214
FXUS63 KFSD 300538
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1238 AM CDT THU APR 30 2026
KEY MESSAGES
- SCATTERED LIGHT SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM
WILL DRIFT SOUTHEAST INTO EARLY THURSDAY MORNING. ADDITIONAL
SCATTERED LIGHT SHOWERS/ISOLATED THUNDERSTORMS ARE POSSIBLE
WITH HEATING AGAIN THURSDAY AFTERNOON-EARLY EVENING.
- PATCHY TO AREAS OF FROST MAY BE POSSIBLE FRIDAY AND SATURDAY
MORNING. TEMPERATURES WILL BE HIGHLY DEPENDENT ON CLOUD COVER
BOTH NIGHTS.
- TEMPERATURES WILL WARM ABOVE NORMAL BY THE UPCOMING WEEKEND
INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 915 PM CDT WED APR 29 2026
DIURNALLY-DRIVEN SHOWERS/THUNDERSTORM WHICH MOVED SOUTH OF I-90
PRIOR TO SUNSET HAS DISSIPATED. HOWEVER, STILL EXPECTING TO SEE
SCATTERED LIGHT SHOWERS DRIFT SOUTHEAST WITH A MID-LEVEL WAVE
THROUGH THE OVERNIGHT, LIKELY EXITING/DIMINISHING BY DAYBREAK
THURSDAY. SOUNDINGS CONTINUE TO SHOW WEAK INSTABILITY ACROSS OUR
SOUTHEAST LATER TONIGHT, SO A STRAY THUNDERSTORM IS POSSIBLE IN
THE PRE-DAWN HOURS, MAINLY IN NORTHWEST IOWA.
THURSDAY MORNING WILL BE DRY, BUT DIURNAL WARMING SHOULD AGAIN
BRING THE POTENTIAL FOR SPOTTY LIGHT SHOWERS OR AN ISOLATED STORM
IN THE AFTERNOON. LIGHTER WINDS ALOFT SHOULD LIMIT THE POTENTIAL
FOR STRONGER GUSTS, ALTHOUGH GENERAL MIXING WILL RESULT IN A
BREEZIER AFTERNOON OVERALL.
DRIER CONDITIONS ARE EXPECTED FOR MOST ON FRIDAY, THOUGH THE
LATEST HRRR/RAP HINT AT SOME POPCORN SHOWERS BRUSHING OUR FAR
EAST (HWY 71/PERHAPS AS FAR WEST AS HWY 59) IN THE AFTERNOON. NOT
SEEING A LOT OF SUPPORT FOR THIS IN OTHER MODELS AT THIS TIME,
BUT THOSE WITH OUTDOOR PLANS MAY WANT TO MONITOR THE LATEST
FORECAST.
DISCUSSION
ISSUED AT 104 PM CDT WED APR 29 2026
THIS AFTERNOON: DIURNAL CU ALREADY FORMING EARLY THIS AFTERNOON,
WHICH COULD EVENTUALLY LEAD TO A FEW SPRINKLES OVER NW IOWA AND SW
MINNESOTA. AN ADDITIONAL AREA OF WEAK WARM ADVECTION ALOFT HAS
DEVELOPED HIGH BASED SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE
JAMES RIVER. HOWEVER, MORE FOCUS FOR SHOWERS AND ISOLATED
STORMS WILL ARRIVE LATER THIS AFTERNOON AND CONTINUE INTO THE
EVENING AS A SHORTWAVE SLIDES SOUTHEAST. SOUNDINGS SHOW 100-500
J/KG MLCAPE THROUGH THE AFTERNOON AND EVENING HOURS, SUGGESTING
A FEW THUNDERSTORMS DEVELOP. STEEP LOW-LVL LAPSE RATES COULD
PROMOTE THE TRANSPORT OF 30-40 MPH GUSTS IN ANY STRONGER SHOWER.
WOULD ALSO NOT BE SURPRISED TO SEE SOME SMALL HAIL ESPECIALLY
WEST OF THE JAMES RIVER.
TONIGHT: CAMS ALL HINT THAT SYNOPTICALLY DRIVE SHOWERS MAY CONTINUE
TO MOVE SOUTHEAST THROUGH THE OVERNIGHT HOURS. MORE CLUSTERING OF
SHOWERS MAY DEVELOP AROUND A COMPACT AREA OF VORTICITY TRACKING
THROUGH THE TRI-STATE AREA. HAVE INCREASED POPS AS A RESULT OF
REASONABLE MODELING OF THIS POTENTIAL. TEMPERATURES WILL FALL
OVERNIGHT, BUT CLOUD COVER WILL POSE THE GREATEST HINDRANCE TO
ANY WIDESPREAD FROST OR FREEZE CONDITIONS.
