746
FXUS63 KFSD 080215
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
915 PM CDT TUE JUL 7 2026
KEY MESSAGES
- THERE IS POTENTIAL FOR STRONG TO SEVERE STORMS TONIGHT. LARGE
HAIL UP TO PING PONG BALL SIZE AND DAMAGING WINDS TO 70 MPH
ARE THE MAIN HAZARDS. AN ISOLATED TORNADO IS POSSIBLE AS WELL.
- STRONG TO SEVERE STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AND
EVENING ALONG SOUTH OF HIGHWAY 18. AT THIS TIME, THERE IS
ONLY A 20-30% CHANCE FOR STORMS TO BECOME SEVERE BUT TRENDS
WILL BE MONITORED.
- HIGH TEMPERATURES LOOK TO RISE TO THE 90S TO 100 DEGREE MARK
TOWARDS THE END OF THIS COMING WEEKEND AND INTO NEXT WEEK.
UPDATE
ISSUED AT 913 PM CDT TUE JUL 7 2026
THE FORECAST FOR TONIGHT REMAINS LARGELY ON TRACK WITH A COUPLE OF
EXCEPTIONS. THE FIRST BEING THE DELAYED ONSET OF CONVECTION. THE
CAMS GUIDANCE FOR TONIGHT CONTINUES TO INDICATE STRONGER STORMS
SHOULD BE ON GOING OVER CENTRAL SOUTH DAKOTA AS OF 9 PM CDT. THIS
DELAY MAY BE DUE TO THE FACT THAT WARMING THROUGH THE MID-LEVELS HAS
BEEN STRONGER TONIGHT THAN ORIGINALLY FORECAST EARLIER TODAY.
THIS WARMING CONTINUES TO KEEP A CAP ON THE ENVIRONMENT
PREVENTING SURFACE BASED CONVECTION FROM INITIATING. SECOND,
CONVERGENCE AT THE SURFACE IS RATHER WEAK. WITH NO STRONG
FORCING FOR ASCENT, THERE JUST ISN'T THE KICK NEEDED TO GET AIR
PARCELS MOVING UPWARD. HOWEVER, IN THE NEXT COUPLE OF HOURS THE
MID-LEVEL WAVE MOVES NORTHEAST THROUGH THE REGION AND THE LLJ
INTENSIFIES. FROM THIS POINT AN INCREASE IN STRONG TO SEVERE
ELEVATED CONVECTION IS STILL ANTICIPATED. THE MAIN THREATS
REMAIN HAIL TO THE SIZE OF A PING-PONG BALL, WIND GUSTS TO 70
MPH, AND HEAVY DOWNPOURS. AS THE SYSTEM GROWS UPSCALE INTO A
LINE, THE MAIN THREAT WILL TRANSITION TO DAMAGING WIND GUSTS AND
HEAVY RAIN. ONE FINAL NOTE: THE BEST STORM DYNAMICS REMAIN
ALONG AND NORTH OF HIGHWAY 14, AND IT IS THIS AREA THAT HAS THE
HIGHEST RISK FOR SEVERE WEATHER. THIS IS OUTLINED IN SPC DAY 1
OUTLOOK OF A SLIGHT (LEVEL 2 OF 5). OUTSIDE OF STORM CHANCES
WINDS WILL BE LIGHT AND VARIABLE AND LOWS WILL BE WARM IN THE
UPPER 60S TO LOW 70S.
SHORT TERM GUIDANCE DIVERGES HERE ON HOW STORMS WILL EVOLVE
WEDNESDAY MORNING THROUGH THE REST OF THE DAY. THE HRRR AND THE RAP
KEEP BROADER SHOWERS AND THUNDERSTORMS GOING ALONG THE SLOW MOVING
FRONT, BRINGING RAIN TO MOST OF THE REGION. THE HIRESARW, FV3, AND
NAMNEST KEEP SHOWERS AND STORMS VERY ISOLATED KEEPING MOST OF THE
REGION DRY. BROADER MID-RANGE GUIDANCE TELLS A SIMILAR STORY WITH
SOME FAVORING MORE WIDESPREAD SHOWERS AND OTHERS MORE ISOLATED. AS
FAR AS THE REST OF WEDNESDAY, PERSISTENT AND THICKER CLOUD COVER
WILL KEEP OUR HIGHS A BIT COOLER THAN THE PAST TWO DAYS, IN THE 80S
TO LOW 90S FOR AREAS ALONG AND SOUTH OF HIGHWAY 18. LOWS WILL BE IN
THE 60S.
