435
FXUS63 KFSD 082328
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
628 PM CDT WED JUL 8 2026
KEY MESSAGES
- A FEW ISOLATED SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE
THROUGH THIS EVENING FOR AREAS OF NORTHWEST IOWA. THE SEVERE
THREAT HAS ENDED, BUT A FEW STRONGER GUSTS TO 45 MPH ARE
POSSIBLE.
- HIGH TEMPERATURES REMAIN ON TRACK TO RISE TO THE 90S TO 100
DEGREE MARK TOWARDS THIS WEEKEND AND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 208 PM CDT WED JUL 8 2026
A FEW LIGHT RAIN SHOWERS PERSIST ACROSS MAINLY NORTHWEST IOWA THIS
AFTERNOON. A SURFACE TROUGH AND ASSOCIATED COLD FRONT CONTINUE TO
TRACK THROUGH THE FORECAST AREA EARLY THIS AFTERNOON. THE MID LEVEL
CLOUDS ASSOCIATED WITH THESE LIGHT RAIN SHOWERS CONTINUE TO SIT OVER
MAINLY NORTHWEST IOWA AND SURROUNDING LOCATIONS. THIS HAS PREVENTED
LOCATIONS IN THIS AREA FROM HEATING OUT. THE COOLER TEMPERATURES
LOOK TO ALSO DELAY NEW CONVECTIVE DEVELOPMENT AS THE COLD FRONT
PUSHES INTO THIS AREA. STILL, THESE CLOUDS LOOK TO CLEAR/BREAK UP
ENOUGH TO ALLOW ADEQUATE INSTABILITY TO DEVELOP WITH A MAGNITUDE UP
TO ABOUT 2,000 J/KG OVER THE COURSE OF THE AFTERNOON TIMEFRAME.
VERTICAL SHEAR VALUES WILL BE ON THE WEAKER SIDE OF THINGS WITH A
MAGNITUDE OF ROUGHLY 20-30 KNOTS. LATEST HI-RES GUIDANCE SHOWS THAT
A SMALL, BI-MODAL SEVERE WEATHER EVENT IS ON THE TABLE FOR THIS
AFTERNOON AND EVENING. STORMS LOOK TO DEVELOP ON BOTH THE PRE-
FRONTAL TROUGH AND TRAILING COLD FRONT. STORM DEVELOPMENT LOOKS TO
TAKE PLACE ACROSS MAINLY NORTHWEST IOWA AND ADJACENT AREAS THIS
AFTERNOON WITH A TIMEFRAME FROM FROM ABOUT 4 PM TO 10 PM. WITH THE
COLD FRONTAL FORCING, STORMS LOOK TO GROW INTO A LINE AS THEY PUSH
OUT OF THE AREA THIS EVENING. WHILE VERTICAL SHEAR MAGNITUDES WILL
BE ON THE LOWER SIDE, HODOGRAPHS SHOW A WEAK BUT CLASSIC VEER-BACK
PROFILE. WITH WEAK COLD ADVECTION ALOFT, LAPSE RATES WILL STEEPEN
JUST A BIT MORE AND ALLOW FOR A LARGE HAIL THREAT. SOUNDINGS DO SHOW
SLIGHTLY MORE SATURATED PROFILES IN THE HAIL GROWTH ZONE (HGZ) WHICH
WILL TONE DOWN THE HAIL THREAT A BIT, WITH SOME OF THE LARGEST
STONES GROWING UP TO HALF DOLLAR SIZE. DCAPE VALUES WILL BE
SUFFICIENT WITH VALUES UP TO 800 TO 1,000 J/KG, KEEPING A DAMAGING
WIND THREAT IN PLACE WITH THE STRONGEST GUSTS UP TO 65 MPH. THE
LARGE HAIL THREAT WILL COME WITH THE INITIAL STORM DEVELOPMENT
BEFORE TRANSITIONING TO A DAMAGING WIND THREAT AS STORMS GROW
UPSCALE. POCKETS OF MODERATE TO HEAVY RAINFALL COULD RESULT IN
LOCALIZED PONDING IN LOW LYING/URBAN AREAS AS STORMS ROLL THROUGH.
