267
FXUS63 KFSD 042047
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
347 PM CDT THU JUN 4 2026
KEY MESSAGES
- SCATTERED STRONG TO SEVERE STORMS REMAIN POSSIBLE THROUGH
ABOUT 1 AM TONIGHT MAINLY NEAR AND NORTH OF HIGHWAY 14 AND
INTO SOUTH-CENTRAL SOUTH DAKOTA. 70 MPH WINDS AND PING PONG
BALL SIZED HAIL WILL BE THE MAIN THREATS, THOUGH TORNADOES
CANNOT BE RULED OUT.
- GOOD AGREEMENT ON THE BETTER CHANCE FOR SCATTERED
THUNDERSTORMS CONTAINING HEAVY RAIN TO BE GENERALLY NEAR
HIGHWAY 14 INTO TONIGHT. SATURATED GROUNDS FROM LAST NIGHT'S
STORMS COULD LEAD TO SOME MINOR FLASH FLOODING AND POTENTIALLY MINOR
RIVER FLOODING.
- WHILE DETAILS ARE FAR MORE UNCERTAIN, AN ISOLATED TO
SCATTERED SEVERE STORM RISK WILL LINGER INTO FRIDAY. THE
GREATER RISKS AT THIS TIME SHIFT SOUTHEAST INTO EASTERN
NEBRASKA, IOWA AND FAR SOUTHERN MINNESOTA.
- TEMPERATURES HEAT UP NEXT WEEK. THERE IS AN INCREASING CHANCE
(30-60%) OF HIGHS EXCEEDING 95 DEGREES ESPECIALLY NEAR AND
WEST OF THE JAMES RIVER BY WEDNESDAY AND THURSDAY.
DISCUSSION
ISSUED AT 336 PM CDT THU JUN 4 2026
SEVERAL BOUNDARIES, SOME LEFT BEHIND FROM YESTERDAY'S
STORMS, ARE NOTED ACROSS THE AREA BY AGITATED LINES OF CU AND
ONGOING THUNDERSTORMS. AMPLE SUNSHINE IN THESE AREAS PRIOR TO
DEVELOPMENT HAS LED TO 1,500-2,000 J/KG TO DEVELOP WITH MID-
LEVEL LAPSE RATES AROUND 7.5 C/KM. SHEAR IS ON THE WEAKER SIDE,
BUT LARGE HAIL TO PING PONG BALLS WILL STILL BE POSSIBLE GIVEN
THE LAPSE RATES. AND WITH THE MYRIAD BOUNDARIES IN PLACE, WILL
HAVE TO WATCH FOR THE THE THREAT OF TORNADOES. THE MAIN BOUNDARY
THAT WILL BE THE FOCUS OF STORMS THROUGH THIS EVENING INTO
TONIGHT STRETCHES FROM WESTERN SOUTH DAKOTA INTO THE EAST-
CENTRAL PART OF THE STATE. AS A SHORTWAVE EMBEDDED WITHIN THE
OTHERWISE ZONAL FLOW MOVES ACROSS THE NORTHERN PLAINS THROUGH
THIS EVENING, THERE SHOULD BE AN UPTICK IN THUNDERSTORM
DEVELOPMENT. THE STORMS CURRENTLY ONGOING AT THE EASTERN END OF
THIS BOUNDARY ARE GOING TO CONTINUE TO LIFT NORTH AND CONTINUE
TO DEVELOP WITH WESTWARD EXTENT AS THE SHORTWAVE ENCROACHES THE
AREA. THE OTHER CONCERN WITH THESE STORMS WILL BE THE HEAVY RAIN
THREAT AS AREAS NEAR AND NORTH OF HIGHWAY 14 ALREADY HAVE
SATURATED GROUNDS. THIS COULD LEAD TO SOME FLASH FLOODING IF
STORMS MOVE TOO SLOWLY OVER AN AREA. AND HEAVY RAIN TO OUR NORTH
MAY ALSO CAUSE SOME MINOR RIVER FLOODING ISSUES DOWNSTREAM
DEPENDING ON HOW MUCH RAIN IS SEEN.
ANOTHER AREA OF STORMS WILL DEVELOP OFF TO OUR WEST. THE BEST SHEAR
IS LOCATED OVER WESTERN SOUTH DAKOTA ON THE WESTERN END OF THE
MAIN BOUNDARY. GUIDANCE SHOWS STORMS DEVELOPING OUT THERE LATE
THIS AFTERNOON/EARLY EVENING MAY TAKE ON SOME BOWING SEGMENTS AS
IT MOVES EASTWARD TOWARDS OUR AREA, ARRIVING BY 9-10 PM WEST OF
THE JAMES RIVER. THIS IS WHERE THE BEST CHANCE OF DAMAGING WIND
GUSTS TO 70 MPH WILL BE, THOUGH STORMS SHOULD GRADUALLY WEAKEN
AS THEY MOVE EASTWARD AS INSTABILITY WANES THROUGH THE NIGHT. IN
OTHER WORDS, AFTER ABOUT MIDNIGHT TO 1 AM, THE SEVERE WEATHER
THREAT SHOULD COME TO AN END. A FEW SHOWERS WILL BE POSSIBLE
HEADING INTO FRIDAY MORNING, BUT NOTHING SEVERE EXPECTED.
