314
FXUS63 KFSD 290526
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1226 AM CDT WED JUL 29 2026
KEY MESSAGES
- WARM AND MOSTLY DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY.
- CHANCES FOR SHOWERS AND STORMS DEVELOP WEDNESDAY EVENING AND
CONTINUE THROUGH MOST OF THE DAY THURSDAY. A SECOND ROUND OF
SHOWERS AND THUNDERSTORMS COULD DEVELOP THURSDAY EVENING. SOME
MAY BE STRONG TO SEVERE WITH STRONG WIND GUSTS AND HEAVY RAIN
THE MAIN THREATS.
- BENEFICIAL RAINFALL IS EXPECTED WEDNESDAY NIGHT THROUGH FRIDAY
MORNING, WITH A 50-90% PROBABILITY OF AT LEAST 0.50 INCHES
ACROSS MOST OF THE REGION.
UPDATE
ISSUED AT 907 PM CDT TUE JUL 28 2026
ISOLATED THUNDERSTORMS THAT HAVE DEVELOPED ALONG THE BUFFALO RIDGE
IN SOUTHWEST MINNESOTA HAVE DISSIPATED THIS EVENING. THIS WILL LEAVE
DRY AND QUIET CONDITIONS FOR THE REST OF THE EVENING AND OVERNIGHT
HOURS. LOW TEMPERATURES REMAIN ON TRACK TO FALL TO THE UPPER 60S TO
LOW 70S.
WEDNESDAY LOOKS TO BE SOMEWHAT OF A RINSE AND REPEAT OF WHAT WE SAW
TODAY. A MID LEVEL RIDGE AXIS WILL BE SITTING RIGHT OVER THE
FORECAST AREA, CONTRIBUTING TO WEAKER VERTICAL SHEAR VALUES OVER THE
AREA. INSTABILITY LOOKS TO STILL BE SUFFICIENT TO ALLOW FOR THE
POTENTIAL OF SOME AFTERNOON SHOWERS AND STORMS TO DEVELOP. TOUGH TO
SAY WHERE SPECIFICALLY STORMS MAY DEVELOP AS NO BOUNDARY WILL BE IN
PLAY. SHOULD SHOWERS AND STORMS DEVELOP, THEY LOOK TO BE DIURNALLY
DRIVEN AND WILL DISSIPATE DURING THE EVENING TIMEFRAME. SEVERE
STORMS ARE NOT EXPECTED. THE POTENTIAL FOR OVERNIGHT CONVECTION
REMAINS BUT IT LOOKS TO BE SUB SEVERE AND WON'T MAKE IT INTO THE
FORECAST AREA UNTIL NEAR DAYBREAK EARLY THURSDAY MORNING.
THE OVERNIGHT STORMS MAY HAVE AN AFFECT ON THE POTENTIAL FOR STORMS
LATER ON THURSDAY. WITH A SURFACE HIGH PUSHING FURTHER OFF TO THE
EAST, ALLOWING FOR MOIST SOUTHERLY RETURN FLOW TO TAKE OVER. THIS
WILL ALLOW DEW POINTS TO MOISTEN INTO THE UPPER 60S AND 70S. IF THE
MORNING SHOWERS AND DISSIPATE FAST ENOUGH TO ALLOW FOR SUFFICIENT
DESTABILIZATION TO TAKE PLACE DURING THE AFTERNOON, THEN ADDITIONAL
SHOWERS AND STORMS WILL BE POSSIBLE. A MID LEVEL WAVE WILL BE
PUSHING THROUGH THE FORECAST AREA WITH BOTH DETERMINISTIC AND
ENSEMBLE GUIDANCE SUGGESTING THAT THIS MID LEVEL WAVE COULD CLOSE
OFF AS IT MOVES OVER THE FORECAST AREA. THESE MODELS ALSO SHOW THE
SURFACE FRONT RESIDING BENEATH THE CENTER OF THIS MID LEVEL WAVE.
