381
FXUS63 KARX 081903
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
203 PM CDT MON SEP 8 2025
KEY MESSAGES
- POTENTIAL (15-70%) SHOWERS AND PERHAPS (10-20%) A RUMBLE OF THUNDER
EARLY TUESDAY MORNING INTO THE EVENING HOURS, MAINLY NORTH OF
INTERSTATE 90. NEITHER SEVERE STORMS NOR FLASH FLOODING ARE
EXPECTED.
- WARMING THROUGH SATURDAY WITH ABOVE NORMAL TEMPERATURES
EXPECTED THIS WEEKEND.
DISCUSSION
ISSUED AT 202 PM CDT MON SEP 8 2025
POTENTIAL SHOWERS, STORMS TUESDAY:
18Z WV SATELLITE REVEALS QUASI-ZONAL FLOW ALOFT WITH A SERIES OF
DISTURBANCES SEEN UPSTREAM OVER MT/ND/SD. AT THE SURFACE, EXPANSIVE
HIGH PRESSURE IS PRESENT IN THE EASTERN CONUS WITH THIS FEATURE
HAVING SHIFTED EASTWARD FAR ENOUGH FOR SOUTHERLY WINDS TO RESUME
ACROSS OUR CWA. DESPITE THE COOL TEMPERATURES LAST NIGHT,
TEMPERATURES HAVE RISE INTO THE LOWER 70S IN SOME LOCATIONS EARLY
THIS AFTERNOON.
LATE TONIGHT, WAVE CURRENTLY OVER ND WILL ADVANCE DOWNSTREAM TO LAKE
SUPERIOR. WITH AVAILABLE MOISTURE ON A SLOW INCREASING TREND, THIS
MAY RESULT IN A SHOWER OR TWO NORTH OF US-10. MOVING AHEAD TO THE
AFTERNOON AND EVENING A MORE POTENT WAVE EJECTS EASTWARD OUT OF SD
FOLLOWING BY ANOTHER DISTURBANCE IN THE EVENING. THESE TWO WILL
LIKELY (50-70%) RESULT IN SHOWERS IN CLARK/TAYLOR COUNTIES, IN
OUR EXTREME WESTERN AREAS, AND POTENTIALLY (15-40%) FARTHER
SOUTH. HOWEVER, PROGGED SOUNDINGS FROM THE 08.12Z EXTENDED HRRR
RUN SUGGEST WARM TEMPERATURES ALOFT AT AROUND 750MB WILL LIMIT
OVERALL COVERAGE OF SHOWERS AND POTENTIAL FOR THUNDERSTORMS, AN
OUTCOME THAT COMPORTS WITH THE 08.12Z HREF, WHICH SUGGESTS A
VERY LOW (10% OR LESS) CHANCE FOR SUPPORTIVE CAPE WITH LOW CIN
OUTSIDE OF OUR FAR WEST. WHEN EXPANDING THE 08.12Z HREF JOINT
PROBABILITY TO INCLUDE DEEP SHEAR, THE CHANCE FOR SEVERE STORMS
IS NEXT TO ZERO ACROSS THE CWA, AN OUTCOME ALSO SUGGESTED BY
08.12Z HRRR NEURAL NETWORK OUTPUT AND 08.00Z ECENS AND GEFS ML-
BASED OUTLOOK. AS FOR HEAVY RAIN, BOTH 08.00Z GEFS/ECENS MEAN
PWATS REMAIN BELOW THE 90TH PERCENTILE OF MODEL CLIMATOLOGY, SO
AM NOT CONCERNED ABOUT THIS EITHER DESPITE THE POTENTIAL FOR A
FEW ROUNDS OF LIGHT SHOWERS IN OUR NORTH.
WARMING TREND THROUGH SATURDAY:
MEDIUM RANGE GUIDANCE ACROSS THE 08.12Z CYCLE CONTINUES TO POINT
TOWARD AN UPPER RIDGE BUILDING OVER THE PLAINS AND SHIFTING EASTWARD
WITH HEIGHTS ALOFT OVER OUR CWA FAVORED TO BE MAXIMIZED FRIDAY
AND/OR SATURDAY. 08.13Z NBM PROBABILISTIC OUTPUT SUGGESTS HIGHS WILL
VERY LIKELY (80%+) RETURN TO THE 80S BOTH AFTERNOONS ALONG AND
SOUTHWEST OF I-94 WITH A VERY SMALL (10%) CHANCE TO REACH 90 WITHIN
THE MISSISSIPPI RIVER VALLEY SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1155 AM CDT MON SEP 8 2025
CIGS: SKC/SCT CONDITIONS INTO TONIGHT WITH AN INCREASE IN A MID
LEVEL VFR DECK AS AN UPPER LEVEL SHORTWAVE TROUGH APPROACHES FROM
THE WEST. ONCE IN THE CIGS SHOULD HOLD THROUGH TUE NIGHT INTO THE
EARLY PART OF WED.
WX/VSBY: SCATTERED TO AREAS OF -SHRA WILL ACCOMPANY THE SHORTWAVE
BUT WILL HAVE TO BATTLE DRIER SUB CLOUD LAYER/SFC INVERSION OVER THE
LOCAL AREA INITIALLY. HIGHER RAIN THREAT MOVES IN LATER TUE NIGHT,
PERSISTING INTO WED. MOST CAMS AND OTHER SHORT TERM GUIDANCE SUGGEST
SCATTERED COVERAGE WITH QPF ALSO ON THE LOWER END (< 1/4"). THUNDER
THREAT ALSO LOW (<30%). GIVEN EXPECTED TIMING, WON'T ADD TO THE
FORECAST NOW.
WINDS: SOUTHERLY THROUGH THE PERIOD AND LOOKING TO STAY "UP"
TONIGHT (10+ KTS). AFTERNOON GUSTS IN THE MID 20 KTS TODAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON
AVIATION...RIECK
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