357
FXUS63 KFSD 041707
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1207 PM CDT TUE AUG 4 2026
KEY MESSAGES
- ADDITIONAL PERIODS OF SCATTERED SHOWERS AND NON-SEVERE,
ISOLATED THUNDERSTORMS CONTINUE INTO THIS EVENING - MAINLY
SOUTH OF INTERSTATE 90. SEVERE WEATHER IS NOT EXPECTED.
- MILDER TEMPERATURES THROUGH WEDNESDAY WITH ABOVE NORMAL
TEMPERATURES FRIDAY INTO THE WEEKEND. ALTHOUGH DETAILS ARE
UNCERTAIN, RAIN CHANCES MAY RETURN TO THE REGION THIS WEEKEND.
UPDATE
ISSUED AT 347 AM CDT TUE AUG 4 2026
SHOWERS AND ELEVATED STORMS CONTINUE TO MOVE EAST THIS MORNING
ACROSS NORTHWESTERN IA INTO THE MO RIVER VALLEY. SEVERE WEATHER RISK
IS VERY LOW. STRONGER STORMS MAY PRODUCE WIND GUSTS TO 50 MPH AND/OR
DIME SIZE HAIL THROUGH 5 AM. STORMS HAVE BEEN VERY PULSY IN NATURE,
LIKELY DUE TO DECREASING SHEAR AND INSTABILITY. STILL EXPECT SHOWERS
AND VERY ISOLATED STORMS TO LINGER THROUGH TODAY AND INTO TONIGHT AS
THE FRONT STALLS THEN SINKS SLOWLY SOUTH. SEVERE WEATHER IS NOT
EXPECTED. RAIN SHOULD END BY LATE TUESDAY NIGHT ALONG THE US HWY 20
CORRIDOR.
NORTHERLY FLOW, CLOUDS, AND CAA KEEP TEMPERATURES TODAY AND TOMORROW
COOLER THAN AVERAGE. INCREASED SKY COVER FROM THE NBM TO ACCOUNT FOR
THICKER CONCENTRATIONS OF WILDFIRE SMOKE ALOFT THROUGH WEDNESDAY
EVENING. MAY SEE SOME SURFACE SMOKE AS WELL, SO MAINTAINED MENTION
AS THOSE WHO ARE VERY SENSITIVE TO THE SMOKE MAY FEEL IMPACTS. DO
NOT EXPECT IMPACTS TO VISIBILITY.
DISCUSSION
ISSUED AT 130 PM CDT MON AUG 3 2026
ELEVATED, POST FRONTAL THUNDERSTORMS ARE EXPECTED TO DEVELOP AROUND
THE JAMES RIVER VALLEY LATER THIS EVENING. TIMING APPEARS TO SUPPORT
THE BETTER CHANCES FROM ABOUT 9 PM TO MIDNIGHT FOR ANY STRONGER
UPDRAFTS. ASSUMING THE MODELS ARE CORRECT WITH THE MOISTURE AROUND
800-700MB BEHIND THE FRONT, ABOUT 1000-1500 J/KG CAPE IS EXPECTED
WITH ABOUT 30-40 KNOTS OF EFFECTIVE SHEAR. THIS MAY SUPPORT HAIL TO
THE SIZE OF QUARTERS AND WITH DCAPE ABOUT 1000-1500 J/KG SOME
STRONGER GUSTS OF 65 TO 70 MPH ARE POSSIBLE. OF NOTE IS THAT THE
FREEZING LEVEL IS AROUND 14000 FEET WHICH WILL LIMIT THE HAIL THREAT
A BIT.
TUESDAY WILL SEE SOME MID LEVEL MOISTURE AND WEAK ELEVATED
INSTABILITY LINGER, WHICH SHOULD DRIVE SCATTERED SHOWERS THROUGHOUT
THE DAY. THE BETTER CHANCES WILL BE SOUTH OF I-90. AMOUNTS WILL NOT
BE VERY HIGH, BUT A FEW LOCATIONS SHOULD GET 0.10" TO 0.25". THE
WIDESPREAD CLOUD COVER AND SCATTERED SHOWERS WILL LIMIT TEMPERATURES
AS WELL, WITH HIGHS GENERALLY IN THE MID 70S.
ANOTHER WAVE WILL MOVE BY ON WEDNESDAY, WITH MORE CLOUD COVER AND
RAIN CHANCES NEAR AND SOUTH OF ROUGHLY THE MISSOURI RIVER. WITH
CLOUD COVER AND SOMEWHAT COOLER LOW TO MID LEVEL TEMPERATURES HIGHS
WILL AGAIN BE BELOW NORMAL, RANGING FROM 75 TO 80 NEAR AND NORTH OF
I-90 TO THE MID 70S SOUTH.
A WARMING TREND WILL SET UP FOR THE WEEKEND AS WEST NORTHWEST FLOW
ALOFT BECOMES MORE WESTERLY. TEMPERATURES SHOULD CLIMB INTO9 THE 80S
ON THURSDAY, THEN MID 80S TO LOWER 90S FRIDAY AND SATURDAY WITH SOME
QUESTION MARKS FOR SUNDAY AS A WAVE COULD BRING SLIGHTLY COOLER
CONDITIONS. WHILE THERE IS NO RAIN IN THE FORECAST DURING THIS TIME,
EACH OF THE MODELS GENERATES WEAK WAVES, WITH LITTLE TO NO AGREEMENT
ON WHEN. SO, AS THE WEEKEND APPROACHES, THERE MAY BE A COUPLE OF
BRIEF PERIODS WHEN SHOWERS AND THUNDERSTORMS DEVELOP.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1205 PM CDT TUE AUG 4 2026
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE MAINLY SOUTH OF
I-90 THROUGH EARLY EVENING. VERY BRIEF MVFR CONDITIONS WILL BE
POSSIBLE WITHIN THIS ACTIVITY. OUTSIDE OF ANY SHOWERS AND STORMS
VFR CONDITIONS ARE EXPECTED. WITH LIGHT WINDS AND MOSTLY CLEAR
SKIES LATER TONIGHT, SOME VERY PATCHY LOW LAND FOG WILL BE
POSSIBLE.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...08
AVIATION...08
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