710
FXUS63 KFSD 191134
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
634 AM CDT WED AUG 19 2026
KEY MESSAGES
- SCATTERED SHOWERS AND STORMS SLIDE EAST INTO EARLY AFTERNOON.
SEVERE WEATHER RISK REMAINS LOW, BUT A STRONGER STORM COULD
PRODUCE SMALL HAIL AND 50 MPH WIND GUSTS THROUGH MID MORNING.
- MOSTLY DRY THIS EVENING AND TONIGHT.
- LATE THURSDAY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
ALONG AN APPROACHING FRONT. BEST CHANCES REMAIN ACROSS
NORTHERN AND CENTRAL MINNESOTA, WITH ISOLATED RISKS FURTHER
SOUTHWEST. STORMS MAY BE CAPABLE OF LARGE HAIL AND LOCALIZED
STRONG WIND GUSTS.
- MOSTLY DRY CONDITIONS HEADING INTO THE WEEKEND WITH HIGHS
EITHER SIDE OF 80 DEGREES. MORNING RAIN ON SUNDAY IS POSSIBLE.
UPDATE
ISSUED AT 306 AM CDT WED AUG 19 2026
AREA OF SHOWERS AND STORMS IS MOVING EAST THIS MORNING ACROSS SOUTH
CENTRAL SD. SEVERE WEATHER RISK REMAINS LOW AT THIS TIME, BUT A
STRONGER STORM IN SOUTH CENTRAL SD AND THE MO RIVER VALLEY COULD
PRODUCE 50 MPH WIND GUSTS AND DIME SIZED HAIL. STORMS SHOULD WEAKEN
AS THEY MOVE AWAY FROM THE INSTABILITY AXIS. THIS ACTIVITY MOVES
EAST ACROSS THE AREA LATE MORNING/EARLY AFTERNOON.
NO SIGNIFICANT CHANGES TO THE FORECAST THIS MORNING AS NORTHWESTERLY
FLOW REMAINS IN PLACE FOR THE NEXT COUPLE OF DAYS. FOR THE REST OF
TODAY, THINK THAT MOST WILL STAY DRY LATER THIS EVENING INTO TONIGHT
WITH SOME STABILIZATION RESULTING FROM THE MORNING CONVECTION.
GUIDANCE DOES HINT AT SOME ISOLATED ACTIVITY LATER IN THE EVENING AS
THE NEXT VORT LOBE AND WAA MOVE INTO THE AREA, ALTHOUGH ANY
INSTABILITY TANKS PRETTY QUICKLY AFTER DARK. SOUNDINGS ARE
RELATIVELY DRY, SO THINK WE'LL STRUGGLE WITH DEVELOPMENT. SEVERE
WEATHER RISK REMAINS LOW, BUT NOT ZERO.
PATCHY FOG MAY DEVELOP LATE TONIGHT INTO EARLY THURSDAY WITH LIGHTER
WINDS AND MORE EFFICIENT COOLING IF SKIES REMAIN MOSTLY CLEAR.
BETTER FORCING LATER THURSDAY AS THE FRONT MOVES THROUGH REMAINS OFF
TO OUR NORTH AND EAST WITH THE MID/UPPER LEVEL WAVE. THAT SAID,
MODELS STILL BRING MUCAPE OF OVER 1500 J/KG AHEAD OF THE FRONT AND
FIRING OFF ISOLATED STORMS ALONG IT. SEVERE RISK IS STILL LOW WITH
SHEAR AROUND 35 KNOTS AND MID LEVEL LAPSE RATES AROUND 6 DEG C/KM,
WHICH COULD MAY BE ENOUGH FOR ISOLATED STRONGER STORMS WITH LARGE
HAIL AND DAMAGING WIND GUSTS.
