228
FXUS63 KFSD 071126
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
626 AM CDT TUE APR 7 2026
KEY MESSAGES
- NARROW SNOW BAND EXPECTED NEAR OR MORE LIKELY SOUTH OF HIGHWAY
20 INTO EARLY THIS MORNING. TRAVEL SOUTH OF SIOUX CITY TOWARDS
OMAHA OR DES MOINES MAY BE IMPACTED.
- A GRADUAL WARMUP THROUGH THE SECOND HALF OF THE WEEK WITH
TEMPERATURES RETURNING ABOVE NORMAL, AND EXCEEDING NORMAL
NEXT WEEKEND.
- A FEW SHOWERS MAY MOVE THROUGH THE AREA WEDNESDAY AND AGAIN
THURSDAY NIGHT, WITH SLIGHTLY HIGHER SHOWER AND THUNDERSTORM
CHANCES THIS WEEKEND. A FEW STRONGER STORMS COULD BE POSSIBLE BY
SUNDAY.
UPDATE
ISSUED AT 456 AM CDT TUE APR 7 2026
DRY LOW LEVEL AIR ONCE AGAIN APPEARS TO BE WINNING OUT BENEATH A
VERY NARROW BAND OF LIGHT ECHOES ALONG THE MISSOURI RIVER VALLEY
EARLY THIS MORNING. BEGINNING TO SEE SOME ENHANCEMENT ON RADAR
TOWARD FAR SOUTHERN PORTION OF DIXON/DAKOTA COUNTIES THOUGH, AND
WITH A MORE FAVORABLE LOW LEVEL MOISTURE PROFILE COULD BEGIN TO
SEE LIGHT SNOW REACH THE GROUND SOUTH OF HIGHWAY 20 IN THE NEXT
2-3 HOURS. WILL LIKELY SEE A RATHER SHARP CUTOFF ON THE NORTHERN
EDGE OF PRECIPITATION, THOUGH, AND WHILE THE FAR SOUTHERN PARTS OF
THE HIGHWAY 20 CORRIDOR COUNTIES MAY SEE SOME LIGHT ACCUMULATION,
NORTHERN PORTIONS MAY SEE LITTLE IF ANY.
THE REMAINDER OF TODAY WE COULD SEE AN AREA OF LIGHT RAIN/SNOW
SWING NORTHEAST ACROSS THE FAR SOUTHEAST COUNTIES OF NORTHWEST
IOWA IN RESPONSE TO A SUBTLE WAVE AND ASSOCIATED WARM ADVECTION.
HOWEVER, THINK ANYTHING MORE THAN A FEW SPRINKLES/FLURRIES WILL
BE TOUGH TO COME BY NORTHWEST OF ROUGHLY SIOUX CITY TO SPENCER
AS MID-LEVELS DRY OUT. 06Z NAM/GFS CONTINUE TO MAINTAIN A DEEPER
STRATUS LAYER OVER NORTHWEST IOWA INTO THIS EVENING WHILE RECENT
CAMS INDICATE MORE SHALLOW LOW LEVEL MOISTURE. WILL HANG ON TO
A CHANCE OF DRIZZLE AS STRONG WARM ADVECTION PERSISTS ATOP THIS
MOIST LAYER, BUT NIGHTTIME TEMPERATURES EXPECTED TO REMAIN WARM
ENOUGH THAT FREEZING IS NOT A CONCERN.
DISCUSSION
ISSUED AT 1239 PM CDT MON APR 6 2026
THIS AFTERNOON: A VERY LIGHT RAIN/SNOW MIX DRIVEN BY 650:700 MB
FRONTOGENESIS MAY CONTINUE ALONG THE MO RIVER VALLEY THIS AFTERNOON,
THOUGH IN MOST AREAS, A DRY SUBCLOUD LAYER FOCUSED AROUND 850 MB
WILL LIMIT ANY ACCUMULATION. ELSEWHERE, VARIABLE CLOUD COVER
CONTINUES AS TEMPERATURES REMAIN 10+ DEGREES BELOW NORMAL.