THIS LOOKS TO POTENTIALLY LIMIT THE STRENGTH OF THE DEEP LAYER
SHEAR. AT THE SAME TIME, MID LEVEL LAPSE RATES ALSO LOOK TO BE NEAR
MOIST NEUTRAL. PRECIPITABLE WATER (PWAT) VALUES LOOK TO CLIMB TO
NEARLY 2.0 INCHES, PLACING THEM AT ABOUT THE 99TH PERCENTILE OF
CLIMATOLOGY. THUS, A HEAVY RAIN THREAT REMAINS POSSIBLE. LATEST
ENSEMBLES CONTINUE TO SHOW A BROAD 50-90% CHANCE FOR RAINFALL
AMOUNTS TO EXCEED A HALF AN INCH. THESE PROBABILITIES DECREASE TO A
30-60% CHANCE FOR EXCEEDING AN INCH. TOUGH TO SAY EXACTLY HOW
CONVECTION WILL EVOLVE, BUT WITH A GENERALLY UNCAPPED ATMOSPHERE IN
PLAY AND THE MID LEVEL WAVE PROVIDING AT LEAST WAVE FORCING FOR
ASCENT, THINK THAT MORE WIDESPREAD CONVECTION COULD DEVELOP ACROSS
THE AREA. WITH THE MID LEVEL WAVE RESIDING RIGHT OVER THE FORECAST
AREA, STORM MOTIONS DO NOT LOOK TO BE FAST, SUGGESTING THAT SLOW
MOVING TO POTENTIALLY SOME TRAINING STORMS WILL BE POSSIBLE. SEVERE
STORMS COULD BE POSSIBLE WITH THIS POTENTIAL HEAVY RAIN THREAT IF
STORMS COULD DEVELOP ON THE PREVIOUSLY MENTIONED FRONT AND POSSIBLY
CONGEAL INTO SOME KIND OF MCS. THIS POTENTIAL REMAINS UNCERTAIN SO
CONTINUE TO CHECK THE LATEST FORECAST FOR THE MOST UP TO DATE
INFORMATION.
DISCUSSION
ISSUED AT 135 PM CDT TUE JUL 28 2026
A VERY SUBTLE WAVE CONTINUES TO MOVE TO THE SOUTHEAST. AS IT DOES SO
CLOUDS WILL DISSIPATE, GRADUALLY BECOMING SCATTERED TO CLEAR.
SIMILAR TO YESTERDAY, SMOKE FROM WILDFIRES WILL RESULT IN AN OVERALL
MILKY APPEARANCE TO THE SKY. HIGHS TODAY WILL WARM INTO THE UPPER
80S TO LOW 90S. DEW POINTS WILL BE LOWER THAN THE PAST COUPLE OF
DAYS BUT STILL IN THE MID 60S TO LOW 70S, HIGHEST OVER NORTHWEST
IOWA. LOCALIZED HIGHER VALUES ARE POSSIBLE IN AREAS WITH LARGE CORN
FIELDS, AS THE PLANTS ADD MOISTURE THROUGH EVAPOTRANSPIRATION. HEAT
INDEX VALUES REMAIN BELOW CRITICAL TODAY. HOWEVER, IT IS STILL
IMPORTANT TO TAKE CARE OF YOURSELF WHILE WORKING IN HOT CONDITIONS.
WINDS TODAY WILL BE SOUTHERLY AND LIGHT. OVERNIGHT THEY BECOME LIGHT
AND VARIABLE. PATCHY AREAS OF FOG ARE POSSIBLE AS OVERNIGHT LOWS
FALL TO THE MID 60S AND LOW 70S, WHICH IS RIGHT AROUND THE DEW POINT
TEMPERATURE. MOST OF THE FOG SHOULD BE CONTAINED TO WATER WAYS AND
LOW AREAS, AND WILL BURN OFF BY MID-MORNING WEDNESDAY.
NORTHWEST FLOW ALOFT CONTINUES FOR WEDNESDAY, KEEPING THE SMOKEY
SKIES IN PLACE. WEDNESDAY DURING THE DAY WILL BE VERY SIMILAR TO
TODAY WITH HIGHS IN THE UPPER 80S AND LOW 90S. SOUTHERLY WINDS
INCREASE IN THE AFTERNOON AS A SHORTWAVE APPROACHES FROM THE WEST.
