028
FXUS63 KARX 171349
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
849 AM CDT WED JUN 17 2026
KEY MESSAGES
- SCATTERED SHOWERS AND STORMS THIS MORNING INTO THE EVENING.
SOME OF THESE STORMS COULD BE SEVERE, HOWEVER THIS DEPENDS ON
WELL WE RECOVER FROM THIS MORNING'S STORMS. LARGE HAIL AND
DAMAGING WINDS WILL CONTINUE TO BE THE MAIN THREATS WITH
TORNADO THREAT DEPENDENT ON AMOUNT OF DESTABILIZATION.
- LOW CONFIDENCE IN PRECIPITATION AND STORMS THURSDAY SLIGHTLY
INCREASES FOR FRIDAY AS TRANSIENT PRECIPITATION DARTS FROM
NORTHWEST TO SOUTHEAST.
DISCUSSION
ISSUED AT 848 AM CDT WED JUN 17 2026
SEVERE STORM CHANCES THROUGH TODAY:
DETAILS (I.E., STRENGTH, TIMING, COVERAGE) SURROUNDING ADDITIONAL
SUBSEQUENT STORM CHANCES THROUGH THE REST OF DAY DEPENDS ON
NORTHERN AND EASTERN EXTENT OF ENERGY CONSOLIDATION BETWEEN LOW
PRESSURE AREAS, EVIDENT IN DISAGREEMENT BETWEEN HIGH RESOLUTION
MODELS (17.00Z).
A MORE PHASED ORIENTATION BETWEEN LOW CENTERS THROUGH THE EARLY
MORNING BEFORE CONSOLIDATING INTO A STRONGER, ELONGATED LOW WOULD
RESULT IN A SOUTHERN SHUNT OF INCREASED MOISTURE, LIMITING /HIGHEST/
LOCAL OVERALL SEVERE THREAT (NAM/FV3 17.00Z).
HOWEVER, MORE HREF MEMBERS (HRRR/ARW 17.00Z) SOLUTIONS SUGGEST A
LESS-PHASED, MORE MERIDIONAL ORIENTATION AND INTERACTION BETWEEN
CONVERGING LOW LEVEL AREAS OF LOWER ISOHEIGHTS ALLOWING INCREASED
MOISTURE TO ADVECT FARTHER NORTH INTO THE FORECAST AREA, CAUSING
UNSTABLE AIR (1000-1500 J/KG SBCAPE) TO BIFURCATE THE SOUTHERN HALF
OF THE FORECAST AREA, INCREASING SEVERE STORM CHANCES THROUGH
THE AFTERNOON AND EVENING AS THE EVENTUAL LOW CENTER DRIVES
BREAKING LINEAR STORMS ACROSS THE FORECAST AREA.
ADDITIONAL STORMS THROUGH THE LATE MORNING INTO THE EARLY AFTERNOON
CANNOT BE RULED OUT AS WELL, SOME OF THESE COULD POTENTIALLY
BECOME SEVERE SHOULD THE PBL RECOVER /IF/ SKIES FIND A WAY TO
CLEAR IN THE WAKE OF DEPARTING STORMS. GIVEN THE MORNING
PRECIPTIATION, THIS IS A LOWER CONFIDENCE SCENARIO BUT AVAILABLE
INSTABILITY AND SHEAR VALUES SUGGEST A SCENARIO TO REMAIN
COGNIZANT OF THROUGH THE DAYTIME HOURS.
MAIN CONCERN FOR LARGE HAIL AND DAMAGING WINDS WITH LATER STORMS AS
WELL. TORNADO RISK WILL HINGE ON AMOUNT OF CLEARING TO DESTABILIZE
THE PBL, SUBSEQUENTLY OVERCOMING ANY LINGERING INVERSION CAUSING
SBCIN/MLCIN.
LOW CONFIDENCE FOR PRECIPITATION THURSDAY:
NORTHERN EXTENT OF INCREASED MOISTURE ADVECTION THROUGH EARLY
WEDNESDAY MORNING ALSO AFFECTS PRECIPITATION CHANCES THROUGH
THURSDAY AS HREF (17.00Z) ALLUDE TO LIMITED (100-300 J/KG) OF SBCAPE
ADVECTING SOUTHEAST ALONG THE SOUTHWEST-NORTHEAST ORIENTED FRONTAL
BOUNDARY WITH MEAGER LOW LEVEL (850MB) COLD AIR ADVECTION.
