151
FXUS63 KFSD 241128
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
628 AM CDT SUN MAY 24 2026
KEY MESSAGES
- SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED BY LATE
AFTERNOON MAINLY ALONG AND EAST OF A WAGNER TO HOWARD TO
ARLINGTON LINE. A FEW STORMS COULD BECOME SEVERE WITH UP TO 2
INCH HAIL AND 65 MPH WIND GUSTS BEING THE PRIMARY HAZARDS.
- TEMPERATURES WILL REMAIN ABOVE AVERAGE TO BEGIN NEXT WEEK BUT
WILL TREND CLOSER TO SEASONABLE AS THE WEEK PROGRESSES.
- CHANCES FOR RAIN (30-50%) WILL REMAIN FOR NEXT WEEK. SHOWERS
AND THUNDERSTORMS ARE POSSIBLE BUT SEVERE WEATHER IS NOT
EXPECTED.
UPDATE
ISSUED AT 400 AM CDT SUN MAY 24 2026
TAKING A LOOK ACROSS THE AREA, MOSTLY CLEAR CONDITIONS CONTINUE WITH
LIGHTER SURFACE WINDS THIS MORNING. WITH ELEVATED DEW POINTS, CAN'T
COMPLETELY RULE OUT SOME PATCHY FOG MAINLY IN OUR RIVER VALLEYS. ANY
PATCHY DEVELOP SHOULD GRADUALLY ERODE WITH A RETURN TO MIXING THIS
MORNING AFTER DAYBREAK. OTHERWISE, THE FIRST HALF OF THE DAY WILL
REMAIN QUIET AS LIGHT SOUTHERLY SURFACE WINDS INCREASE. THIS
COMBINED WITH INCREASING WARM AIR ADVECTION WILL HELP HIGHS APPROACH
THE LOW TO UPPER 80S AND POTENTIALLY LOW 90S ALONG THE JAMES RIVER
VALLEY. THE SECOND HALF OF THE DAY IS BIT LESS CERTAIN. LOOKING
ALOFT, WE'RE STILL ON TRACK FOR SCATTERED SHOWERS AND THUNDERSTORMS
FROM THE LATE AFTERNOON INTO THE OVERNIGHT HOURS AS A FEW SHORTWAVES
PASS THROUGH THE AREA.
WHILE THERE ARE STILL SOME DIFFERENCES AMONG THE CAMS MAINLY DUE TO
WEAKER FORCING; WE'LL LIKELY SEE STORMS INITIATE SOMEWHERE ALONG THE
MISSOURI RIVER VALLEY BETWEEN 4-7 PM AND GRADUALLY SPREAD EASTWARDS
DURING THE COURSE OF THE EVENING. WITH AN UNSTABLE ENVIRONMENT
CHARACTERIZED BY 1500-2000 J/KG OF MLCAPE AND 35-45 KTS OF 0-6 KM
SHEAR, STRONGER STORMS COULD QUICKLY BECOME SEVERE WITH LARGE HAIL
UP TO 2 INCHES (HEN EGG SIZED) AND DAMAGING WINDS UP TO 65 MPH BEING
THE PRIMARY HAZARDS. THIS ALSO FURTHER SUPPORTED BY STEEP LAPSE
RATES (7.5-8.5 DEGREES/KM) AND INVERTED V SOUNDINGS. OTHERWISE,
COULD SEE ADDITIONAL DEVELOPMENT ACROSS FAR EASTERN SD AND
SOUTHWESTERN MN AS A SECONDARY WAVE CATCHES UP TO THE FIRST WHICH
COULD BRING ADDITIONAL CHANCES FOR STRONGER STORMS BY LATE EVENING
(9PM-12 AM). LASTLY, SHOULD SEE MOST OF THIS ACTIVITY EXIT EAST OF
OUR AREA BETWEEN 12AM-2AM AS TEMPERATURES DECREASE INTO THE LOW TO
UPPER 50S FOR THE NIGHT.
