076
FXUS63 KFSD 180510
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1210 AM CDT THU JUN 18 2026
KEY MESSAGES
- ISOLATED SHOWERS ON THURSDAY COULD PRODUCE WIND GUSTS TO 40
MPH.
- STRONG TO SEVERE STORMS COULD RETURN ON SATURDAY ALONG WITH
LOCALLY HEAVY RAIN. SPECIFIC DETAILS ARE UNCERTAIN, BUT AS OF
NOW, THE HIGHEST PROBABILITIES FOR SEVERE STORMS REMAINS SOUTH
AND WEST OF THE AREA.
UPDATE
ISSUED AT 856 PM CDT WED JUN 17 2026
SCATTERED SHOWERS AND VERY ISOLATED THUNDERSTORMS CONTINUE TO
PIVOT ACROSS MAINLY SOUTHWEST MINNESOTA ASSOCIATED WITH AN UPPER LOW
MOVING TOWARDS THE NORTHERN GREAT LAKES. THIS ACTIVITY, ALONG
WITH SOME SHOWERS MOVING SOUTHWARD ACROSS NORTHERN SOUTH DAKOTA,
WILL FADE OVER THE NEXT HOUR OR TWO AS WE LOSE DAYTIME HEATING.
TO OUR SOUTH, A FEW SHOWERS MAY DEVELOP ALONG A BOUNDARY OVER
NORTHERN NEBRASKA. EVEN IF THIS ACTIVITY WERE TO CLIP FAR
NORTHEASTERN NEBRASKA SOUTH OF HIGHWAY 20 TONIGHT, A DRY SUB-
CLOUD LAYER WILL MORE THAN LIKELY PREVENT ANY OF IT FROM
REACHING THE GROUND.
OTHERWISE, WINDS WILL CONTINUE TO DIMINISH THROUGH THE
OVERNIGHT HOURS, THOUGH THEY WON'T GO COMPLETELY CALM. THIS
SHOULD PREVENT ANY FOG FROM DEVELOPING, BUT CAN'T RULE A LITTLE
BIT OF IT IF WINDS CAN GO CALM IN ANY AREAS THAT SAW RAINFALL
TODAY. CHANCES OF THIS ARE QUITE LOW, LESS THAN 15% AT THIS
TIME. BELOW NORMAL TEMPERATURES ARE EXPECTED TONIGHT, WITH LOWS
RANGING FROM THE AROUND 50 NORTH TO CLOSER TO 60 SOUTH.
THE FORECAST FOR RAIN CHANCES TOMORROW REMAINS ON TRACK, SEE
DISCUSSION BELOW FOR DETAILS. OTHERWISE, WE'LL HAVE A PLEASANT LATE
SPRING DAY FOR THURSDAY WITH HIGHS IN THE 70S AND LIGHTER WINDS
(OUTSIDE OF THE STRONGER GUST POTENTIAL WITH SHOWERS).
DISCUSSION
ISSUED AT 144 PM CDT WED JUN 17 2026
A STRONG JET MAX CONTINUES TO WRAP AROUND THE SOUTH SIDE OF AN UPPER
LEVEL LOW, BRINGING STRONG WINDS TO THE AREA. PEAK MIXING SUGGESTS
THAT WIND GUSTS COULD APPROACH 50 MPH. MODEL SOUNDINGS ALSO INDICATE
SOME WEAKER SURFACE BASED INSTABILITY THIS AFTERNOON, WHICH WILL
LIKELY GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THE
MAIN CONCERNS FROM ANY OF THIS ACTIVITY WILL BE THE POTENTIAL TO MIX
DOWN EVEN STRONGER WINDS, POSSIBLY 60 TO 65 MPH. THESE STRONGER
WINDS WILL REMAIN MUCH MORE ISOLATED.
THURSDAY WILL SEE DEEP, BUT WEAKENING NORTHWEST FLOW ACROSS THE
AREA. WE WILL LIKELY SEE A THREAT FOR ISOLATED SHOWERS WITH LOCALLY
GUSTY WINDS TO 40 MPH AS SURFACE BASED PEAK MIXING CAPE CLIMBS TO
ABOUT 200 J/KG.
THURSDAY NIGHT INTO FRIDAY A WEAK WAVE WILL APPROACH AND BRING SOME
ELEVATED MOISTURE RETURN AND VERY WEAK INSTABILITY. FOR NOW ANY
IMPACTS FROM THIS WILL BE VERY MINOR.
THE NEXT SYSTEM OF INTEREST WILL COME SATURDAY, BUT WITH SOME
DIFFERENCES FROM MODEL TO MODEL. THE 6Z EC ENSEMBLE IS BRINGING A 20-
30 PERCENT CHANCE FOR 2+" OF RAIN TO AROUND THE MISSOURI RIVER INTO
PARTS OF NORTHWEST IA WHILE THE 12Z GFS ENSEMBLE AND 12Z CANADIAN
ENSEMBLE LEAVE THESE BETTER CHANCES FARTHER SOUTH AND CLOSER TO I-
80. CLASSICALLY THE HEAVIER RAIN MANY TIMES FALLS BETWEEN ROUGHLY
THE SURFACE TO 850 MB BOUNDARY AND FOR NOW THAT REMAINS SOUTH OF THE
AREA, BUT WILL NEED TO BE MONITORED IN CASE IT DRIFTS NORTH.
REGARDLESS, FLOODING POTENTIAL IS FAIRLY LOW AS RAINFALL HAS BEEN
SPOTTY AT BEST LATELY.
BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS ARE EXPECTED MONDAY THROUGH WEDNESDAY NEXT WEEK. A FEW
SHORTWAVES ARE EXPECTED TO MOVE THROUGH, WITH SLIGHTLY BETTER
CHANCES MONDAY AND WEDNESDAY.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1209 AM CDT THU JUN 18 2026
PATCHY FOG CANNOT BE ENTIRELY RULED OUT IN AREAS THAT SAW RAIN
ON WEDNESDAY AND WHERE WINDS CAN GO CALM TONIGHT. WITH WINDS LIKELY
REMAINING ELEVATED ENOUGH, THE CHANCE OF FOG IS LOW, LESS THAN 20%.
SCATTERED SHOWERS AND VERY ISOLATED THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EVENING MAINLY OVER SOUTHWEST MINNESOTA AND ADJACENT
AREAS OF NORTHWEST IOWA. MAYBE A FEW SHOWERS COULD SNEAK INTO
EASTERN SOUTH DAKOTA, BUT CHANCES OF IMPACTS TO KFSD ARE VERY LOW,
LESS THAN 15%. WINDS WILL GRADUALLY PICK UP THROUGHOUT THE DAY
TODAY, BUT ONLY GUST AS HIGH AS AROUND 20 KTS IN THE AFTERNOON.
HIGHER GUSTS UP TO 35 KTS WILL BE POSSIBLE IN ANY OF THE
AFOREMENTIONED SHOWERS/STORMS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SAMET
DISCUSSION...08
AVIATION...SAMET
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