579
FXUS63 KFSD 281718
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1218 PM CDT TUE JUL 28 2026
KEY MESSAGES
- WARM AND MOSTLY DRY CONDITIONS PREVAIL TODAY INTO WEDNESDAY,
WITH LESS WARM AND WETTER CONDITIONS EXPECTED LATER THIS WEEK.
- A FEW AFTERNOON SHOWERS AND THUNDERSTORMS ARE POSSIBLE (30%)
IN MAINLY SOUTHWEST MINNESOTA TODAY. SEVERE STORMS ARE NOT
EXPECTED BUT STRONGER STORMS MAY BE CAPABLE OF WIND GUSTS UP
TO 50 MPH AND HAIL UP TO DIME SIZE (0.75").
- SHOWERS CHANCES INCREASE LATER THURSDAY/THURSDAY NIGHT, WITH
MODERATE (50-70%) PROBABILITY OF RAINFALL EXCEEDING 0.50 INCH.
SCATTERED THUNDERSTORMS ARE ALSO EXPECTED, WITH AN ISOLATED
STRONG TO SEVERE STORM POSSIBLE.
UPDATE
ISSUED AT 440 AM CDT TUE JUL 28 2026
EXPANSIVE MID-LEVEL CLOUDS BLANKET THE AREA EARLY THIS MORNING,
GROWING IN COVERAGE AHEAD OF A SUBTLE APPROACHING WAVE. DRY AIR
PERSISTS IN THE SUB-CLOUD LAYER, BUT CANNOT RULE OUT A FEW
SPRINKLES AS THE WAVE SLIDES THROUGH. DECREASING CLOUDS ARE
GENERALLY EXPECTED BEHIND THE DEPARTING WAVE, ALLOWING FOR HIGHS
IN THE UPPER 80S TO MID 90S THIS AFTERNOON. WILL HAVE TO WATCH
FOR SPOTTY SHOWERS/STORMS TO DEVELOP ALONG A SUBTLE BOUNDARY FROM
NORTHEAST SD INTO SOUTHWEST MN BY LATE AFTERNOON/EVENING. SEVERE
STORMS ARE NOT EXPECTED, BUT THE AFOREMENTIONED DRY SUB-CLOUD
LAYER COULD SUPPORT ERRATIC STRONGER WIND GUSTS UP TO 50 MPH,
WITH PERHAPS SOME SMALL HAIL IN STRONGER CORES.
A QUIET DAY WEDNESDAY THOUGH MODELS SUGGEST A FAIR AMOUNT OF SMOKE
ALOFT TOPPING THE UPPER RIDGE INTO THE NORTHERN PLAINS.
FAIR CONSENSUS SHOWING A STRONGER TROUGH SLOWLY PUSHING ACROSS
THE REGION DURING THE LATTER PART OF THIS WEEK, THOUGH NOT A SLAM
DUNK AS THE LONG-RANGE ENSEMBLES DO SHOW INCREASING SPREAD IN THE
STRENGTH OF THE TROUGH AS IT MOVES EAST ACROSS THE DAKOTAS AND
MINNESOTA. THAT SAID, BENEFICIAL RAINFALL IS POSSIBLE, WITH LREF
PROBABILITIES INDICATING MODERATE (50-70%) POTENTIAL FOR 24-HOUR
RAINFALL TOTALS EXCEEDING 0.50 INCH BY FRIDAY MORNING. WITH THE
DIVERGENCE IN POSSIBLE SOLUTIONS, SEVERE WEATHER POTENTIAL IS
UNCERTAIN. HOWEVER, LATER THURSDAY/THURSDAY EVENING WILL BE A
PERIOD TO WATCH WITH CAPE/SHEAR JOINT PROBABILITIES SUPPORTING A
POTENTIAL FOR A FEW STRONGER STORMS.
DISCUSSION
ISSUED AT 153 PM CDT MON JUL 27 2026
HOT AND HUMID CONDITIONS IMPROVE BEHIND A COLD FRONT THAT PASSED
THROUGH THE REGION THIS MORNING. WINDS BEHIND THE FRONT ARE OUT OF
THE NORTH AND A BIT BREEZY WITH GUSTS TO AROUND 20 MPH. DEWPOINTS
ARE FALLING RAPIDLY TO THE LOW 60S. HOWEVER, HIGHS ARE STILL
EXPECTED TO CLIMB INTO THE 90S AND LOW 100S, AND SO HEAT INDEX
VALUES WILL BE 100 TO 104 DEGREES F. A HEAT ADVISORY REMAINS IN
EFFECT FOR AREAS ALONG AND SOUTH OF I-90 UNTIL 8 PM CDT.
