092  
FXUS63 KFSD 220335  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
1035 PM CDT SUN JUL 21 2024  
   
KEY MESSAGES
 
 
- FOG IS POSSIBLE LATE TONIGHT INTO MONDAY MORNING, WITH THE  
BETTER CHANCES NEAR AND EAST OF I-29 AND WEST OF THE JAMES  
RIVER WHICH SAW RAIN THIS EVENING.  
 
- ISOLATED TO SCATTERED DAILY SHOWERS AND THUNDERSTORMS CONTINUE THROUGH  
TUESDAY. SEVERE STORMS ARE NOT EXPECTED, BUT SOME SMALL HAIL  
AND OCCASIONAL FUNNELS OR LANDSPOUT TORNADOES COULD BE  
POSSIBLE.  
 
- TEMPERATURES BEGIN TO WARM FOR THE SECOND HALF OF THE WEEK  
THROUGH NEXT WEEKEND. HIGH PROBABILITIES (>70%) FOR  
TEMPERATURES AT OR ABOVE 90 DEGREES ARE LIKELY ALONG AND WEST  
OF THE JAMES RIVER VALLEY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 257 PM CDT SUN JUL 21 2024  
 
BROAD TROUGHINESS WITH VERY WEAK MID LEVEL WAVES ROTATING THROUGH  
THE FLOW WILL CONTINUE INTO TUESDAY WHICH WILL LEAD TO OCCASIONAL  
PERIODS OF ISOLATED SHOWERS AND THUNDERSTORMS. NONE OF THE  
THUNDERSTORMS ARE EXPECTED TO BE SEVERE, BUT BRIEF HEAVY RAIN AND  
LIGHTNING WILL BE POSSIBLE. ISOLATED FUNNELS AND VERY BRIEF  
LANDSPOUT TORNADOES DURING THE AFTERNOON AND EARLY EVENING WILL ALSO  
BE POSSIBLE WITH FAIRLY LOW LFC'S AND VERY WEAK FLOW IN THE LOW  
LEVELS. BECAUSE OF THIS WEAK FLOW AND MOSTLY CLEAR SKIES AT NIGHT  
FOG WILL BE POSSIBLE IN THE MORNING. AS FOR TEMPERATURES THEY WILL  
REMAIN A BIT BELOW NORMAL, BUT ONLY BY A COUPLE OF DEGREES AS  
TEMPERATURES SLOWLY WARM MONDAY INTO TUESDAY WITH MORE WIDESPREAD  
HIGHS IN THE LOWER 80S.  
 
DRIER AND WARMER WEATHER RETURNS THURSDAY INTO SATURDAY AS UPPER  
LEVEL RIDGING BUILDS ACROSS THE PLAINS. SHOULD SEE WIDESPREAD HIGHS  
IN THE MID AND UPPER 80S WITH LOWS GENERALLY IN THE 60S, ALTHOUGH BY  
LATE IN THE WEEK LOWS MAY ONLY FALL INTO THE LOWER 70S AND HIGHS  
WEST OF I-29 SHOULD REACH THE LOWER 90S. IF ANY THUNDERSTORMS CAN  
DEVELOP IT APPEARS THE BETTER CHANCE WOULD BE IN CENTRAL THROUGH  
NORTHEAST SD WHERE THE AXIS OF BETTER INSTABILITY SHOULD BE. BY  
SUNDAY MODELS DO START TO HINT AT SOME WEAK ENERGY ACROSS THE  
NORTHERN PLAINS WHICH COULD SPARK A SHOWER OR THUNDERSTORM. OF  
COURSE THIS FAR OUT CONFIDENCE REMAINS ON THE LOWER SIDE.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
 
 
ISSUED AT 1027 PM CDT SUN JUL 21 2024  
 
CALM WINDS PREVAIL OVERNIGHT INTO MONDAY MORNING, SO EXPECT FOG  
TO DEVELOP ONCE AGAIN TONIGHT. MODELS SHOW THE GREATEST CHANCES  
OF IFR CONDITIONS OR LOWER TO BE IN RIVER VALLEYS, AND FOR AREAS  
WHICH SAW SHOWERS/STORMS SUNDAY EVENING. MVFR CONDITIONS MAY BE  
MORE WIDESPREAD FOR AREAS EAST OF I-29 THAN TO THE WEST. FOG  
TONIGHT IS EXPECTED TO BE SHALLOW, AND SHOULD MIX OUT QUICKLY  
MID TO LATE MONDAY MORNING.  
 
ISOLATED SHOWERS AND STORMS DEVELOP ONCE AGAIN DURING THE  
AFTERNOON AND EVENING MONDAY. BRIEF HEAVY DOWNPOURS AND  
LIGHTNING ARE THE MAIN THREATS.  
 
OUTSIDE OF FOG AND CONVECTION, VFR CONDITIONS ARE EXPECTED.  
 

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

 
 

 
 
DISCUSSION...08  
AVIATION...SG  
 
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