255
FXUS63 KFSD 290336
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1036 PM CDT WED MAY 28 2025
KEY MESSAGES
- AREAS OF PATCHY DENSE FOG MAY IMPACT YOUR THURSDAY MORNING
COMMUTE. AREAS ALONG AND WEST OF THE JAMES RIVER VALLEY ARE
MOST LIKELY TO SEE FOG.
- THURSDAY WE WILL AGAIN HAVE ISOLATED TO SCATTERED LIGHT
SHOWERS, MAINLY EAST OF THE JAMES RIVER VALLEY. ISOLATED
FUNNELS ALONG AND SOUTH OF HIGHWAY 20 ARE POSSIBLE AGAIN
THURSDAY AFTERNOON.
- WARMER TEMPERATURES RETURN BY THE WEEKEND WITH MANY LOCATIONS
EXPECTED TO SEE HIGHS IN THE 80S WITH QUIET CONDITIONS.
DISCUSSION
ISSUED AT 221 PM CDT WED MAY 28 2025
TODAY AND TONIGHT: SOME BREAKS IN THE CLOUDS HAVE HELPED WARM
SURFACE TEMPERATURES THIS AFTERNOON INTO THE LOW TO MID 60S. LOOKING
ALOFT WE SEE THE UPPER LOW STALLED OVER EASTERN SOUTH DAKOTA AND
WESTERN MINNESOTA. AS THIS LOW PIVOTS AROUND, WEAK EMBEDDED WAVES
WILL KEEP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH THIS EVENING. ELEVATED INSTABILITY OF 100-400 J/KG
COULD SUPPORT SOME STRONGER STORMS CAPABLE OF PRODUCING LIGHTNING
AND SMALL HAIL. A DRY SUBCLOUD LAYER COULD ALLOW FOR SOME
EVAPORATIVE COOLING THAT ENHANCES SOME OF THE DOWNDRAFTS. SOME
STORMS COULD PRODUCE GUSTS 30-40 MPH. SIMILAR TO YESTERDAY, HIGH
VORTICITY AND ENHANCED STRETCHING POTENTIAL RESIDES ACROSS MUCH OF
THE REGION. THIS MAY ALLOW A FEW WEAK FUNNELS TO FORM THROUGH THIS
EVENING. WHILE IT IS DIFFICULT TO KNOW EXACTLY WHERE A FUNNEL MAY
DEVELOP, THE POTENTIAL EXISTS ACROSS MOST OF SOUTHEASTERN SOUTH
DAKOTA, NORTHEASTERN NEBRASKA, NORTHWESTERN IOWA, AND SOUTHWESTERN
MINNESOTA. TOTAL ACCUMULATION THROUGH THIS EVENING WILL BE LIGHT, A
COUPLE HUNDREDTHS TO A TENTH. SHOWERS ARE EXPECTED TO DIMINISH AFTER
SUNSET. SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY, KEEPING OUR LOW
TEMPERATURES A BIT WARMER IN THE MID TO UPPER 40S.
THURSDAY: SIMILAR TO THIS MORNING, THURSDAY MORNING HAS THE
POTENTIAL FOR PATCHY DENSE FOG DEVELOPMENT. AREAS THAT RECEIVED RAIN
THIS AFTERNOON, AND AREAS ALONG AND WEST OF THE JAMES RIVER VALLEY
ARE MORE LIKELY TO SEE FOG DEVELOPMENT. SOUTHWESTERN MINNESOTA AND
NORTHWESTERN IOWA MAY ALSO SEE PATCHY DENSE FOG. THURSDAY MORNING
THE UPPER CLOSED LOW OPENS INTO A POSITIVELY TILTED TROUGH. AS THIS
TROUGH PIVOTS TO THE SOUTHEAST THROUGH THE AFTERNOON IT WILL BRING
ISOLATED TO SCATTERED LIGHT SHOWERS ONCE AGAIN. MOST GUIDANCE KEEPS
SHOWERS CONFINED TO AREAS EAST OF THE JAMES RIVER. THERE IS SOME
WEAK ELEVATED INSTABILITY, GENERALLY LESS THAN 200 J/KG, SO SOME
LIGHTNING IS POSSIBLE, BUT SEVERE IS NOT EXPECTED. ONCE AGAIN,
PLENTIFUL VORTICITY AND ENHANCED STRETCHING POTENTIAL EXIST TO
CREATE MORE WEAK FUNNELS. THE ARE MOST LIKELY FOR FUNNEL
DEVELOPMENT WILL BE ALONG AND SOUTH OF HIGHWAY 20. PARTLY TO
MOSTLY CLOUDY SKIES WILL ONCE AGAIN LIMIT OUR HIGHS JUST A
LITTLE IN THE LOW 70S. LOWS WILL FALL TO THE MID TO UPPER 40S.
