308
FXUS63 KFSD 071946
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
246 PM CDT WED MAY 7 2025
KEY MESSAGES
- A LOW (<30%) CHANCE OF SCATTERED SHOWERS AND A FEW RUMBLES OF THUNDER
CONTINUES THIS AFTERNOON AND EVENING. IF SHOWERS DEVELOP,
RAINFALL AMOUNTS WILL BE LIGHT, LESS THAN A TENTH OF AN INCH.
- WARM, DRY WEATHER CONTINUES THROUGH SATURDAY WITH HIGHS IN THE UPPER
70S TO THE MID 80S.
- VERY WARM AND BREEZY SUNDAY INTO THE NEXT WEEK. EXPECT DAILY
HIGHS IN THE 80S WITH SOME LOCATIONS APPROACHING 90 DEGREES.
CRITICAL FIRE DANGER IS POSSIBLE SUNDAY INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 246 PM CDT WED MAY 7 2025
TONIGHT: SATELLITE AS OF 3 PM IS SHOWING SOME GLACIATED CUMULUS
FIELDS, RESULTING IN SOME MID LEVEL ECHOES ON RADAR. A WEAK 600-
700MB DISTURBANCE SLIDING IN THIS EVENING CONTINUES TO BRING LOW TO
MODERATE (<50%) CHANCES OF SCATTERED SHOWERS AND THUNDERSTORMS NEAR
AND SOUTH OF THE HIGHWAY 20 CORRIDOR THROUGH THE EVENING. MUCAPE
UNDER 200 J/KG AND VERY WEAK WINDS ALOFT SHOULD PREVENT ANY
ORGANIZED STORMS OR SEVERE WEATHER, BUT A VERY DRY SUBCLOUD LAYER
COULD BRING AN ISOLATED STRONGER GUST WITH ANY STORMS (UP TO 45
MPH). MOST 12Z CAM GUIDANCE SUGGESTS THE BEST CHANCE OF ANY RAIN
FROM 4 PM TO 10 PM TONIGHT WITH POTENTIAL FOR RAIN AS FAR NORTH AS A
SPENCER TO SIOUX CENTER TO YANKTON LINE. THE DRY SUBCLOUD LAYER AND
WEAKLY UNSTABLE REGIME SHOULD BRING MOST SITES UNDER 0.10 INCHES OF
RAIN (IF NOT JUST VIRGA) AND PERHAPS A FEW LOCATIONS COULD RECEIVE
UP TO 0.25 INCHES WITH ANY OCCASIONAL THUNDERSTORM.
ASIDE FROM OCCASIONAL RAIN FOR A FEW LOCATIONS, IT SHOULD LARGELY BE
A NICE EVENING WITH LINGERING CIRRUS, TEMPERATURES IN THE 70S, AND A
GUSTY NORTHEAST BREEZE. AS THE UPPER LOW OVER THE SOUTHERN PLAINS
MEANDERS EAST INTO THE MID MISSISSIPPI VALLEY HEADING INTO THURSDAY,
OUR REGION BECOMES MORE DOMINATED BY STRONG SFC RIDGING. DRIER AIR
SHOULD CLEAR CLOUDS FROM NORTH TO SOUTH LATE TONIGHT, PROMOTING
COOLING INTO THE MID 40S (HIGHWAY 14/NORTH) TO LOWER 50S (HIGHWAY
20/SOUTH) BY EARLY THURSDAY.
THURSDAY: NAM/HREF GUIDANCE SUGGESTS POTENTIAL FOR SCATTERED STRATUS
NEAR AND EAST OF I-29 THURSDAY MORNING. IF THIS OCCURS, MODEL
SOUNDINGS FAVOR CLOUDS LIFTING WITH DIURNAL MIXING INTO A CUMULUS
FIELD IN THE AFTERNOON. THIS MAY IMPACT MORNING INSOLATION/HEATING
THOUGH, WITH THE 13Z NBM COMING IN A FEW DEGREES COOLER FOR HIGHS
THAN THE LAST FEW RUNS - IN THE LOW TO UPPER 70S (VS PREVIOUS 70S TO
LOWER 80S). AS WE COME UNDER STRONG SUBSIDENCE WITH STRONG MID AND
LOW LEVEL RIDGING, EXPECT ANOTHER DRY DAY WITH MOSTLY EASTERLY WINDS
A BIT LIGHTER THAN TODAY.
