830
FXUS63 KFSD 092330
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
630 PM CDT TUE JUN 9 2026
KEY MESSAGES
- A HEAT ADVISORY IS IN EFFECT FOR MOST AREAS NEAR AND SOUTH OF
I-90 THROUGH 9 PM. CONTINUE TO STAY HYDRATED AND TAKE FREQUENT
BREAKS IF WORKING OR PLAYING OUTSIDE.
- A POTENTIALLY SIGNIFICANT SEVERE WEATHER THREAT DEVELOPS
TONIGHT. INITIAL STORMS BRING A LARGE HAIL THREAT TOWARD
CENTRAL SOUTH DAKOTA AND NEBRASKA IN THE EVENING,
TRANSITIONING TO DAMAGING WINDS POTENTIALLY IN EXCESS OF 80
MPH FARTHER EAST INTO THE NIGHT. ISOLATED TORNADOES ARE
POSSIBLE.
- THE MAIN TIMING FOR STRONG TO SEVERE STORMS IS BETWEEN 7 PM
AND 3 AM TONIGHT. THE PEAK WINDOW FOR 80+ MPH WIND GUSTS IS 9
PM TO 2 AM. THESE KINDS OF WINDS COULD PRODUCE TORNADO-LIKE
DAMAGE, SO MAKE SURE TO HAVE MULTIPLE WAYS OF RECEIVING
WEATHER ALERTS THAT CAN ALSO WAKE YOU UP IN THE MIDDLE OF THE
NIGHT!
- THE THREAT FOR SEVERE WEATHER CONTINUES TO TREND EAST OF THE
AREA WEDNESDAY AFTERNOON. HOWEVER, CAN'T RULE OUT A STRONGER
STORM NEAR AND SOUTH OF HIGHWAY 20 EARLY THURSDAY MORNING,
THOUGH UNCERTAINTY OF SEVERE POTENTIAL REMAINS HIGH.
DISCUSSION
ISSUED AT 315 PM CDT TUE JUN 9 2026
A HOT AND HUMID DAY CONTINUES ACROSS THE AREA AS TEMPERATURES HAVE
SOARED INTO THE 90S WITH HEAT INDICES IN THE MIDDLE 90S SO FAR,
THOUGH STARTING TO SEE SOME SPOTS INTO THE UPPER 90S TO AROUND
100 IN PARTS OF NORTHWEST IOWA. THE HEAT ADVISORY REMAINS IN
EFFECT UNTIL 9 PM FOR AREAS NEAR AND SOUTH OF I-90, SO CONTINUE
TO STAY HYDRATED OUT THERE! SEEING SOME AREAS OF CU DEVELOP
ACROSS THE AREA THIS AFTERNOON, AND WITH PLENTY OF INSTABILITY
IN PLACE AND THE HEAT ERODING THE CAP, CAN'T RULE OUT A STRAY
SHOWER OR THUNDERSTORM THROUGH THE AFTERNOON. THE 09.12Z REFS
ENSEMBLE IS THE MOST EXCITED ABOUT THIS AS IT SHOWS 20-40%
CHANCE OF HOURLY MEASURABLE PRECIPITATION THIS AFTERNOON OVER
SOUTHWEST MINNESOTA, BUT THIS REMAINS AN OUTLIER AND SO THE
OFFICIAL FORECAST CALLS FOR A LESS THAN 15% CHANCE OF RAIN AS
THERE WON'T BE MUCH UPPER LEVEL SUPPORT TO GET STORMS GOING. BUT
IF A STORM IS ABLE TO DEVELOP, THEN LARGE HAIL UP TO PING PONG
BALL IN SIZE WILL BE POSSIBLE GIVEN STEEP MID LEVEL LAPSE RATES
AND EFFECTIVE BULK SHEAR ON THE ORDER OF 40-45 KTS.
