501
FXUS63 KFSD 230845
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
345 AM CDT MON JUN 23 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS PUSH TO THE EAST THROUGH THE
MORNING, WITH ANY ADDITIONAL RAINFALL MOST LIKELY CONFINED TO
NORTHWESTERN IA AND THE LOWER MISSOURI RIVER VALLEY THROUGH
TUESDAY. SEVERE STORM CHANCES ARE LOW THROUGH THE PERIOD.
- AN ACTIVE PATTERN WILL CONTINUE THROUGH MID WEEK. WHILE SOME
UNCERTAINTY REMAINS, THE BETTER CHANCE FOR ISOLATED SEVERE
STORMS AND HEAVY RAINFALL WILL BE TUESDAY NIGHT INTO
WEDNESDAY NIGHT.
DISCUSSION
ISSUED AT 339 AM CDT MON JUN 23 2025
A BROAD AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES ROUGHLY
FROM JUST EAST OF THE INTERSTATE 29 CORRIDOR AND WESTWARD EARLY THIS
MORNING - THIS IN ASSOCIATION WITH A COLD FRONT PUSHING ACROSS THE
REGION COLLOCATED WITH A SERIES OF SHORTWAVES LIFTING NORTHWARD ON A
SOUTHWESTERLY UPPER LEVEL FLOW. THE FRONTAL BOUNDARY IS CURRENTLY
DRAPED FROM SOUTHWESTERN MN INTO NORTHEASTERN NE, AND HAVE SEEN A
FEW POCKETS OF HEAVIER RAIN WITH TRAINING CELLS DUE TO CONVERGENCE
ALONG THE LOW LEVEL JET AND A MEAN FLOW NEARLY PARALLEL TO THE
FRONTAL BOUNDARY. THIS ENTIRE AREA OF PRECIPITATION IS EXPECTED TO
WORK EASTWARD AND WEAKEN THROUGH EARLY TO MID MORNING AS THE BETTER
UPPER LEVEL FORCING DRIFTS TO THE NORTH AND THE LOW LEVEL JET VEERS
TO THE EAST. THE FRONTAL BOUNDARY WILL COMPLETELY EXIT OUR AREA SOME
TIME BY LATE MORNING/EARLY AFTERNOON AS IT PUSHES INTO SOUTHERN IA
AND SOUTHERN NE BY THE END OF THE DAY. WHILE SOME RISK OF
SHOWERS/ISOLATED THUNDERSTORMS WILL REMAIN OVER NORTHWEST IA DURING
THE DAY, MODELS WOULD SUGGEST THAT MOST OF THIS ACTIVITY WILL REMAIN
TO THE SOUTH OF OUR CWA. ANY RISK OF SEVERE STORMS IS LOW WITH THE
BETTER INSTABILITY BEING SHUNTED TO OUR SOUTH. IT WILL BE A MUCH
MORE PLEASANT DAY IN TERMS OF TEMPERATURES WITH COLD AIR ADVECTION
BEHIND THE AFOREMENTIONED FRONTAL BOUNDARY. DEW POINTS WILL BE
FALLING THROUGH THE DAY (TO 40S AND 50S FOR ALL BUT FAR NORTHWESTERN
IA), AND HIGHS WILL BE NEARLY 20 DEGREES LOWER THAN YESTERDAY - ONLY
IN THE UPPER 70S TO LOWER 80S. IN ADDITION, WINDS ARE EXPECTED TO BE
MUCH LIGHTER THAN RECENT DAYS.
FOR TONIGHT THROUGH THE DAY ON TUESDAY, RAIN CHANCES WILL MAINLY BE
CONFINED TO AREAS THROUGH THE LOWER MISSOURI RIVER CORRIDOR AND
NORTHWEST IA AS THE AFOREMENTIONED FRONT BEGINS TO WORK BACK TO THE
NORTH. NOT EXPECTING HEAVY RAIN WITH MAYBE A COUPLE TENTHS OF AN
INCH THROUGH THE PERIOD. THE BETTER INSTABILITY REMAIN BOTTLED UP TO
OUR SOUTH, SO THE RISK OF SEVERE STORMS IS LOW. TEMPERATURES TONIGHT
WILL BE FAIRLY PLEASANT - MID 50S TO LOWER 60S, WITH HIGHS ON
TUESDAY MAINLY MID TO UPPER 70S UNDER A COOLISH EASTERLY FLOW.
FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT, RAIN CHANCES INCREASE
AGAIN AS THE FRONTAL BOUNDARY WORKS NORTHWARD BACK INTO OUR AREA AS
A SERIES OF SHORTWAVES TRAVERSE THE PERSISTENT SOUTHWESTERLY UPPER
LEVEL FLOW. INSTABILITY BEGINS TO INCREASE A BIT THROUGH THIS PERIOD
(PRIMARILY WEDNESDAY AFTERNOON), THOUGH BULK SHEAR LOOKS TO REMAIN
ON THE WEAKER SIDE. WHILE THERE MAY BE A LOW RISK OF SEVERE STORMS
DURING THIS PERIOD, THE GREATER RISK MAY BE HEAVY RAINFALL. THIS
WILL BE FOCUSED ON TUESDAY NIGHT AND WEDNESDAY NIGHT - WITH
INCREASING MOISTURE FLUX CONVERGENCE IN THE VICINITY OF THE STALLED
FRONTAL BOUNDARY VIA AN INCREASING LLJ BOTH NIGHTS, THIS COLLOCATED
WITH PWAT VALUES IN THE TOP 1 PERCENT COMPARED TO CLIMATOLOGY.
WARMER TEMPERATURES AND HUMIDITY LOOK TO RETURN ON WEDNESDAY WITH
HIGHS BACK INTO THE 80S AND DEW POINTS IN THE MID 60S TO LOWER 70S.
RAINFALL CHANCES LOOK TO FINALLY BE ON A DOWNWARD TREND BY THE END
OF THE WEEK (THURSDAY THROUGH SATURDAY), THIS AS THE PERSISTENT
UPPER LEVEL JET WHICH HAS BEEN PARKED TO OUR WEST SHIFTS OUT OF THE
REGION AND THE UPPER LEVEL PATTERN TRANSITIONS TO A LESS AMPLIFIED
FLOW. COULD SEE A RETURN OF SHOWER/THUNDERSTORM CHANCES BY THE END
OF NEXT WEEKEND AS AN UPPER LEVEL TROUGH DROPS INTO THE NORTHERN
PLAINS, THOUGH CONFIDENCE IS LOW. TEMPERATURES FOR THE END OF THE
WEEK INTO THE WEEKEND WILL LIE ON THE WARMER SIDE OF SEASONAL
AVERAGES.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1115 PM CDT SUN JUN 22 2025
SHOWERS AND STORMS CONTINUE ALONG/WEST OF I-29 AT 4Z, AND EXPECT
THESE TO CONTINUE TO MOVE NORTH/NORTHEAST OVERNIGHT. ALTHOUGH
SEVERE RISK HAS DIMINISHED, AN ISOLATED STRONG TO SEVERE STORM
IS POSSIBLE. EXPECT MVFR TO IFR CONDITIONS WITH CONVECTION.
ADDITIONALLY, GUIDANCE CONTINUES TO SHOW MVFR CEILINGS DURING
THE DAY MONDAY FOR NORTHEASTERN NE AND NORTHWESTERN IA, SO HAVE
KEPT KSUX INTO MVFR THROUGH THE AFTERNOON. SHOWER AND STORM
CHANCES REMAIN IN PLACE FOR NORTHEASTERN NE INTO SOUTH CENTRAL
MN DURING THE DAY MONDAY INTO MONDAY EVENING.
WINDS BEHIND THE SURFACE FRONT HAVE SHIFTED TO THE NORTHWEST,
WITH WINDS AHEAD OF THE FRONT STILL OUT OF THE SOUTH BUT
CONTINUE TO SHIFT OVERNIGHT AS THE FRONT MEANDERS EAST. OUTSIDE
OF THUNDERSTORMS, EXPECT GUSTS AROUND 20 TO 25 KNOTS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...JM
AVIATION...SG
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