IN ADDITION TO HEAT THERE IS A MARGINAL RISK (LEVEL 1 OF 5) FOR
STRONG TO SEVERE THUNDERSTORMS. A SHALLOW WAVE WILL PASS THROUGH THE
REGION, TRIGGERING STORMS OVER WESTERN SOUTH DAKOTA LATE THIS
AFTERNOON INTO THE EARLY EVENING. THESE WILL TRAVEL EAST AND BEGIN
TO IMPACT AREAS OF CENTRAL SOUTH DAKOTA SOME TIME AFTER 9 PM CDT. AS
STORMS APPROACH THEY WILL BE ENCOUNTERING AN INCREASINGLY STABLE
ENVIRONMENT. WHILE SEVERE WEATHER CANNOT BE RULED OUT, THE AREA MOST
LIKELY TO SEE ANY STRONGER STORMS WILL BE WEST OF THE JAMES RIVER.
THE MAIN RISK WITH STORMS WILL BE DAMAGING WIND GUSTS OF 65 MPH.
STORM INTENSITY WILL WEAKEN AS THEY CONTINUE EAST BECOMING SCATTERED
RAIN SHOWERS AND WEAK THUNDERSTORMS. RAIN ACCUMULATION WILL BE
LIGHT, A TRACE TO A HUNDREDTH FOR MOST OF THE CWA. WEST OF THE JAMES
RIVER MAY SEE UP TO A TENTH OF AN INCH. SHOWERS MAY LINGER INTO THE
MORNING COMMUTE TUESDAY, BUT IMPACTS SHOULD BE MINIMAL.
TUESDAY SURFACE HIGH PRESSURE SETTLES OVER CENTRAL SOUTH DAKOTA
TURNING WINDS TO THE SOUTHEAST. HIGHS WILL BE COOLER, IN THE 80S
EAST OF HIGHWAY 81, AND IN THE LOW 90S TO THE WEST. DEW POINTS WILL
CLIMB INTO THE MID 60S TO LOW 70S AND WILL RESULT IN MUGGY
CONDITIONS ONCE AGAIN. HOWEVER, HEAT INDEX VALUES WILL REMAIN BELOW
CRITICAL. STILL, IT'S IMPORTANT TO MAINTAIN PROPER HYDRATION AND TO
TAKE BREAKS OUT OF THE HEAT. WEDNESDAY WILL BE ANOTHER QUIET DAY
WITH HIGHS IN THE 90S.
WEDNESDAY NIGHT A SHORT WAVE WILL WORK THROUGH THE UPPER RIDGE
BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS A VERY
LARGE DIFFERENCE IN MID-RANGE GUIDANCE ON CONVECTIVE PARAMETERS,
THEREFORE THE SEVERITY OF THE STORMS IS UNCERTAIN. THURSDAY
ISOLATED TO SCATTERED LIGHT SHOWERS WILL CONTINUE PERIODICALLY
THROUGH THE DAY. THURSDAY AFTERNOON A STRONGER UPPER WAVE MOVES
INTO THE REGION. THIS WILL RESULT IN ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS. MID-RANGE GUIDANCE CONTINUES TO HAVE A WIDE
RANGE OF SOLUTIONS, AND SEVERITY OF STORMS IS ONCE AGAIN IN
QUESTION. OVER THE COMING DAYS THE TRENDS WILL BE MONITORED AND
UPDATES ISSUED AS DETAILS BECOME CLEAR.
AN UPPER LEVEL RIDGE WILL PUSH INTO THE REGION BEHIND THE WAVE FOR
THE WEEKEND. PARTLY CLOUDY SKIES AND HIGHS IN THE 80S TO LOW 90S
WITH DRY CONDITIONS ARE EXPECTED.
ONE FINAL NOTE: SMOKE FROM WILDFIRES IN THE WESTERN US AND CANADA IS
EXPECTED TO BEGIN TO FLOW INTO THE REGION TODAY. THIS WILL RESULT IN
MILKY LOOKING SKIES AND A DECREASE IN AIR QUALITY. YOU MAY EVEN BE
ABLE TO SMELL SMOKE AT TIMES DEPENDING ON HOW DEEPLY WE MIX EACH
DAY. WITH OUR CURRENT UPPER LEVEL PATTERN SMOKE IS EXPECTED TO
REMAIN IN THE FORECAST THROUGH AT LEAST THE MIDDLE OF THE WEEK.
PEOPLE WHO ARE SENSITIVE TO AIR POLLUTANTS SHOULD USE PRECAUTIONS.
FOR THE LATEST ON AIR QUALITY PLEASE VISIT AIRNOW.GOV.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1217 PM CDT TUE JUL 28 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE PERIOD. SCATTERED
CLOUDS WILL CONTINUE TO DISSIPATE LEAVING MOSTLY CLEAR SKIES.
SMOKE FROM WILDFIRES REMAINS IN THE UPPER LEVELS BUT HAS NOT
BEEN MIXING DOWN ENOUGH TO IMPACT FLIGHT OPERATIONS. WINDS WILL
BE LIGHT AND VARIABLE FOR THE MAJORITY OF THE PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...JH
DISCUSSION...AJP
AVIATION...AJP
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