605
FXUS63 KFSD 251131
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
631 AM CDT FRI SEP 25 2026
KEY MESSAGES
- SCATTERED SHOWERS LIKELY SOUTH OF I-90 WITH AREAS OF DRIZZLE
NEAR AND NORTH TODAY. RAIN WON'T BE AS WIDESPREAD TODAY AS
WHAT WE SAW THURSDAY, BUT BE PREPARED FOR OCCASIONAL POCKETS
OF LIGHT RAIN.
- THE ACTIVE WEATHER PATTERN CONTINUES BRINGING A HIGH CHANCE
(>90%+) OF ADDITIONAL RAIN LATER TONIGHT INTO SATURDAY AND
AGAIN LATER MONDAY INTO TUESDAY (>50%).
- DAYTIME TEMPERATURES REMAIN BELOW NORMAL, BUT SHOULD CLIMB
CLOSER TO NORMAL SUNDAY AND MONDAY.
UPDATE
ISSUED AT 314 AM CDT FRI SEP 25 2026
ANOTHER DREARY DAY ON TAP WITH ABUNDANT LOW LEVEL MOISTURE ACROSS
THE AREA. THE DIFFERENCE WILL MAINLY COME DOWN TO MID AND UPPER
LEVEL MOISTURE AND WHETHER OR NOT A LITTLE RAIN CAN DEVELOP OR IF WE
END UP WITH MOSTLY DRIZZLE. THE LATEST MODEL SOUNDINGS STRONGLY HINT
AT A DEEP DRY LAYER FROM ABOUT 400MB TO 700MB THIS MORNING,
BASICALLY CUTTING OFF THE DGZ. THE EXCEPTION MAY BE CLOSER TO THE
SIOUX CITY AREA WHERE A WAVE IN NE DRIFTS NORTH AND INTRODUCES SOME
MID LEVEL MOISTURE. LONG STORY SHORT, MOSTLY DRIZZLE POTENTIAL THIS
MORNING EXCEPT AROUND THE SIOUX CITY AREA.
BY THIS AFTERNOON THIS WEAK PIECE OF ENERGY DRIFTS FARTHER NORTH AND
TRIES TO BRING SOME OF THIS MID LEVEL MOISTURE TOWARDS I-90. THIS
SHOULD BRING SOME SCATTERED SHOWERS/PATCHY LIGHT RAIN INTO THE
JAMES RIVER VALLEY AND TO NEAR AND JUST NORTH OF I-90. RAINFALL
AMOUNTS THROUGH SUNSET SHOULD GENERALLY BE LESS THAN A TENTH OF AN
INCH, MAYBE CLOSER TO A QUARTER INCH NEAR SIOUX CITY.
A STRONGER WAVE SHIFTS NORTH LATER TONIGHT THROUGH SATURDAY MORNING.
THIS DEEPENS THE WARM AIR ADVECTION AND BRINGS JUST A TOUCH OF WEAK
INSTABILITY, WITH SOUNDINGS LOOKING FAIRLY MOIST NEUTRAL SUGGESTING
A FAIRLY EFFICIENT RAIN ENVIRONMENT. RIGHT NOW LOOKS LIKE JUST
ENOUGH INSTABILITY TO PRODUCE A FEW RUMBLES OF THUNDER LATE TONIGHT
INTO SATURDAY MORNING. THE LATEST HIGH RES MODELS AND ENSEMBLE OUTPUT
ALL FAIRLY CONSISTENT ON BRINGING THE HIGHER RAINFALL TOTALS DURING
THIS TIME TO AREAS NEAR AND EAST OF HIGHWAY 81, AND PARTICULARLY IN
PARTS OF NORTHWEST IA. NEAR AND EAST OF HIGHWAY 81 AMOUNTS WILL
LIKELY BE HALF AN INCH TO AN INCH WITH ISOLATED POCKETS OF 2 INCHES.
WHILE FLASH FLOODING AND RIVER FLOODING REMAIN UNLIKELY, PONDING OF
WATER ON ROADS WITH THE HEAVIER DOWNPOURS WILL BE POSSIBLE.
