219
FXUS63 KFSD 310338
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1038 PM CDT FRI MAY 30 2025
KEY MESSAGES
- LIGHT WINDS, AND WARM HIGHS IN THE 80S WITH A FEW 90S POSSIBLE
THIS WEEKEND.
- WILDFIRE SMOKE FROM CANADA HAS BEEN DRIFTING SOUTH OVER THE
REGION TODAY AND WILL CONTINUE THROUGH THE WEEKEND. AN AIR
QUALITY ALERT HAS BEEN ISSUED FOR THE STATE OF MINNESOTA
THROUGH MONDAY.
- CONTINUED FILTRATION OF THE SMOKE TO GROUND LEVEL MAY RESULT
IN EXPANDED AIR QUALITY ALERTS THIS WEEKEND, AND SOME MINOR
REDUCTIONS IN VISIBILITY ARE POSSIBLE.
- THUNDERSTORM RISKS RETURN LATE MONDAY AFTERNOON AND PEAK
MONDAY NIGHT. SEVERE WEATHER RISKS WILL BE POSSIBLE ESPECIALLY
WEST OF I-29 MONDAY NIGHT.
DISCUSSION
ISSUED AT 223 PM CDT FRI MAY 30 2025
TODAY AND TONIGHT: TAKING A LOOK AT GOES SATELLITE, WE SEE THE SMOKE
FROM CANADIAN WILDFIRES STREAMING SOUTH-SOUTHEAST ON THE UPPER LEVEL
WINDS. THIS AFTERNOON, SMOKE HAS BEGUN TO SETTLE TOWARD THE SURFACE.
IMPACTS IN SOUTHEASTERN SOUTH DAKOTA REMAIN LIMITED, HOWEVER, ALL OF
MINNESOTA HAS BEEN PLACED UNDER AN AIR QUALITY ALERT THAT CONTINUES
THROUGH 6 PM MONDAY. WINDS TODAY WILL BE LIGHT AND SOUTHWESTERLY TO
WESTERLY, BECOMING LIGHT AND VARIABLE OVERNIGHT. LOWS FOR TONIGHT
WILL BE AROUND AVERAGE FOR THIS TIME OF YEAR, IN THE LOW TO MID 50S.
THE WEEKEND: THIS WEEKEND WILL BE DOMINATED BY AN UPPER LEVEL RIDGE
AND SURFACE HIGH PRESSURE. SKIES WILL BE MAINLY CLEAR OF CLOUDS, BUT
WILL BE OBSCURED BY THICKENING WILDFIRE SMOKE. SUBSIDENCE ALOFT WILL
HELP TO BRING THE SMOKE NEARER TO THE SURFACE. THIS COMBINED WITH A
DEEP, WELL MIXED BOUNDARY LAYER WILL FURTHER TRANSPORT SMOKE CLOSER
TO THE SURFACE. SATURDAY AND SUNDAY WE MAY EXPERIENCE SOME
REDUCTIONS IN VISIBILITY AND AIR QUALITY.
SATURDAY MORNING, A FAST MOVING WAVE WILL PASS THROUGH THE REGION,
BRINGING LOW CHANCES FOR LIGHT RAIN SHOWERS OVER CENTRAL SOUTH
DAKOTA. HOWEVER, THERMODYNAMIC PROFILES INDICATE THE SYSTEM WILL BE
LOW ON MOISTURE WITH A VERY DRY SUBCLOUD LAYER. ANY SHOWERS THAT DO
DEVELOP WILL LIKELY NOT REACH THE GROUND. ENSEMBLE GUIDANCE SUPPORTS
THIS WITH LESS THAN A 10% CHANCE OF MEASURABLE (>=0.01") RAIN.
