602
FXUS63 KFSD 120745
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
245 AM CDT SUN JUL 12 2026
KEY MESSAGES
- AN EXTENDED STRETCH OF HOT TEMPERATURES CONTINUES THROUGH LATE
THIS WEEK. HIGHS IN THE 90S TO 100 DEGREES EXPECTED. THE
CUMULATIVE NATURE OF THE HEAT COULD LEAD TO SOME HEAT HEALTH
CONCERNS.
- PATCHY MORNING FOG IS POSSIBLE EACH DAY, BUT WIDESPREAD DENSE
FOG REMAINS UNLIKELY.
- MINIMAL PRECIPITATION IS EXPECTED OVER THE NEXT 7 DAYS, WITH
THE LREF PROBABILITY OF >0.25" THROUGH MONDAY THE 20TH NO
GREATER THAN 20% IN ANY ONE LOCATION.
UPDATE
ISSUED AT 244 AM CDT SUN JUL 12 2026
NO SIGNIFICANT CHANGES TO THE FORECAST EARLY THIS MORNING. WINDS
HAVE REMAINED A BIT ELEVATED THUS FAR, SO HAVE NOT SEEN MUCH IN THE
WAY OF FOG. HOWEVER, MUCH OF THE HI RES GUIDANCE THIS MORNING
CONTINUES TO SHOW AT LEAST SPOTTY FOG DEVELOPMENT IN THE RIVER
VALLEYS AND INTO NORTHWESTERN IA. WIDESPREAD DENSE FOG IS NOT
EXPECTED BUT SOME LOCATIONS COULD SEE VISIBILITY ONCE AGAIN THIS
MORNING BELOW TWO MILES. TEMPERATURES ARE IN THE UPPER 60S AND 70S
WITH CLEAR SKIES.
MINOR ADJUSTMENT (A DEGREE OR TWO) TO THE FORECAST LOWS THIS MORNING
THROUGH THE NEXT COUPLE OF MORNINGS, WITH THE WARMER SOIL
TEMPERATURES AND FORECAST/OB TRENDS. CONFIDENCE REMAINS HIGH IN THE
CONTINUED WARM AND DRY CONDITIONS THROUGH MUCH OF NEXT WEEK, WITH
HIGHS IN THE 90S TO LOWER 100S AND LOWS IN THE UPPER 60S AND 70S.
RELATIVELY LOWER HUMIDITY STILL KEEPS HEAT INDICES JUST BELOW
CRITERIA THROUGH THE EARLY PART OF THE WEEK, BUT WILL CONTINUE TO
MONITOR TRENDS AS WARMER DAYS ARE EXPECTED BY MID WEEK.
ADDITIONALLY, NUMEROUS DAYS OF DRY AND HOT CONDITIONS MAY LEAD TO
SOME LOCALLY ELEVATED FIRE CONCERNS AS FINER FUELS BEGIN TO DRY.
WITH LOTS OF SUNSHINE, THOSE SPENDING TIME OUTDOORS SHOULD TAKE
PRECAUTIONS TO LIMIT BOTH SUN AND HEAT EXPOSURE WITH HIGH UV INDEX
IN ADDITION TO THE HOT TEMPERATURES.
DISCUSSION
ISSUED AT 1221 PM CDT SAT JUL 11 2026
THIS AFTERNOON: IT'S A HOT DAY ACROSS THE REGION WITH PLENTY OF
SUNSHINE. HIGH TEMPERATURES CLIMBING INTO THE 90S IN MOST
LOCATIONS, BUT WITH DEW POINTS MIXING DOWN LOWER INTO THE 60S, HEAT
INDEX VALUES REMAIN BELOW CRITICAL VALUES. THAT SAID, ANYONE
SPENDING TIME OUTDOORS OVER THE NEXT DAYS WILL NEED TO TAKE
PREVENTATIVE ACTIONS FROM A VERY HIGH UV INDEX.
TONIGHT: WINDS AGAIN TURN LIGHT AND VARIABLE THROUGH THE NIGHT. THE
NBM HAS BEEN BIASED A BIT TOO COLD WITH OVERNIGHT LOWS THE PAST
DAYS, BUT WE WILL BEGIN TO SEE DEW POINTS LOWER A BIT AT NIGHT WHICH
COULD LEAD TO SOME LOWS INTO THE UPPER 60S. HREF PROBABILITIES SHOW
LESS POTENTIAL FOR FOG THIS MORNING THAN LAST NIGHT, HOWEVER, THE
FAVORED AREAS WOULD AGAIN BE ACROSS NW IOWA FOR PATCHY MORNING FOG.