BY SATURDAY NIGHT THE WAVE IS MOSTLY EAST OF THE AREA WITH WEAK
UPPER LEVEL TROUGHING REMAINING IN PLACE. MODEL SOUNDINGS LINGER THE
LOW LEVEL MOISTURE, BUT DOES SUGGEST IT WILL BECOME MORE SHALLOW.
THERE IS ALSO A LITTLE WEAK ELEVATED INSTABILITY THAT APPEARS TO BE
WEAKLY CAPPED, BUT MIGHT ALLOW FOR SCATTERED SHOWERS SATURDAY NIGHT,
ON TOP OF PATCHY DRIZZLE. FARTHER WEST, IF ENOUGH CLEARING OCCURS,
FOG WILL BE POSSIBLE FOR AREAS NEAR AND WEST OF THE JAMES
VALLEY.
DISCUSSION
ISSUED AT 242 PM CDT THU SEP 24 2026
AN AREA OF STEADY LIGHT TO LOCALLY MODERATE RAINFALL
EXTENDS FROM AROUND A SLAYTON TO YANKTON LINE AND POINTS EAST.
THIS AREA OF RAIN WILL GRADUALLY PUSH EAST THROUGH THE REMAINDER
OF THE AFTERNOON AND START TO FALL APART THIS EVENING OVER
NORTHWEST IOWA. HOWEVER, PATCHY DRIZZLE WILL BE POSSIBLE AFTER
THIS RAIN DEPARTS ESPECIALLY ALONG AND EAST OF I-29. A BIT DRIER
IN THE LOW-LEVELS OVER PARTS OF NORTHWEST IOWA TONIGHT, SO IT
MAY TAKE A BIT LONGER FOR DRIZZLE TO DEVELOP THERE. FARTHER
WEST, ESPECIALLY INTO SOUTH-CENTRAL SOUTH DAKOTA, WE WILL SEE
SOME BREAKS IN THE CLOUDS WHICH WILL ALLOW TEMPERATURES TO WARM
INTO THE MIDDLE 70S. SOME INSTABILITY (AROUND 500-750 J/KG) WILL
BE PRESENT ALONG AND AHEAD OF A WEAK FRONT OVER SOUTH-CENTRAL
SOUTH DAKOTA WHERE THIS HEATING IS OCCURRING, BUT PLENTY OF DRY
MID-LEVEL AIR SHOULD PREVENT SCATTERED SHOWERS AND STORMS FROM
DEVELOPING IN THESE LOCATIONS. IN THE OFF CHANCE (<10%) WE GET A
STORM, SEVERE WEATHER IS NOT EXPECTED AS WEAK EFFECTIVE SHEAR
LOOKS TO BE PLACE.
HEADING INTO TONIGHT, A FEW SHOWERS WILL CONTINUE TO BE POSSIBLE
MAINLY ALONG THE HIGHWAY 20 CORRIDOR. LOW STRATUS LOOKS TO SPREAD
BACK WEST THROUGH THE NIGHT, BUT BEFORE IT SPREADS BACK INTO SOUTH-
CENTRAL SOUTH DAKOTA, PATCHY FOG CAN'T BE RULED OUT THERE. DRIZZLE
WILL BEGIN TO BECOME MORE LIKELY HEADING INTO EARLY TOMORROW MORNING
AS CLOUD CEILINGS CONTINUE TO FALL, SO KEEP THE RAIN GEAR HANDY FOR
YOUR FRIDAY MORNING COMMUTE. SCATTERED LIGHT SHOWERS WILL DEVELOP
THROUGHOUT THE DAY, WITH CHANCES GRADUALLY LIFTING NORTHWARD THROUGH
THE AFTERNOON DUE TO STRENGTHENING WARM AIR ADVECTION AT 850 MB.
THESE WILL BE MORE OF THE HIT OR MISS VARIETY UNLIKE WHAT WE
SAW TODAY, SO KEEP THAT UMBRELLA NEARBY BUT RAIN TOTALS WILL
ONLY BE A FEW HUNDREDTHS TO A TENTH OF AN INCH DURING THE DAY ON
FRIDAY, EXCEPT FOR LOCALLY HIGHER AMOUNTS ALONG THE HIGHWAY 20
CORRIDOR FRIDAY MORNING. LOWERED THE HIGH TEMPERATURES A BIT
FROM THE NBM FOR FRIDAY GIVEN THE CLOUD COVER AND DRIZZLE, WITH
HIGHS MOSTLY IN THE LOWER 60S. IF SOME PEAKS OF SUN CAN BE
REALIZED, A FEW MIDDLE TO UPPER 60S FOR HIGHS WILL BE POSSIBLE.