A POTENTIALLY SIGNIFICANT SEVERE WEATHER THREAT IS IN STORE FOR THE
AREA TONIGHT. A NEGATIVELY TILTED TROUGH WILL MOVE INTO THE NORTHERN
PLAINS TONIGHT AS A COOL FRONT APPROACHES THE AREA. AHEAD OF THIS, A
HIGHLY UNSTABLE ATMOSPHERE WILL BE IN PLACE, WITH GUIDANCE SHOWING
2,500-3,500 J/KG OF CAPE AVAILABLE DESPITE THE LOSS OF DAYTIME
HEATING. TWO AREAS OF STORMS LOOK TO DEVELOP LATE THIS AFTERNOON,
ONE OVER WESTERN SOUTH DAKOTA AND ONE OVER CENTRAL NEBRASKA. THE
FIRST AREA WILL LIFT MAINLY NORTHEAST OF THE AREA THROUGH THIS
EVENING, BUT COULD CLIP THE HIGHWAY-14 CORRIDOR NEAR AND WEST OF THE
JAMES RIVER. MOST OF THE 09.12Z GUIDANCE KEPT THE GREATER CHANCES
NORTH OF THE AREA, THOUGH SOME OF THE LATEST HRRR RUNS HAVE TRENDED
A BIT FARTHER SOUTH. IF THIS WERE TO CLIP OUR AREA, LOOK FOR THIS TO
HAPPEN BETWEEN 10 PM AND 1 AM. DAMAGING WINDS TO 70 MPH WOULD BE THE
MAIN THREAT WITH THIS ACTIVITY, THOUGH LARGE HAIL UP TO GOLF BALL IN
SIZE WILL BE POSSIBLE AS WELL. CAN'T RULE OUT A TORNADO GIVEN THE
LOW LEVEL CURVATURE OF THE HODOGRAPHS, BUT STORMS WILL LIKELY BE
BECOMING MORE ELEVATED WITH TIME THROUGH THE EVENING, DIMINISHING
THE TORNADO THREAT, BUT NOT REDUCING IT TO ZERO AS STORMS MOVE
THROUGH.
THE SECOND AREA TO WATCH THAT DEVELOPS OVER CENTRAL
NEBRASKA HAS THE BETTER CHANCE OF BECOMING THE "MAIN SHOW" SO TO
SPEAK REGARDING THE SEVERE WEATHER THREAT. STORMS THAT DEVELOP IN
THIS AREA WILL QUICKLY LIFT NORTH-NORTHEAST AND FORM INTO A LINE OR
A COUPLE OF LINEAR CLUSTERS AS THEY QUICKLY SWING THROUGH THE AREA.
THIS ACTIVITY WILL LIKELY CROSS THE MISSOURI RIVER AROUND 10 TO 11
PM, MOVE ACROSS THE I-90 CORRIDOR AROUND MIDNIGHT, AND EXITS OUT OF
OUR SOUTHWEST MINNESOTA AND NORTHERN IOWA COUNTIES BY 2 TO 3 AM.
GUIDANCE CONTINUES TO BE CONSISTENT IN BRINGING IN THE STRONGEST
WINDS WITH THIS ACTIVITY, LIKELY OWING TO THE GREATER INSTABILITY.
THIS IS WHERE WE COULD SEE GUSTS AS HIGH AS 80 MPH OR SLIGHTLY
HIGHER, BRINGING THE POTENTIAL FOR DESTRUCTIVE STRAIGHT-LINE WINDS.
NOT EXPECTING WIDESPREAD 80+ MPH GUSTS GIVEN THE WEAKER SHEAR, BUT
WIDESPREAD 40-60 MPH WINDS LOOK LIKELY DEPENDING ON HOW MANY
INDIVIDUAL CLUSTERS END UP DEVELOPING. MID LEVEL LAPSE RATES
WILL BE AROUND 7.5-8 C/KM AND LARGE CAPE PROFILES WILL ALSO
PROMOTE HAIL POTENTIALLY TO THE SIZE OF 2 INCHES OR SLIGHTLY
LARGER AS THE STORMS CROSS THE MISSOURI AND ARE MORE ISOLATED,
AND THEN UP TO GOLF BALL IN SIZE AS STORMS TURN MORE LINEAR.
GUIDANCE SHOWS THE BETTER SOUTH- SOUTHWESTERLY LOW LEVEL JET OF
UP TO 40-45 KTS DEVELOPING SOUTH OF I- 90 AND INTO NORTHWEST
IOWA AND FAR NORTHEAST NEBRASKA, SO WILL HAVE TO WATCH FOR A
TORNADO OR TWO, THOUGH THE ELEVATED NATURE OF THE STORMS WILL
TEND TO LIMIT THIS THREAT OVERALL.
