284
FXUS63 KFSD 011817
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
117 PM CDT MON JUN 1 2026
KEY MESSAGES
- CONTINUED UNSETTLED CONDITIONS REMAIN IN THE REGION THROUGH
THE WEEK. NO WIDESPREAD SEVERE WEATHER RISKS, BUT CONDITIONAL
AND HIGHLY LOCALIZED RISKS WILL BE POSSIBLE.
- FOCUS AREAS FOR THE MAJORITY OF THE SEVERE WEATHER RISKS
AHEAD WILL BE WEST OF I- 29 AND ESPECIALLY ALONG OR WEST OF
THE JAMES RIVER VALLEY.
- TEMPERATURES REMAIN IN THE 80S THROUGH THE WEEK AND RISE
TOWARDS THE UPPER 80S BY THE END OF THE WEEKEND.
DISCUSSION
ISSUED AT 112 PM CDT MON JUN 1 2026
THIS AFTERNOON/EVENING: RATHER STABLE CONDITIONS ACROSS THE REGION
EARLY THIS AFTERNOON, OUTSIDE OF A LONE ELEVATED STORM OVER NORTH
CENTRAL IOWA. SATELLITE SHOWS A WEAK MID-LVL WAVE CROSSING CENTRAL
NEBRASKA AND LIFTING TOWARDS THE TRI-STATE AREA. SOUNDINGS
CLOSER TO HOME SHOW A VERY STABLE LAYER THAT SHOULD PREVENT ANY
SURFACE BASED CONVECTION TO DEVELOP AS TEMPERATURES RISE TOWARDS
THE 80S. WHAT THIS WAVE MAY DO IS BRIEFLY SLOW THE RISE IN
TEMPERATURES, BUT BRING A CHANCE FOR A FEW HIGH BASED SPRINKLES.
A SECOND AREA WE'LL BE MONITORING TODAY IS RIGHT ALONG THE
EASTWARD EDGE OF THE CWA WHERE A BIT LESS INHIBITION IS IN
PLACE. WITH A VERY WEAK SHEAR PROFILE, ANY STORM THAT DEVELOPS
IS NOT EXPECTED TO BE STRONG TO SEVERE.
TONIGHT: MOST OF THE FOCUS DURING THE OVERNIGHT HOURS WILL BE
ACROSS THE NEBRASKA PANHANDLE, BLACK HILLS REGION, AND WESTERN
KANSAS. AS YET ANOTHER WAVE EJECTS OUT OF THE CENTRAL ROCKIES,
WE SHOULD SEE RENEWED CONVECTION DEVELOP AND QUICKLY TRY TO
CONGEAL INTO ONE OR MORE CLUSTERS AS THEY CROSS WESTERN
NEBRASKA AND SOUTH DAKOTA. LATEST CAMS CONTINUE TO HINT AT
THESE STORMS TRYING TO SLOWLY LIFT NORTHEAST BUT SHOULD WEAKEN
AS THEY REACH A MORE STABLE ATMOSPHERE. THAT SAID, COULD
CONTINUE TO SEE A LIMITED WIND RISK INTO SOUTH CENTRAL SOUTH
DAKOTA AND ALONG PORTIONS OF THE MISSOURI RIVER VALLEY BY 3AM.
FURTHER NORTH, THE ABUNDANCE OF LOW-LVL MOISTURE COMBINED WITH
LIGHT WINDS COULD LEAD TO PATCHY FOG DEVELOPING.
TUESDAY: WE'LL HAVE TO KEEP A CLOSE EYE ON THE PROGRESSION OF THE
CONVECTION IN NEBRASKA AS GUIDANCE DOES SHOW SIGNS OF A DEVELOPING
MCV THAT MAY TRACK EAST AND SLOWLY NORTH DURING THE DAY. AT THIS
POINT, DESTABILIZATION OF THE BOUNDARY LAYER WILL NEED TO BE WATCHED
AS WE COULD SEE POCKETS OF 2000 J/KG MLCAPE DEVELOP IN A NARROW
CORRIDOR AHEAD OF THIS WAVE. ISOLATED TO SCATTERED STORMS COULD
DEVELOP BASED ON THE WEAKENING OF CONVECTIVE INHIBITION
SOMEWHERE BETWEEN THE JAMES RIVER AND I-29. EFFECTIVE SHEAR
REMAINS VERY WEAK. BUT THERE MAY STILL BE APPRECIABLE 0-1KM
HELICITY TO LEAD TO A FEW ROTATING STORMS/FUNNELS. HOWEVER THE
WIDESPREAD SEVERE RISK REMAINS LOW AND MORE FOCUSED ON MARGINAL
HAIL, BUT COULD SEE FUTURE OUTLOOKS EXTENDED FURTHER EAST.
