336
FXUS63 KFSD 262351
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
651 PM CDT FRI JUN 26 2026
KEY MESSAGES
- SUMMER HEAT AND HUMIDITY WILL MAKE ITS RETURN STARTING SUNDAY
INTO NEXT WEEK. HEAT INDICES UP TO THE LOW 100S WILL LEAD TO
MAJOR TO EXTREME HEAT RISK. BEGIN PLANNING NOW TO REDUCE THE
RISK OF HEAT ILLNESS AND IMPACTS.
- AN ISOLATED CHANCE FOR STRONGER STORMS WILL BE POSSIBLE FROM
SATURDAY NIGHT INTO SUNDAY. PRIMARY RISKS WOULD BE UP TO GOLF
BALL SIZED HAIL AND DAMAGING WINDS UP TO 65 MPH.
- AN ACTIVE PATTERN ALOFT COULD LEAD TO ADDITIONAL CHANCES FOR
STRONGER STORMS FROM EARLY TO MID NEXT WEEK. HOWEVER, SOME
UNCERTAINTY STILL REMAINS.
DISCUSSION
ISSUED AT 222 PM CDT FRI JUN 26 2026
CURRENTS & TONIGHT: A WARM AND BREEZY DAY CONTINUES! TAKING A LOOK
ACROSS THE AREA, WE'RE CONTINUING TO SEE A FEW SPRINKLES TO VERY
LIGHT SHOWERS LIFT OUT OF PORTIONS OF FAR EASTERN SD AND SOUTHWESTERN
MN THIS AFTERNOON WITH MAINLY LIGHT ACCUMULATIONS. WHILE THIS VERY
LIGHT ACTIVITY COULD PERSIST FOR THE NEXT HOUR OR TWO, SHOULD SEE
MOST OF THIS ACTIVITY PUSH OUT OF OUR AREA BY LATE AFTERNOON. FROM
HERE, MOSTLY QUIET CONDITIONS WILL RETURN AS CLOUD COVER THINS INTO
THE EVENING HOURS. OTHERWISE, WEAK MID-LEVEL RIDGE WILL SHIFT OUR
QUASI-ZONAL FLOW ALOFT BACK TO MORE SOUTHWESTERLY OVERNIGHT SETTING
THE STAGE FOR OUR NEXT PRECIPITATION CHANCES FROM SATURDAY INTO
SUNDAY. LASTLY, A WARMER NIGHT WILL BE ON TAP AS OVERNIGHT LOWS ONLY
FALL INTO THE UPPER 50S TO MID 60S.
SATURDAY & SUNDAY: LOOKING INTO THE REST OF THE WEEKEND, QUIETER
CONDITIONS WILL TEMPORARILY RETURN BY SATURDAY AS WEAK RIDGING MOVE
OVERHEAD. CLOUD COVER WILL GRADUALLY INCREASE DURING THE DAY AS A
LIFTING WARM FRONT BRINGING IN STRENGTHENING WARM AIR ADVECTION
(WAA). THIS COMBINED WITH DEEPER MIXING AND A TIGHTENING SPG WILL
NOT ONLY LEAD TO THE RETURN OF BREEZY SOUTHEASTERLY WINDS, BUT ALSO
A SLIGHT BUMP IN TEMPERATURES WITH HIGHS PEAKING IN UPPER 70S TO MID
80S. LOOKING ALOFT, SOUTHWESTERLY FLOW WILL LEAD TO MULTIPLE PIECES
OF ENERGY LIFTING OUT OF THE BLACK HILLS INTO NORTHEASTERN SD. WHILE
WE CAN'T COMPLETELY RULE OUT SOME ISOLATED SHOWERS IN OUR FAR
NORTHWEST DURING THE AFTERNOON, THE MAIN CONCERNS WILL DEVELOP FROM
SATURDAY EVENING INTO SUNDAY MORNING AS A DEVELOPING TRIPLE POINT
LIFTS OUT OF THE NEBRASKA PANHANDLE WITH A SURFACE LOW. GIVEN THE
SLIGHTLY WEAKER CAP AND STRENGTHENING LLJ, CURRENT THOUGHTS ARE THAT
THE INCREASING FORCING WITH THE TRIPLE POINT COULD BE ENOUGH TO
BREAK THE CAP AND GENERATE A FEW THUNDERSTORMS BY SUNDAY MORNING.
IF STORMS CAN DEVELOP, THEY COULD BECOME STRONG WITH A DECENTLY
UNSTABLE ENVIRONMENT CHARACTERIZED BY AROUND 1200-1800 J/KG OF CAPE
AND AROUND 40-50 KTS OF 0-6 KM BULK SHEAR. STRONGER STORMS WOULD BE
CAPABLE OF PRODUCING UP TO GOLF-BALL SIZED HAIL AND DAMAGING WIND
GUSTS UP TO 65 MPH. NONETHELESS, THERE ARE STILL SOME LOCATIONAL
DIFFERENCES BETWEEN SHORT-RANGE GUIDANCE SO ITS A BIT HARD TO PIN
DOWN A SPECIFIC AREA OF FOCUS RIGHT NOW. WITH ALL THIS IN MIND, MOST
OF OUR AREA IS NOW OUTLINED IN AN SPC DAY 2 MARGINAL RISK (LEVEL 1
OF 5) FOR SEVERE WEATHER SO MAKE SURE TO MULTIPLE WAYS TO RECEIVE
WARNING INFORMATION! FROM HERE, QUIETER CONDITIONS SHOULD RETURN
FROM LATE MORNING ONWARDS AS THE UPPER-LEVEL RIDGE STRENGTHENS
SETTING THE STAGE FOR A RETURN OF DANGEROUS HEAT. WHILE THE EARLY
MORNING STORMS COULD POTENTIALLY AFFECT OUR TEMPERATURES, SOUTHERLY
SURFACE WINDS COMBINED WITH A PUSH OF STRONG WWA ALOFT COULD BOOST
OUR HIGHS TO THE LOW TO UPPER 90S WITH HEAT INDICES IN THE 90S TO
LOW 100S. WHILE THIS WOULD FALL INTO OUR HEAT ADVISORY CRITERIA,
WILL LIKELY WAIT UNTIL THINGS GET CLOSER TO FINALIZE ANY TYPE OF
HEAT HEADLINE. LASTLY, GIVEN THE WARMER OVERNIGHT TEMPERATURES (60S-
70S); WE'LL HAVE TO BE ON THE LOOKOUT FOR A FEW RECORD WARM LOWS
ACROSS THE AREA FROM SUNDAY INTO MONDAY (CHECK CLIMATE SECTION
BELOW.)