RAIN CHANCES WILL INCREASE FRIDAY NIGHT INTO SATURDAY MORNING AS THE
MAIN UPPER WAVE PIVOTS THROUGH THE AREA. THE HIGHEST RAINFALL TOTALS
DURING THIS TIME FRAME WILL GENERALLY BE OVER NORTHWEST IOWA AND
ADJACENT AREAS OF SOUTHEAST SOUTH DAKOTA AND FAR NORTHEAST NEBRASKA,
WHERE AROUND A HALF AN INCH TO AN INCH OF RAIN CAN BE EXPECTED. A
FEW POCKETS OF 1-1.5" OF RAIN (15-25% CHANCE) CAN'T BE RULED OUT
MAINLY ALONG AND SOUTHEAST OF A SPENCER TO SIOUX CITY LINE. THIS
RAIN SHOULD BE SPREAD OUT LONG ENOUGH WHERE FLASH FLOODING CONCERNS
WILL BE LOW WHERE THESE HIGHEST AMOUNTS OCCUR, BUT STILL BE PREPARED
FOR WET ROADS IF TRAVELING ESPECIALLY EARLY SATURDAY MORNING.
SHOWERS AND VERY ISOLATED STORMS WILL GRADUALLY PUSH EAST THROUGH
THE AFTERNOON, THOUGH ONCE AGAIN SOME PATCHY DRIZZLE WILL REMAIN
POSSIBLE AFTER ANY OF THE RAIN SHOWERS END AT LEAST THROUGH THE
EARLY EVENING SATURDAY. DRIZZLE DETAILS WILL BE REFINED AS WE
GET CLOSER TO THE SATURDAY AFTERNOON. THOUGH SOME VERY PATCHY
DRIZZLE WILL BE POSSIBLE INTO SUNDAY MORNING, SHOULD MOSTLY SEE
DRY WEATHER FOR THE DAY. THIS SHOULD ALLOW FOR SOME OF THE
WARMEST TEMPERATURES THAT WE'VE SEE OVER THE PAST FEW DAYS, WITH
HIGHS IN THE UPPER 60S TO MIDDLE 70S. ULTIMATELY, THESE
TEMPERATURES WILL BE DEPENDENT ON HOW QUICKLY WE CAN SCATTER OUT
ANY MORNING CLOUDS, SO EXPECT CHANGES TO THE FORECASTED
TEMPERATURES AS WE APPROACH SUNDAY.
RAIN CHANCES DO LOOK TO RETURN ONCE AGAIN ON MONDAY, BUT ESPECIALLY
MONDAY NIGHT INTO TUESDAY. THIS WILL BE AS THE WEST COAST LONGWAVE
TROUGH FINALLY SWINGS INTO THE AREA. WILL HAVE TO WATCH FOR ANY
HEAVY RAIN ONCE AGAIN WITH THIS ACTIVITY, ESPECIALLY ON TOP OF THE
RAINFALL WE'VE SEEN THE PAST WEEK. LREF PROBABILITIES SHOW AROUND A
30-40% CHANCE OF AT LEAST AN INCH OF RAINFALL MONDAY NIGHT THROUGH
TUESDAY NIGHT, FOCUSED OVER NORTHWESTERN IOWA. TRENDS WILL CONTINUE
TO BE MONITORED AS WE GET CLOSER TO NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 628 AM CDT FRI SEP 25 2026
WIDESPREAD IFR CONDITIONS THROUGH THE PERIOD. DRIZZLE WILL BE
FAIRLY WIDESPREAD THROUGH THE MORNING, WITH SHOWERS DEVELOPING
THROUGH THE DAY, MOVING FROM SOUTH TO NORTH. RAIN WILL
OVERSPREAD THE AREA TONIGHT THROUGH SATURDAY MORNING WITH THE
MOST PERSISTENT RAINFALL NEAR AND EAST OF HIGHWAY 81 OVERNIGHT.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...08
DISCUSSION...SAMET
AVIATION...08
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