THURSDAY-FRIDAY: THE SECOND IN A SERIES OF THREE SHORTWAVE ROTATING
AROUND A BROAD UPPER TROUGH WILL ARRIVE ON THURSDAY. SIMILAR TO
TODAY, WE'LL SEE RAPID DESTABILIZATION AHEAD OF THE WAVE
LEADING TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE
AFTERNOON AND EARLY EVENING. LOW-LVL TEMPS ARE EVEN A BIT COOLER
THAN TODAY, SO SOME GRAUPEL COULD BE POSSIBLE. THE THIRD AND
FINAL WAVE ROTATING THROUGH THE REGION IS PROGGED TO MOVE INTO
THE REGION EARLY FRIDAY MORNING. THIS WAVE COULD HOLD ONTO
ENOUGH LOW-MID LVL CLOUD COVER TO KEEP TEMPERATURES FROM FALLING
BELOW FREEZING, THOUGH WITH LIGHT WINDS ANY BREAK IN CLOUDS MAY
RESULT IN FROST TO NEAR FREEZE CONDITIONS. COOLER NORTHERLY
FLOW UNDER SURFACE HIGH PRESSURE WILL LEAD TO QUIET WEATHER ON
FRIDAY. THOUGH AGAIN, AFTERNOON CU WILL LIKELY FILL THE SKY.
HIGHS REMAIN IN THE MIDDLE TO UPPER 50S.
SATURDAY-SUNDAY: AS WE'VE BEEN DISCUSSING THE PAST DAYS, WE'LL BEGIN
TO SEE WARMER TEMPERATURES ARRIVE THIS WEEKEND, BUT REMAIN IN A
PATTERN THAT SUGGESTS A FRONTAL BOUNDARY SLIDING THROUGH THE REGION
EVERY 1-2 DAYS. THIS RESULTS IN A GREAT SATURDAY, WITH
SOUTHWESTERLY SURFACE WINDS AND HIGHS IN THE MIDDLE TO UPPER 60S.
MODEL CLUSTERING SUPPORTS THE PASSAGE OF A COLD FRONT EARLY ON
SUNDAY. HIGH TEMPERATURES ONCE SUGGESTED TO BE IN THE UPPER 70S A
FEW DAYS AGO, WILL LIKELY ONLY REACH INTO THE MIDDLE TO UPPER 60S.
THE PASSAGE OF THIS FRONT MAY NOT RESULT IN ANY MORE THAN SPRINKLES
EARLY SUNDAY MORNING.
MONDAY-TUESDAY: THIS AFOREMENTIONED PATTERN CONTINUES INTO THE
MIDDLE OF THE WEEK SUGGESTING TEMPERATURES REMAIN NEAR TO
SLIGHTLY ABOVE NORMAL, WITH PRECIPITATION CHANCES SURROUNDING A
FRONTAL PASSAGE LATE TUESDAY GROWING TO NEAR 30 PERCENT IN LREF
AND NBM GUIDANCE.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1239 AM CDT THU APR 30 2026
SCATTERED VFR SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM WILL
MOVE SOUTHEAST ACROSS THE REGION INTO EARLY-MID THURSDAY MORNING.
THUNDER RISK AT SPECIFIC TERMINALS IS TOO LOW TO INCLUDE IN THE
TAF, BUT WOULD BE FAVORED TOWARD KSUX/PORTIONS OF NORTHWEST IA.
SHOWERS WILL EXIT NORTHWEST IOWA SHORTLY AFTER DAYBREAK THURSDAY.
HOWEVER, WEAK INSTABILITY COULD TRIGGER ADDITIONAL SPOTTY SHOWERS
OR AN ISOLATED THUNDERSTORM THURSDAY AFTERNOON TO EARLY EVENING.
LIGHT AND VARIABLE WINDS WILL SETTLE TO NORTHERLY EARLY THURSDAY,
WITH GUSTS UP TO 20KT IN THE AFTERNOON, DIMINISHING QUICKLY AT
SUNSET.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...JH
DISCUSSION...DUX
AVIATION...JH
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