095
FXUS63 KARX 051829
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
129 PM CDT WED AUG 5 2026
KEY MESSAGES
- CLOUDS GRADUALLY DEPART THIS AFTERNOON WITH OVERNIGHT FOG AND
CLEARER SKIES FOR THURSDAY.
- TEMPERATURES WARM BACK UP TO AROUND AVERAGE FOR THE END OF THE
WEEK INTO NEXT WEEK.
- SEVERAL ROUNDS OF SHOWERS AND STORMS POSSIBLE NEARLY DAILY
STARTING FRIDAY AFTERNOON AND GOING THROUGH EARLY NEXT WEEK.
MAIN RISK FROM THESE STORMS MAY COME IN THE FORM OF HEAVY RAIN
AS STORMS MAY TRACK OVER THE SAME AREAS FOR MULTIPLE DAYS.
DISCUSSION
ISSUED AT 129 PM CDT WED AUG 5 2026
THIS AFTERNOON - THURSDAY: DRY AND SEASONAL
ISOLATED SHOWERS GRADUALLY DEPART NORTHEAST IOWA AND
SOUTHWESTERN WISCONSIN THIS AFTERNOON WITH MOST AREAS STAYING
DRY. CLOUDS LIKEWISE DEPART WITH FOG BECOMING INCREASINGLY
LIKELY FOR AREAS THAT RECEIVED RAIN LAST NIGHT AND THIS MORNING,
MAINLY ALONG AND SOUTHEAST OF A CHARLES CITY, IA TO WISCONSIN
RAPIDS, WI LINE. MUCH OF THE MOS GUIDANCE IS HINTED AT
VISIBILITIES OF 1/2 OF A MILE OR LESS BY TOMORROW MORNING AND
THE CONCEPTUAL MODEL FITS A POTENTIAL DENSE FOG SCENARIO GIVEN
THE NEW PRECIPITATION AND ANTECEDENT CLOUDY SKIES DURING THE
DAY, WHICH WILL ALLOW FOR SATURATION TO HAPPEN QUICKER THIS
EVENING ONCE THE CLOUDS CLEAR.
WITH THE LOWER TROPOSPHERIC THETA-E RIDGE HAVING SLID FURTHER
SOUTHEAST INTO IOWA AND ILLINOIS, MID-LEVEL RIDGING WILL TAKE
CONTROL FOR TONIGHT INTO THURSDAY. ONCE THE FOG BURNS OFF DURING
THE MORNING, LOOK FOR SUNNY SKIES AND WARMER TEMPERATURES
RISING BACK TO NEAR AVERAGE.
FRIDAY - EARLY NEXT WEEK: PERIODIC STORMS W/ A HEAVY RAIN
THREAT?
CYCLONIC FLOW LINGERS ACROSS SOUTH-CENTRAL CANADA FROM FRIDAY
INTO EARLY NEXT WEEK, WITH THE LOCAL AREA TRANSITIONING TO
ZONAL/QUASI-NORTHWEST FLOW ON THE SOUTHERN PERIPHERY OF THIS
CUTOFF LOW. MULTIPLE PERTURBATIONS EJECT FROM THIS LOW ACROSS
THE REGION, STARTING LATE FRIDAY AND CONTINUING INTO EARLY NEXT
WEEK. THE ZONAL LOWER TROPOSPHERIC BAROCLINIC ZONE LOOKS TO
REMAIN SITUATED SOMEWHERE BETWEEN IOWA AND SOUTHERN MINNESOTA
DURING THIS PERIOD, OSCILLATING PERIODICALLY WITH EACH PASSING
WAVE OF STORMS. THE EXACT POSITION OF THIS BOUNDARY WILL DICTATE
THE TRACK OF OUR STORMS AND HOW THE NEXT DAY'S STORMS WILL
EVOLVE.
IF THE BOUNDARY HAPPENS TO STALL OVER THE SAME AREAS FOR
MULTIPLE DAYS, WE COULD SEE A HEAVY RAINFALL/FLOODING THREAT
MATERIALIZE. THANKFULLY, THERE IS NOT AN ANOMALOUSLY MOIST
AIRMASS IN PLACE, SO ANY HEAVY RAIN RISK WILL BE MORE DRIVEN BY
MESOSCALE PROCESSES AND RELY ON STORMS TRAINING OVER THE SAME
LOCALES. EVEN THE GLOBAL ENSEMBLES ARE NOT TERRIBLY EXCITED FOR
RAINFALL WITH LITTLE SIGNAL FOR OVER 1" OF RAIN--BUT
CONCEPTUALLY THE PATTERN IS IN PLACE FOR IT TO OCCUR. WITH AN
INCREASING SHEAR PROFILE LATE IN THE WEEKEND AND EARLY NEXT
WEEK, THE RISK FOR MORE ORGANIZED AND STRONGER CONVECTION
LIKEWISE INCREASES. HOWEVER, LIKE WITH THE HEAVY RAIN RISK, ANY
SEVERE WEATHER RISK REMAINS TOUGH TO PIN DOWN AT THIS TIME.
WITH THE INCREASING RISK FOR CONVECTION EACH DAY AND WEAK NORTH
TO EAST FLOW TO THE NORTH OF THE BOUNDARY, THE TEMPERATURE
FORECAST FOR THE WEEKEND AND EARLY NEXT WEEK HAS COOLED MODESTLY
FROM WHAT WAS BEING FORECAST A FEW DAYS AGO, WITH HIGHS AT OR
SLIGHTLY COOLER THAN AVERAGE.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1225 PM CDT WED AUG 5 2026
PRIMARY CONCERN OVER THE NEXT 24 HOURS IS THE LIKELIHOOD (70%)
OF FOG ACROSS MUCH OF NE IA AND SW WI TONIGHT INTO EARLY
THURSDAY AS LIGHT WINDS THROUGH THE LOWER 4 KFT OF THE
ATMOSPHERE OCCUR AND SKIES CLEAR. EXPECT IFR/LIFR CONDITIONS,
PARTICULARLY IN RIVER VALLEYS, SO HAVE INCLUDED THIS AT LSE.
EXPECT ADDITIONAL ADJUSTMENTS OVER THE 2 TAF CYCLES. OTHERWISE,
WINDS WILL GENERALLY LIGHT AND VARIABLE UNTIL LATE IN THE PERIOD
WHEN SOUTHERLY WINDS AT 5 TO 10 KNOTS RETURN.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...FERGUSON
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