NEXT WEEK: HEADING INTO THE NEW WEEK, THE FOCUS WILL CONTINUE TO BE
ON THE HEAT AS UPPER-LEVEL RIDGING CONTINUES TO BUILD OVER THE
EASTERN CONUS. WITH SOUTHERLY SURFACE WINDS IN PLACE AND MULTIPLE
PUSHES OF WARMER AIR ALOFT, EXPECT TEMPERATURES TO CONTINUE TO HOVER
IN THE LOW TO UPPER 90S FROM MONDAY ONWARDS WITH HEAT INDICES (HI)
IN THE 90S TO LOW 100S DEGREE MARKS AT TIMES. WHILE CONDITIONS WON'T
QUITE MAKE IT INTO EXCESSIVE HEAT TERRITORY, WE COULD SEE MANY AREAS
TOUCH HEAT ADVISORY CRITERIA (HI>100) AT TIMES EACH DAY SO THIS WILL
BE SOMETHING TO WATCH MOVING FORWARD. EITHER WAY, THE CONDITIONS
WILL LEAD TO MODERATE TO MAJOR HEAT RISK FOR MOST AREAS FROM MONDAY
THROUGH THURSDAY SO MAKE SURE TO DRINK PLENTY OF WATER AND TO LIMIT
ANY STRENUOUS ACTIVITIES! OTHERWISE, WE'LL ALSO HAVE TO KEEP ANY EYE
TO THE SKIES THROUGH LATE WEEK AS SOUTH-SOUTHWESTERLY FLOW ALOFT
HELPS USHERS IN MULTIPLE PIECES OF ENERGY INTO THE AREA THROUGH WEAK
PERTURBATIONS. WITH PLENTY OF HEAT IN THE FORECAST, ALL THAT WOULD
BE NEEDED IS A STRONG ENOUGH TRIGGER TO BREAK THROUGH THE CAP TO GET
SOMETHING STRONG TO SEVERE. WHILE THE PROBABILITIES OF THIS ARE LOW
(30% OR LESS) AT THIS TIME, THE CHANCES AREN'T ZERO EITHER SO MAKE
SURE TO MONITOR YOU LOCAL FORECAST FOR THE LATEST CHANGES.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 650 PM CDT FRI JUN 26 2026
MVFR TO LOCALLY IFR STRATUS LOOKS TO DEVELOP AND MOVE INTO THE
AREA LATE TONIGHT FROM THE MISSOURI RIVER VALLEY LIFTING NORTHWARD
TO THE HIGHWAY 14 CORRIDOR BY AROUND SUNRISE. THIS STRATUS DECK
LOOKS TO GRADUALLY LIFT AND ERODE THROUGH THE LATE MORNING HOURS AND
INTO THE EARLY AFTERNOON. A STRAY SHOWER OR THUNDERSTORM CANNOT
BE RULED OUT IN THE LATE AFTERNOON MAINLY WEST OF I-29, BUT
CHANCES ARE LOW (LESS THAN 20%).
SOUTHEASTERLY WINDS CAN BE EXPECTED THROUGH THE PERIOD. IT WILL
REMAIN RELATIVELY BREEZY OVERNIGHT ESPECIALLY WEST OF I-29,
WHERE SUSTAINED WINDS WILL BE AROUND 10-15 KTS, LESSENING WITH
EASTWARD EXTENT THROUGH THE REST OF THE AREA. WINDS WILL
INCREASE THROUGH THE DAY ON SATURDAY AREA-WIDE, WITH GUSTS
PEAKING AROUND 25-35 KTS, STRONGEST ONCE AGAIN WEST OF I-29.
CLIMATE
ISSUED AT 222 PM CDT FRI JUN 26 2026
BUILDING HEAT ACROSS THE AREA FROM SUNDAY ONWARDS WILL LEAD TO
THE INCREASED POTENTIAL FOR A FEW TEMPERATURE RECORDS BEING
EITHER TIED OR SET:
RECORD HIGHS:
MONDAY (06/29): KFSD(101|2002) KSUX(100|2022)
WEDNESDAY (07/01): KFSD(97|1948) KSUX(101|1911) KMHE(100|1900)
THURSDAY (07/02): KFSD(101|1911) KSUX(99|1911) KHON(100|2012)
RECORD WARM LOWS:
MONDAY (06/29): KFSD(77|2020) KSUX(80|1931) KHON(75|2020)
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...05
AVIATION...SAMET
CLIMATE...05
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