GUSTS OF 15-25 MPH ARE EXPECTED WITH GUSTS INCREASING AS YOU MOVE
TOWARD CENTRAL SOUTH DAKOTA. SHOWERS AND THUNDERSTORMS FORM IN THE
LATE AFTERNOON AND EVENING OVER WESTERN SOUTH DAKOTA AND PROGRESS
EAST. STORMS WILL REACH CENTRAL SOUTH DAKOTA AND OUR WESTERN CWA
BORDER AROUND MIDNIGHT. THERE REMAINS SOME VARIANCE IN MID-
RANGE GUIDANCE ON HOW THIS WAVE AND RESULTING STORMS WILL
EVOLVE, THEREFORE UNCERTAINTY IN SEVERITY REMAINS HIGH. MODEL
SOUNDINGS SHOW A DRY SUBCLOUD LAYER AND TALL SKINNY CAPE. THIS
INDICATES THE MOST LIKELY THREATS WILL BE STRONG TO MARGINALLY
SEVERE WIND GUSTS AND PERIODIC HEAVY RAINFALL. A WEAK LLJ HELPS
TO MAINTAIN CONVECTION THROUGH MUCH OF THE DAY THURSDAY.
MEANWHILE, AN UPPER LEVEL TROUGH DEVELOPS OVER THE PACIFIC NORTHWEST
AND SPEEDS EAST. THE MID-LEVEL AND UPPER TROUGHS DEEPEN AND A
SURFACE LOW FORMS OVER EASTERN WYOMING AND WESTERN SOUTH DAKOTA.
SIMILAR TO WEDNESDAY NIGHT'S STORMS, UNCERTAINTY IN STORM EVOLUTION
IS HIGH DUE TO WIDE VARIANCE IN GUIDANCE. IN ADDITION, THE
ACTIVITY AND OUTFLOWS FROM STORMS EARLIER IN THE DAY WILL LIKELY
PLAY A ROLE IN EVENING DEVELOPMENT. THE MOST LIKELY SCENARIO IS
A FEW ISOLATED STRONG TO SEVERE SUPERCELLS FORM OVER CENTRAL
SOUTH DAKOTA AND QUICKLY GROW UPSCALE INTO AN MCS WITH DAMAGING
WIND GUSTS AND PERIODIC HEAVY RAIN THE PRIMARY THREAT. THIS
TRACKS EAST THROUGH THE OVERNIGHT AND EARLY FRIDAY MORNING,
BRINGING BENEFICIAL RAINFALL TO MUCH OF THE AREA. LREF
PROBABILITIES OF 0.50 INCHES OF RAIN OR MORE ARE 55-75% REGION
WIDE. THIS PROBABILITY IS FOR TOTAL RAINFALL FROM WEDNESDAY
NIGHT THROUGH FRIDAY MORNING.
THURSDAY WILL BE COOLER DUE TO CLOUDS AND RAIN WITH HIGHS IN THE LOW
TO MID 80S. FRIDAY CONTINUED CAA WILL RESULT IN HIGHS SLIGHTLY
COOLER IN THE UPPER 70S TO LOW 80S. A BEAUTIFUL WEEKEND IS IN STORE
WITH MOSTLY SUNNY SKIES AND HIGHS RIGHT AROUND AVERAGE FOR THIS TIME
YEAR IN THE MID 80S.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1224 AM CDT WED JUL 29 2026
VFR CONDITIONS ARE MAINLY EXPECTED FOR THE TAF PERIOD. CLEAR SKIES
AND LIGHT WINDS BEGIN THE PERIOD. SOME FOG COULD DEVELOP (30%
CHANCE) ACROSS PARTS OF NORTHWEST IOWA BEFORE DAYBREAK. AS OF NOW,
THIS LOOKS TO BE EAST OF ALL TAF SITES. AFTERNOON SHOWERS AND
THUNDERSTORMS ARE POSSIBLE BUT THIS POTENTIAL REMAINS LOW SO HAVE
OMITTED FROM ALL TAFS. SOUTHEASTERLY WINDS WILL FINISH OUT THE TAF
PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...MEYERS
DISCUSSION...AJP
AVIATION...MEYERS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page