TONIGHT: CAMS REALLY PICKING UP ON A GREAT NW TO SE ORIENTED
MESOSCALE BANDED FEATURE DEVELOPING AFTER DARK, MOSTLY IMPACTING
AREAS ALONG OR SOUTH OF HIGHWAY 20. GIVEN INSTABILITY WITHIN THE
BAND, ANY TRAVELERS HEADING SOUTH OF SIOUX CITY TOWARDS OMAHA WILL
NEED TO BE PREPARED FOR TRAVEL IMPACTS THROUGH DAYBREAK. THERE
REMAINS SOME VARIABILITY IN THE LOCATION OF THE FRONTOGENESIS
ASSOCIATED WITH THIS PRECIPITATION, WITH HRRR FOCUSED TOO FAR
NORTH MOST OF THIS MORNING. HAVE FAVORED THE NAM/RAP FOR UPDATES
OVERNIGHT, BUT WE'LL NEED TO WATCH THIS CLOSELY. FURTHER NORTH,
AN EASTERLY WIND AND SCATTERED CLOUD LAYER WILL ALLOW
TEMPERATURES TO DROP INTO THE 20S, SOME 10 DEGREE BELOW NORMAL.
TUESDAY: WEAK MID-LVL FLOW WILL KEEP VORTICITY STREAMING THROUGH
THE CENTRAL PLAINS ON TUESDAY. EVENTUALLY, 925:850 MB WINDS WILL
TURN SOUTHERLY, ALLOWING WARM ADVECTION TO SPREAD BACK NORTHWARD.
EVENTUALLY A DEEPER LOW LVL MOISTURE FIELD WILL TRACK NORTH, AND
WITH PERSISTENT LOW-LVL WARM ADVECTION, CAN'T RULE OUT VERY LIGHT
SNOW, DRIZZLE, OR FREEZING DRIZZLE IN THE AFTERNOON. HAVE WENT WITH
A HIGHER POP BUT LOW QPF FORECAST. THE ABUNDANCE OF CLOUDS SHOULD
AGAIN HOLD TEMPERATURES BACK BELOW NORMAL, WITH MOST AREAS
STRUGGLING TO REACH 40 DEGREES.
WEDNESDAY: BY WEDNESDAY, WE'LL BEGIN TO SEE A STRONGER UPPER TROUGH
TRACK EASTWARD THROUGH THE CANADIAN ROCKIES, ALLOWING A FRONTAL
BOUNDARY TO FORM ACROSS THE WESTERN DAKOTAS. A FEW LINGERING SPITS
MAY CONTINUE INTO WEDNESDAY MORNING AHEAD OF THIS BOUNDARY, BUT THE
GREATER STORY WILL BE THE ADVECTION OF MUCH WARMER LOW-LVL AIR
NORTHWARD. LATEST GUIDANCE HAS TIMED THE ARRIVAL OF THIS FRONT
SLIGHTLY FASTER THAN PREVIOUS SOLUTIONS, MEANING LOW-LVL MOISTURE
WILL BE SCOURED EAST QUICKLY IN THE DAY. IN THE WAKE OF THIS FRONT,
A WARM WESTERLY DOWNSLOPE WIND WILL BOTH LOWER RH VALUES INTO THE 25
TO 35 PERCENT RANGE, BUT ALLOW PROMOTE HIGHS IN THE LOWER 60S
AND GUSTY 30 MPH WINDS AT TIMES. THIS COMBINATION, ALONG WITH
DRYING OUT FINE FUELS MAY LEAD TO ELEVATED FIRE DANGER IN THE
AFTERNOON.
