230
FXUS63 KFSD 091742
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1242 PM CDT TUE SEP 9 2025
KEY MESSAGES
- SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EAST OF I-29 WILL
CONTINUE TO MOVE EASTWARD THIS AFTERNOON. ADDITIONAL ISOLATED
DEVELOPMENT WILL BE POSSIBLE EAST OF INTERSTATE 29 LATE THIS
AFTERNOON/EVENING. RISK OF SEVERE STORMS IS LOW.
- CANADIAN WILDFIRE SMOKE DRIFTS ACROSS THE REGION TODAY,
LINGERING THROUGH AT LEAST MID-WEEK.
- TEMPERATURES WARM TO WELL ABOVE NORMAL FOR THURSDAY THROUGH
SATURDAY.
- LOW (<40%) RAIN CHANCES SPREAD IN NEXT WEEKEND, BUT CONFIDENCE
IN DETAILS IS LOW AT THIS TIME.
DISCUSSION
ISSUED AT 325 AM CDT TUE SEP 9 2025
A MID LEVEL SHORTWAVE TRACKING ACROSS THE REGION HAS TRIGGERED
ISOLATED SHOWERS AND THUNDERSTORMS WEST OF INTERSTATE 29 VERY EARLY
THIS MORNING. HI-RES GUIDANCE HAS NOT HANDLED THIS ACTIVITY
ESPECIALLY WELL, THOUGH AS THE WAVE TRACKS INTO CENTRAL IA/MN BY MID
MORNING ANY REMAINING SHOWERS AND STORMS ARE EXPECTED TO COME TO AN
END. MAY SEE ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT EAST OF
INTERSTATE 29 LATE THIS AFTERNOON/EVENING AS ANOTHER WEAK SHORTWAVE
DROPS THROUGH MN ON THE BACKSIDE OF THE EXITING UPPER LEVEL TROUGH.
BASED ON LATEST HI-RES GUIDANCE THIS ACTIVITY WOULD BE ISOLATED IF
IT DEVELOPS AT ALL. ALTHOUGH THERE WILL BE INSTABILITY IN PLACE
(MLCAPE AROUND 1200 J/KG), WITH WEAK MID/UPPER LEVEL WINDS AND NO
SIGNIFICANT FORCING, THE RISK OF SEVERE STORMS IS LOW. OTHERWISE,
FAIRLY THICK CANADIAN WILDFIRE SMOKE WILL CONTINUE TO STREAM OVER
THE AREA TODAY. CURRENT GUIDANCE INDICATES THAT SOME OF THIS SMOKE
MAY MIX DOWN TO THE SURFACE, THOUGH THE GREATER RISK OF THIS WILL
RESIDE OVER SOUTH CENTRAL SD. IN TERMS OF TEMPERATURES TODAY, 850 MB
TEMPERATURES INCREASE SLIGHTLY OVER YESTERDAY, AND LOOKING AT HIGHS
IN THE MID 70S EAST OF INTERSTATE 29 TO MID 80S TO THE WEST.
AFTER TODAY, THE MAIN STORY WILL BE WARMING TEMPERATURES AS UPPER
LEVEL RIDGING BUILDS OVER THE REGION THROUGH FRIDAY. ENSEMBLES
CONTINUE TO INDICATE 700/850 MB TEMPERATURES IN THE 90TH PERCENTILE
OR GREATER WITH RESPECT TO CLIMATOLOGY FOR THURSDAY THROUGH
SATURDAY. THIS WILL BE REALIZED WITH TEMPERATURES WELL ABOVE
SEASONAL AVERAGES DURING THIS PERIOD, WITH HIGHS IN THE 80S TO LOWER
90S. ALONG WITH THAT WILL COME AFTERNOON DEW POINTS IN THE MID 60S,
BRINGING A TASTE OF SUMMER BACK TO THE AREA. SHOWER AND THUNDERSTORM
CHANCES REMAIN LOW (LESS THAN 20%) FOR WEDNESDAY THROUGH FRIDAY.
RAINFALL CHANCES INCREASE A BIT BY NEXT WEEKEND AS THE UPPER LEVEL
RIDGE SHIFTS TO THE EAST WHEN A WESTERN CONUS TROUGH NUDGES INTO OUR
AREA. SHORTWAVES TRAVERSING THE SOUTHWESTERLY UPPER FLOW WILL BRING
A BETTER POTENTIAL FOR SHOWER AND THUNDERSTORM ACTIVITY DURING THE
PERIOD. IN THAT PATTERN, MAY SEE A POSSIBILITY OF SOME SEVERE
STORMS, WITH CURRENT MACHINE LEARNING PROBABILITIES FOCUSING ON A
BETTER POTENTIAL AS WE MOVE INTO SUNDAY. EVEN SO, THERE ARE STILL
MANY DETAILS THAT NEED TO BE REFINED THIS FAR OUT.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1242 PM CDT TUE SEP 9 2025
SCATTERED SHOWERS/ISOLATED THUNDER HAVE NOW MOVED EAST OF TAF
AIRFIELDS AS OF 09.1730Z. WHILE SOME ADDITIONAL ISOLATED
ACTIVITY IS POSSIBLE LATE AFTERNOON/EVENING AT KFSD/KSUX, NOT
ENOUGH CONFIDENCE IN SPATIAL COVERAGE TO INCLUDE IN 18Z
FORECAST.
BIGGER CONCERN WILL BE TIMING OF LOW STRATUS AT KFSD/KSUX THAT
HAS BEEN STUBBORN TO LIFT/DISSIPATE THIS MORNING. MOST RECENT
GUIDANCE SUGGESTS IMPROVING CONDITIONS TO VFR BY MID-AFTERNOON,
BUT WILL NEED TO MONITOR TRENDS AND UPDATE AS NECESSARY. ONCE
THESE LOWER CLOUDS MOVE OUT, EXPECT VFR THROUGH THE REMAINDER
OF THE EVENING.
SOME HINTS AT FOG POTENTIAL OVERNIGHT AT KFSD/KSUX. WILL
INTRODUCE 3SM/BR AT 10.13Z. ANY FOG THAT DOES DEVELOP IS EXPECTED
TO DISSIPATE BY MID-WEDNESDAY MORNING.
WINDS THROUGH THE PERIOD WILL BE LIGHT, GENERALLY FROM THE
SOUTH-SOUTHEAST DURING DAYLIGHT HOURS AND LIGHT/VARIABLE
OVERNIGHT.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...JM
AVIATION...ROGERS
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