797
FXUS63 KFSD 251134
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
634 AM CDT SAT APR 25 2026
KEY MESSAGES
- SHOWERS AND VERY ISOLATED THUNDERSTORMS EXPECTED THROUGH THIS
EVENING WITH THE GREATEST CHANCES ACROSS SOUTHEASTERN SOUTH
DAKOTA INTO FAR WESTERN MINNESOTA (80%+). CHANCES TAPER OFF
THROUGH LATE EVENING AND TONIGHT, BUT SCATTERED (30-40%
CHANCE) SHOWERS REMAIN.
- SCATTERED TO NUMEROUS (80-100%) SHOWERS AND STORMS EXPECTED
AGAIN SUNDAY INTO MONDAY. AREAS OF HEAVIER RAINFALL ARE
POSSIBLE BUT FOR NOW FLOODING AND FLASH FLOODING CHANCES
REMAIN LOW (LESS THAN 20 PERCENT).
- ISOLATED SEVERE RISK FOR AREAS SOUTH OF A LINE FROM LAKE ANDES
TO SIOUX FALLS TO CHEROKEE SUNDAY NIGHT; CONFIDENCE REMAINS
LOW IN OCCURRENCE (LESS THAN 20%). IF A STRONGER STORM
DEVELOPS, DAMAGING WIND GUSTS AND HAIL ARE THE PRIMARY
THREATS.
- SEASONABLE TEMPERATURES EXPECTED THROUGH NEXT WEEK, WITH HIGHS
MOSTLY IN THE MID 50S TO MID 60S.
UPDATE
ISSUED AT 259 AM CDT SAT APR 25 2026
RAIN CONTINUES TO MOVE TO THE NORTHEAST EARLY THIS MORNING AS A MID
LEVEL WAVE SLIDES ACROSS NORTHERN SD. RAIN IS REACHING THE GROUND
NOW FROM CHAMBERLAIN TO MARSHALL, WITH AREAS FURTHER TO THE SOUTH
AND EAST STILL STRUGGLING WITH SATURATION. HAVE REFINED THE SHORT
TERM POPS TO BETTER REFLECT AREAL COVERAGE FOLLOWING SOME OF THE
CONSSHORT GUIDANCE. EXPECT MORE LOCATIONS TO SATURATE THROUGH THE
OVERNIGHT, SO SHOULD SEE SHOWERS EXPAND BY DAYBREAK AS ADDITIONAL
PRECIPITATION MOVES NORTH OUT OF CENTRAL NE. LIGHTNING HAS TAPERED
DOWN OVER THE LAST HOUR OR SO, BUT CAN'T ENTIRELY RULE OUT A RUMBLE
OR TWO OF THUNDER. TEMPERATURES ARE IN THE UPPER 30S TO MID 50S, AND
EXPECT MORNING LOWS IN THE UPPER 30S TO MID 40S. SOUNDINGS STILL
HINT AT POSSIBLY AN HOUR OR SO OF SNOW MIXING IN WITH THE COLDER
TEMPERATURES IN SOUTH CENTRAL SD, BUT NOT EXPECTING ANY IMPACTS OR
ACCUMULATIONS IF THIS OCCURS.
FORECAST THROUGH TODAY AND TONIGHT REMAINS ON TRACK, WITH WAA AND A
SUBTLE MID LEVEL WAVE KEEPING SHOWERS AROUND THE AREA, WITH ISOLATED
THUNDERSTORMS. SEVERE WEATHER IS NOT EXPECTED WITH SCANT
INSTABILITY. HIGHS REMAIN ON TRACK TO BE IN THE MID/UPPER 40S FOR
SOUTH CENTRAL SD IN TO THE MID 60S IN NORTHWESTERN IA. SOMEWHAT
BREEZY CONDITIONS ALONG WITH RAIN AND CLOUDS WILL MAKE IT FEEL A BIT
COOLER.
DISCUSSION
ISSUED AT 1243 PM CDT FRI APR 24 2026
UPPER LEVEL LOW PRESSURE WELL TO THE NORTH OF THE AREA WILL SWING A
SMALLER PIECE OF ENERGY INTO THE AREA TONIGHT INTO SATURDAY. FAIRLY
STRONG MID LEVEL FRONTAL FORCING DEVELOPS IN RESPONSE TO THIS WAVE,
WITH SOME OF THE STRONGER FORCING IN THE 700-750MB LAYER. LATE
TONIGHT INTO SATURDAY MORNING THE FRONT CLOSER TO 800-850 MB LOOKS
TO BE MORE ACTIVE AND COULD SHIFT SOME OF THE BETTER PRECIPITATION
CLOSER TO I-90. OVERALL AMOUNTS WITHIN THIS BAND OF RAINFALL WILL
LIKELY BE ABOUT A QUARTER TO THREE QUARTERS OF AN INCH. INSTABILITY
IS MINIMAL SO OTHER THAN A FEW ROGUE LIGHTNING STRIKES THIS WILL
MAINLY BE A WELCOME RAIN EVENT.