SOME LIMITING FACTORS OTHER THEN THE WEAKER BULK SHEAR THAN COMPARED
TO AREAS TO OUR NORTH, WILL BE THE FACT THAT SOME SOUNDINGS,
PARTICULARLY THE 09.12Z NAM, SHOW A WARM LAYER AROUND 750 MB THAT
COULD LIMIT SOME STORMS FROM FORMING. THE WARM LAYER IS FAIRLY
SHALLOW THOUGH, BUT STILL COULD PUT A STOP TO AT LEAST SOME OF THE
STORMS DEVELOPING. EVEN WITH THIS, THAT WARM LAYER DOES ERODE ON
THAT NAM RUN OVER NORTHWEST IOWA, SO STORMS STILL GO OFF THERE
IF THIS RUN ENDS UP COMING TO FRUITION. BUT STILL, IF THAT WARM
LAYER ENDS UP BEING STRONGER THAN EXPECTED, THIS COULD PUT A
DENT INTO THUNDERSTORM CHANCES. EITHER WAY, BE SURE TO REMAIN
WEATHER AWARE TONIGHT AND MAKE SURE TO HAVE MULTIPLE WAYS OF
RECEIVING ALERTS THAT CAN ALSO WAKE YOU UP IN THE MIDDLE OF THE
NIGHT. ALSO KEEP IN MIND THAT IF ANY STORM PRODUCES 80+ MPH
STRAIGHT LINE WINDS, THIS COULD DO SIMILAR DAMAGE TO TORNADOES,
SO KNOW WHERE YOUR TORNADO SAFE PLACE IS EVEN THOUGH THE TORNADO
THREAT IS LOW.
NOT MUCH TIME TO LOOK INTO THE FORECAST AFTER TONIGHT'S EVENT, BUT
THE SEVERE WEATHER THREAT CONTINUES TO TREND FARTHER EAST FOR
WEDNESDAY AFTERNOON DUE MOST GUIDANCE MOVING THE COOL FRONT EAST OF
THE AREA BY PEAK DAYTIME HEATING. WILL HAVE TO WATCH EARLY THURSDAY
MORNING AS THE MAIN WAVE MOVES THROUGH AS AROUND 50-60+ KTS OF BULK
SHEAR DEVELOPS WITH THIS. CURRENT INDICATIONS IS THAT THE BEST
INSTABILITY WILL BE PUSHED SOUTH OF THE AREA AS THIS WAVE MOVES
THROUGH, BUT FOLKS NEAR AND SOUTH OF HIGHWAY 20 WILL NEED TO STAY UP
TO DATE WITH THE LATEST FORECAST IN CASE GREATER INSTABILITY TRENDS
NORTH. OTHERWISE, LOOK FOR GENERALLY COOLER TEMPERATURES HEADING
INTO EARLY NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 620 PM CDT TUE JUN 9 2026
MAINLY VFR CONDITIONS WITH OCCASIONAL MVFR TO IFR CONDITIONS
WILL BE POSSIBLE THIS TAF PERIOD. TAKING A LOOK AT SATELLITE
IMAGERY, MOSTLY CLEAR CONDITIONS CONTINUE THIS EVENING AS A
"CUE" FIELD BEGINS TO BUILD ACROSS THE MISSOURI RIVER VALLEY.
SHOULD SEE THE QUIETER CONDITIONS CONTINUE OVER THE NEXT FEW
HOURS BEFORE SCATTERED SHOWERS AND THUNDERSTORMS PROGRESS ACROSS
THE AREA THIS EVENING. DECIDED TO CONTINUE THE TREND OF ADDING
TEMPO GROUPS IN FOR BOTH KFSD & KHON SINCE THAT IS WHERE WE'RE
MOST CONFIDENT. HOWEVER, DECIDED TO ALSO ADD IN PROB30 GROUP
INTO KSUX WITH THE POTENTIAL FOR LINGERING SHOWERS TO MOVE
THROUGH THAT AREA. OTHERWISE, BREEZY SOUTHERLY WINDS WILL
CONTINUE WELL INTO THE OVERNIGHT HOURS BEFORE WESTERLY WINDS
RETURN BY LATE WEDNESDAY MORNING
FSD WATCHES/WARNINGS/ADVISORIES
SD...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR SDZ059>071.
MN...NONE.
IA...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR IAZ001-002-
012>014-020>022-031-032.
NE...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NEZ013-014.
DISCUSSION...SAMET
AVIATION...05
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