438  
FXUS63 KFSD 151851  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
151 PM CDT WED JUL 15 2026  
   
KEY MESSAGES
 
 
- HOT CONDITIONS CONTINUE INTO THE WEEKEND. HIGHS IN THE 90S TO  
AROUND 100 EXPECTED. FRIDAY APPEARS TO BE THE HOTTEST DAY.  
DEW POINTS REMAIN A BIT BELOW SEASONAL NORMALS, AIDING IN  
LOWER RELATIVE HUMIDITY. HOWEVER, THE CUMULATIVE NATURE OF THE  
HEAT COULD LEAD TO SOME HEAT IMPACTS.  
 
- VERY PATCHY MORNING FOG IS POSSIBLE DAILY, BUT WIDESPREAD  
DENSE FOG REMAINS UNLIKELY. FOG WILL LIKELY BE CONFINED TO  
RIVER VALLEYS AND NEARBY AREAS, BUT COULD REDUCE VISIBILITY  
BELOW TWO MILES AT TIMES.  
 
- PRECIPITATION IS VERY UNLIKELY (LESS THAN 10%) THROUGH  
SATURDAY NIGHT. SUNDAY INTO MONDAY CHANCES RISE TO 15-25%,  
WITH SOME GROWING CONFIDENCE THE BETTER CHANCES WILL BE SUNDAY  
EVENING INTO THE NIGHT.  
 

 
   
DISCUSSION
 
 
ISSUED AT 150 PM CDT WED JUL 15 2026  
 
VERY LITTLE CHANGE TO THE FORECAST FOR THE NEXT SEVERAL DAYS AS  
UPPER LEVEL RIDGING CONTINUES TO PRODUCE HOT TEMPERATURES. SO FAR  
WITH DEW POINTS MOSTLY IN THE 60S, HEAT INDICES AND HEAT RISKS HAVE  
REMAINED A BIT MUTED, BUT IF YOU NEED TO BE OUTDOORS TAKE ANY  
NECESSARY HEAT PRECAUTIONS AS IT IS STILL IN THE 90S. WITH A BIT  
STRONGER SOUTHERLY WIND TONIGHT AND THURSDAY NIGHT OVERNIGHT LOWS  
WILL TREND WARMER, LIKELY ONLY FALLING TO 70 TO 75 DEGREES. FOG  
CHANCES MAY BE LOWER AS WELL BECAUSE OF THE WIND.  
 
FRIDAY WILL SEE A FRONT APPROACH FROM THE NORTH AS NORTHWEST FLOW  
ALOFT INCREASES A BIT, WHICH SHOULD AID IN BRINGING SURFACE WINDS  
AROUND TO A BIT MORE SOUTHWESTERLY DIRECTION. THIS SHOULD HELP WITH  
DEEPER MIXING AND LIKELY HIGHER TEMPERATURES, WITH MOST LOCATIONS  
CLIMBING TO 95 TO 102 DEGREES, WARMEST IN CENTRAL SD. RIGHT NOW  
FRIDAY APPEARS TO SEE THE BEST CHANCE FOR A HEAT HEADLINE. THIS  
FRONT WILL SLIDE INTO THE AREA FRIDAY NIGHT INTO SATURDAY MORNING,  
BUT IS NOT EXPECTED TO PRODUCE ANY SHOWERS OR STORMS.  
 
A BIT BETTER DIP IN UPPER LEVEL FLOW MOVES THROUGH SUNDAY NIGHT  
WHICH LOOKS LIKE THE BEST CHANCE FOR ISOLATED TO SCATTERED SHOWERS  
AND STORMS. FOR NOW SUNDAY APPEARS TO BE ON THE DRY SIDE WITH ANY  
SHOWER AND STORM CHANCES MOVING IN SUNDAY NIGHT. THERE SOME HINTS OF  
ELEVATED MOISTURE AND VERY WEAK INSTABILITY ON SUNDAY MORNING AROUND  
10-15 KFT WHICH COULD PRODUCE SOME WEAK ACCAS SHOWERS, BUT  
CONFIDENCE VERY LOW ON THIS.  
 
