850
FXUS63 KFSD 110815
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
315 AM CDT FRI JUL 11 2025
KEY MESSAGES
- SCATTERED SHOWERS AND ISOLATED STORMS WILL PERSIST THROUGH THE
MORNING HOURS, MAINLY OVER THE LOWER MISSOURI RIVER VALLEY
INTO NORTHWEST IOWA. LOCALLY HEAVY DOWNPOURS WILL BE POSSIBLE
OVER THAT AREA THROUGH EARLY MORNING.
- A LOW END (LEVEL 1 OF 5) RISK OF SEVERE STORMS DEVELOPS BY
LATE THIS AFTERNOON, AS A FRONT BRINGS SCATTERED THUNDERSTORMS
SOUTHWARD INTO THE REGION. THE MAIN THREATS WITH THE
STRONGEST STORMS WILL BE UP TO QUARTER SIZED HAIL, STRONG
WINDS UP TO 60 MPH, AND HEAVY DOWNPOURS.
- TEMPERATURES COOL SATURDAY, BUT HEAT AND HUMIDITY BUILD BACK IN
FOR SUNDAY THROUGH TUESDAY.
- THUNDERSTORM RISKS RETURN FOR TUESDAY INTO WEDNESDAY, WITH
SOME THREAT OF SEVERE STORMS POSSIBLE.
DISCUSSION
ISSUED AT 307 AM CDT FRI JUL 11 2025
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE
LOWER MISSOURI RIVER VALLEY INTO NORTHWEST IA VERY EARLY THIS
MORNING - THIS IN ASSOCIATION WITH AN UPPER LEVEL TROUGH SITUATED
OVER THE REGION. LATEST GUIDANCE INDICATES A DOWNWARD TREND IN
SHOWER COVERAGE OVER THAT AREA THROUGH THE MORNING INTO THE EARLY
AFTERNOON AS THE TROUGH SLOWLY SHIFTS TO THE EAST, BUT WILL KEEP
THE FLOOD WATCH IN EFFECT UNTIL 12Z FOR POSSIBLE HEAVIER
DOWNPOURS. ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP OVER CENTRAL SD BY LATE AFTERNOON - PUSHING EASTWARD
THROUGH THE EVENING AS A COLD FRONT MOVES SLOWLY ACROSS THE
REGION. ALTHOUGH MLCAPE WILL BE IN THE RANGE OF 1500-2000 J/KG
BY AFTERNOON, 0-6 BULK SHEAR LOOKS TO BE GENERALLY LESS THAN 20
KTS. IN ADDITION MID LEVEL LAPSE RATES ARE NOT OVERLY IMPRESSIVE
AT 6-7 C/KM, SO THE SEVERE THREAT LOOKS TO REMAIN ON THE LOW
SIDE - THOUGH CANNOT RULE OUT A STRONGER STORM WITH SMALL HAIL
AND BRIEF GUSTY WINDS. IT WILL BE ANOTHER WARM AND MUGGY DAY
WITH HIGHS IN THE MID TO UPPER 80S COMBINED WITH DEW POINTS IN
THE UPPER 60S TO LOWER 70S.
COULD SEE A FEW LINGERING SHOWERS EARLY TONIGHT AS ANOTHER UPPER
LEVEL TROUGH MOVES THROUGH THE REGION, THOUGH THIS ACTIVITY WILL
DIMINISH LATER IN THE NIGHT WITH LITTLE ADDITIONAL RAINFALL
ACCUMULATION EXPECTED. WITH COLD AIR ADVECTION BEHIND THE
AFOREMENTIONED FRONT, TEMPERATURES WILL FALL INTO THE UPPER 50S TO
LOWER 60S BY SATURDAY MORNING.
A MUCH NICER DAY IN STORE FOR SATURDAY AS WEAK SURFACE HIGH PRESSURE
BUILDS INTO THE AREA AND AN 850 MB THERMAL TROUGH SWINGS THROUGH THE
REGION. HIGHS IN THE UPPER 70S TO MID 80S WILL FEEL QUITE PLEASANT
AS DEW POINTS FALL INTO THE 50S TO LOW 60S.
THE COOLER CONDITIONS WILL BE BRIEF HOWEVER, AS HIGH PRESSURE PUSHES
OFF TO THE EAST AND A SOUTHERLY FLOW RETURNS TO THE REGION FOR
SUNDAY INTO TUESDAY OF NEXT WEEK. WITH WARMING 850 MB TEMPERATURES,
HIGHS WILL CLIMB BACK INTO THE UPPER 80S AND 90S EACH DAY. IN
ADDITION, WITH A RETURN OF LOW LEVEL MOISTURE DEW POINTS WILL PUSH
BACK INTO THE 60S TO LOWER 70S. OUR NEXT BEST CHANCE OF SHOWERS AND
STORMS WILL COME ON TUESDAY INTO WEDNESDAY AS A STRONG COLD FRONT
MOVES THROUGH THE REGION. TOO SOON TO GET A HANDLE ON THE SEVERE
STORM POTENTIAL FOR THAT PERIOD, THOUGH IT WILL BE SOMETHING TO KEEP
AN EYE ON. WITH THE PASSAGE OF THE FRONT, MUCH COOLER TEMPERATURES
WILL DROP BACK INTO THE AREA FOR WEDNESDAY AND THURSDAY.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1035 PM CDT THU JUL 10 2025
SHOWERS AND OCCASIONAL THUNDERSTORMS WILL CONTINUE TO TRAIN EAST
NEAR YANKTON AND SIOUX CITY OVERNIGHT. THE STRONGEST STORMS WILL
BRING MVFR VISIBILITY, HEAVY DOWNPOURS, AND SMALL HAIL. ISOLATED
SHOWERS AND STORMS ARE POSSIBLE FURTHER NORTH AT HURON AND SIOUX
FALLS, BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THE TAF AT THIS
TIME. WE'LL DRY OUT HEADING INTO FRIDAY MORNING BEFORE ANOTHER
ROUND OF SCATTERED SHOWERS AND STORMS DEVELOPS FRIDAY AFTERNOON
INTO EVENING. LIGHT SOUTHERLY WINDS PERSIST OVERNIGHT, GUSTING
UP TO 20 KTS DURING THE DAY FRIDAY. A PASSING FRONT WILL SHIFT
WINDS TO THE NORTH LATE FRIDAY AFTERNOON AND EVENING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR IAZ031-032.
NE...FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR NEZ013-014.
DISCUSSION...JM
AVIATION...BP
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