677
FXUS63 KFSD 111153
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
653 AM CDT SAT APR 11 2026
KEY MESSAGES
- PERIODS OF SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS WILL
SPREAD NORTH TODAY, MAINLY ALONG/EAST OF HIGHWAY 81. MOSTLY
LIGHT ACCUMULATIONS EXPECTED.
- ELEVATED TO LOCALLY NEAR CRITICAL FIRE CONCERNS ARE EXPECTED
BY SUNDAY AS UNSEASONABLE WARMTH RETURNS ALONG WITH BREEZY
WESTERLY WINDS. THIS ALONG WITH CRITICAL RH VALUES (18%-30%)
WILL LEAD TO HIGH TO VERY HIGH FIRE DANGER WITH THE FOCUS
BEING FROM SOUTH-CENTRAL SOUTH DAKOTA TO SOUTHWEST MINNESOTA.
- RENEWED CHANCES FOR SHOWERS AND STORMS RETURN ON MONDAY AND
TUESDAY WITH THE POTENTIAL FOR A FEW STRONGER STORMS. HOWEVER,
SOME DETAILS REMAIN UNCERTAIN.
UPDATE
ISSUED AT 422 AM CDT SAT APR 11 2026
EARLY MORNING ACCAS (SPOTTY HIGH-BASED SHOWERS AND A FEW STORMS)
DEVELOPED AROUND 1 AM. THIS HAS CONTINUED TO BUBBLE AND LIFT
SLOWLY NORTHEAST IN A BROAD WARM ADVECTION REGIME. HAVE UPDATED
EARLY MORNING PRECIP CHANCES TO ACCOUNT FOR THIS ACTIVITY.
AN ADDITIONAL SURGE OF WARM ADVECTION IS SEEN IN SOME HIGH-RES
GUIDANCE THROUGH MID-MORNING. BEGINNING TO SEE THIS DEVELOPMENT
IN NORTHEAST NEBRASKA, AND CAMS ARE CONSISTENT IN SHOWING THIS
ACTIVITY EXPAND IN COVERAGE AS IT LIFTS NORTH THIS MORNING
BEFORE WEAKENING/MOVING EAST OF THE FORECAST AREA BY MIDDAY.
WHILE A FEW HIGH-BASED STORMS ARE AGAIN POSSIBLE, SEVERE WEATHER
IS NOT EXPECTED.
SPC HAS MAINTAINED A MARGINAL (LEVEL 1 OF 5) RISK FOR SEVERE
STORMS ACROSS SOUTHEAST PORTIONS OF OUR FORECAST AREA IN THE
LATEST DAY 1 (TODAY AND TONIGHT) AND DAY 2 (SUNDAY-SUNDAY NIGHT)
OUTLOOKS. FOR DAY 1, THE PRIMARY CONCERN WOULD BE AN ISOLATED
STRONG TO SEVERE STORM IN NORTHWEST IOWA AS THE LOW LEVEL JET
INCREASES LATER THIS EVENING INTO THE OVERNIGHT HOURS. WHILE A
COUPLE OF THE MORE ROBUST HIGH-RES MODELS DEPICT A STRONGER
STORM DEVELOPING, THE MAJORITY OF THE CAMS LACK MUCH MORE THAN
A LINGERING DRIZZLE POTENTIAL FROM WIDESPREAD STRATUS, WITH
MARGINAL MID- LEVEL LAPSE RATES AND GENERALLY WEAK DEEP LAYER
SHEAR LIMITING SEVERE POTENTIAL TONIGHT.
FOR DAY 2, STORM DEVELOPMENT DURING PEAK HEATING/INSTABILITY
DEPENDS ON TIMING OF A MODEST SHORTWAVE SLIDING ACROSS THE
AREA. LATEST MODELS BRING THE WAVE THROUGH IN THE MORNING TO
MIDDAY WHICH COULD SUPPRESS ACTIVITY AS WE MOVE THROUGH THE
AFTERNOON. IF THE TIMING OF THIS WAVE IS DELAYED, INSTABILITY IS
SUFFICIENT TO SUPPORT A FEW STORMS, THOUGH DEEP LAYER SHEAR IS
ON THE WEAK SIDE, SO OVERALL SEVERE THREAT IS STILL UNCERTAIN.