WEAK UPPER LEVEL SUPPORT AND LOW TO MID LEVEL WARM ADVECTION
CONTINUES THROUGH MOST OF SATURDAY AND GIVEN SOME VERY WEAK
INSTABILITY IN THE SOUNDINGS, SCATTERED SHOWERS WILL REMAIN LIKELY
THROUGH THE DAY. SOME ISOLATED THUNDERSTORMS WILL ALSO BE POSSIBLE,
BUT SEVERE WEATHER IS NOT EXPECTED TONIGHT THROUGH SATURDAY. THE
BETTER CHANCES FOR RAIN SHOULD REMAIN MOSTLY NORTH OF I-90 BUT COULD
BE A LITTLE MORE SPREAD OUT ACROSS THE AREA WITH ISOLATED TO
SCATTERED ACTIVITY AND MORE DISORGANIZED FORCING.
WEAK UPPER LEVEL RIDGING BUILDS AHEAD OF A STRONGER WAVE SATURDAY
NIGHT INTO SUNDAY MORNING. THIS COULD BE A PERIOD WHERE ACTIVITY IS
THE MOST ISOLATED.
UPPER LEVEL SUPPORT RAPIDLY INCREASES SUNDAY AFTERNOON INTO SUNDAY
NIGHT, LEADING TO THE AREAS BEST CHANCE FOR SOME HEAVIER RAIN SUNDAY
NIGHT INTO MONDAY. MARGINALLY STEEP ELEVATED LAPSE RATES ALONG WITH
STRONG LOW LEVEL MOISTURE CONVERGENCE WILL LEAD TO SHOWERS AND
THUNDERSTORMS FOR MUCH OF THE AREA. THE TRENDS TO WATCH FOR ON SUNDAY
NIGHT WILL BE THE POTENTIAL FOR THE BETTER FORCING TO PRODUCE
HEAVIER RAINFALL WEST OF I-29 TOWARDS CENTRAL INTO NORTHEAST SD AND
ANOTHER AREA CLOSER TO NORTHWEST IA AND POINTS SOUTH WHERE DEEPER
INSTABILITY COULD PRODUCE AN MCS WITH THAT ACTIVITY SHIFTING MORE
EASTWARD. A VERY SMALL THREAT FOR SEVERE WEATHER IN NORTHEAST NE AND
NORTHWEST IA SUNDAY NIGHT, ALTHOUGH MODEL SOUNDINGS AND ENSEMBLE
OUTPUT INDICATE ONLY A VERY SMALL CHANCE FOR CAPE VALUES ABOVE 1000
J/KG.
LOW PRESSURE ALOFT DEEPENS OVER SOUTHEAST SD SUNDAY NIGHT AND SLOWLY
DRIFTS EAST THROUGH MONDAY. THIS WILL CONTINUE THE THREAT FOR RAIN
INTO MONDAY AFTERNOON, LIKELY ENDING MONDAY EVENING MOST LOCATIONS.
RAINFALL AMOUNTS CONTINUE TO TREND HIGHER WITH THE LATEST NAM
PRODUCING A FAIRLY LARGE AREA OF 2-4" OF RAIN FOR MOST OF SOUTHEAST
SD THROUGH TONIGHT THROUGH MONDAY. THE LATEST GFS IS VERY SIMILAR,
JUST A TOUCH LOWER ON AMOUNTS WITH THE CANADIAN AND RRFS A LITTLE
FARTHER NORTH AND WEST WITH THE HEAVY RAIN AMOUNTS. THE LATEST 50TH
PERCENTILE FROM THE GEFS GIVES THE AREA 1-2" WITH THE HIGHER AMOUNTS
NORTH OF I-90. THE CANADIAN ENSEMBLE PARKS THE HIGHER 2" AMOUNTS
ACROSS MOST OF SOUTHEAST SD. THE 6Z EC ENSEMBLE VERY SIMILAR TO THIS
OUTPUT AS WELL.
ONCE THIS SYSTEM FINALLY EXITS, MAINLY NORTH TO NORTHWEST FLOW ALOFT
IS EXPECTED TUESDAY INTO FRIDAY WHICH WILL KEEP SEASONALLY COOL
TEMPERATURES CLOSE TO NORMAL IN PLACE EACH DAY. WHILE THERE WILL BE
A FEW CHANCES FOR SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM THE
ACTIVITY LOOKS TO REMAIN FAIRLY ISOLATED AND FAIRLY LIGHT.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 630 AM CDT SAT APR 25 2026
SHOWERS CONTINUE TO MOVE TO THE NORTHEAST THIS MORNING, WITH
PERIODS OF SHOWERS AND VERY ISOLATED STORMS THROUGH THE REST OF
THE TAF PERIOD. MVFR STRATUS AND VISIBILITY EXPECTED WITH
SHOWERS THROUGH THE PERIOD, ALTHOUGH CONDITIONS MAY VARY BETWEEN
CATEGORIES, INCLUDING LOWER MVFR CONDITIONS LATER TODAY IN
HEAVIER SHOWERS. HAVE CONTINUED TO OMIT ANY -TSRA MENTION GIVEN
LOW CONFIDENCE IN TIMING AND COVERAGE.
WINDS THROUGH THE PERIOD WILL SEE SOME VARIABILITY IN DIRECTION,
WITH GUSTS TODAY BETWEEN 15 AND 20 KNOTS AT TIMES.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...08
AVIATION...SG
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