THE STORM THREAT WILL END THIS EVENING, LEAVING MOSTLY QUIET
CONDITIONS FOR THE OVERNIGHT HOURS. LOW TEMPERATURES WILL FALL TO
THE 60S.
SEASONABLE AND MOSTLY DRY CONDITIONS WILL RETURN FOR THE END OF THE
WEEK WITH HIGH TEMPERATURES REMAINING IN THE 80S TO JUST TOUCHING
90F. WINDS WILL BE LIGHT, MAKING FOR A PLEASANT THURSDAY AND FRIDAY.
HEIGHTS BEGIN TO RISE ALOFT ON SATURDAY, BEGINNING TO WARM
TEMPERATURES WITH HIGHS RISING TO THE 80S AND 90S. SUNDAY WILL KICK
OFF THE FIRST DAY OF NEAR TO ABOVE NORMAL TEMPERATURES AS MEDIUM
RANGE AND ENSEMBLE GUIDANCE SHOW A 600 DAM RIDGE BUILDING INTO THE
NORTHERN PLAINS. THIS RIDGE LOOKS TO PERSIST THROUGH THE FIRST HALF
OF NEXT WEEK, BRINING HOT AND HUMID CONDITIONS WITH IT. THE
ENSEMBLES SHOW A 60-100% CHANCE FOR HIGHS TO EXCEED 90F SUNDAY
THROUGH TUESDAY NEAR AND WEST OF I-29. CHANCES FOR EXCEEDING 100F
DROP TO 40-70% FOR THE SAME PERIOD OF TIME WITH TUESDAY HAVING THE
HIGHEST PROBABILITIES. THE ENSEMBLES ALSO SHOW A BROAD 40-100%
CHANCE FOR DEW POINTS TO EXCEED 60F AS WELL. ALL THESE PROBABILITIES
TO SAY THAT HOT AND HUMID CONDITIONS ARE EXPECTED LATE THIS WEEKEND
AND INTO EARLY NEXT WEEK. A FEW ENSEMBLE MEMBERS SHOW THE RIDGE
BEGINNING TO FLATTEN NEXT WEDNESDAY WHICH COULD BEGIN TO TREND
TEMPERATURES DOWN. THERE REMAINS UNCERTAINTY REGARDING HOW LONG THE
RIDGE REMAINS STRONG SO SOMETHING TO KEEP AN EYE ON HEADING
FORWARD.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 626 PM CDT WED JUL 8 2026
STRONG THUNDERSTORMS HAVE EXITED TO THE SOUTHEAST OF OUR REGION. A
FEW ISOLATED LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH EARLY THIS
EVENING FOR AREAS OF NORTHWEST IOWA.
A MIX OF VFR AND MVFR IS EXPECTED TO PREVAIL FOR THE MAJORITY OF THE
PERIOD. A SHALLOW INVERSION HAS BEGUN TO FORM TRAPPING MOISTURE JUST
ABOVE THE SURFACE. WINDS DECREASE TO LIGHT AND VARIABLE AFTER SUNSET
AND AS THE SURFACE CONTINUES TO COOL AREAS OF PATCHY DENSE FOG ARE
EXPECTED TO FORM. CEILINGS AND VISIBILITY MAY DROP TO IFR AT TIMES
IN THE EARLY MORNING HOURS OF THURSDAY. AREAS ALONG AND EAST OF I-29
ARE THE MOST LIKELY TO SEE DENSE FOG. CEILINGS AND VISIBILITY
IMPROVE BY MID-MORNING AND THE REST OF THE DAY WILL BE MOSTLY SUNNY
WITH LIGHT NORTHEAST WINDS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...MEYERS
AVIATION...AJP
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