIS AFTERNOON. THE AFOREMENTIONED COLD FRONT
WILL BEGIN TO APPROACH THE NORTH CENTRAL WISCONSIN LATE THIS EVENING
AND COULD PROVIDE ENOUGH LIFT TO SUPPORT ADDITIONAL THUNDERSTORM
DEVELOPMENT. THERE IS SLIGHTLY BETTER SHEAR FURTHER NORTH AROUND 25
KTS BUT CAMS CONTINUE TO SHOW LACKLUSTER CONFIDENCE IN STORMS
MAINTAINING THEIR FORM INTO OUR NORTHERNMOST COUNTIES. INSTABILITY
WILL START TO WANE INTO THE OVERNIGHT HOURS WITH MOST RAIN/SHOWER
ACTIVITY COMING TO AN END BEFORE MIDNIGHT.
SATURDAY - SUNDAY: AIR QUALITY CONCERNS RETURN
INCREASED SOUTHEASTERLY FLOW THIS MORNING FINALLY HELPED TO
KICK THE SMOKE OUT OF THE REGION, ALLOWING FOR AIR QUALITY TO
IMPROVE. UNFORTUNATELY THIS WILL BE RATHER SHORT-LIVED AS WINDS
TURN TO THE NORTH/NORTHWEST BEHIND THE COLD FRONT. WHILE SOME
LOW LEVEL SMOKE WILL RETURN IN PART DURING THE DAY TOMORROW, THE
MORE CONCERNING NEAR SURFACE SMOKE LOOKS TO POTENTIALLY MAKE
ITS RETURN SATURDAY NIGHT INTO SUNDAY MORNING. THAT BEING SAID,
THERE'S STILL A LOT OF UNCERTAINTY IN REGARDS TO THE FIRE
BEHAVIOR UP NORTH AND SUBSEQUENT SMOKE PRODUCTION SO THE
ISSUANCE OF FUTURE AIR QUALITY ALERTS WILL BE DEFERRED UNTIL
HIGHER CONFIDENCE IN IMPACTS IS MORE CERTAIN. OTHERWISE, DRY
CONDITIONS ARE EXPECTED THROUGH THE WEEKEND WITH POST FRONTAL
TEMPERATURES SLIGHTLY COOLER IN THE MID TO UPPER 80S.
MONDAY - MONDAY NIGHT: STRONG TO SEVERE STORMS POSSIBLE
THE NEXT CHANCE FOR SIGNIFICANT WEATHER LOOKS TO COME MONDAY AS AN
UPPER TROUGH DIVES SOUTHEAST OUT OF THE CANADIAN PLAINS AND INTO THE
UPPER MIDWEST. AN OCCLUDING SURFACE LOW IS EXPECTED TO SWING AROUND
THE HUDSON BAY/CENTRAL ONTARIO LATE THIS WEEKEND. AT THE SURFACE, A
WARM FRONT LOOKS TO MOVE EAST INTO WISCONSIN EARLY MONDAY WITH A
COLD FRONT LAGGING BEHIND ACROSS THE NORTHERN PLAINS/MINNESOTA. A
500 JET STREAK IS ALSO EXPECTED TO OVERSPREAD THE REGION PROVIDING
ADDITIONAL SUPPORT ALOFT BY MONDAY AFTERNOON/EVENING. THE
COMBINATION OF AMPLE INSTABILITY IN THE OCCLUDING WARM SECTOR,
EFFECTIVE BULK SHEAR ON THE MAGNITUDE OF 30-40 KTS, UPPER LEVEL
SUPPORT FROM THE JET STREAK AND TROUGH AXIS, AND EVENTUAL
SURFACE LIFT FROM THE COLD FRONT WILL ALLOW FOR THE POTENTIAL
FOR SEVERE WEATHER MONDAY AFTERNOON AND EVENING. THIS LOOKS TO
BE AN ALL HAZARDS TYPE OF EVENT WITH LARGE HAIL, DAMAGING WIND
GUSTS, A FEW TORNADOES, AND HEAVY RAINFALL ALL BEING OF CONCERN.
THERE'S STILL MANY DETAILS TO IRON OUT, ESPECIALLY WITH THE
TIMING OF THE BOUNDARIES BUT ENOUGH CONFIDENCE IN THE PARAMETER
SPACE HAS WARRANTED A 15% DAY 4 SEVERE WEATHER OUTLOOK FROM THE
STORM PREDICTION CENTER.
TUESDAY - END OF NEXT WEEK:
ONCE THE COLD FRONT PASSES AND THE STORMS CLEAR OUT LATE MONDAY
NIGHT, THERE SHOULD BE A NOTICEABLE DIFFERENCE ACROSS THE AREA WITH
AN OVERALL MUCH COOLER AIRMASS EXPECTED FOR MID NEXT WEEK.
TEMPERATURES TUESDAY AND WEDNESDAY WILL FINALLY DROP BELOW AVERAGE
INTO THE UPPER 70S TO LOW 80S WITH DRY CONDITIONS EXPECTED AS A WEAK
SURFACE HIGH PRESSURE MOVES IN BEHIND THE FRONT. WHILE A QUICK
MOVING DISTURBANCE MAY BRING SOME LOW RAIN CHANCES TO THE AREA BY
LATE WEEK, EXPECT GENERALLY DRY CONDITIONS AND NEAR NORMAL
TEMPERATURES TO ROUND OUT THE NEXT WORK WEEK.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 624 PM CDT FRI JUL 17 2026
PRIMARILY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. A
SURFACE FRONT CURRENTLY OVER NORTHERN WISCONSIN/CENTRAL
MINNESOTA WILL MOVE SOUTHEASTWARD THROUGH THE EVENING, BRINGING
SOME POTENTIAL FOR SHOWERS AND STORMS LATE TONIGHT/EARLY
SATURDAY MORNING. THIS POTENTIAL REMAINS LOW, ONLY 10-30% AND
FOCUSED NORTH OF I-90 SO HAVE NOT INCLUDED MENTIONS IN THE TAFS.
THERE IS SOME CONCERN FOR LOW LEVEL WIND SHEAR OVERNIGHT,
MAINLY FOR THOSE SITES WITHIN THE RIVER VALLEYS GIVEN AN
INCREASING LOW LEVEL WIND FIELD AROUND THE APPROACHING FRONT,
BUT A DISTINCT LACK OF DIRECTIONAL SHEAR IS EXPECTED TO RESULT
IN LOW LEVEL WIND SHEAR REMAINING BELOW THE 30KT THRESHOLD.
AFTER THE FRONT PASSES THROUGH, GENERALLY BETWEEN 05Z-12Z,
WINDS VEER TO THE NORTHWEST BECOMING 10-15KT. SMOKE AND
ASSOCIATED VISIBILITY IMPACTS LOOK TO RETURN NEAR THE END OF THE
TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...BARENDSE
AVIATION...FALKINHAM
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