094
FXUS63 KFSD 251718
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1218 PM CDT THU JUN 25 2026
KEY MESSAGES
- NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES PREVAIL THROUGH THE
END OF THE WEEK. A COUPLE PASSING SHOWER AND STORM CHANCES
LINGER THROUGH THE END OF THE WEEK AS WELL.
- GROWING CONFIDENCE IN AN EXTENDED PERIOD OF HEAT AND HUMIDITY
BEGINNING SUNDAY INTO NEXT WEEK. HEAT AND HUMIDITY COULD
BRING VERY LOW PROBABILITIES FOR THUNDERSTORMS EACH DAY.
- A LOW CHANCE FOR STRONG TO POSSIBLY SEVERE THUNDERSTORMS
SATURDAY NIGHT INTO SUNDAY MORNING AND AGAIN MONDAY INTO
MONDAY NIGHT. FOR NOW, THE GREATEST RISK REMAINS OFF TO THE
WEST AND NORTH OF THE AREA.
UPDATE
ISSUED AT 254 AM CDT THU JUN 25 2026
FORECAST REMAINS ON TRACK THIS MORNING.
HIGH CLOUDS ARE INCREASING FROM THE SOUTHWEST, BUT EXPECT CONDITIONS
TO STAY DRY WITH THE BEST MOISTURE ACROSS NE. FOG CHANCES LOOK LOW
(LESS THAN 20%) EARLY THIS MORNING WITH SLIGHTLY HIGHER WINDS AND
DEW POINT DEPRESSIONS. IF FOG DEVELOPS, WOULD EXPECT IT TO BE PATCHY
AND SHALLOW. WE'LL START TODAY IN THE 50S. A PLEASANT AND SLIGHTLY
COOLER THAN AVERAGE DAY ON TAP TODAY WITH INCREASING CLOUDS AND
HIGHS IN THE 70S.
ENJOY THESE COOLER TEMPERATURES AS CONFIDENCE CONTINUES TO INCREASE
IN THE POTENTIAL FOR POSSIBLY DANGEROUS HEAT SUNDAY INTO EARLY NEXT
WEEK. 25.00Z ENSEMBLE PROBABILITY OF HIGHS EXCEEDING 90 DEGREES ARE
INCREASING AND EXPANDING ACROSS THE AREA, WITH 50-90% CHANCE SUNDAY
AND/OR MONDAY. HEATRISK CLIMBS IN TO THE MAJOR AND POSSIBLY EXTREME
CATEGORIES, WITH HEAT INDEX VALUES NEAR 105. CURRENT FORECAST VALUES
APPROACH RECORD WARM HIGHS AND LOWS FOR SIOUX FALLS (MONDAY) AND
SIOUX CITY (SUNDAY AND MONDAY). PLAN AHEAD TO REDUCE RISK OF HEAT
ILLNESS THIS WEEKEND INTO EARLY NEXT WEEK, ESPECIALLY IF YOU ARE
PLANNING TO SPEND TIME OUTDOORS.
DISCUSSION
ISSUED AT 105 PM CDT WED JUN 24 2026
A VERY WEAK WAVE IN SOUTHWEST SD WILL DRIFT THROUGH FAR SOUTHEAST SD
AND NORTHERN NE LATE THIS AFTERNOON INTO THE EVENING. MODEL
SOUNDINGS INDICATE SOME WEAK ELEVATED INSTABILITY WITH SOME FAIRLY
DRY AIR BELOW THIS MORE MOIST, SLIGHTLY UNSTABLE LAYER. THIS MAY
ALLOW A FEW WIND GUSTS TO 40 MPH IF THE SHOWERS CAN DEVELOP. OVERALL
THIS THREAT SHOULD COME TO AN END BY ABOUT 11 PM.
THURSDAY SHOULD PROVE TO BE A VERY PLEASANT DAY WITH LIGHT NORTHERLY
WINDS AND HIGHS IN THE 70S.