AS INDICATED IN THE DAY 3 OUTLOOK, MONDAY AFTERNOON-EVENING
WOULD BRING THE MORE FAVORABLE SET-UP FOR SOME STRONG TO SEVERE
STORMS, WITH ANOTHER MID-LEVEL WAVE SLIDING EAST ATOP A WARM
FRONT LIFTING NORTH THROUGH IOWA AND MINNESOTA. STILL SOME
VARIANCE AMONG MODELS IN PLACEMENT OF BETTER INSTABILITY AND
SHEAR, SO PLEASE MONITOR THE FORECAST THROUGH THE WEEKEND FOR
THE LATEST UPDATES.
DISCUSSION
ISSUED AT 230 PM CDT FRI APR 10 2026
IT'S A FAIRLY PLEASANT AND SUNNY FRIDAY AFTERNOON
ACROSS THE AREA! CHANGES ARE ON THE WAY THOUGH; IT WILL GET
WARMER... BUT ALSO A BIT STORMIER. WARM AIR ADVECTION (WAA)
INCREASES TONIGHT, HELPING TO BRING SOME SHOWERS INTO THE AREA
EARLY SATURDAY MORNING. THESE SHOWERS WILL MOVE INTO THE
MISSOURI RIVER VALLEY AT FIRST AND LIFT NORTHEASTWARD INTO
SATURDAY MORNING. A FEW RUMBLES OF THUNDER WILL BE POSSIBLE WITH
THIS ACTIVITY, BUT SEVERE WEATHER IS NOT EXPECTED. WITH THE
RETURN OF SOUTHERLY FLOW AND CLOUD COVER ASSOCIATED WITH THE
AFOREMENTIONED SHOWERS, EXPECT A MUCH MILDER NIGHT TONIGHT WITH
LOWS IN THE UPPER 30S TO LOW 40S.
WARM AIR ADVECTION SHOWERS WILL BE ONGOING SATURDAY MORNING
ESPECIALLY EAST OF I-29. THESE SHOWERS WILL PUSH OFF TO OUR EAST
INTO NORTH CENTRAL IOWA AND SOUTH CENTRAL MINNESOTA THROUGH THE
EARLY AFTERNOON. SATURDAY WILL BE WARMER AND BREEZY, BUT WITH
SHOWERS AROUND AND INCREASING MOISTURE DUE TO CONTINUED SOUTHERLY
FLOW, THE FIRE WEATHER DANGER WILL BE LOW. THE ONLY PLACE WHERE WE
COULD SEE ELEVATED FIRE WEATHER CONCERNS SATURDAY AFTERNOON WOULD BE
OVER SOUTH CENTRAL SOUTH DAKOTA WHERE CLOUDS DECREASE THE QUICKEST
AND THUS IT WILL BE A BIT WARMER OUT THAT WAY. OFF TO OUR WEST, AN
UPPER WAVE WILL BE MOVING ACROSS THE ROCKIES AND SENDING IMPULSES
OUR WAY. ADDITIONAL SHOWERS AND STORMS MAY DEVELOP OVERNIGHT
SATURDAY INTO SUNDAY AS THE LOW LEVEL JET STRENGTHENS, ALLOWING FOR
AROUND 1000-1500 J/KG OF INSTABILITY TO MOVE ACROSS THE AREA. ANY
STORMS WILL BE ELEVATED GIVEN THE CAPPED LOW LEVELS, LEADING TO
LARGE HAIL UP TO THE SIZE OF QUARTERS AS THE MAIN THREAT IF A STORM
CAN BECOME SEVERE. THE BETTER CHANCES OF AN ISOLATED SEVERE STORM
WILL BE OVER NORTHWEST IOWA EARLY SUNDAY MORNING, RIGHT WHERE THE
STORM PREDICTION HAS THE AREA IN A LEVEL 1 OUT OF 5 MARGINAL
RISK FOR SEVERE WEATHER.
A SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN PLAINS ON SUNDAY
AND IN RESPONSE, A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE RED
RIVER VALLEY INTO SOUTHERN CANADA. WEST-SOUTHEWESTERLY FLOW WILL
RETURN TO AREA IN THE WAKE OF THIS SYSTEM AND BRING A PUNCH OF
MUCH DRIER AIR INTO THE AREA, ESPECIALLY WEST OF I-29. THIS IS
WHERE RELATIVE HUMIDITY (RH) VALUES WILL DROP BELOW 30%, WITH RH
VALUES AS LOW AS 18-20% POSSIBLE IN SOUTH CENTRAL SOUTH DAKOTA.