STRONGER WEST AND NORTHWEST FLOW ALOFT CONTINUES ALONG THE CANADIAN  
BORDER INTO NORTHERN MN EARLY NEXT WEEK, POSSIBLY BECOMING A BIT  
MORE PRONOUNCED BY MONDAY NIGHT INTO WEDNESDAY. THIS SHOULD SUPPORT  
TEMPERATURES BACK TO AROUND NORMAL OR MAYBE A TOUCH BELOW. THIS MAY  
BRING SOME PATCHY SHOWERS AND STORMS TO THE AREA AS WELL.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
 
 
ISSUED AT 1147 AM CDT WED JUL 15 2026  
 
VFR THROUGH THE PERIOD. SOME 3-6 KFT DIURNALLY DRIVEN CUMULUS IS  
EXPECTED THROUGH ABOUT SUNSET. PATCHY FOG WILL AGAIN BE POSSIBLE  
BUT IMPACTS WILL BE MINIMAL.  
 

 
   
CLIMATE
 
 
ISSUED AT 252 AM CDT WED JUL 15 2026  
 
DAILY RECORD HIGHS FOR OUR FOUR CLIMATE SITES (HURON, MITCHELL,  
SIOUX FALLS, AND SIOUX CITY) ARE ALL SQUARELY INTO THE 100-110+  
RANGE THROUGH THE NEXT WEEK, SO NOT EXPECTING ANY RECORD HIGHS.  
RECORD WARM LOWS ARE IN THE UPPER 70S TO LOWER 80S SO AGAIN, NOT  
EXPECTED ANY RECORDS HERE EITHER AT THIS TIME.  
 
LOOKING AT THE DURATION OF THE HEAT VIA CONSECUTIVE 90+ DEGREE DAYS,  
WE MAY APPROACH THE TOP 10 LIST FOR SOME LOCATIONS IF 90+ DEGREE  
HIGHS REMAIN IN PLACE THROUGH EARLY NEXT WEEK. WITH HEAT LOOKING TO  
BREAK INTO THE 80S MID TO LATE NEXT WEEK, WE WILL NOT BE ANYWHERE  
CLOSE TO THE LONGEST STREAK OF 90S FOR ANY CLIMATE SITES.  
 
LONGEST STREAK (YEAR OF OCCURRENCE):  
- HON: 23 DAYS (1941, 1974)  
- MHE: 27 DAYS (1936)  
- FSD: 19 DAYS (1910)  
- SUX: 27 DAYS (1936)  
 
TO BREAK INTO THE TOP 10 LIST, WE'D HAVE TO MATCH OR EXCEED THE  
FOLLOWING STREAKS FOR EACH CLIMATE SITES:  
 
- HON: 11 DAYS; OCCURRED 6 TIMES, LAST IN 1991  
- MHE: 15 DAYS; OCCURRED 3 TIMES, LAST IN 1964  
- FSD: 11 DAYS; OCCURRED 4 TIMES, LAST IN 1989  
- SUX: 12 DAYS; OCCURRED 5 TIMES, LAST IN 1955  
 
CURRENT (THROUGH TUESDAY, 7/13) STREAKS ARE:  
- HON: 4 DAYS; STREAK BEGAN JULY 10  
- MHE: 4 DAYS; STREAK BEGAN JULY 10  
- FSD: 2 DAYS; STREAK BEGAN JULY 12  
- SUX: 0 DAYS; LAST HIT 90+ ON JULY 8  
 

 
   
FSD WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
MN...NONE.  
IA...NONE.  
NE...NONE.  
 

 
 

 
 
DISCUSSION...08  
AVIATION...08  
CLIMATE...SG  
 
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