202
FXUS63 KFSD 291718
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1218 PM CDT WED APR 29 2026
KEY MESSAGES
- SCATTERED CONVECTIVE SHOWERS AND ISOLATED THUNDERSTORMS MAY
DEVELOP WEDNESDAY. SEVERE STORMS NOT EXPECTED, BUT A FEW WIND
GUSTS TO 30+ MPH MAY BE POSSIBLE. SCATTERED SPRINKLES TO SHOWERS
POSSIBLE AGAIN THURSDAY.
- THE FROST/FREEZE WARNING PROGRAM HAS BEEN ACTIVATED FOR THE
AREA, WITH A FEW AREAS OF CONCERN THIS WEEK. THURSDAY NIGHT
MAY FEATURE THE MOST CONCERNING TEMPERATURES NEAR OR BELOW FREEZING.
- TEMPERATURES WILL WARM ABOVE NORMAL BY THE UPCOMING WEEKEND
INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 315 AM CDT WED APR 29 2026
PATCHY AND LOCALLY DENSE FOG HAS DEVELOPED EARLY THIS MORNING WEST
OF I-29, MAINLY IN THE RIVER VALLEYS, WHERE SKIES HAVE CLEARED. HAVE
SEEN A COUPLE OF OBSERVATIONS AND AREA DOT CAMS WITH VISIBILITY
BELOW HALF A MILE. SURFACE TEMPERATURES SHOULD BE WARM ENOUGH TO
LIMIT ANY SLICK SPOTS, BUT CAN'T RULE OUT ISOLATED SLICK SPOTS WITH
TEMPERATURES BELOW FREEZING. PATCHY FROST IS ALSO POSSIBLE IN THE
NORTHWESTERN FORECAST AREA WHERE TEMPERATURES ARE NEAR/BELOW
FREEZING. MAY SEE SOME PATCHY FOG EAST OF I-29 BY DAYBREAK AS
STRATUS CLEARS, BUT CONFIDENCE IS LOWER IN THIS AREA. NOT
ANTICIPATING THE NEED FOR A DENSE FOG ADVISORY AS DENSE FOG REMAINS
FAIRLY LOCALIZED.
NO OTHER CHANGES TO THE FORECAST. STILL ANTICIPATE CONVECTIVE
SHOWERS AND ISOLATED STORMS TO DEVELOP LATER TODAY WITH WEAK
INSTABILITY OVER THE AREA. WITH DRY AIR BELOW THE CLOUD LAYER, WIND
GUSTS OF 30+ MPH ARE POSSIBLE WITH SHOWERS AND ISOLATED
THUNDERSTORMS. NORTHWESTERLY FLOW ALLOWS ADDITIONAL WEAK WAVES TO
MOVE THROUGH THE AREA, KEEPING SHOWER CHANCES AROUND THROUGH
THURSDAY. COOLER THAN AVERAGE TEMPERATURES PREVAIL LEADING TO
NIGHTLY RISKS FOR FROST. MOST WIDESPREAD RISKS APPEAR TO BE THURSDAY
NIGHT AND FRIDAY NIGHT. THOSE WITH SENSITIVE VEGETATION WILL WANT TO
KEEP AN EYE ON THE FORECAST.
DISCUSSION
ISSUED AT 1222 PM CDT TUE APR 28 2026
THIS AFTERNOON: THE PASSAGE OF MID-LVL VORTICITY THROUGH THE CENTRAL
PLAINS WILL CONTINUE TO BRING A RISK FOR SPRINKLES TO VERY
LIGHT RAIN SHOWERS INTO THE TRI-STATE ARE INTO THE EARLY
OVERNIGHT HOURS.
TONIGHT: LINGERING SPRINKLES TO LIGHT SHOWERS MAY CONTINUE
THROUGH VERY EARLY WEDNESDAY MORNING, FOCUSING INTO NW IOWA AS
THE NIGHT MOVES ON. FURTHER NORTHWEST, DEPENDING ON CLEARING,
TEMPERATURES MAY FALL INTO THE 30S. HAVE TRENDED TEMPERATURES
SLIGHTLY WARMER THAN NBM GUIDANCE GIVEN INCREASED CLOUDS, AS
WELL AS THE OBSERVATION THAT WET GROUND HELD TEMPERATURES UP
1-3 DEGREES LAST NIGHT. NEVERTHELESS, IF TD SPREADS WERE A BIT
MORE SUFFICIENT, PATCHY FROST COULD DEVELOP.
