571
FXUS63 KFSD 301754
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1254 PM CDT TUE JUN 30 2026
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE REST OF THIS
WEEK AND INTO THE WEEKEND, WITH HUMIDITY INCREASING DAILY.
HOWEVER, WE'LL REMAIN BELOW HEAT ADVISORY LEVELS.
- SEVERE WEATHER RISKS DEVELOP AFTER MIDNIGHT BRINGING POCKETS
OF STRONG WINDS AND SEVERE HAIL INTO WEDNESDAY MORNING. SOME
UNCERTAINTY LINGERS ON COVERAGE OF STRONGEST STORMS.
- AN UNSETTLED PATTERN CONTINUES INTO THE HOLIDAY WEEKEND WITH
NEARLY DAILY RISKS FOR CONVECTION FOCUSED IN THE EVENING AND
OVERNIGHT HOURS.
- BEYOND WEDNESDAY'S EVENING ISOLATED TO SCATTERED SEVERE RISKS,
CONCERNS ARE GROWING FOR MORE WIDESPREAD SEVERE STORMS
THURSDAY EVENING INTO FRIDAY AND AGAIN FRIDAY INTO SATURDAY
WITH ONE OR MORE OVERNIGHT STORM COMPLEXES POSSIBLE.
DISCUSSION
ISSUED AT 1247 PM CDT TUE JUN 30 2026
THIS AFTERNOON/EVENING: OVERNIGHT STORMS HAVE DRIVEN DRIER AIR
SOUTHEAST INTO THE CWA THIS AFTERNOON, BOTH AT THE SURFACE BUT ALSO
ALOFT. RICHER LOW-LVL THETA-E AIRMASS ISN'T TOO FAR AWAY THOUGH
FOCUSED ALONG HIGHWAY 20 INTO PORTIONS OF SOUTHWESTERN NEBRASKA.
THEREFORE EXPECT A CONTINUATION OF QUIET CONDITIONS, BUT STILL ABOVE
NORMAL TEMPERATURES INTO THIS EVENING. ONE THING TO NOTE TODAY IS
THE ARRIVAL OF WILDFIRE SMOKE THROUGH THE REGION. THIS SMOKE LAYER
IS PRODUCING A MILKY SKY, BUT ALSO SOME MINOR DOWNWARD MIXING OF
SMOKE TO THE SURFACE CREATING AIR QUALITY IMPACTS.
TONIGHT: SHORT TERM GUIDANCE CONTINUES TO SHOW A SHORTWAVE EJECTING
OUT OF THE CENTRAL ROCKIES LATER THIS EVENING. THE APPROACH OF
THIS WAVE WILL DO TWO THINGS. FIRSTLY INDUCING A 40+ KNOT LLJ
THROUGH THE PLAINS WHICH WILL BEGIN THE NORTHWARD ADVANCEMENT OF
RICHER AND MORE UNSTABLE AIR INTO THE CWA AFTER MIDNIGHT.
SECONDLY, INDUCING CONVECTION ACROSS SOUTHWESTERN AND SOUTHERN
NEBRASKA BY MID-EVENING. THE APPROACH OF THIS WAVE WILL PUSH
CONVECTION NORTHWARD INTO THE MO RIVER VALLEY AFTER MIDNIGHT,
WITH ADDITIONAL SCATTERED CONVECTION FORMING ON THE ADVANCING
ELEVATED WARM FRONT FURTHER EAST INTO IOWA. SOUNDINGS DO SHOW AN
INCREASE IN MUCAPE TOWARDS THE 2000 J/KG MARK AHEAD OF THIS
WAVE. ANTICIPATING SOME STRONGER WIND GUSTS FORMING WITH
CONVECTION AS IT CROSSES NEBRASKA LATER THIS EVENING AND ANY NEW
UPDRAFT ON THE LEADING EDGE OF ADVANCING LOW-LVL MOISTURE COULD
PRODUCE SOME SEVERE HAIL. THE UNCERTAINTY TONIGHT IS JUST HOW
FOCUSED ANY STRONGER CLUSTER DEVELOPMENT COULD BECOME. LATEST
HREF 2-5KM UPDRAFT HELICITY PLOTS SUGGEST THAT AT LEAST A
NARROW CORRIDOR THROUGH SE SOUTH DAKOTA INTO PORTIONS OF THE
TRI-STATE AREA COULD SEE SOME HIGHER SEVERE WEATHER POTENTIAL AS
MID-LVL FLOW TURNS PARALLEL TO STORM MOVEMENT. THAT SAID, WOULD
EXPECT FAIRLY WIDESPREAD 30 TO 50 MPH WIND GUSTS INTO THE JAMES
RIVER VALLEY, WITH POTENTIAL FOR A MORE LOCALIZED POCKET OR
MORE INTENSE GUSTS THAT APPROACH 70 MPH WITH HAIL. THE STORM
RISK WILL CONTINUE THROUGH 12Z INTO SW MINNESOTA WHERE WE'LL
NEED TO WATCH REDEVELOPING UPDRAFTS TRY TO FORM ON THE VEERING
LLJ.
