514  
FXUS63 KFSD 090253  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
953 PM CDT TUE JUL 8 2025  
   
KEY MESSAGES
 
 
- ISOLATED THUNDERSTORMS POSSIBLE ALONG AND WEST OF THE JAMES  
RIVER VALLEY INTO WEDNESDAY MORNING. WHILE NOT LIKELY TO BE  
SEVERE, SOME SMALL HAIL COULD BE POSSIBLE.  
 
- MESOSCALE CONVECTIVE SYSTEM LIKELY TO DEVELOP WEDNESDAY NIGHT  
OVER CENTRAL AND NORTH CENTRAL SOUTH DAKOTA, BUT A HIGH DEAL  
OF UNCERTAINTY ON WHERE THIS CLUSTER OF STORMS KEEPS FORECAST  
CONFIDENCE INTO THURSDAY LOWER.  
 
- GREATEST STORM CHANCES INTO THE WEEKEND FOCUS AROUND THURSDAY  
INTO FRIDAY. MIXED STORM MODES COULD BRING A VARIETY OF  
SEVERE WEATHER RISKS, BUT SLOW STORM MOTION MAY ALSO BRING  
LOCALLY HEAVY RAIN RISKS.  
 
- TRENDS FAVOR DRIER AND SLIGHTLY COOLER WEATHER INTO THE  
WEEKEND, BUT RAIN RISKS MAY RETURN AS EARLY AS SUNDAY INTO  
MONDAY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 216 PM CDT TUE JUL 8 2025  
 
THIS AFTERNOON: WEAK COLD FRONT SLIPPING SOUTHWARD ACROSS THE CWA  
THIS AFTERNOON. SOUNDINGS SUGGEST THE ATMOSPHERE IS RELATIVELY  
UNCAPPED BY MID-AFTERNOON ESPECIALLY OVER SOUTHWEST MN AND  
NORTHERN IOWA, AND WITH A PASSING MID-LVL IMPULSE IN CENTRAL MN,  
AN ISOLATED SPRINKLE/SHOWER OR WEAK THUNDERSTORM COULD DEVELOP  
INTO EARLY EVENING.  
 
TONIGHT: FAIRLY CONSISTENT SIGNALS FOR ISOLATED TO SCATTERED  
ELEVATED CONVECTION FORMING ON THE NOSE OF THE 30 KNOT LLJ INTO  
SOUTH CENTRAL SOUTH DAKOTA AND AREAS WEST OF THE JAMES RIVER AFTER  
MIDNIGHT TONIGHT. THE VEERING LLJ COULD PUSH THIS RISK INTO THE  
SIOUX CITY AREA WEDNESDAY MORNING. POINT SOUNDINGS WOULD SUGGEST  
UPWARDS OF 1200-1500 J/KG MUCAPE, BUT LOWER EFFECTIVE SHEAR AND  
MODEST MID-LVL LAPSE RATES SHOULD PRECLUDE SEVERE STORMS.  
 
WEDNESDAY: LINGERING CONVECTION MAY CONTINUE INTO MID-LATE MORNING,  
BUT SHOULD WEAKEN AS THE LLJ DISSIPATE AND BACKS TOWARDS WESTERN  
SOUTH DAKOTA. TEMPERATURES THEN BEGIN TO WARM INTO THE 80S.  
AGAIN, SOUNDINGS SHOW A NEARLY UNCAPPED ENVIRONMENT IN THE  
AFTERNOON AND EVENING HOURS, BUT THE ABSENCE OF FORCING  
MECHANISM SHOULD PRECLUDE CONVECTIVE DEVELOPMENT. IF A PIECE OF  
MID-LVL VORTICITY DOES MOVE SOUTHEAST EARLIER, THEN WE'LL HAVE  
TO MONITOR FOR ISOLATED TO SCATTERED CONVECTION IN WESTERN MN  
AND FAR EASTERN SOUTH DAKOTA IN THE AFTERNOON/EVENING.  
 
WEDNESDAY NIGHT: A MORE CONSISTENT SIGNALS FOR CONVECTIVE  
DEVELOPMENT WILL BE STRONGER OVER WESTERN SOUTH DAKOTA WEDNESDAY  
EVENING AS A MID-LVL SHORTWAVE ENTERS THE PLAINS. DISCRETE ACTIVITY  
SHOULD BEGIN TO MERGE INTO ONE OR MORE CLUSTERS AS IT BEGINS TO  
TRACK EAST AND SOUTHEAST INTO THURSDAY MORNING. UNCERTAINTY  
CONTINUES ON THE EXACT TRACK OF THESE MCS, WHICH THEORETICALLY  
SHOULD FOLLOW THE INSTABILITY GRADIENT TOWARDS THE CWA AFTER  
MIDNIGHT. WEAKENING MID-LVL SHEAR AND THE OVERALL STABILIZATION OF  
THE BOUNDARY LAYER SHOULD WEAKEN THIS CONVECTION AS IT MOVES INTO  
THE CWA, BUT TRENDS WILL NEED TO BE MONITORED.  
 
