007  
FXUS63 KFSD 070313  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
1013 PM CDT SAT SEP 6 2025  
   
KEY MESSAGES
 
 
- FROST IS POSSIBLE SUNDAY MORNING. BETTER CHANCES WILL BE IN  
SOUTHWEST MN AND EAST CENTRAL SD WHERE TEMPERATURES MAY FALL  
INTO THE LOWER 30S.  
 
- CHANCES FOR ISOLATED TO SCATTERED THUNDERSTORMS MONDAY. SOME COULD  
BE STRONG TO SEVERE.  
 
- ADDITIONAL CHANCES FOR THUNDERSTORMS IN THE LATTER HALF OF  
NEXT WEEK. TEMPERATURES SHOULD BE NEAR TO A BIT ABOVE NORMAL  
ALL WEEK.  
 

 
   
UPDATE
 
 
ISSUED AT 419 PM CDT SAT SEP 6 2025  
 
LATEST DATA PROVIDING A STRONGER SUGGESTION THAT TEMPERATURES  
WILL DROP INTO THE MIDDLE 30S A BIT MORE WIDESPREAD THAN EARLIER  
THOUGH. WINDS ARE EXPECTED TO WEAKEN RATHER QUICKLY THIS  
EVENING, WITH DIURNAL CU FIELD DISSIPATING AND LEADING TO RAPID  
RADIATIONAL COOLING. BASED ON SATURDAY MORNING'S LOWS, COULD SEE  
A FEW AREAS FALL INTO THE LOWER 30S, ESPECIALLY IN AREAS FROM  
BROOKINGS TO PIPESTONE, TO SHELDON. WILL GO AHEAD AND ISSUE A  
FROST ADVISORY IN AREAS WHERE PROBABILITIES OF SUB-36 DEGREE  
TEMPERATURES ARE THE HIGHEST (>60%). ADDITIONALLY, AREAS NEAR  
SIOUX CITY MAY ONCE AGAIN SEE NEAR TO RECORD LOW TEMPERATURES.  
 

 
   
DISCUSSION
 
 
ISSUED AT 209 PM CDT SAT SEP 6 2025  
 
ANY DIURNALLY DRIVEN CUMULUS THIS AFTERNOON WILL RAPIDLY DIMINISH  
AROUND SUNSET AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.  
THIS WILL LEAD TO LIGHT WINDS AND COOL TEMPERATURES WITH PATCHY  
FROST POSSIBLE. THE BETTER CHANCES WILL BE IN EAST CENTRAL SD  
AND SOUTHWEST MN. WHILE WIDESPREAD FROST IS NOT EXPECTED, IF YOU  
HAVE ANYTHING OUTSIDE THAT MIGHT BE SUSCEPTIBLE TO FROST, BRING  
IT INSIDE. OTHERWISE LOWS SHOULD BE IN THE MID 30S TO LOWER  
40S.  
 
SUNDAY MORNING WILL START OFF CHILLY, BUT WITH ABUNDANT SUNSHINE,  
LIGHT WINDS AND HIGHS IN THE UPPER 60S TO LOWER 70S A VERY PLEASANT  
LATE SUMMER/EARLY FALL DAY IS EXPECTED.  
 
SUNDAY NIGHT INTO EARLY MONDAY MORNING UPPER LEVEL SUPPORT SPREADS  
ACROSS THE HIGH PLAINS AND WARM ADVECTION DEVELOPS IN THE MID LEVELS  
AHEAD OF THIS ENERGY. MODEL SOUNDINGS CONTINUE TO INDICATE SOME  
MOISTURE AROUND 800 MB AS THE WARM AIR ADVECTION DEVELOPS WHICH  
BRINGS SOME WEAK INSTABILITY, BUT CONFIDENCE TOO LOW TO INCLUDE ANY  
SHOWER OR THUNDERSTORM THREAT. WOULD NOT BE SURPRISED IF SOME  
ACTIVITY DEVELOPS, JUST LOW CONFIDENCE ON WHERE.  
 
ON MONDAY THIS UPPER LEVEL ENERGY MOVES INTO WESTERN AND NORTHERN SD  
WITH A SURFACE FRONT EXPECTED TO WORK INTO CENTRAL SD. AHEAD OF THIS  
FRONT THE ATMOSPHERE BECOMES MODERATELY UNSTABLE WITH CAPE VALUES  
ROUND 1500 J/KG LIKE. SHEAR IS WEAK, BUT GIVEN THE EXPECTED  
INSTABILITY AN ISOLATED SEVERE STORM IS NOT OUT OF THE QUESTION. THE  
BETTER CHANCES WOULD BE IN CENTRAL SD LATE AFTERNOON AND EARLY  
EVENING IF ANYTHING CAN BREAK THE CAPPING INVERSION AND THEN ACROSS  
THE REMAINDER OF THE AREA FROM MID EVENING INTO THE EARLY OVERNIGHT  
HOURS AS THE WAVE MOVES EAST AND LLJ VEERS AND FOCUSES EAST OF I-29  
AFTER MIDNIGHT.  
 
TUESDAY INTO WEDNESDAY SHOULD BE MAINLY DRY AS UPPER LEVEL RIDGING  
SLOWLY BUILDS AHEAD OF A DEEPENING LARGE SCALE TROUGH TO THE WEST.  
SOME LINGERING WARM AIR ADVECTION EAST OF I-29 ON TUESDAY MORNING  
COULD SUPPORT AND ISOLATED SHOWER OR THUNDERSTORM.  
 
WEDNESDAY NIGHT INTO SATURDAY WILL SEE THIS UPPER LEVEL RIDGE  
PARTIALLY BREAK DOWN WITH SOUTHWESTERLY UPPER LEVEL JET ENERGY  
BRINGING OCCASIONAL WAVES ONTO THE NORTHERN PLAINS DURING THIS TIME.  
THIS WILL LIKELY BRING A FEW ROUNDS OF SHOWERS AND THUNDERSTORMS AND  
WITH SOME INSTABILITY SOME ISOLATED CHANCES FOR SEVERE WEATHER.  
CURRENTLY THE DEEPER SHEAR DOES NOT APPEAR TO SUPPORT ANY ORGANIZED  
SEVERE WEATHER POTENTIAL.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
 
 
ISSUED AT 1011 PM CDT SAT SEP 6 2025  
 
VFR CONDITIONS WITH LIGHT WINDS CONTINUE THROUGH THE NIGHT.  
SUNSET SATELLITE IMAGERY CLEARLY SHOWED A THIN SMOKE LAYER  
ALOFT, SO WILL INCLUDE A HIGH BASED CEILING IN TAF THROUGH MID-  
MORNING SUNDAY.  
 
A FEW DIURNAL CU POSSIBLE AGAIN SUNDAY AFTERNOON, WITH SOME  
INDICATIONS THAT A SCATTERED MID-LVL DECK MAY BEGIN TO FORM AND  
MOVE NORTHEAST SUNDAY EVENING.  
 

 
   
FSD WATCHES/WARNINGS/ADVISORIES
 
 
SD...FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR SDZ038>040-  
052>056.  
MN...FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR MNZ071-080-089-  
090-097-098.  
IA...FROST ADVISORY FROM 3 AM TO 9 AM CDT SUNDAY FOR IAZ001>003-  
012>014-021.  
NE...NONE.  
 

 
 

 
 
UPDATE...DUX  
DISCUSSION...08  
AVIATION...DUX  
 
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