SUNDAY: PRETTY MUCH AN IDENTICAL DAY ON SUNDAY, WITH A BIT MORE
SOUTHWESTERLY WIND FETCH WEST OF I-29. THIS WILL RESULT IN HIGH
TEMPERATURE CREEPING A COUPLE DEGREES WARMEST WEST OF I-29. HOWEVER
WITH DEEPER MIXING, DEW POINT MIX DOWNWARDS FURTHER, AND WILL AGAIN
KEEP HEAT INDEX VALUES BELOW CRITICAL THRESHOLDS.
MONDAY-FRIDAY: REALLY NO MAJOR CHANGES IN THE FORECAST FOR THE
UPCOMING WORK WEEK. THE MID-LVL RIDGE CONTINUES TO BUILD THROUGH
THE NORTHERN PLAINS CENTERING ITSELF ALONG THE ND/SD BORDER BY
MONDAY AND THEN BUILDING SOUTHWARD AND BROADENING BY THE MIDDLE OF
THE WEEK ALONG I-90. THE RESULT WILL BE DAILY HIGHS IN THE 90S TO
EVEN LOWER 100S IN A FEW AREAS WEST OF I-29. THE DAILY DIRECTION OF
THE SURFACE WINDS WILL DICTATE SOME VARIANCE IN WARMING, WITH
SOUTHWESTERLY WIND FETCH ALLOWING FOR DEEPER MIXING AND SLIGHTLY
HIGHER AFTERNOON HIGHS. RECORDS THIS WEEK APPEAR TO BE SAFE EVEN
IF 100S ARE REACHED. MOST RECORDS FOR THE UPCOMING WEEK RANGE
FROM 104-113 DEGREES STEMMING FROM SOME SEVERE PAST DROUGHT
YEARS). FORTUNATELY NO EXTREME RISES IN DEW POINTS ARE
EXPECTED, WHICH WILL KEEP HEAT INDEX VALUES BELOW 100 DEGREES IN
MOST AREAS. WILL CONSIDER HEAT HEADLINES FOR PORTIONS OF THE
JAMES RIVER VALLEY AREAS AND WESTWARD BY MONDAY WHERE HIGHS DO
BEGIN TO CROSS THE 100 MARK, BUT HEAT INDEX VALUES REMAIN 1-3
DEGREES BELOW CRITERIA. ECE/GEFS PROBABILITIES CONTINUE TO
HIGHLIGHT THE JAMES RIVER VALLEY WITH A 60%+ PROBABILITY OF
EXCEEDING 100 THROUGH TUESDAY, HOWEVER AS SOUTHWESTERLY WINDS
EXPAND EASTWARD LATE IN THE WEEK, THOSE PROBABILITIES TO EXPAND
INTO THE I-29 CORRIDOR. A SIDE NOTE WITH ALL OF THE HEAT
CONCERNS THIS WEEK. DAILY RH VALUES DO FALL NEAR OR BELOW 20%
WEST OF THE JAMES RIVER INTO THE WEEK WITH AFTERNOON WIND GUSTS
APPROACHING 25 MPH. WE MAY BEGIN TO SEE SOME INCREASE IN FIRE
DANGER GIVEN THE DRY OUT OF FINE FUELS.
SATURDAY-SUNDAY: WE MAY BEGIN TO SEE SOME BREAK IN THE RIDGE BY
NEXT WEEKEND, AS A WEAK MID-LVL WAVE FLOWS NORTHWARD THROUGH THE
PLAINS AND A SECOND WAVE CROSSES NEAR THE CANADIAN BORDER. WHILE
THIS COULD BRING SOME CLOUDS TO NEXT WEEKEND, LOW-LVL MOISTURE
TRANSPORT THROUGH THE CENTRAL PLAINS VEERS OFF QUICKLY EAST, AND THE
CANADIAN WAVE IS ONLY BRINGING LIMITED PACIFIC MOISTURE WITH IT.
PRECIPITATION CHANCES REMAIN LOW AT THIS POINT, WITH LREF GUIDANCE
INDICATING NO MORE THAN A 17% PROBABILITY OF >0.25" OF PRECIPITATION
THROUGH MONDAY MORNING.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1134 PM CDT SAT JUL 11 2026
MAINLY VFR CONDITIONS WILL CONTINUE THIS TAF PERIOD. TAKING A
LOOK AT SATELLITE IMAGERY, MOSTLY CLEAR CONDITIONS CONTINUE THIS
EVENING. THE ONLY AVIATION CONCERNS WILL BE SOME PATCHY RIVER
VALLEY FOG THAT DEVELOPS OVERNIGHT AS SURFACE WINDS LIGHTEN.
WITH OCCASIONAL MVFR TO IFR VSBYS POSSIBLE AT TIMES, DECIDED TO
ADD A TEMPO GROUP TO KSUX. LASTLY, MAINLY SOUTHERLY WINDS WILL
CONTINUE WITH MARGINALLY BREEZY CONDITIONS EXPECTED AT TIMES.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...DUX
AVIATION...05
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