THURSDAY: ANOTHER MID-LVL SHORTWAVE ENTERS THE CENTRAL PLAINS ON  
THURSDAY. DEPENDING ON THE TRACK OF OVERNIGHT MCS ACTIVITY, ONE OR  
MORE OUTFLOW BOUNDARIES MAY DEVELOP AND STALL NEAR THE CWA DURING  
THE DAY. IT'S ALSO COMPLETELY POSSIBLE THAT A MORE EASTWARD TRACKING  
AND SLOWER MCS IN THE MORNING COULD STABILIZE THE AREA THOUGH  
THE AFTERNOON. NEVERTHELESS, THESE FEATURES, ALONG WITH A POORLY  
DEFINED FRONT STRETCHING ACROSS CENTRAL SOUTH DAKOTA INTO  
NEBRASKA WILL SERVE AS FOCI FOR CONVECTION LATER IN THE  
AFTERNOON OR EVENING. INSTABILITY IN THE REGION SHOULD BE  
MODERATE TO SIGNIFICANT IN MOST AREAS, BUT TRUE EFFECTIVE SHEAR  
MAY BE A BIT MORE MARGINAL. SHOULD CONVECTION FORM LOCALLY, THEN  
LARGE HAIL UP TO 2" MAY BE POSSIBLE ALONG WITH 70 MPH WINDS.  
WE'LL ALSO WATCH ONE OR MORE MCS DEVELOPING FURTHER WEST AND  
TRACK TOWARDS THE CWA INTO FRIDAY MORNING. THE INCREASE IN THE  
NOCTURNAL LLJ AND INCREASING LOW-LVL SHEAR COULD INCREASE THE  
SEVERE RISK OVERNIGHT, AS WELL AS THE LOCALIZED HEAVY RAIN  
THREAT (PWAT AOA 130-150% OF NORMAL). THE DIFFICULTY IS  
PINPOINTING THE CORRIDOR OF HEAVY RAIN AS MOST PROBABILISTIC  
DATA IS WASHED OUT GIVEN THE LARGE VARIETY IN CONVECTIVE  
SCENARIOS. CURRENT ENSEMBLE APPROACH WOULD PLACE THE GREATEST  
RISKS OF EXCESSIVE RAINFALL OVER PORTIONS OF NORTHWESTERN IOWA  
AND ADJACENT AREAS OF MN/SD/ND.  
 
FRIDAY: THERE HAS BEEN A SLIGHT SLOWDOWN IN THE PASSAGE OF A MID-  
LVL TROUGH ON FRIDAY, OWING TO HIGHER RAIN CHANCES CONTINUING INTO  
THE EARLY AFTERNOON HOURS. WHILE NOT LIKELY TO BE SEVERE, THIS  
CONTINUED RAIN RISK COULD IMPACT ANY OUTDOOR EVENTS IN THE AREA  
BEFORE NORTHERLY LOW-LVL FLOW CLEAR PRECIPITATION BY MID-AFTERNOON/  
 
SATURDAY-MONDAY: SATURDAY INTO SUNDAY CONTINUES TO REMAIN DRY  
THROUGH THE AREA AS WEAK MID-LVL RIDGING MOVES INTO THE PLAINS.  
HOWEVER, THE OVERALL SYNOPTIC PATTERN CONTINUES TO FLATTEN IN  
CONSECUTIVE MODEL RUNS, ALREADY SHOWING A RETURN TO A MORE ACTIVE  
ZONAL FLOW BY LATE SUNDAY INTO MONDAY. SATURDAY WILL FEATURE COOLER  
TEMPERATURES, WITH TEMPERATURES RISING ON SUNDAY BACK TOWARDS  
THE 90S. THE RETURN OF MEANINGFUL LOW-LVL MOISTURE AND  
INSTABILITY SUGGESTS THE INCREASED SEVERE WEATHER PROBABILITIES  
EARLY NEXT WEEK IN MACHINE LEARNING MODELS HAVE SOME VALIDITY  
AND THUS SHOULD BE MONITORED.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
 
 
ISSUED AT 950 PM CDT TUE JUL 8 2025  
 
ISOLATED SHOWERS/THUNDERSTORMS WILL BE POSSIBLE THROUGH CENTRAL  
SD INTO THE JAMES RIVER VALLEY LATE TONIGHT INTO WEDNESDAY  
MORNING. ALTHOUGH THIS ACTIVITY COULD APPROACH KHON AND KSUX, AT  
THIS TIME GUIDANCE WOULD SUGGEST THAT THIS ACTIVITY WILL REMAIN  
WEST OF THE TAF SITES. ANY SHOWERS/STORMS WOULD END BY MID  
MORNING ON WEDNESDAY. ADDITIONAL SHOWERS AND THUNDERSTORMS MAY  
DEVELOP THROUGH CENTRAL SD ON WEDNESDAY EVENING, AND THIS  
ACTIVITY COULD AFFECT KHON TOWARD THE END OF THE TAF PERIOD.  
 

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

 
 

 
 
DISCUSSION...DUX  
AVIATION...JM  
 
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