365
FXUS63 KFSD 301815
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
115 PM CDT WED JUL 30 2025
KEY MESSAGES
- A FEW SCATTERED SHOWERS WITH AN OCCASIONAL RUMBLE OF THUNDER
WILL BE POSSIBLE TODAY. HOWEVER, SEVERE WEATHER IS NOT
EXPECTED.
- NEXT SHOWER AND THUNDERSTORM CHANCES LIKELY OCCUR OVER THE
WEEKEND. HOWEVER, UNCERTAINTY REMAINS IN THE COVERAGE AND
SEVERITY WITH THIS DEVELOPING ACTIVITY.
- TEMPERATURES WILL TREND BELOW NORMAL HEADED INTO THE WEEKEND
WITH HIGHS MAINLY IN THE 70S AND LOW 80S.
UPDATE
ISSUED AT 956 AM CDT WED JUL 30 2025
WILL BE KEEPING AN EYE ON AN MCV THAT IS IN SOUTH CENTRAL SD
THIS MORNING AND IS EXPECTED TO DRIFT EASTWARD. THE HI-RES
MODELS THAT HAVE THIS FEATURE ARE INDICTING SCATTERED SHOWERS
AND THUNDERSTORMS DEVELOPING BY EARLY AFTERNOON, MAINLY SOUTH
OF I-90. THAT AREA HAS HAD QUITE A BIT OF RAIN THE PAST WEEK.
STORM MOTION LOOKS PRETTY SLOW AND MODEL SOUNDINGS HAVE
RELATIVELY WEAK CAPE (500-1000 J/KG) WITH THE FREEZING LEVEL
AROUND 12-13 KFT, SO LIKELY SOME EFFICIENT RAINERS. THE HRRR AND
ARW SEEM TO BE HANDLING THINGS BEST THUS FAR. THE NAM 3KM AND
NSSL HAVE CONVECTION IN NORTHWEST IA FROM 12-15Z THIS MORNING
WHICH IS NOT HAPPENING SO THEY ARE BEING RULED OUT. THE MODELS
HANDLING THE MCV BETTER ARE PRODUCING A SMALL AREA OF 1-3",
POSSIBLY UP TO 4" WHICH WOULD FALL OVER A SHORT PERIOD OF TIME
WITH THE FOCUSED AREA SOUTH OF I-90 IN FAR SOUTHEAST SD THEN
INTO NORTHWEST IA. FOR NOW THE BETTER CHANCES WILL BE BETWEEN
SIOUX FALLS AND SIOUX CITY, BUT WILL MONITOR FOR ANY CHANGES IN
THIS SUBTLE, WEAKLY FORCED ENVIRONMENT.
DISCUSSION
ISSUED AT 302 AM CDT WED JUL 30 2025
TODAY & TONIGHT: ANOTHER DREARY DAY AHEAD! TAKING A LOOK ACROSS THE
AREA, THE FOCUS CONTINUE TO BE ON A REMNANT AREA OF LIGHT TO
MODERATE SHOWERS PROGRESSING INTO CENTRAL IA THIS MORNING. WHILE
THIS ACTIVITY WILL LIKELY LEAD TO ABOUT AN ADDITIONAL 0.25" TO 0.50"
AN INCH ACROSS PORTIONS OF NORTHWESTERN IA, THE HEAVY RAINFALL
THREAT HAS MOSTLY COME TO AN END WITH MOST OF THIS ACTIVITY EXPECTED
TO LEAVE OUR FAR SOUTHEASTERN ZONES BETWEEN 08Z-10Z (3 TO 5 AM).
FROM HERE, ANOTHER DREARY DAY IS AHEAD AS A LINGERING STRATUS/MID-
LEVEL DECK STICKS AROUND FOR THE MAJORITY OF THE DAY. THIS ALONG
WITH LIGHT NORTHEASTERLY SURFACE WINDS AND LINGERING MID-LEVEL COLD
AIR ADVECTION (CAA) SHOULD HELP KEEP OUR TEMPERATURES BELOW NORMAL
WITH HIGHS LIKELY PEAKING IN THE MID TO UPPER 70S FOR THE DAY.
