238
FXUS63 KARX 150613
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
113 AM CDT MON JUN 15 2026
KEY MESSAGES
- REMAINING COOLER THAN NORMAL THROUGH MUCH OF THE WEEK WITH
DAYTIME HIGHS AND OVERNIGHT LOWS A FEW DEGREES BELOW NORMAL.
- INITIAL STORM CHANCES MONDAY NIGHT THROUGH TUESDAY WITH LOW
CONFIDENCE FOR STRONG STORMS OR HEAVY RAIN LOCALLY.
- MORE WIDESPREAD (60%-80%) HEAVY RAIN AND STORM CHANCES
WEDNESDAY. LOCAL STORM STRENGTH AND ACCOMPANYING SEVERE THREAT
DEPENDS ON EXACT STORM TRACK AS HIGHEST CONFIDENCE REMAINS
WELL SOUTH OF THE LOCAL FORECAST AREA. CURRENT LOW CONFIDENCE
(15%-30%) MAINLY FOR SOUTHERN AND WESTERN COUNTIES LOCALLY.
DISCUSSION
ISSUED AT 109 AM CDT MON JUN 15 2026
REMAINING COOL THROUGH MUCH OF THE WEEK:
RE-INTENSIFICATION OF THE SYNOPTIC MID LEVEL CYCLONE OVER
HUDSON BAY FROM UNIFICATION OF A RETROGRADING EXTRATROPICAL
CYCLONE OVER EASTERN CANADA ON GOES WV IMAGERY CAUSES A COOLER
THAN NORMAL FORECAST OVER THE UPPER MISSISSIPPI RIVER VALLEY
THROUGH MUCH OF THE WEEK. WHILE ECMWF EXTREME FORECAST INDEX
(-0.5) AND THE ACCOMPANYING SHIFT OF TAILS DOESN'T PAINT ANY
WIDESPREAD COLD OVER THE UPPER MISSISSIPPI RIVER VALLEY,
DETERMINISTIC AND ENSEMBLE LONG TERM MODEL SOLUTIONS SUGGEST
10TH TO 25TH (SPC RAOB CLIMATOLOGY @ MPX) 850MB TEMPERATURES FOR
MUCH OF THE PERIOD, OUTSIDE OF TEMPORARY TRANSIENT WARM AIR
ADVECTION DURING PASSING EXTRATROPICAL CYCLONES MONDAY NIGHT AND
WEDNESDAY. CURRENT FORECAST CONFIDENCE FOR DAYTIME HIGHS IN THE
MID 70S THROUGH THE WORK WEEK, POTENTIALLY INCREASING INTO THE
WEEKEND, WITH OVERNIGHT LOWS IN THE MID 50S.
PRECIPITATION & STORM CHANCES MONDAY NIGHT/TUES:
INITIAL PRECIPITATION CHANCES MONDAY NIGHT ACCOMPANY PASSAGE OF
INITIAL APPENDAGE OF MID LEVEL VORTICITY ADVECTION MONDAY NIGHT
THROUGH TUESDAY FROM NORTHWEST TO SOUTHEAST. WHILE CURRENT MODEL
CONFIDENCE (50-70%) HAS INCREASED OVER PREVIOUS RUNS FOR LOCATION OF
SURFACE LOW TRAVERSING OVER THE LOCAL FORECAST AREA, OVERNIGHT
DIURNAL TIMING LIMITS LOCAL INSTABILITY AND THEREFORE LOCAL STORM
THREAT.
GIVEN THE SYNOPTIC FORCING, HAVE INCREASED PRECIPITATION CHANCES
SLIGHTLY FROM THE NBM USING HIGH RESOLUTION MODELS. ALTHOUGH, LOCAL
CONFIDENCE IN HEAVY RAIN REMAINS LOW AS PHASING OF THE UPPER LEVEL
WAVE WILL CAUSE THE LIMITED LEFTOVER MOISTURE TO FALL SLIGHTLY
FARTHER SOUTH, SUBSEQUENTLY TAPPING INTO INCREASED MOISTURE SOUTH OF
THE FORECAST AREA. PRECIPITATION CHANCES EXIT EAST OF THE FORECAST
AREA BY TUESDAY EVENING.
WEDNESDAY STORM CHANCES, LIMITED SEVERE STORM CONFIDENCE:
AN APPENDAGE OF THE SYNOPTIC MID LEVEL CYCLONE OVER HUDSON BAY
CAUSES AN AREA OF MID LEVEL CONFLUENCE AND SUBSEQUENT
INTENSIFICATION IN A WIDESPREAD RIBBON OF POSITIVE MID LEVEL
VORTICITY ADVECTION FROM THE CANADIAN WEST COAST. SUBSEQUENT NEAR
ZONAL CYCLOGENESIS OF A ROCKY MOUNTAIN LOW ON WEDNESDAY IS EXPECTED
NEAR OR OVER THE FORECAST AREA, ABDICATING OVERALL CONFIDENCE FOR
INSTABILITY WITHIN THE WARM SECTOR WELL SOUTH OF THE FORECAST AREA.
DEPENDING ON DIURNAL TIMING OF CYCLOGENESIS IN RELATION TO THE
FORECAST AREA, A WINDOW OF STRONG TO SEVERE STORMS COULD BE POSSIBLE
WITHIN THE TIGHTENING WARM SECTOR BEING DRAWN NORTH BEFORE THE LOW
OCCLUDES. MACHINE LEARNING SEVERE HAZARD MODELS SHOW A SMALL HUMP OF
INCREASED, ALBEIT RELATIVELY LOW (15%-30%), PROBABILITIES GRAZING
SOUTHERN HALF OF THE FORECAST AREA PRIMARILY. ALTHOUGH, INTER-MODEL
DIFFERENCE IN NORTHERN AND EASTERN EXTENT OF THIS NODE OF SPATIALLY-
RELATIVE HIGHER PROBABILITIES VARIES, HIGHEST AND INCREASING MOST IN
RECENT FENGWU (14.00Z). THEREFORE, WILL BE IMPORTANT TO REMAIN
COGNIZANT OF POTENTIAL IN COMING FORECASTS AS PATTERN BECOMES LESS
AMBIGUOUS.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1219 AM CDT MON JUN 15 2026
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS AT THE TERMINALS.
WINDS OVERNIGHT WILL BE LIGHT AT LESS THAN 10 KTS OUT OF A GENERAL
WESTERLY DIRECTION. WINDS ARE EXPECTED TO PICK UP SOME BY MID
TO LATE MORNING BUT SUSTAINED SPEEDS SHOULD STAY LESS THAN 15
KTS WITH CONFIDENCE IN GUSTS TOO LOW TO INCLUDE WITH THIS
PACKAGE.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...BARENDSE
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