DISCUSSION
ISSUED AT 106 PM CDT TUE AUG 18 2026
THIS AFTERNOON: A WEAK FRONTAL BOUNDARY CONTINUES TO SINK SOUTHWARD
EARLY THIS AFTERNOON, WITH NOTICEABLE STRATO-CU FIELD
DEVELOPING ALONG THE HIGHWAY 20 CORRIDOR. THE REMAINDER OF THE
AFTERNOON IS LIKELY TO REMAIN DRY IN MOST LOCATIONS, OUTSIDE OF
VERY ISOLATED DEVELOPMENT ALONG THIS AFOREMENTIONED BOUNDARY.
THIS EVENING/TONIGHT: SOME GUIDANCE SHOWS ISOLATED DEVELOPMENT THIS
EVENING ALONG A WEAK CONVERGENCE ZONE IN SW MINNESOTA AND NORTHERN
IOWA. THIS CONVECTION MAY ALSO BE SPARKED BY A WEAK AREA OF
VORTICITY DROPPING THROUGH THE DAKOTAS FROM THE NORTHWEST. ANY STORM
THAT DEVELOPS WILL BE IN AN AREA OF MLCAPE AOA 1000-1500 J/KG, WITH
SUFFICIENT SHEAR TO PROMOTE PERHAPS A ROTATING STORM.
ANTICIPATING THE SEVERE WEATHER RISKS TO REMAIN LOW.
FURTHER WEST, ADDITIONAL CONVECTION IS EXPECTED TO FORM OVER THE
BLACK HILL REGION THIS EVENING AS A STRONGER WAVE ENTERS THE AREA.
THE TRACK OF THIS WAVE, ALONG WITH HOW THE LLJ PROPAGATES OVERNIGHT,
SHOULD PUSH SOME OF THIS ACTIVITY INTO SOUTH CENTRAL SD AFTER 1AM.
MUCAPE REMAINS QUITE LOW, WITH MARGINAL MID-LVL LAPSE RATES, SO
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. THOUGH, A FEW GUSTY
WIND GUSTS COULD REMAIN POSSIBLE THROUGH 3AM. THERE REMAINS
REASONABLE AGREEMENT THAT THIS CONVECTION COULD TRACK ALONG THE MO
RIVER VALLEY INTO EASTERN NEBRASKA BY DAYBREAK. THIS IS AN AREA
WHERE HIGHER POPS WILL BE FOCUSED.
WEDNESDAY: THE DEPARTURE OF THIS SHORTWAVE SHOULD LEAD TO A PERIOD
OF SUBSIDENCE AND QUIET WEATHER WELL INTO WEDNESDAY. CLOUD COVER MAY
BE MORE SUBSTANCIAL OVER THE SOUTHERN HALF OF THE CWA THANKS TO MID-
UPR CLOUDS FROM CONVECTION. BY THE AFTERNOON SOUTHWESTERLY SURFACE
WINDS WILL RETURN, ALLOWING HIGH TEMPERATURES TO RISE INTO THE UPPER
70S TO LOWER 80S. CONVECTION RISKS IN THE AFTERNOON AND EVENING MAY
BE QUITE NARROWED TO A ZONE AHEAD OF AN APPROACHING SURFACE FRONT IN
NORTH CENTRAL SD. FURTHER SOUTHEAST, THERE DOESN'T SEEM TO BE ANY
STRONG FOCUSING MECHANISM, WITH WEAK CONVECTIVE INHIBITION LIKELY
KEEPING THE AREA FREE OF ANY ISOLATED LARGER STORM GROWTH. WHILE
SURFACE AND LOW-LVL FOCUS REMAINS ABSENT, WE'LL NEED TO WATCH THE
PRESENCE OF ANY WEAK VORTICITY IN THE NW FLOW. FURTHER NORTHWEST,
ANY CONVECTION THAT DEVELOPS ALONG THE FRONTAL BOUNDARY MAY TRY TO
TRACK SOUTHEAST, THOUGH LESSENING INSTABILITY SHOULD LIMIT THE
OVERALL SEVERE RISKS.