IT WILL BE BREEZY AND WARM, WITH WIND GUSTS AROUND 30 MPH AND
HIGHS INTO THE 80S. ALL THIS WILL LEAD TO ELEVATED TO
POTENTIALLY CRITICAL FIRE WEATHER CONCERNS FOR AREAS WEST OF
I-29, SO SUNDAY WILL BE A DAY TO AVOID OUTDOOR BURNING. WINDS
LOOK TO DECREASE THROUGH THE LATE AFTERNOON, SO THIS COULD
LIMIT THE EXTENT OF THE FIRE WEATHER THREAT INTO SUNDAY EVENING,
BUT KEEP IN MIND IT WILL STILL BE DRY AND WARM.
THE ACTIVE WEATHER PATTERN CONTINUES INTO MONDAY AS A DEEP TROUGH
OVER THE CENTRAL WEST COAST BEGINS TO MOVE EASTWARD. MONDAY LOOKS TO
HAVE THE BETTER CHANCES FOR SEVERE WEATHER COMPARED TO SUNDAY
MORNING, THOUGH UNCERTAINTY REMAINS ESPECIALLY WITH THE LOCATION OF
STORM DEVELOPMENT. THE 10.12Z ECMWF HAS STORMS DEVELOPING OVER OUR
AREA, WHILE THE 10.12Z RUNS OF THE NAM AND RRFS HAVE STORMS NOT
DEVELOPING UNTIL EAST OF THE AREA. THIS IS AT LEAST IN PART DUE
TO TIMING AND PLACEMENT DIFFERENCES IN THE POSITION OF A
SURFACE LOW, WITH THE ECMWF SLOWER WITH THIS AND THE NAM AND
RRFS BEING FASTER. THESE FINER DETAILS WILL NEED TO BE IRONED
OUT BEFORE WE COULD START LOOKING INTO INDIVIDUAL SEVERE
THREATS, THOUGH A SLOWER SOLUTION WOULD FAVOR SURFACE BASED
STORMS WHILE A FASTER SOLUTION WOULD FAVOR ELEVATED
THUNDERSTORMS. THE PARENT TROUGH WILL EJECT ACROSS THE AREA ON
TUESDAY, AND THIS COULD POTENTIALLY LEAD TO ANOTHER THREAT OF
STRONGER STORMS AS YET ANOTHER LOW PRESSURE SYSTEM MOVES ACROSS
THE REGION. A FEW SHOWERS MAY LINGER INTO WEDNESDAY, BUT MODELS
DIVERGE SIGNIFICANTLY FROM THERE. WITH NO BIG PUSHES OF COLD AIR
ADVECTION FOLLOWING ANY OF THESE SYSTEMS, WE LOOK TO REMAIN
WARM INTO MUCH OF NEXT WEEK WITH HIGHS POSSIBLY STAYING THE 70S
EVEN INTO WEDNESDAY AND THURSDAY OF NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 653 AM CDT SAT APR 11 2026
MVFR TO IFR CONDITIONS WILL EXPAND NORTH-NORTHEAST ACROSS THE
FORECAST AREA THIS MORNING, ACCOMPANIED BY SCATTERED HIGH-BASED
SHOWERS AND PERHAPS A FEW ISOLATED THUNDERSTORMS. POTENTIAL FOR
THUNDER IS TOO LOW TO INCLUDE AT KFSD, BUT A LITTLE BETTER AT
KSUX SO DID INCLUDE TS IN A PROB30 GROUP EARLY IN THE TAF
PERIOD. ALSO A REMOTE CHANCE FOR AN ISOLATED STORM DEVELOPING
AROUND KSUX LATE THIS EVENING, SO INCLUDED A BRIEF WINDOW OF
POTENTIAL THERE AS WELL, THOUGH CONFIDENCE IS LOWER THAN THE
CHANCES THIS MORNING.
IFR OR EVEN LIFR CEILINGS MAY BE ACCOMPANIED BY MVFR-LOCALLY IFR
VISIBILITY IN FOG AND/OR DRIZZLE THIS AFTERNOON INTO TONIGHT.
SOUTHEAST TO SOUTH WINDS WILL OCCASIONALLY GUST 25-30KT INTO THE
EARLY EVENING, WITH GUST POTENTIAL WANING AFTER SUNSET AS THE
BOUNDARY LAYER STABILIZES WITHIN THE LOWERING STRATUS LAYER. IN
THE ABSENCE OF GUSTS, A SOUTHERLY LOW LEVEL JET WILL PRODUCE A
PERIOD OF LOW LEVEL WIND SHEAR LATE EVENING THROUGH THE END OF
THE TAF PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...JH
DISCUSSION...SAMET
AVIATION...JH
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