BETTER FOCUS FOR CONVECTION WILL BE ACROSS FAR WESTERN SD ALONG
A FRONTAL BOUNDARY EDGING INTO THE STATE. AS YET ANOTHER WAVE
EJECTS INTO THE PLAINS SCATTERED CONVECTION ALONG THIS BOUNDARY
SHOULD DEVELOP AND BEGIN TO TRACK EAST NORTHEAST. ONE THING TO
NOTE TODAY IS THAT MID-LVL HEIGHTS MAY BE RISING ACROSS CENTRAL
SD IN THE EVENING, WITH 700 MB TEMPERATURES ALSO RISING. THE
MORE MERIDIONAL 700:500 FLOW SHOULD PREVENT A STRONG EASTWARD
SHIFT AFTER DARK.
WEDNESDAY/THURSDAY: UNCERTAINTY GROWS WITH THE WEDNESDAY AND
THURSDAY FORECAST AS WE REMAIN STUCK IN THIS GENERAL MID-LVL
SOUTHWESTERLY FLOW PATTERN. THE AFOREMENTIONED FRONT WILL ATTEMPT TO
SLIDE EASTWARD ON WEDNESDAY, THOUGH A MUCH MORE E COMPLICATED
FORECAST IN REGARDS TO THE ENVIRONMENT AHEAD OF THE FRONT. YET
ANOTHER WEAK MID-LVL AREA OF VORTICITY TRACKS THROUGH THE TRI-STATE
AREA, INCREASING THE RISKS FOR MID-LVL CLOUDS BUT ALSO A FEW SHOWERS
AND ISOLATED THUNDERSTORMS BY THE AFTERNOON. THE AREA WITH THE
GREATEST RISKS FOR STRONG CONVECTION WILL BE ALONG THAT FRONTAL
BOUNDARY IN CENTRAL SOUTH DAKOTA BY MID-LATE AFTERNOON. ADDITIONAL
SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE INTO THE OVERNIGHT
HOURS FURTHER EAST AS THE LLJ INTENSIFIES. LATEST NBM GUIDANCE
SUGGESTS 8- 95% POPS IN THIS TIMEFRAME, BUT MY CONFIDENCE IN
OVERALL COVERAGE IS NOT AS HIGH AS THAT CHANCE SUGGESTS. A BIT
OF A REPEAT PERFORMANCE ON THURSDAY, WITH THE GREATEST SEVERE
RISKS AGAIN FOCUSED WEST OF THE JAMES RIVER AND INTO
SOUTHWESTERN SOUTH DAKOTA BY THE AFTERNOON.
FRIDAY-SUNDAY: MID-LVL TROUGHING MOVES THROUGH THE DAKOTAS ON
FRIDAY, POTENTIALLY PUSHING STRONG CONVECTIVE RISKS FURTHER EAST
INTO MN/IA. CONFIDENCE IS VERY LOW IN THIS TIME PERIOD GIVEN ALL OF
THE VARIOUS UNCERTAINTY ASSOCIATED WITH THE FORECAST IN THE DAYS
BEFORE. CONFIDENCE RISES FOR NEXT WEEKEND WITH DRIER WEATHER AND
NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES LIKELY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1205 PM CDT MON JUN 1 2026
LOCALIZED MVFR CEILINGS CONTINUE TO MIX-OUT EARLY THIS
AFTERNOON. WE'LL BE WATCHING MID-UPR CLOUDS MOVING NORTHEAST OUT
OF NEBRASKA THIS AFTERNOON AND EVENING. WHILE A VERY LOW CHANCE,
A FEW SPRINKLES MAY DEVELOP.
ANY CONVECTION THAT FORMS IN NEBRASKA WILL LIFT NORTHEAST AFTER
MIDNIGHT, SPREADING AN OVERCAST MID-UPR CLOUD DECK THROUGH THE
MO RIVER VALLEY. THE WAVE ASSOCIATED WITH THIS CONVECTION COULD
BRING ENHANCED CLOUD COVER AND SCATTERED SHOWERS AND
THUNDERSTORMS INTO THE TRI-STATE AREA BY MID-DAY. VERY LOW
CONFIDENCE ON THIS DEVELOPMENT.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...DUX
AVIATION...DUX
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