DISCUSSION
ISSUED AT 218 PM CDT SAT MAY 23 2026
QUIET CONDITIONS PERSIST THIS AFTERNOON AS WEAK SURFACE RIDGING
REMAINS IN PLACE. THIS WILL CHANGE OVER THE NEXT FEW HOURS AS WEAK
THUNDERSTORMS LOOK TO DEVELOP ALONG THE MISSOURI RIVER VALLEY. THESE
STORMS ARE NOT EXPECTED TO BE SEVERE AS INSTABILITY VALUES WILL WEAK
ON THE ORDER OF ABOUT 500 J/KG AND DEEP LAYER SHEAR BE MODEST AT
ABOUT 30 KNOTS. DCAPE WILL BE MODEST AT AROUND 800 J/KG,
CONTRIBUTING TO THE CHANCE FOR GUSTY WINDS. ISOLATED WIND GUSTS UP
TO 40-50 MPH IS POSSIBLE IN THE WEAK STORMS BEFORE THEY DISSIPATE
DURING THE LATE EVENING TIMEFRAME. LOW TEMPERATURES WILL FALL TO 40S
TO LOW 50S TONIGHT.
SUNDAY WILL BE MOSTLY DRY DURING THE DAY AS SATURDAY'S UPPER LEVEL
WAVE WILL PUSH EAST OF THE AREA, PROMOTING SUBSIDENCE ON ITS
BACKSIDE. THE SUBSIDENCE ALONG WITH STEEPENING MID LEVEL LAPSE RATES
FROM AN ARRIVING EML WILL RESULT IN WARM TEMPERATURES UP TO THE 80S
TO JUST ABOUT TOUCHING 90F. THE WARMEST TEMPERATURES LOOK TO OCCUR
IN SOUTH CENTRAL SOUTH DAKOTA. THIS ALSO LOOKS TO BE THE SAME AREA
WHERE CONVECTION INITIATES AS THESE HIGH TEMPERATURES WILL COME
CLOSE TO REACHING CONVECTIVE TEMPERATURES AND HAVE MINIMAL
INHIBITION. THIS LOOKS TO BE ALONG A WEAK DRYLINE LIKE BOUNDARY
BEFORE SPREADING EASTWARDS. THESE STORMS WILL PUSH INTO A MUCH MORE
UNSTABLE ENVIRONMENT WITH CAPE VALUES UP TO AROUND 2,000 J/KG.
THOUGH DRY AIR ENTRAINMENT MAY LOWER CAPE VALUES CLOSER TO 1,500
J.KG. THE LOW LEVELS WILL BE ON THE DRIER SIDE THOUGH WHICH LOOKS
TO RESULT IN INVERTED-V LIKE SOUNDINGS. THUS, DCAPE VALUES UP TO 800
TO 1,000 J/KG ARE EXPECTED WHICH LOOK TO CONTRIBUTE TO DAMAGING
WINDS UP TO ABOUT 65 MPH. HODOGRAPHS REVEAL GENERALLY LONG AND
STRAIGHT SHEAR PROFILES. SOME CURVATURE IN THE LOW LEVELS IS
POSSIBLE AS THE LOW LEVEL JET (LLJ) STRENGTHENS IN THE EVENING.
HOWEVER, WITH SUCH DRY AIR IN PLACE, LCLS WILL BE HIGHER, BASED NEAR
850 MB. THUS, A TORNADO THREAT IS NOT EXPECTED. WITH LONG MID AND
UPPER LEVEL SHEAR PROFILES SHOWN BY THE HODOGRAPH, MID LEVEL AND
UPPER LEVEL VENTING CAN OCCUR, WHICH WILL CONTRIBUTE TO A LARGE HAIL
THREAT WITH HAIL UP TO 2 INCHES IN DIAMETER. 0-6KM SHEAR MAGNITUDES
OF ABOUT 40 KNOTS WILL KEEP THE SEVERE STORM THREAT GOING INTO THE
EVENING TIMEFRAME BEFORE NOCTURNAL STABILIZATION AND INCREASING
INHIBITION END SEVERE STORM CHANCES. THERE REMAINS SOME UNCERTAINTY
ABOUT THE COVERAGE OF STORMS THOUGH AS REMAINING CIN COULD PROHIBIT
MORE WIDESPREAD THUNDERSTORM COVERAGE. AT THE SAME TIME, MID LEVEL
HEIGHTS WILL BE RISING ALOFT. IN FACT, 500 MB HEIGHTS LOOK TO RISE
ABOUT 6DAM ALOFT! THIS IS NOT AS FAVORABLE FOR SEVERE STORMS THOUGH
NOT COMPLETELY HARMFUL AS MESOSCALE PROCESSES CAN OVERCOME THIS
LIMITATION. STILL, SOMETHING WE WILL CONTINUE TO MONITOR. COULD SEE
WEAK SHOWERS PERSIST INTO THE NIGHT EAST OF I-29. LOW TEMPERATURES
WILL BE ON THE WARMER SIDE, ONLY FALLING TO THE 50S TO PERHAPS LOW
60S OVERNIGHT.