WEDNESDAY-THURSDAY: WE'LL REMAIN WITHIN THE INFLUENCE OF A
LARGE UPPER TROUGH ROTATING THROUGH CENTRAL CANADA AND MOVING
TOWARDS HUDSON BAY BY THE END OF THE WEEK. THIS TROUGH WILL KEEP
TEMPERATURES COOLER THAN NORMAL, BUT ALSO BRING RISKS FOR
SCATTERED SHOWERS THROUGH THURSDAY. A QUICK WARMUP WEDNESDAY
MORNING, COMBINED WITH INCREASING LOW-LVL CAA SHOULD ASSIST IN
THE DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS BY MID-DAY.
SOUNDINGS SHOW A RATHER STEEP LOW-LVL LAPSE RATE, WITH A POCKET
OF WEAK INSTABILITY SUGGESTING AT LEAST ISOLATED THUNDER
MENTIONING THROUGH THE AFTERNOON. WINDS AT THE TOP OF THE MIXED
LAYER ARE NOT ALL THAT STRONG, BUT A POCKET OF 30+ MPH WINDS IN
SHOWERS COULD BE POSSIBLE. A SIMILAR STORY FOR THURSDAY, WITH
RAIN CHANCES PERHAPS MORE FOCUSED IN THE MORNING HOURS AND AGAIN
LATE AFTERNOON. ONE HAZARD TO WATCH WILL BE THE OVERNIGHT LOW
TEMPERATURES WEDNESDAY NIGHT BUT ESPECIALLY THURSDAY NIGHT.
CLOUD COVER MAY PREVENT ANY STRONG DROP INTO THURSDAY, BUT WITH
LESS CLOUDS AND LIGHT WINDS FRIDAY MORNING POTENTIAL FOR
WIDESPREAD SUB-32 LOWS WILL BE POSSIBLE. THE PROBABILITIES OF
<32 DEGREE TEMPERATURES FROM BOTH THE HREF AND NBM ARE SITTING
AROUND 50% ALONG THE BUFFALO RIDGE THURSDAY MORNING. MORE
WIDESPREAD 40%-60% PROBABILITIES OF <32 PRESENT THEMSELVES
FRIDAY MORNING AREAWIDE WITH PROBABILITIES OF <35 DEGREES NEARLY
90+%. ALL THIS TO SAY, WITH THE ACTIVATION OF FROST/FREEZE
PROGRAM HEADLINES TODAY, POTENTIAL IS GROWING FOR HEADLINES INTO
FRIDAY.
FRIDAY-SUNDAY: THE LARGE UPPER TROUGH SWINGS FURTHER EAST
FRIDAY, REBOUNDING TEMPERATURES TOWARDS THE UPPER 50S WITH DRY
WEATHER. HEIGHTS SLOWLY RISE DURING THE UPCOMING WEEKEND,
SIGNALING A GRADUAL RISE IN TEMPERATURES EACH DAY. A PLEASANT
SATURDAY IS EXPECTED WITH HIGHS RISING THROUGH THE 60S. THE
PASSAGE OF A WEAK FRONT EARLY SUNDAY WILL HAVE MINIMAL IMPACTS
ON TEMPERATURES WITH HIGHS AGAIN RISING INTO THE UPPER 60S TO
LOWER 70S.
MONDAY-TUESDAY: MID-LVL FLOW PATTERNS REMAIN SPLIT, WITH A
DOMINANT SOUTHERN STREAM FLOW KEEPING THE RISKS FOR SEVERE
WEATHER AND EXTREME WARMUP OVER THE SOUTHERN US. FURTHER NORTH,
LINGERING INFLUENCE OF WEST TO NORTHWESTERLY UPPER FLOW KEEPS
TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL. THE PASSAGE OF
ANOTHER WEAK FRONT MONDAY MAY BRING LOW RISKS FOR RAIN, WITH
GREATER POTENTIAL SHOWING UP IN EXTENDED MODEL GUIDANCE BY THE
MIDDLE OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1215 PM CDT WED APR 29 2026
SCATTERED CU FIELD CONTINUES TO BUILD THIS AFTERNOON, WITH A
WEAK WING OF WARM ADVECTION IN THE JAMES RIVER VALLEY CURRENTLY
PRODUCING LIGHT SHOWERS.
VFR SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE INTO THE
OVERNIGHT HOURS. WHILE SEVERE STORMS AREN'T EXPECTED, A FEW
30-40 MPH WIND GUSTS COULD BE POSSIBLE.
EVENTUALLY THE WAVE RESPONSIBLE FOR THIS ACTIVITY WILL MOVE
SOUTHEAST OF THE TRI-STATE AREA AFTER 2AM, LEAVING HIGHER CLOUDS
IN PLACE. WINDS REMAIN LIGHT AND VARIABLE INTO THURSDAY.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...DUX
AVIATION...DUX
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