THURSDAY-FRIDAY: THE AFOREMENTIONED UPPER WAVE TRACKS INTO THE GREAT
LAKES BY THE END OF THE WEEK, PUSHING COOLER CANADIAN AIR SOUTHWARD
INTO THE PLAINS. HIGH TEMPERATURES ONLY RETREAT SLIGHTLY INTO THE
MIDDLE 50S, NEAR CLIMATOLOGICAL NORMALS. MEDIUM RANGE MODELS BEGIN
TO DIVERGE A BIT AT THE END OF THE WEEK, SUGGESTING AN INCREASING
RISK OF SHOWERS AND ISOLATED THUNDERSTORMS THURSDAY NIGHT INTO
FRIDAY OVER THE SOUTHEASTERN 1/3 OF THE CWA. THE LATEST NBM WOULD
SUGGEST AROUND A 50% PROBABILITY OF >0.10" OF QPF ALONG AND
SOUTHEAST OF A LINE FROM YANKTON TO JACKSON INTO FRIDAY MORNING. THE
REMAINDER FRIDAY SHOULD BE DRY, AS HIGH PRESSURE ONCE AGAIN PUSHES
DRIER AIR SOUTHEASTWARD.
NEXT WEEKEND: WE'RE CONTINUING TO SEE INCREASED POTENTIAL FOR A
PATTERN SHIFT BY NEXT WEEKEND AND INTO THE FOLLOWING WEEK. MID-LVL
HEIGHTS ARE PROJECTED TO RISE OVER THE SOUTHEASTERN US, ALLOWING
MORE PERSISTENT TROUGHING TO DEVELOP ALONG AND WEST OF THE ROCKIES.
THIS SHIFT IN MID-LVL FLOW SHOULD RESULT IN ABOVE NORMAL
TEMPERATURES AS WELL AS INCREASED SHOWER AND THUNDERSTORM POTENTIAL
ACROSS THE PLAINS INTO NEXT WEEK. THAT SAID, THERE REMAINS QUITE A
BIT OF SPREAD IN TEMPERATURE GUIDANCE FOR SATURDAY AND SUNDAY, WITH
THE DETERMINISTIC NBM PUSHED TOWARDS THE 75TH PERCENTILE. HOWEVER
ON SUNDAY, THE NBM IS SUGGESTING A 10-15 DEGREE SPREAD IN HIGH
TEMPERATURES, WITH THE DETERMINISTIC NEAR THE 25TH PERCENTILE IN THE
MID-70S. SHOULD DEEP SOUTHWESTERLY FLOW DEVELOP, THEN MUCH WARMER
TEMPERATURES INTO THE 80S ARE POSSIBLE.
AS FAR AS PRECIPITATION IS CONCERNED, WE'RE AT LEAST BEGINNING TO
SEE SIGNS OF MORE INSTABILITY TRACKING NORTHEAST OVER THE
WEEKEND GIVEN THE MORE MERIDIONAL LOW-LVL FLOW TRAJECTORIES.
WHILE A GREAT DEAL OF SPREAD CONTINUES IN ENSEMBLE GUIDANCE,
SEVERAL MACHINE LEARNING CONVECTIVE OUTLOOK MODELS ARE
INDICATING RISING POTENTIAL FOR SEVERE STORMS MOVING NORTHWARD
INTO THE PLAINS AND UPPER MIDWEST BY THE END OF THE WEEKEND.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 626 AM CDT TUE APR 7 2026
VFR CONDITIONS TO BEGIN THIS PERIOD, BUT MVFR-IFR STRATUS IS
EXPECTED TO EXPAND NORTHWARD INTO THE AREA THIS AFTERNOON INTO
TONIGHT. COULD SEE MVFR VISIBILITY IN FOG OR POSSIBLY DRIZZLE
ALONG WITH THE LOWEST STRATUS AFTER SUNSET THIS EVENING, BUT
CONFIDENCE IS TOO LOW TO INCLUDE THE REDUCED VISIBILITY AT THIS
TIME.
RELATIVELY LIGHT EAST WINDS WILL TURN SOUTHEAST TO SOUTH BY LATE
MORNING, WITH GUSTS AT OR ABOVE 25KT BECOMING MORE FREQUENT THIS
AFTERNOON INTO THE OVERNIGHT. AS WINDS DIMINISH SLIGHTLY AFTER
08/06Z, AN INCREASING LOW LEVEL JET WILL RESULT IN LOW LEVEL WIND
SHEAR ACROSS THE REGION.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...JH
DISCUSSION...DUX
AVIATION...JH
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