WARM TEMPERATURES CONTINUE THROUGH MONDAY AS UPPER LEVEL HEIGHTS
CONTINUE TO BUILD ALOFT. HIGHS LOOK TO REACH UP TO THE 80S ABOUT 90F
ACROSS THE AREA. THE WARMEST TEMPERATURES LOOK TO OCCUR ACROSS
CENTRAL AND SOUTH CENTRAL SOUTH DAKOTA. THE WARMTH LOOKS TO CONTINUE
AS HEIGHTS LOOK TO CONTINUE TO RISE ALOFT AND STAY THAT WAY THROUGH
THE ENTIRETY OF NEXT WEEK. MEDIUM RANGE GUIDANCE, ALONG WITH THE
ENSEMBLES STRONGLY SUPPORT AN OMEGA BLOCK PATTERN ALOFT. THE RIDGE
AXIS LOOKS TO BE PARKED OVER THE CENTRAL PLAINS. WHILE THE UPPER
LEVEL PATTERN WOULD SUPPORT WARMER TEMPERATURES, LATEST GUIDANCE
SUGGESTS THAT A SURFACE HIGHS WILL PUSH INTO THE GREAT LAKES REGION
AND WILL RESULT IN COOLER, EASTERLY FLOW. THUS, HIGH TEMPERATURES
LOOK TO SLOWLY COOL FROM THE 80S TO LOW 90S DOWN TO THE 70S AND 80S
THROUGHOUT THE WEEK.
PRECIPITATION CHANCES LOOK TO REMAIN MODEST AT ABOUT 30-50% THROUGH
THE WEEK. THESE PROBABILITIES CAN CHANGE THOUGH DEPENDING ON HOW THE
LOW LEVELS SET UP. THE GOOD NEWS IS THAT THIS PATTERN IS NOT
EXPECTED TO RESULT IN ANY APPRECIABLE WIND SHEAR ACROSS THE AREA.
ENOUGH LOW LEVEL MOISTURE COULD RESULT IN SUFFICIENT INSTABILITY
THOUGH, LEADING TO SHOWER AND STORM CHANCES. THE GOOD NEWS IS THAT
NO ORGANIZED SEVERE WEATHER THREAT IS EXPECTED THOUGH NON-SEVERE
STORMS REMAIN POSSIBLE FOR THE WEEK AHEAD. CONTINUE TO MONITOR THE
LATEST FORECAST FOR THE MOST UP TO DATE INFORMATION.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 620 AM CDT SUN MAY 24 2026
MOSTLY VFR CONDITIONS WITH OCCASIONAL MVFR TO IFR VSBYS WILL BE
POSSIBLE THIS TAF PERIOD. TAKING A LOOK AT SATELLITE IMAGERY,
MOSTLY CLEAR CONDITIONS PERSIST THIS MORNING. WITH LIGHTER
SURFACE WINDS, THAT HAS LED TO A FEW PATCHY AREAS OF MVFR FOG
DEVELOPING MAINLY ALONG OUR RIVER VALLEYS. SHOULD SEE MOST OF
THIS ERODE BY MID-MORNING. OTHERWISE, SHOWERS AND THUNDERSTORMS
WILL RETURN BY LATE AFTERNOON TO EARLY EVENING. WHILE GUIDANCE
IS STILL ALL OVER THE PLACE WITH THE INITIAL DEVELOPMENT, WENT
AHEAD AND ADDED PROB30 GROUPS INTO KFSD AND KSUX FOR EARLY
EVENING JUST IN CASE SOMETHING GOES UP OVERHEAD. LASTLY,
SOUTHERLY WINDS WILL INCREASE THIS AFTERNOON WITH GUSTS BETWEEN
15-25 MPH POSSIBLE. COULD ALSO SEE A FEW HOURS OF LLWS TONIGHT
AS THE NOCTURNAL JET STRENGTHENS NEAR KFSD AND KSUX.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...05
DISCUSSION...MEYERS
AVIATION...05
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