WEDNESDAY: MORNING CONVECTION COULD DO ONE OF TWO THINGS. COMPLETELY
DISSIPATE WITH THE PASSAGE OF THE MID-LVL SHORTWAVE, OR FESTER
DEEPER INTO THE MORNING HOURS AS THE LLJ CONTINUES TO CONVERGE INTO
SW MINNESOTA. LINGERING CONVECTION COULD CONTINUE A LOW END HAIL
RISK. A MORE LIKELY SCENARIO IS THAT WE SEE SOME STABILIZATION
BEHIND THE DEPARTING WAVE WITH AN EML BEGINNING TO BUILD IN BY EARLY
AFTERNOON. GUIDANCE HAS BACKED OFF SLIGHTLY ON THE POTENTIAL FOR
WIDESPREAD REDEVELOPMENT IN THE AFTERNOON AND EVENING. THIS IS
LIKELY DUE TO A LACK OF A STRONG LIFTING MECHANISM, CONTINUED
LINGERING EML INTO THE EVENING, AND DEPARTURE OF MID-LVL JET. THE
NEARBY PRESENCE OF MID-LVL VORTICITY ACROSS CENTRAL AND NORTHERN
SOUTH DAKOTA AND POTENTIAL OF LEFT OVER BOUNDARY FROM MORNING
CONVECTION, AND THEN REDEVELOPMENT OF THE EVENING LLJ WILL FORCE AT
LEAST A 20-40% POP FOR CONVECTION BY THE EVENING INTO THE OVERNIGHT
HOURS MOSTLY ALONG AND EAST OF I-29 AND NORTH OF HIGHWAY 14. GIVEN
INSTABILITY AND PRESENCE OF SUFFICIENT REMAINING EFFECTIVE SHEAR,
ISOLATED TO SCATTERED SUPERCELLS COULD BE POSSIBLE, POTENTIALLY
MERGING INTO ONE OR MORE EASTWARD PROGRESSING CLUSTERS IN THE
LATE EVENING. THIS WOULD BE FAVORED OVER PORTIONS OF SOUTHERN
MINNESOTA. GREATEST CONCERNS WOULD BE 2" HAIL BUT WITH
SIGNIFICANT MID-LVL DRY AIR AND STEEP 0-2KM LAPSE RATES STRONG
WINDS WOULD ALSO BE LIKELY.