THEREFORE, HAVE INCREASED A LINE OF LOW POPS (<24%) AWAY FROM NBM
BASED ON HIGH RESOLUTION SOLUTIONS ALBEIT A BIT MORE SPATIALLY AND
TEMPORALLY AGREEABLE THAN INDIVIDUAL MEMBER SOLUTIONS.
FRIDAY PRECIPITATION CHANCES:
THE TAIL END OF THE EXTENDED RIBBON OF MID LEVEL POSITIVE VORTICITY
LIFTS SLIGHTLY NORTHEAST AS THE SYNOPTIC PATTERN BEGINS TO CHANGE,
CAUSING ADDITIONAL, ALBEIT TRANSIENT, PRECIPITATION AND STORM
CHANCES TO DART ACROSS THE FORECAST AREA FOR FRIDAY. LOW CONFIDENCE
IN STORMS AS MOST (75%) MEMBERS OF EPS (16.18Z) SUGGEST 500-1000
J/KG OF MUCAPE ACROSS THE AREA WHILE GEFS (17.00Z) LIMITS SBCAPE
BELOW 500 J/KG SOMEWHERE NEAR/OVER THE FORECAST AREA. ACCOMPANYING
SHEAR VALUES WILL BE SPATIALLY LIMITED IN THE LOWER LEVELS,
PRIMARILY AND STRONGEST UNIDIRECTIONALLY IN THE MID LEVELS FROM THE
STRONGER MID TO UPPER LEVEL WINDS.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 557 AM CDT WED JUN 17 2026
MVFR TO VFR CONDITIONS CURRENTLY PRESENT ACROSS THE REGION. AREAS OF
SHOWERS AND STORMS ARE MOVING SOUTHEAST THROUGH THE NORTHERN GREAT
PLAINS AND MIDWEST EARLY THIS MORNING. MOST OF THE HEAVIER ACTIVITY
HAS STAYED WELL TO OUR SOUTH ACROSS CENTRAL IOWA WITH MOST OF THE
ACTIVITY ACROSS THE DRIFTLESS REGION BEING LIGHT AND SCATTERED IN
NATURE. ANOTHER ROUND OF RAIN AND STORMS WILL DEVELOP THIS AFTERNOON
THOUGH THERE IS STILL SIGNIFICANT UNCERTAINTY WITH THIS BATCH AS IT
WILL HINGE QUITE A BIT ON THE MORNING ACTIVITY AND HOW QUICKLY IT
VACATES. THE CHANCE FOR POPS WILL REMAIN QUITE HIGH SO HAVE GONE
WITH PREVAILING SHOWERS BUT INSTABILITY IS LESS CERTAIN SO HAVE GONE
WITH PROB30S FOR THE THUNDERSTORM COVERAGE. THE AFTERNOON PREVAILING
GROUPS MAY NEED TO BE ADJUSTED TO TEMPOS AS COVERAGE MAY BE A BIT
MORE SCATTERED IN NATURE GIVEN LATEST HI-RESOLUTION CAMS. MVFR TO
IFR CIGS WILL BUILD IN OVER THE COMING HOURS AND CONTINUE THROUGH
THE END OF THE PERIOD AT THE TERMINALS WITH GENERALLY MVFR TO IFR
VISIBILITIES EXPECTED WITH THE SHOWERS AND STORMS. RAIN WILL START
TO COME TO AN END AFTER 00Z, MOVING OFF TO THE EAST. SOUTHERLY WINDS
WILL CONTINUE TO PICK UP OVER THE COMING HOURS AND VEER QUICKLY TO
THE WEST/NORTHWEST BEHIND A FRONTAL BOUNDARY THAT PASSES THROUGH
THIS AFTERNOON. GUSTS WILL GRADUALLY DIMINISH INTO THE EVENING HOURS
BUT SHOULD HANG ON THROUGH THE END OF THE PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...BARENDSE
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