LASTLY, COULD SEE SOME SCATTERED SHOWERS DEVELOP ACROSS PARTS OF THE
AREA FROM THE LATE MORNING TO LATE AFTERNOON AS A WEAK MID-LEVEL
WAVE MOVES THROUGH THE AREA. WHILE SEVERE WEATHER IS NOT EXPECTED,
THERE SHOULD BE JUST ENOUGH INSTABILITY (300-600 J/KG) AND SHEAR (30-
35 KTS) FOR AN OCCASIONAL STROKE OF LIGHTNING WITH STRONGER UPDRAFTS.
NONETHELESS, MOST OF THIS ACTIVITY SHOULD GRADUALLY DIMINISH INTO
THE EVENING.
THURSDAY & FRIDAY: LOOKING INTO THE LATTER PARTS OF THE WEEK,
QUIETER CONDITIONS WILL TEMPORARILY RETURN BY THURSDAY AS SURFACE
HIGH SLIDES DOWN FROM SASKATCHEWAN/MANITOBA. WHILE THIS WILL LIKELY
HELP KEEP OUR RAIN CHANCES AT BAY (FOR NOW), THIS ALONG WITH
LINGERING CAA ALOFT WILL ALSO HELP BRING IN SOME FALL-LIKE
TEMPERATURES TO START THE MONTH OF AUGUST WITH DAILY HIGHS LIKELY
SITTING IN THE LOW TO UPPER 70S HEADED INTO THE WEEKEND. SHIFTING
GEARS HERE, WE'LL HAVE TO WATCH FOR POTENTIAL FOG DEVELOPMENT EACH
NIGHT AS LIGHTER WINDS WITH THE SURFACE HIGH AND LINGERING LOW-LEVEL
MOISTURE DUE CORN SWEAT COULD CREATE AN IDEAL ENVIRONMENT FOR PATCHY
DEVELOPMENT MAINLY EAST OF I-29. LASTLY, AS THE MID TO UPPER-LEVEL
PORTIONS OF THE RIDGE MOVES OVERHEAD BY LATE FRIDAY; OUR SHOWER AND
THUNDERSTORMS CHANCES (30%-40%) WILL INCREASE MAINLY WEST OF I-29
HEADING INTO SATURDAY AS MID-LEVEL WAVE "RIDES THE RIDGE" INTO OUR
AREA. WHILE UNCERTAINTY REMAINS ON COVERAGE AND SEVERITY AT THIS
TIME, ITS WORK NOTING THAT SOME OF THE MACHINE LEARNING GUIDANCE HAS
SOME LOW PROBABILITIES (15%-30%) OF SEVERE WEATHER IN THERE FOR
FRIDAY INTO SATURDAY. WITH THIS IN MIND, CONTINUE TO MONITOR THE
FORECAST UPDATES.
SATURDAY ONWARDS: HEADING INTO THE EXTENDED PERIOD, AN ACTIVE
PATTERN WILL CONTINUE WITH MULTIPLE WAVES RIDING THE RIDGE INTO OUR
AREA BETWEEN SATURDAY AND SUNDAY. WHILE THIS COULD LEAD TO
ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS, UNCERTAINTY
REMAINS ON THE LOCATION AND SEVERITY OF DEVELOPING ACTIVITY. LOOKING
ALOFT, THE MID TO UPPER-LEVEL RIDGE WILL START TO STRENGTHEN INTO
THE BEGINNING OF NEXT WEEK LEADING TO MULTIPLE PUSHES OF WARM AIR
ADVECTION (WAA) ALOFT. WITH THIS IN MIND, A WARMING TREND LIKELY
OCCURS FROM ABOUT MONDAY ONWARDS WITH HIGHS INCREASING FROM THE LOW
70S TO LOW 80S TO THE LOW TO UPPER 80S BY WEDNESDAY. LASTLY, MORE
PRECIPITATION CHANCES WILL BE POSSIBLE BETWEEN TUESDAY NIGHT AND
WEDNESDAY. HOWEVER, LONG-RANGE GUIDANCE BEGINS TO DIVERGE IN TERMS
OF SOLUTIONS.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 113 PM CDT WED JUL 30 2025
OCCASIONAL MVFR CEILINGS ARE EXPECTED THROUGH THE AFTERNOON, BUT
AFTER SUNSET MAINLY VFR CONDITIONS ARE EXPECTED. ALSO OF CONCERN
THIS AFTERNOON INTO THE EVENING WILL BE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS MAINLY SOUTH OF I-90 INTO NORTHWEST IA.
THE MAIN THREATS WITH THE STORMS WILL BE LIGHTNING, BRIEF FUNNEL
CLOUDS AND LOCALLY HEAVY RAIN.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...08
DISCUSSION...05
AVIATION...08
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