THURSDAY-FRIDAY: WE'LL STAY IN A HIGHLY UNSTABLE ENVIRONMENT
FOR THE END OF THE WEEK AND INTO THE UPCOMING HOLIDAY WEEKEND
THE COMBINATION OF THE SERN RIDGE AND WESTERN CONUS TROUGH KEEPS
SOUTHWEST TO QUASI-ZONAL FLOW THROUGH THE PLAINS. THIS PATTERN
IS ONE THAT WILL KEEP TEMPERATURES ABOVE NORMAL, BUT ALSO ALLOW
DEW POINTS TO REMAIN IN THE UPPER 60S TO LOWER 70S. THE
COMBINATION WILL ALLOW MODERATE TO HIGH INSTABILITY TO BUILD
EACH AFTERNOON AND CONTINUE INTO THE OVERNIGHT. BY THURSDAY
AFTERNOON, WE'LL BE KEEPING AN EYE ON THE DEVELOPMENT OF A
STATIONARY FRONT LIFTING NORTHWARD AS A WARM FRONT IN THE
AFTERNOON AND EVENING. WHILE AND EML WILL BE IN PLACE, ANY
SUBTLE WAVE COULD TRIGGER ISOLATED TO SCATTERED STRONG
CONVECTION IN THE TRI-STATE AREA. GREATER CONFIDENCE HOWEVER IN
THE DEVELOPMENT OF SEVERE CONVECTION ON THE WESTERN HIGH PLAINS
AND BLACK HILLS REGION IN THE AFTERNOON THAT WOULD TRANSLATE
EAST AS A STRONG TO SEVERE FORWARD PROPAGATING HIGH WIND
POTENTIAL MCS INTO FRIDAY MORNING.
WE'LL NEED TO SEE HOW THINGS PLAY OUT THURSDAY INTO FRIDAY TO HAVE A
STRONG HANDLE ON THE SEVERE POTENTIAL THAT MAY DEVELOP FRIDAY
EVENING AND OVERNIGHT. SOME GUIDANCE THIS MORNING HINTS AT THE
OVERNIGHT MCS LAYING OUT A STRONG OUTFLOW BOUNDARY THAT COULD SERVE
AS A FOCUS FOR RENEWED SEVERE CONVECTION FRIDAY EVENING AND
OVERNIGHT.
4TH OF JULY: CONFIDENCE LOWERS EACH DAY GIVEN THE UNCERTAINTY IN
THE CONVECTIVE DEVELOPMENT THE PREVIOUS DAYS. THAT SAID, THE
OVERALL SYNOPTIC PATTERN REMAINS PROBLEMATIC AS A STATIONARY
BOUNDARY LINGER IN THE AREA AND THE FLATTENED MID-LVL FLOW BRINGS
INCREASED POTENTIAL FOR DAILY SHORTWAVE ACTIVITY EASTWARD INTO THE
PLAINS. TEMPERATURES REMAIN NEAR TO ABOVE NORMAL WITH HUMID, BUT NOT
OPPRESSIVE CONDITIONS FAVORED. BOTTOM LINE IS ANYONE WITH OUTDOOR
PLANS THE 3RD AND 4TH NEEDS TO BE AWARE OF THE FORECAST AND THE
STORM POTENTIAL THAT MAY DEVELOP. ADDITIONALLY, WITH THE POTENTIAL
FOR MULTIPLE MCS, THERE MAY BE SOME CONCERNS FOR EXCESSIVE RAINFALL
IN AREAS THAT SEE REPEATED CONVECTION. CONTINUE TO MONITOR THIS
RISK.
SUNDAY-MONDAY: THE SYNOPTIC PATTERN SHIFTS BY SUNDAY INTO NEXT WEEK
AS MID-LVL RIDGING BUILDS THROUGH THE PLAINS. NBM PROBABILISTIC DATA
WOULD SUGGEST A FAIRLY NORMAL 25/75TH SPREAD FOR HIGH TEMPERATURES
FROM THE MID 80S TO THE LOWER 90S INTO EARLY NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1216 PM CDT TUE JUN 30 2026
VFR CONDITIONS CONTINUE INTO THE EVENING HOURS. EVENTUALLY
THUNDERSTORMS OVER CENTRAL NEBRASKA AND WESTERN IOWA WILL
SPREAD AN OVERCAST MID-LVL CLOUD DECK NORTHWARD. THIS CONVECTION
WILL SPREAD NORTHEAST OVERNIGHT IMPACTING ANY ONE LOCATION FOR
1-3 HOURS. STRONG WIND GUSTS MAY BE POSSIBLE, BUT CONFIDENCE IS
LOW ON HOW HIGH THOSE GUSTS MAY BE.
ONCE THIS CONVECTION PASSES, VFR CONDITIONS RETURN WITH A LIGHT
AND VARIABLE SURFACE WIND.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...DUX
AVIATION...DUX
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