THURSDAY: ANY PRECIPITATION RISK CONTINUES TO LOOK MINIMAL HEADING
INTO THURSDAY MORNING AS A STRONGER EML BEGINS TO BUILD INTO THE
REGION. SOUTHWESTERLY SURFACE WINDS OVERNIGHT MAY KEEP OVERNIGHT
LOW TEMPERATURES FROM FALLING SIGNIFICANTLY. THE AFOREMENTIONED
SURFACE BOUNDARY FROM WEDNESDAY WILL SINK SOUTHEAST THROUGH THE
DAY ON THURSDAY PROVIDING A FOCUS MECHANISM FOR STORMS BY LATE
AFTERNOON AND EVENING. MLCAPE APPROACHING 2000-3000 J/KG MAY DEVELOP
ALONG THIS BOUNDARY AS DEW POINTS TRY TO QUICKLY SURGE NORTHWARD.
THE LINGERING QUESTIONS FOR CONVECTIVE DEVELOPMENT ARE FOCUSED
ON THE TRACK OF MID-LVL VORTICITY IN THE LATE AFTERNOON, ALONG WITH
CONVECTIVE INHIBITION AHEAD OF THE BOUNDARY. THE TRACK OF SHORTWAVE
ENERGY COULD FAVOR MORE DEVELOPMENT IN CENTRAL AND NORTHERN MINNESOTA,
WITH ONLY ISOLATED STORMS FURTHER SOUTHWEST ALONG THE BOUNDARY. WHILE
INSTABILITY IS GREATER, SHEAR IS A BIT MORE MARGINAL SUGGESTING
LESS ORGANIZATION TO ANYTHING THAT DEVELOPS.
FRIDAY-MONDAY: MID-LVL HEIGHTS BEGIN TO RISE OVER THE ROCKIES AS THE
RIDGE AMPLIFIES. THE LINGERING, BUT SHARPER, NW FLOW PATTERN
OVER THE DAKOTAS MAY BRING ONE MORE WAVE INTO THE REGION FRIDAY.
HOWEVER THE SOUTHWARD PASSAGE OF THURSDAYS FRONT SHOULD PUSH
THE BEST BOUNDARY LAYER MOISTURE SOUTH OF THE AREA. THE RIDGE
AXIS BEGINS TO PUSH EASTWARD AS WE MOVE INTO THE UPCOMING
WEEKEND. A PLEASANT SATURDAY IS LIKELY IN THE REGION WITH HIGHS
EITHER SIDE OF 80. INCREASING LOW-LVL WARM ADVECTION INTO SUNDAY
COULD BRING ELEVATED SHOWERS AND THUNDERSTORMS EASTWARD INTO
SUNDAY MORNING, ALONG WITH MORE CLOUDS AND SLIGHTLY WARMER HIGHS
INTO THE LOWER TO MIDDLE 80S. AT THIS TIME, RAIN COVERAGE MAY
BE LIMITED WITH ONLY A 20-30% POP.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 628 AM CDT WED AUG 19 2026
WATCHING A FEW AREAS OF CONVECTION MOVE EAST-SOUTHEAST THIS
MORNING, MAINLY ACROSS SOUTH CENTRAL SD/NORTHERN NE AND ANOTHER
NEAR/NORTH OF US HWY 14. THINK KFSD AND KSUX WILL MISS OUT ON
TSRA, AND KFSD MAY MISS OUT ON -SHRA ALL TOGETHER IF TRENDS
CONTINUE. SHOWERS/STORMS TAPER DOWN LATE MORNING/EARLY
AFTERNOON ACROSS THE AREA. FURTHER EAST, HAVE SEEN SOME VERY
PATCHY FOG LEADING TO MVFR VIS AT TIMES, WHICH SHOULD COME TO AN
END BY MID MORNING.
CONFIDENCE IS LOW ON ANY FURTHER CONVECTION THIS EVENING INTO
TONIGHT. PATCHY FOG LOOKS TO DEVELOP AGAIN BY EARLY THURSDAY
MORNING, MAINLY IN/NEAR RIVER VALLEYS.
OUTSIDE OF CONVECTION AND FOG, VFR CONDITIONS PREVAIL.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...DUX
AVIATION...SG
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page