879
FXUS63 KFSD 290850
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
350 AM CDT TUE JUL 29 2025
KEY MESSAGES
- MORE ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS
EVENING AND OVERNIGHT MAINLY ALONG AND SOUTH OF I-90. A FEW
STORMS COULD BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS
BEING THE PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL BE A
SECONDARY THREAT.
- NEXT SHOWER AND THUNDERSTORM CHANCES LIKELY OCCUR OVER THE
WEEKEND. HOWEVER, UNCERTAINTY REMAINS IN THE COVERAGE AND
SEVERITY OF DEVELOPING ACTIVITY.
- TEMPERATURES WILL TREND BELOW NORMAL HEADED INTO THE WEEKEND
WITH HIGHS MAINLY IN THE 70S AND LOW 80S.
DISCUSSION
ISSUED AT 350 AM CDT TUE JUL 29 2025
TODAY & TONIGHT: A SLIGHTLY COOLER DAY AHEAD! TAKING A LOOK AT
SATELLITE IMAGERY, MOSTLY CLEAR CONDITIONS HAVE RETURNED TO THE AREA
WITH A FEW LINGERING AREAS OF STRATUS WEST OF THE JAMES RIVER. WHILE
WE COULD SEE THIS AREA OF STRATUS EXPAND INTO AREAS NORTH OF I-90
THROUGH DAYBREAK, SHOULD SEE MOST AREAS BREAK FREE CLOSER TO MID-
MORNING. FROM HERE, SLIGHTLY COOLER TEMPERATURES ARE AHEAD AS A
COMBINATION OF NORTHERLY TO NORTHEASTERLY SURFACE WINDS AND
LINGERING AREAS OF WILDFIRE SMOKE ALOFT KEEP OUR TEMPERATURES IN THE
80S TO LOW 90S WITH THE WARMEST CONDITIONS SOUTH OF U.S. HIGHWAY-18.
WITH THIS AND DEWPOINTS IN THE UPPER 60S TO MID 70S THIS EVENING,
THE STAGE IS SET FOR OUR NEXT PRECIPITATION CHANCES (30%-70%).
LOOKING ALOFT, ISOLATED SHOWERS AND THUNDERSTORMS LIKELY START
ACROSS CENTRAL SD BY LATE AFTERNOON AS A MID-LEVEL WAVE TRAVERSES
THE STATE. AS THIS WAVE INTERSECTS A SOUTHWARD PROGRESSING 925-850
MB BOUNDARY IN THE WARM SECTOR, SHOULD SEE COVERAGE RAPIDLY EXPAND
MAINLY ACROSS AREAS ALONG AND SOUTH OF I-90 DURING THE EVENING
HOURS. THIS DEVELOPING ACTIVITY WILL LIKELY PROGRESS TO THE EAST-
SOUTHEAST WITH THE BOUNDARY AND INVERTED TROUGH DURING THE OVERNIGHT
HOURS BEFORE EXITING OUR AREA BY WEDNESDAY MORNING. SHIFTING TO THE
SEVERE RISK, WHILE THE BETTER SHEAR WILL BE SLIGHTLY OFFSET FROM THE
BETTER INSTABILITY; THERE SHOULD BE JUST ENOUGH CO-LOCATION ALONG
AND SOUTH OF I-90 FOR A FEW ISOLATED TO SCATTERED STRONG STORMS TO
DEVELOP. WITH PLENTY OF INSTABILITY (2000-3000 J/KG) AND LAPSE RATES
CLOSER TO 7-8 DEGREES C/KM, ANY INITIAL SEMI-DISCRETE STORMS WILL BE
CAPABLE OF PRODUCING UP TO PING-PONG SIZED HAIL (1.5").
AS COVERAGE EXPANDS AND THINGS GROW MORE UPSCALE, SHOULD SEE THE
THREAT TRANSITION TO STRONG WINDS WITH GUSTS UP TO 65 MPH POSSIBLE.
LASTLY, 10-12 KFT WARM CLOUD DEPTHS AND PWATS BETWEEN 1.5 TO 2
INCHES (90TH PERCENTILE) AT TIMES WILL LEAD TO POCKETS OF MODERATE
TO HEAVY RAINFALL DEVELOPING MAINLY ACROSS AREAS SOUTH OF HIGHWAY-
18. WITH THIS IN MIND, IF "TRAINING" OCCURS ACROSS THE SAME AREAS
OVER PROLONGED PERIODS OF TIME, THERE COULD BE SOME FLASH FLOODING
CONCERNS.
WEDNESDAY ONWARDS: HEADING INTO THE MIDWEEK, ANY LINGERING SHOWER
ACTIVITY WILL LIKELY PERSIST THROUGH THE MORNING HOURS OF WEDNESDAY
BEFORE PUSHING TO OUR SOUTHEAST. FROM HERE, FALL-LIKE TEMPERATURES
ARE AHEAD AS LINGERING COLD AIR ADVECTION (CAA) AND EASTERLY TO
NORTHEASTERLY WINDS KEEP OUR TEMPERATURES LOCKED INTO THE 70S
THROUGH THURSDAY. AS UPPER-LEVEL RIDGING BUILDS INTO THE NORTHERN
PLAINS BY FRIDAY, OUR PRECIPITATION CHANCES WEST OF HIGHWAY-281 WILL
INCREASE OVER THE WEEKEND AS A STATIONARY BOUNDARY GRADUALLY
PROGRESSES INTO OUR AREA. WHILE THE SEVERITY OF THIS ACTIVITY
REMAINS UNCERTAIN AT THIS TIME, DECIDED TO LEAVE THE DEFAULT NBM
POPS IN FOR THIS PERIOD. LASTLY, WE'LL LIKELY SEE THE COOLER STRING
OF TEMPERATURES CONTINUE THROUGH AT LEAST SUNDAY WITH HIGHS MAINLY
IN THE 70S TO LOW 80S
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1135 PM CDT MON JUL 28 2025
A MIX OF VFR TO IFR AS A LINE OF THUNDERSTORMS CONTINUE TO PROGRESS
ACROSS THE COUNTY WARNING AREA. CURRENTLY STORMS ARE LOCATED EAST OF
THE SD/MN/IA BORDER. THESE STORMS HAVE A HISTORY OF PRODUCING VERY
STRONG WIND GUSTS IN EXCESS OF 75 MPH. THESE STORMS WILL CONTINUE TO
PROGRESS EASTWARD AND THE STRONGEST STORMS SHOULD BE EAST OF THE
AREA AROUND 29.09Z. IN ADDITION, LINGERING NON-SEVERE SHOWERS AND
THUNDERSTORMS ALONG AND SOUTH OF I-90. THESE SHOULD MOVE EAST AND
DISSIPATE OVER THE NEXT FEW HOURS.
CEILINGS ARE IMPROVING FROM WEST TO EAST AS THE CLOUDS BEGIN TO
BREAK UP AND MOVE OUT. HOWEVER, DUE TO THE RAIN, PATCHY DENSE FOG
AND/OR LOW STRATUS WILL BE POSSIBLE INTO TUESDAY MORNING. EXPECT
THESE TO BURN OFF SHORTLY AFTER SUNRISE.
WINDS TUESDAY WILL BE NORTHEASTERLY SUSTAINED AT 9-12 KTS WITH GUSTS
TO 20 KTS. WINDS BECOME LIGHT TUESDAY EVENING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...05
AVIATION...AJP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page