307
FXUS63 KFSD 012241
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
541 PM CDT THU MAY 1 2025
KEY MESSAGES
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE
THROUGH THE AFTERNOON. SEVERE STORMS ARE NOT EXPECTED, BUT
LOCALLY STRONG GUSTS OVER 40 MPH MAY BE POSSIBLE IN SOUTH
CENTRAL SOUTH DAKOTA.
- LATER THIS EVENING, ANOTHER ROUND OF SHOWERS TO THUNDERSTORMS
WILL BE POSSIBLE. MOST OF THIS ACTIVITY TRACKS THROUGH THE
JAMES AND MISSOURI RIVER VALLEYS BRINGING POTENTIAL FOR
RAINFALL OVER 0.50" AT TIMES.
- AN EXTENDED PERIOD OF WARM AND DRY WEATHER IS LIKELY THROUGH
THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK.
- LIGHT RAIN CHANCES RETURN BY THE MIDDLE OF NEXT WEEK, BUT
CURRENTLY OUTLOOKS SUGGEST LOW RAINFALL TOTALS AND NO SEVERE
WEATHER RISKS.
DISCUSSION
ISSUED AT 203 PM CDT THU MAY 1 2025
THIS AFTERNOON: LINGERING LIGHT RAIN CONTINUES TO MOVE INTO
SOUTH CENTRAL MINNESOTA AND NORTH CENTRAL IOWA THIS AFTERNOON.
MEANWHILE WE'RE SEEING THE DEVELOPMENT OF SCATTERED SHOWERS AND
A FEW THUNDERSTORMS WEST OF I-29 WITHIN AN AREA OF WEAK LOW-LVL
COLD ADVECTION, DPVA, AND MODEST INSTABILITY (100-400 J/KG).
THIS SCATTERED ACTIVITY WILL PERSIST THROUGH THE AFTERNOON, AND
MAY BEGIN TO SLOWLY DIMINISH THIS EVENING. HOWEVER, MORE DIRECT
INFLUENCE FROM VORTICITY MOVING THROUGH NW NEBRASKA AND SW SOUTH
DAKOTA IS LIKELY TO KEEP SCATTERED ACTIVITY MOVING SOUTHEAST
INTO THE EVENING. DEEPER MIXING LEADING TO HIGH CLOUD BASES MAY
LEAD TO OCCASIONAL WIND GUSTS OVER 40 MPH THROUGH THE MO RIVER
VALLEY THIS EVENING.
TONIGHT: WHILE SOME OF THE MORE DIURNALLY DRIVEN ACTIVITY WILL FADE
EARLY IN THE EVENING, WE'LL CONTINUE TO SEE MORE SYNOPTICALLY DRIVEN
SHOWERS AND ISOLATED STORMS MOVE THROUGH CENTRAL AND SOUTHERN SOUTH
DAKOTA DURING THE OVERNIGHT HOURS. THIS ACTIVITY, DRIVEN BY YET
ANOTHER LOBE OF VORTICITY SWEEPING INTO CENTRAL SOUTH DAKOTA LATE
THIS EVENING, WILL PUSH RATHER HIGH POPS THROUGH THE JAMES AND
ESPECIALLY MISSOURI RIVER VALLEY INTO DAYBREAK FRIDAY. QPF AMOUNTS
ARE LIKELY TO RANGE BETWEEN 0.10 AND 0.50", HOWEVER HREF LPMM DATA
SUGGESTS ISOLATED POTENTIAL FOR UPWARDS OF 1.0" OF RAIN.
FRIDAY: THE BROAD UPPER TROUGH WILL SLOWLY PIVOT SOUTHEAST OVERHEAD
OF THE TRI-STATE AREA ON FRIDAY. WHILE THE GREATEST RISKS FOR
SHOWERS ARE LIKELY TO SHIFT SOUTH OF THE CWA, GIVEN INCREASING LOW-
LVL COLD ADVECTION AND LINGERING DPVA, ANY CLEARING AND ULTIMATELY
ANY SURFACE HEATING MAY BE SELF-DESTRUCTING, WITH A VERY LOW RISK
FOR AFTERNOON SPRINKLES AT TIMES. HIGHS RISE ONLY INTO THE UPPER
50S TO LOWER 60S.
SATURDAY-MONDAY: WE'RE HEADED TOWARDS WHAT LOOKS LIKE A GREAT
WEEKEND THROUGH MOST OF THE CENTRAL US, THANKS TO THE DEVELOPMENT OF
AN OMEGA BLOCK. OUTSIDE OF PERHAPS SOME PATCHY FOG SATURDAY
MORNING, WINDS WILL STAY FAIRLY LIGHT THROUGH THE DAY WITH HIGHS
RISING INTO THE MIDDLE TO UPPER 60S. WINDS WILL AGAIN REMAIN LIGHT
ON SUNDAY, THOUGH WITH A BIT MORE SOUTHEASTERLY FETCH AND HIGH
CIRRUS AND WEAK LOW-LVL COLD ADVECTION EMANATING FROM THE LARGE
UPPER LOW OVER THE OHIO RIVER VALLEY, HIGHS MAY ONLY RISE
TOWARDS THE 70 DEGREE MARK. A CARBON COPY DAY FOR MONDAY AS WE
REMAIN SOLIDLY UNDER THE INFLUENCE OF THE MID-LVL RIDGE.
TUESDAY-THURSDAY: THE OMEGA BLOCK MAY BEGIN TO BREAK DOWN BY THE
MIDDLE OF THE WEEK, ONLY TO BE REPLACED BY A REX BLOCK. THIS
PATTERN DEVELOPMENT WILL AGAIN LEAD TO SEASONAL TEMPERATURES, BUT
ONLY MODEST RISKS FOR PRECIPITATION. ENSEMBLES SUGGEST LESS THAN A
20% PROBABILITY FOR LIGHT RAIN TO REACH THE CWA BY LATE TUESDAY AND
WEDNESDAY.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 539 PM CDT THU MAY 1 2025
DIURNALLY DRIVEN SHOWERS AND VERY ISOLATED THUNDERSTORMS WILL
SLOWLY DIMINISH THROUGH SUNSET. HOWEVER THE CHANCE FOR SHOWERS
AND AN ISOLATED THUNDERSTORM WILL CONTINUE THROUGH FRIDAY
MORNING AS LOW PRESSURE MOVES SOUTHEAST THROUGH THE WESTERN HIGH
PLAINS AND BRINGS AN INCREASED CHANCE TO CENTRAL PARTS OF SD.
THE REMAINDER OF THE AREA SHOULD SEE MORE ISOLATED ACTIVITY
AFTER SUNSET. OTHERWISE, LATE TONIGHT INTO THE MIDDLE OF FRIDAY
MORNING SOME IFR CEILINGS WILL BE POSSIBLE WITH THE BETTER
CHANCES ACROSS SOUTHWEST MN, BUT CONFIDENCE A BIT LOW ON
OCCURRENCE AS SATURATION AT THIS LEVEL IS SHORT LIVED IN ALL OF
THE MODELS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...DUX
AVIATION...08
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