THE QUASI-STATIONARY FRONT CONTINUES TO SLOWLY SINK SOUTHEAST
THROUGH THE DAY WEDNESDAY. FAIRLY GOOD THETA-E ADVECTION BRINGS IN
MORE RICH, UNSTABLE AIR THAT POOLS ALONG THE SOUTH SIDE, MAINLY OVER
NORTHEAST NEBRASKA, EXTREME SOUTHEAST SOUTH DAKOTA, AND NORTHWEST
IOWA. A STRONG CAP WILL BE IN PLACE FOR MUCH OF THE AFTERNOON, BUT
WILL BEGIN TO ERODE BY THE EARLY EVENING. SIMILAR TO TONIGHT A
SHALLOW MID-LEVEL WAVE WILL PROGRESS EAST THROUGH THE REGION AT THE
SAME TIME THE LLJ INCREASES. THIS SHOULD WORK TO TRIGGER ANOTHER
ROUND OF POTENTIALLY STRONG TO SEVERE THUNDERSTORMS WITH HAIL TO THE
SIZE OF A QUARTER AND 60 MPH WIND GUSTS.
DISCUSSION
ISSUED AT 229 PM CDT TUE JUL 7 2026
QUIET CONDITIONS PERSIST THIS AFTERNOON WITH HIGH TEMPERATURES
WARMING TO THE MID TO UPPER 80S AND LOW 90S. LATEST SATELLITE AND
SURFACE OBS SHOW A , OUTFLOW BOUNDARY FROM MORNING STORMS THAT IS
SET UP ALONG FROM HURON SOUTH DAKOTA TO DE SMET SOUTH DAKOTA, TO
CANBY MINNESOTA. THE MAIN EFFECTIVE BOUNDARY IS ALSO VISIBLE ON
SATELLITE WELL NORTHWEST OF THE AREA. THESE BOUNDARIES WILL SERVE AS
THE AREAS FOR NEW THUNDERSTORMS TO DEVELOP ON LATER THIS AFTERNOON
AS A MID LEVEL WAVE INTERACTS WITH THE BOUNDARIES. LARGE HAIL UP TO
PING PONG BALL SIZE AND DAMAGING WINDS TO 70 MPH WILL BE THE MAIN
HAZARDS. WHILE THE TORNADO THREAT WILL BE MOSTLY NORTH AND WEST OF
THE AREA, A LOCAL/ISOLATED TORNADO THREAT IS POSSIBLE ALONG THE
BOUNDARY AS THE MEAN WIND IS ORIENTED PARALLEL TO IT, ALLOWING FOR A
LONGER RESONANCE TIME FOR A STORM TO INGEST THE BOUNDARY DRIVEN
HELICITY. THESE STORMS LOOK TO DEVELOP LATER THIS AFTERNOON AROUND 5
PM OR LATER AS THE MID LEVEL WAVE CATCHES UP TO THE BOUNDARY. A
SECOND ROUND OF SHOWERS AND SOME STORMS WILL DEVELOP ACROSS THE
BLACK HILLS THIS AFTERNOON AND PUSH EASTWARDS. THESE STORMS WILL
CROSS THE STATE OF SOUTH DAKOTA AND GET INTO LOCATIONS EAST RIVER
THIS EVENING. THE ENVIRONMENT DOES NOT LOOK ALL THAT FAVORABLE AS
LESS MOISTURE (AND ASSOCIATED INSTABILITY) WILL BE AVAILABLE IN THIS
AREA. AT THE SAME TIME, VERTICAL SHEAR WILL ALSO BE WEAKER IN THIS
SAME AREA AS WELL. WHILE THE STRENGTHENING LOW LEVEL JET COULD KEEP
ELEVATED SHOWERS AND ISOLATED STORMS GOING, ANY STORM THAT PERSISTS
INTO THE FORECAST AREA IS NOT EXPECTED TO BE STRONG TO SEVERE ANY
CHANCE FOR A STRONG TO SEVERE STORM WILL COME TO AN END BY 3 AM OR A
LITTLE EARLIER. THOUGH THESE SHOWERS MAY PERSIST THROUGH THE
FORECAST AREA OVERNIGHT.
LATEST GUIDANCE SHOWS THESE SHOWERS CONTINUING TO PERSIST THROUGHOUT
THE DAY ON WEDNESDAY. THIS WILL BRING SOME CLOUD COVER TO THE AREA
WHICH WILL KEEP TEMPERATURES JUST A LITTLE BIT COOLER. AS THE SAME
TIME, THE PREVIOUSLY MENTIONED BOUNDARY WILL BE SLIDING SOUTHWARDS
THROUGH THE AREA. THIS BOUNDARY LOOKS TO SLIDE JUST FAR ENOUGH TO
THE SOUTH THAT ADDITIONAL SHOWERS AND PERHAPS A FEW THUNDERSTORMS
COULD DEVELOP ON IT. LATEST HI-RES GUIDANCE SHOWS THESE STORMS
DEVELOPING ACROSS PARTS OF NORTHWEST IOWA TOMORROW AFTERNOON BEFORE
EXITING THE AREA IN THE EVENING. WHILE THIS LOOKS TO BE THE
CONSENSUS AMONGST THE GUIDANCE, SOME UNCERTAINTY REGARDING HOW FAR
SOUTH THE BOUNDARY GETS REMAINS. IF THE BOUNDARY GETS HUNG UP, THEN
SEVERE STORM CHANCES COULD INCREASE DURING THE DAYLIGHT HOURS
TOMORROW. AS OF NOW, THE LATEST REFS SHOWS A 20-30% CHANCE FOR
REFLECTIVITY VALUES TO EXCEED 40 DBZ. THUS, THINK THE MOST LIKELY
SCENARIO FOR TOMORROW IS FOR ELEVATED SHOWERS AND WEAK STORMS PUSH
THROUGH THE MAJORITY OF THE AREA. THE EXCEPTION WILL BE PORTIONS OF
NORTHWEST IOWA, GENERALLY NEAR AND SOUTH/SOUTHEAST OF HIGHWAY-60
WHERE A PRE-FRONTAL TROUGH WHERE ENOUGH SURFACE HEATING COULD RESULT
IN A FEW SEVERE STORMS DURING THE AFTERNOON TIMEFRAME. WILL KEEP AN
EYE ON THIS POTENTIAL. ANY CHANCE FOR STRONG TO SEVERE STORMS WILL
COME TO AN END DURING THE EVENING HOURS AS THE SURFACE BOUNDARY AND
PRE-FRONTAL TROUGH PUSH SOUTHEAST OF THE AREA.