ANOTHER UPPER-WAVE MOVES ACROSS THE NORTHERN GREAT LAKES REGION
TOMORROW AFTERNOON AND EVENING, AND THIS COULD SET OFF SOME
ISOLATED THUNDERSTORMS MAINLY NEAR AND EAST OF I-29 AND
ESPECIALLY TOWARDS THE HIGHWAY 20 CORRIDOR. CAN'T RULE OUT SOME
STRONG TO SEVERE THUNDERSTORMS WITH THIS ACTIVITY, BUT THIS WILL
BE HIGHLY DEPENDENT ON HOW STORMS DEVELOP TONIGHT. ALSO, THE
GREATER INSTABILITY WILL ALSO BE SOUTH OF THE AREA, LIKELY
KEEPING THE GREATEST THREAT TO OUR SOUTH.
RIDGING ALOFT BUILDS IN SATURDAY AND SO WE SHOULD FINALLY HAVE A DRY
DAY. THIS WILL BE QUICKLY REPLACED WITH ANOTHER ACTIVE UPPER PATTERN
HEADING INTO EARLY NEXT WEEK, WHICH WILL LEAD TO INCREASED SHOWER
AND STORM CHANCES SUNDAY AND MONDAY. JUST LIKE THE PAST FEW EVENTS,
ENSEMBLES SHOW THE INSTABILITY SUFFICIENT FOR SEVERE WEATHER LARGELY
IN PLACE, BUT THERE WILL BE QUESTIONS ON HOW MUCH SHEAR THERE
WILL BE WITH AND OF COURSE ANY OTHER MESOSCALE FEATURES THAT
CAN'T BE RESOLVED THIS FAR OUT. HEAT ALSO LOOKS TO BUILD IN NEXT
WEEK, ESPECIALLY BY WEDNESDAY AND THURSDAY WHEN LREF
PROBABILITIES OF HIGHS EXCEEDING 95 DEGREES ARE AROUND 30-60%
NEAR AND WEST OF THE JAMES RIVER, WITH A 10-30% OF HIGHS EVEN
EXCEEDING 100 DEGREES IN THESE AREAS. RECENT RAINFALL MAY MEAN
THAT THE FORECAST MODELS COULD BE OVERDOING POTENTIAL HEATING,
BUT THIS WILL BE SOMETHING THAT NEEDS TO BE WATCHED CLOSELY OVER
THE NEXT COUPLE OF DAYS.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1249 PM CDT THU JUN 4 2026
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THROUGH THE
AFTERNOON AND ESPECIALLY INTO THE EVENING AND OVERNIGHT HOURS. THE
BEST CHANCE OF STORMS WILL BE NEAR HIGHWAY 14 WEST OF I-29 INTO
SOUTH-CENTRAL SOUTH DAKOTA. THIS PUTS THE GREATEST CONFIDENCE FOR
STORMS OVER KHON, ESPECIALLY FOR THE OVERNIGHT ROUND. OTHERWISE, LOW
STRATUS LOOKS TO DEVELOP NEAR AND EAST OF I-29 TONIGHT INTO TOMORROW
MORNING WHERE STORM CHANCES ARE THE LOWEST. THIS WILL BRING MAINLY
MVFR CONDITIONS TO THOSE AREAS, BUT LOCALLY IFR CIGS WILL BE
POSSIBLE ESPECIALLY OVER NORTHWEST IOWA AND FAR NORTHEAST NEBRASKA.
WE'LL SEE WINDS INCREASE SLIGHTLY THROUGH THE AFTERNOON, SUSTAINED
AROUND 5-15 KTS, HIGHEST IN SOUTH-CENTRAL SOUTH DAKOTA. WINDS WILL
BECOME LIGHT AND VARIABLE TO CALM OVERNIGHT, AND REMAIN ON THE
LIGHTER SIDE INTO TOMORROW MORNING. STRONG TO SEVERE STORMS WILL
BRING A RISK OF HIGHER WIND GUSTS, LOCALLY AS HIGH AS 50 KTS
THROUGH ABOUT 05.07Z.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...SAMET
AVIATION...SAMET
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