HIGHS WILL BE WARM, APPROXIMATELY 10 DEGREES ABOVE AVERAGE FOR
SATURDAY, IN THE UPPER 70S TO MID 80S. FOR SUNDAY, HIGHS WILL BE 10-
15 DEGREES ABOVE NORMAL, IN THE MID TO UPPER 80S. AVERAGE FOR THE
END OF MAY IS IN THE MID 70S. HIGHS FOR BOTH DAYS HAVE BEEN TRIMMED
BACK JUST A LITTLE AFTER COORDINATION WITH NEIGHBORS DUE TO THE
INFLUENCE OF THE SMOKE.
MONDAY-TUESDAY: BY MONDAY MORNING AN UPPER TROUGH WILL TAKE SHAPE
OVER THE ROCKIES AND BEGIN TO PUSH OUR UPPER RIDGE TO THE EAST. A
COLD FRONT DRAPED FROM NORTHERN MANITOBA SOUTHWEST INTO UTAH
COMBINED WITH SOUTHERLY WINDS AT THE SURFACE WILL WORK TO CHANNEL
MOISTURE NORTHWARD INTO THE REGION. DEW POINTS BY MID-DAY MONDAY
WILL BE IN THE LOW TO MID 60S, AS HIGHS CLIMB INTO THE UPPER
80S TO LOW 90S. THROUGH THE DAY, INSTABILITY AND LAPSE RATES BEGIN
TO STEEPEN. COMBINED WITH MODERATE 0-6 KM BULK SHEAR, AND AN
INCREASING LOW LEVEL JET, STRONG TO SEVERE THUNDERSTORMS ARE
POSSIBLE BEGINNING LATE MONDAY AFTERNOON. THESE ARE EXPECTED TO
BEGIN AS DISCRETE CELLS AND QUICKLY GROW UPSCALE INTO A LINE. DCAPE
VALUES IN THE 1000-1500 J/KG RANGE INDICATE STRONG DOWNDRAFT GUSTS
ARE LIKELY. LARGE HAIL IS ALSO POSSIBLE, BUT CONFIDENCE IS LIMITED
DUE TO A HIGH FREEZING LEVEL AND A DEEP WARM CLOUD LAYER INDICATED
IN MODEL SOUNDINGS. CONSIDERING THIS WARM LAYER, AND PRECIPITABLE
WATER VALUES IN THE 97-99TH PERCENT FOR CLIMATOLOGY, THERE IS A
CHANCE THAT LOCALLY HEAVY RAINFALL MAY BE OCCUR. THE GFS, CAN,
AND EC HAVE ALL BEGUN TO KEY ON HIGHER POCKETS OF RAINFALL
GREATER THAN AN INCH, THOUGH COVERAGE AND LOCATION OF HIGHER
TOTALS IS IN LOW AGREEMENT.
THE COLD FRONT PUSHES SOUTHEAST OF THE REGION TUESDAY AFTERNOON.
LINGERING SHOWERS CONTINUE THROUGH TUESDAY EVENING. HIGHS FOR
TUESDAY WILL BE NOTICEABLY COOLER THAN MONDAY, IN THE MID 60S
TO LOW 70S.
WEDNESDAY-AND-BEYOND: WEDNESDAY LOOKS TO DRY OUT BEFORE THE NEXT
TROUGH BRINGS RENEWED CHANCES FOR RAIN THURSDAY. THE PATTERN LOOKS
TO REMAIN ACTIVE INTO THE WEEKEND WITH PERIODIC CHANCES FOR SHOWERS
AND THUNDERSTORMS.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1035 PM CDT FRI MAY 30 2025
SKIES WILL BE MAINLY CLOUD FREE FOR MOST OF THE AREA THROUGH
THE TAF PERIOD, THOUGH THERE WILL BE A THICK LAYER OF SMOKE
ALOFT. SOME OF THIS SMOKE MAY BEGIN TO MAKE IT TO THE SURFACE BY
SATURDAY, THOUGH AT THIS TIME VISIBILITIES LOOK TO REMAIN IN
THE VFR RANGE. LIGHT NORTHWEST WINDS WILL PREVAIL THROUGH THE
PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...AJP
AVIATION...JM
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