UPPER LEVEL TROUGHING BEGINS TO DEVELOP TO THE WEST ON FRIDAY WHICH
WILL TURN WINDS MORE TO THE SOUTHEAST AND BECOME A BIT MORE GUSTY.
EXPECTING MORE WIDESPREAD HIGH TEMPERATURES INTO THE 80S. OVERALL
DRY CONDITIONS ARE EXPECTED BUT SOME ELEVATED WEAK INSTABILITY
IN THE MID LEVEL COULD BRING SOME SHOWERS TO AREAS WEST OF THE
JAMES RIVER LATE THURSDAY NIGHT INTO FRIDAY MORNING.
SATURDAY SHOULD PROVE TO BE DRY AS WELL, ALTHOUGH A VERY WEAK WAVE
WILL MOVE NORTH THROUGH CENTRAL SD AND COULD BRING SOME ISOLATED
SHOWERS TO THAT AREA. LOW LEVEL MOISTURE CONTINUES TO INCREASE
AHEAD OF THIS TROUGHINESS TO THE WEST, WHICH WILL INCREASES THE
INSTABILITY THROUGH THE DAY. HOWEVER, AT THIS TIME SOME STRATO
CUMULUS IS EXPECTED TO BE IN PLACE FOR A GOOD CHUNK OF SATURDAY
WHICH WILL LIKELY LEAD TO A SIGNIFICANT CAPPING INVERSION.
SATURDAY NIGHT MAY PROVE TO BE OUR BETTER CHANCE FOR SEVERE WEATHER,
ESPECIALLY WEST OF I-29. FOR NOW THE BETTER CHANCES LOOK TO BE
NORTHWEST OF THE AREA, BUT GIVEN THE STRENGTH OF THE WAVE TO THE
WEST, THE STRENGTH OF THE LLJ AND THE VERY DEEP INSTABILITY, WILL
NEED TO WATCH OUT FOR AN MCS TO BUILD SOUTHEAST INTO THE AREA.
ONCE THIS LLJ BARRELS NORTH ON SUNDAY, THE CHANCES FOR SHOWERS AND
STORMS SHOULD STAY MAINLY NORTH OF THE AREA. SUNDAY WILL BE THE
FIRST HOT DAY WITH HIGHS INTO THE 90S AND HEAT INDICES LIKELY
BETWEEN 95 TO 105.
HOT AND POTENTIALLY HUMID CONDITIONS WILL BUILD INTO THE AREA
THROUGH MUCH OF NEXT WEEK. FASTER SOUTHERLY FLOW ALOFT WILL REMAIN
OVER PARTS OF CENTRAL SD, WHICH MAY ALLOW FOR AN OCCASIONAL CHANCE
FOR SHOWERS AND STORMS AS WELL AS CLOUD COVER, SO WEST OF I-29 WILL
SEE A BETTER CHANCE TO COME UP SHORT ON HIGH TEMPERATURES AT TIMES,
WHILE NEAR AND EAST OF I-29 WILL LIKELY SEE THE BETTER CHANCES FOR
THESE HOTTER CONDITIONS WITH LOWER CHANCES FOR SHOWERS AND
STORMS.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1212 PM CDT THU JUN 25 2026
VFR CONDITIONS WILL PERSIST THIS TAF PERIOD. BESIDES SOME SPOTTY
SHOWERS THIS AFTERNOON ACROSS MISSOURI VALLEY AND NEAR KHON BY
FRIDAY MORNING, MOST AREAS SHOULD REMAIN QUIET. OTHERWISE, LIGHT
AND VARIABLE WINDS THIS AFTERNOON WILL BECOME MARGINALLY BREEZY
SOUTHEASTERLY WINDS INTO FRIDAY AFTERNOON WITH GUSTS BETWEEN
20-30 MPH EXPECTED AT TIMES.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...08
AVIATION...05
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