THURSDAY LOOKS TO BE A PLEASANT SUMMER DAY AS HIGH TEMPERATURES WARM
TO THE 80S AND WINDS STAY LIGHT OUT OF THE NORTH/NORTHEAST. HIGH
TEMPERATURES LOOK TO WARM TO 80S WHILE HUMIDITY VALUES REMAIN
MODEST. THERE LOOKS TO BE ENOUGH INSTABILITY TO DEVELOP A FEW
SHOWERS TO AN ISOLATED THUNDERSTORM. ANY STORM THAT DOES DEVELOP IS
NOT EXPECTED TO BE STRONG TO SEVERE AS VERTICAL SHEAR PROFILES WILL
BE WEAK. AS OF NOW, ONLY HAVE A 20-40% CHANCE FOR THESE SHOWERS TO
WEAK STORMS TO DEVELOP. CHANCES FOR RAIN WILL BE TRENDING DOWNWARDS
INTO THE EVENING HOURS AS THE BOUNDARY LAYER STABILIZES.
FRIDAY WILL SEE CONTINUED NEAR SEASONABLE TEMPERATURES WITH HIGHS
IN THE 80S TO LOW 90S. HIGHS WILL BEGIN TO WARM AS AN UPPER LEVEL
RIDGE BEGINS TO BUILD ON SATURDAY. HIGHS WILL WARM A BIT MORE TO THE
MID 80S TO MID 90S SATURDAY AFTERNOON. THE RIDGE LOOKS TO BUILD UP
OVER THE ROCKY MOUNTAINS ON SUNDAY BEFORE QUICKLY TRANSLATING TO
OVER THE NORTHERN PLAINS BY EARLY NEXT WEEK. BOTH DETERMINISTIC AND
ENSEMBLE GUIDANCE PLACES THE PEAK OF THE RIDGE UP TO 597 TO 600 DAM.
THIS WILL RESULT IN MUCH HOTTER TEMPERATURES RETURNING TO THE AREA
WITH HIGH TEMPERATURES INTO THE 90S TO POTENTIALLY THE LOW 100S. THE
ENSEMBLES SUPPORT THIS AS THEY SHOW A BROAD 40-100% CHANCE FOR HIGH
TEMPERATURES TO EXCEED 90F AND A 40-70% CHANCE FOR HIGHS TO BREAK
100F. THE HIGHEST PROBABILITIES LIE ACROSS CENTRAL SOUTH DAKOTA.
WITH THE CENTER OF THE RIDGE PLACES DIRECTLY OVER THE NORTHERN
PLAINS, THE UPPER LEVEL JET AND ASSOCIATED GRADIENTS WILL BE NORTH
OF THE AREA. THIS LOOKS TO LEAVE MOSTLY DRY AND HOT CONDITIONS
SUNDAY THROUGH TUESDAY AT THIS TIME. HUMID CONDITIONS WILL ACCOMPANY
THE HEAT SO HEAT HEADLINES WILL BE POSSIBLE.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 634 PM CDT TUE JUL 7 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS PERIOD. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A
COLD FRONT AND MOVE IN FROM THE WEST LATER THIS EVENING INTO THE
OVERNIGHT. SOME OF THESE COULD BE STRONG TO SEVERE PRODUCING HAIL TO
THE SIZE OF A GOLF BALL AND WIND GUSTS TO 60 KTS. AREAS UNDER
STRONGER STORMS COULD SEE CEILING AND VISIBILITY DECREASES DOWN TO
MVFR AND BRIEF IFR. SOME ERRATIC WIND GUSTS WILL ALSO BE POSSIBLE AS
THE STORMS PROGRESS THROUGH. WINDS BEHIND THE FRONT WILL BECOME
NORTHERLY AND LIGHT THROUGH WEDNESDAY. DUE TO THE SLOW MOVING NATURE
OF THIS SYSTEM, SHOWERS AND STORMS COULD LINGER THROUGH THE END OF
THE PERIOD, ESPECIALLY AT KFSD AND KSUX.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...AJP
DISCUSSION...MEYERS
AVIATION...AJP
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