FRIDAY AND SATURDAY: WARMER, DRY WEATHER PREVAILS THROUGH THE
WEEKEND. A WEAK RIDGE-RIDING FRONT SLIDES INTO THE REGION FRIDAY
NIGHT WITH A VERY LOW (<20%) BUT NONZERO CHANCE FOR ISOLATED SHOWERS
AND STORMS NEAR AND NORTH OF THE HWY 18 CORRIDOR AND ACROSS
SOUTHWEST MINNESOTA. FORTUNATELY DEEP LAYER SHEAR AND INSTABILITY
SHOULD BE WEAK ENOUGH TO PREVENT ANY SEVERE WEATHER THREAT, BUT
GUSTY WINDS CANNOT BE RULE OUT WITH A DRY SUBCLOUD LAYER.
THE BIGGER STORY HEADING INTO THE WEEKEND IS HIGH CONFIDENCE
REGARDING HIGHS IN THE 80S FRIDAY AND SATURDAY WITH A DRY TASTE OF
SUMMER. HEIGHTS INCREASE ALOFT WITH UPPER RIDGING NEAR THE TOP 3% OF
MODEL CLIMATOLOGY OVER THE WEEKEND.
SUNDAY: A HOT, DRY, AND BREEZY MOTHER'S DAY IS IN STORE ON SUNDAY AS
WE REMAIN UNDER THE INFLUENCE OF STRONG UPPER RIDGING AND A CENTRAL
CONUS REX BLOCKING PATTERN. ALTHOUGH RIDGING ALOFT IS CENTERED
SLIGHTLY UPSTREAM (WESTERN TO CENTRAL DAKOTAS), OUR POTENTIAL TO MIX
INTO 90TH PERCENTILE 850MB TEMPERATURES, VERY DRY SOUNDING PROFILE,
AND INCREASING SFC PRESSURE GRADIENT MAKES FOR A PERIOD OF ENHANCED
FIRE DANGER THAT BEARS WATCHING.
MONDAY AND BEYOND: THE PATTERN CHANGES VERY LITTLE FOR MONDAY WITH
CONTINUED POTENTIAL FOR CRITICAL FIRE DANGER AMIDST HOT, DRY AIR AND
GUSTY WINDS. HIGH CONFIDENCE VIA EURO AND GEFS GUIDANCE IN ABOVE
NORMAL TEMPERATURES PERSISTING THROUGH AT LEAST THE MIDDLE OF NEXT
WEEK. UPPER TROUGHING COMES ONSHORE IN THE PACIFIC NORTHWEST MONDAY.
AS THIS SYSTEM PROGRESSES EAST THROUGH THE NORTHERN CONUS, RAIN
CHANCES INCREASE MID TO LATE WEEK.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1229 PM CDT WED MAY 7 2025
VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING AS MID TO HIGH
CLOUDS LINGER IN THE REGION. SATELLITE AND RADAR AT 1730Z SHOW
SCATTERED MID LEVEL CUMULUS WITH WEAK ECHOES NEAR HURON, BUT IT
IS UNLIKELY ANY RAIN FROM THIS WOULD REACH THE SURFACE. CUMULUS
DEVELOPMENT HAS BEGUN NEAR THE HWY 20 CORRIDOR, WHERE SCATTERED
SHOWERS AND WEAK STORMS ARE POSSIBLE SOUTH OF A LINE FROM
SPENCER TO SIOUX CENTER TO YANKTON THIS AFTERNOON AND EVENING.
RETAINED PROB30 GROUP AT KSUX DURING PERIOD WITH GREATEST CHANCE
OF SEEING ANY RAIN FROM 22Z-02Z.
12Z MODELS RUNS SUGGEST INCREASED CHANCE OF 2-4 KFT STRATUS
DEVELOPMENT AS EARLY AS 10Z, LINGERING INTO THE MORNING NEAR
AND EAST OF THE I-29 CORRIDOR. THIS WOULD MAINLY IMPACT KSUX,
BUT COULD SEE NEAR MVFR CEILINGS BRIEFLY AT KFSD AS WELL.
NORTHEAST OR EAST WINDS WILL GUST INTO THE TEENS TO LOWER 20S
THROUGH EARLY EVENING. EXPECT EASTERLY WINDS TO PREVAIL THROUGH
THURSDAY MORNING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...BP
AVIATION...BP
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