FRIDAY-THE WEEKEND: FINALLY BY FRIDAY THE UPPER WAVE MOVES OFF TO
THE GREAT LAKES REGION, AND AN UPPER RIDGE BUILDS IN FROM THE WEST.
HEIGHT RISES IN THE MID TO UPPER LAYERS AND WAA FROM THE SURFACE
THROUGH 850 MB ON SOUTHWESTERLY LIGHT WINDS WILL BEGIN A WARMING
TREND THROUGH THE WEEKEND. SUNNY SKIES FRIDAY WILL BE COUPLED WITH
SLIGHTLY ABOVE AVERAGE HIGHS REACHING THE UPPER 70S TO LOW 80S.
OVERNIGHT LOWS WILL BE AROUND AVERAGE FOR THIS TIME OF YEAR, IN THE
MID 50S.
SATURDAY A FAST MOVING SHORTWAVE EMBEDDED IN THE UPPER NORTHWESTERLY
FLOW WILL PASS NEAR THE REGION. THE GFS KEEPS IT WELL WEST OF US,
HOWEVER THE EC, CAN, AND NAM ALL HAVE IT SKIRTING SOMEWHERE THROUGH
OUR REGION. SHOULD THE FORECAST FOLLOW ONE OF THESE SOLUTIONS A
QUICK SHOT OF MORNING LIGHT SHOWERS IS POSSIBLE. MOISTURE IS LACKING
IN THE LOW LEVELS SO THERE IS THE QUESTION OF WILL ANY RAIN REACH
THE GROUND. WITH DETAILS THIS UNCERTAIN, CONFIDENCE AT THIS POINT IS
LOW. HAVE LEFT NBM POPS AS THEY ARE. BY AFTERNOON, ANY SHOWERS WILL
DRY UP, AND MOSTLY SUNNY SKIES WILL PREVAIL. HIGH TEMPERATURES FOR
SATURDAY WILL BE IN THE LOW TO MID 80S. LOWS WILL BE IN THE 50S.
SUNDAY WILL BE ANOTHER WARM DAY UNDER HIGH PRESSURE. ESATS TABLES
INDICATE THAT BY SUNDAY AFTERNOON OUR MID-LEVEL TEMPERATURES WILL BE
APPROACHING THE 90TH PERCENTILE OF CLIMATOLOGY. ENSEMBLES INDICATE A
HIGH LIKELIHOOD OF TEMPERATURES BEING 80 DEG F OR WARMER,
BETWEEN 70- 100%. CONSIDERING THIS, HIGHS IN THE MID TO UPPER
80S SEEMS LIKELY WITH A FEW AREAS APPROACHING 90. LOWS FOR
SUNDAY NIGHT WILL BE VERY WARM, IN THE 60S.
NEXT WEEK: MONDAY CONTINUES TO BE IN THE 90TH PERCENTILE FOR
CLIMATOLOGY FOR BOTH HEIGHTS AND TEMPERATURES. HIGHS WILL BE SIMILAR
TO SUNDAY WITH WIDESPREAD 80S, AND A FEW LOCATIONS IN SOUTHWESTERN
MINNESOTA, AND ALONG THE SOUTHERN MISSOURI RIVER VALLEY POSSIBLY
REACHING FOR 90. THOUGH WE WILL BE VERY WARM, HIGH RECORDS ARE IN
THE UPPER 90S, AND SO IT DOES NOT LOOK LIKE WE WILL BREAK ANY.
MONDAY EVENING THE UPPER RIDGE BEGINS TO BREAK DOWN AND A MORE
ACTIVE PATTERN LOOKS TO SET UP FOR THE MIDDLE PART OF NEXT WEEK. A
DEEP TROUGH OVER THE ROCKIES WILL SEND OUT A COUPLE WAVES THAT WILL
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH AT LEAST
THURSDAY. DETAILS ARE UNCERTAIN BUT IT LOOKS LIKE AREA WIDE RAINFALL
IS IN STORE FOR NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1035 PM CDT WED MAY 28 2025
WINDS WILL BE LIGHT OVERNIGHT, AND THERE ARE LOW PROBABILITIES
(20-30%) FOR PATCHY FOG FORMATION - MAINLY FROM THE JAMES RIVER
VALLEY AND WESTWARD. WITH THE LOW CONFIDENCE, DID NOT INCLUDE
IN TAFS AT THIS TIME.
ISOLATED SHOWERS/THUNDERSTORMS WILL AGAIN BE POSSIBLE ON
THURSDAY. WINDS WILL REMAIN LIGHT.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...AJP
AVIATION...JM
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