779
FXUS63 KFSD 272330
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
630 PM CDT TUE MAY 27 2025
KEY MESSAGES
- A FEW ADDITIONAL ISOLATED TO SCATTERED SHOWERS THIS AFTERNOON.
SOME WEAK THUNDERSTORMS ARE ALSO POSSIBLE WITH SMALL HAIL AND
WIND GUSTS OF 30-40 MPH THE MAIN THREATS. ADDITIONAL
ACCUMULATION OF A HUNDREDTH OF SO POSSIBLE.
- BRIEF, WEAK FUNNELS ARE POSSIBLE THIS AFTERNOON. AREA MOST
LIKELY TO SEE THEM IS ALONG AND NORTH OF I-90.
- PATCHY FOG WILL BE POSSIBLE LATE TONIGHT INTO WEDNESDAY MORNING.
- SCATTERED LIGHT SHOWERS RETURN WEDNESDAY (20-50% CHANCE)
REMAIN POSSIBLE FOR WEDNESDAY.
- WARMER TEMPERATURES RETURN BY THE WEEKEND WITH MANY LOCATIONS
EXPECTED TO SEE HIGHS IN THE 80S WITH QUIET CONDITIONS.
DISCUSSION
ISSUED AT 225 PM CDT TUE MAY 27 2025
THIS AFTERNOON AND TONIGHT: SCATTERED LIGHT SHOWERS CONTINUE THIS
AFTERNOON AND EVENING AS A LOBE OF HIGHER MOISTURE SWINGS DOWN FROM
THE NORTHWEST. THERE REMAINS LOW CHANCES FOR SOME THUNDER WITH THESE
STORMS, BUT WITH ELEVATED CAPE OF AROUND 150 J/KG OR LESS CONFIDENCE
IS LOW. SHOULD ANY STRONGER STORMS DEVELOP, THE MAIN THREATS WILL BE
SMALL HAIL, AND WIND GUSTS OF 30-40 MPH. ADDITIONAL ACCUMULATION OF
A HUNDREDTH OR SO IS POSSIBLE. AN ADDITIONAL CONCERN THIS AFTERNOON
IS THE POSSIBILITY OF THE FORMATION OF WEAK FUNNEL CLOUDS. HIGH
VORTICITY THANKS TO THE UPPER LEVEL LOW SPINNING OVERHEAD
COMBINED WITH LOW SHEAR, COLD MID-LEVEL TEMPERATURES, AND MODEST
LAPSE RATES COULD RESULT IN THE FORMATION OF BRIEF FUNNELS.
CONFIDENCE IN THEIR FORMATION IS LOW, DUE TO AN OVERALL DECREASE
IN INSTABILITY, HOWEVER IT IS NOT ZERO. SHOULD ANY FUNNELS FORM, THE
MOST LIKELY AREA TO SEE THEM WILL BE ALONG AND NORTH OF I-90. THREAT
OF FUNNELS WILL DECREASE WITH THE LOSS OF AFTERNOON SURFACE HEATING
THIS EVENING.
BY AROUND 6 PM, MOST OF THE SHOWER ACTIVITY WILL HAVE MOVED OFF TO
THE EAST, WITH SOME LINGERING IN WESTERN IOWA AND MINNESOTA INTO THE
OVERNIGHT. LIGHT AND VARIABLE WINDS WITH HIGH SURFACE RELATIVE
HUMIDITY (>95%) WILL ALLOW FOR SOME PATCHY DENSE FOG TO DEVELOP,
MOSTLY EAST OF THE JAMES RIVER VALLEY. OVERNIGHT LOWS WILL FALL TO
THE MID 40S.
WEDNESDAY: A BRIEF REPRIEVE IN RAIN WEDNESDAY MORNING WILL BE
FOLLOWED BY RENEWED CHANCES FOR ISOLATED TO SCATTERED LIGHT RAIN.
THE UPPER LOW STALLS FOR MOST OF WEDNESDAY OVER EASTERN SOUTH DAKOTA
AND NORTH DAKOTA, AND WESTERN MINNESOTA. AS IT DOES SO AN EMBEDDED
SHORT WAVE AND ASSOCIATED VORTICITY MAX WILL ROTATE THROUGH,
TRIGGERING AFTERNOON SHOWERS. COVERAGE IS EXPECTED TO BE MORE SPOTTY
THAN TODAY DUE TO THE FACT THAT THE BETTER SURFACE MOISTURE WILL BE
EAST OF THE REGION. DRIER AIR WILL UNDERCUT THE MID-LEVEL MOISTURE,
MAKING IT HARDER FOR SHOWERS TO REACH THE SURFACE. THERE IS SOME
DISAGREEMENT IN GUIDANCE ON HOW MUCH INSTABILITY WILL BE
AVAILABLE, BUT IN GENERAL 100-300 J/KG OF MLCAPE MAY BE ENOUGH
FOR A FEW WEAK THUNDERSTORMS TO FORM. CONTINUED COOL CONDITIONS
FOR WEDNESDAY WITH HIGHS REACHING THE MID TO UPPER 60S. LOWS
WILL FALL TO THE MID TO UPPER 40S.
THURSDAY-FRIDAY: SHOWERS END OVERNIGHT AND BY THURSDAY MORNING WE'LL
HAVE MOSTLY SUNNY SKIES. ALOFT WE SEE THE UPPER LOW BEGIN TO SHIFT
SOUTHEAST. AS IT DOES SO, A WEAK VORTICITY LOBE AND WAA MAY TRIGGER
SOME ISOLATED LIGHT AFTERNOON SHOWERS. A GENERAL LACK OF SATURATION
IN THE DGZ WILL MEAN THESE SHOWERS WILL BE VERY LIGHT AND DRIZZLY IN
NATURE, IF THEY CAN MAKE IT TO THE GROUND AT ALL. CONFIDENCE IN
THURSDAY SHOWERS IS LOW, LESS THAN 25%, AND MOST LOCATIONS WILL NOT
SEE ANY RAIN. HIGHS WILL WARM INTO THE LOW TO MID 70S WITH LOWS
FALLING TO THE UPPER 40S TO LOW 50S.
FOR FRIDAY WE FINALLY AND TRULY DRY OUT AS A DEEP UPPER LEVEL RIDGE
BUILDS IN OVER CENTRAL CANADA, EXTENDING DOWN OVER THE CENTRAL
PLAINS. WINDS AT THE SURFACE THROUGH THE 850 MB LAYER WILL BE
SOUTHWESTERLY. WAA WILL WARM 850 MB TEMPERATURES INTO THE 12-16 DEG
C RANGE. GOOD MIXING THROUGH THIS LAYER MEANS SURFACE TEMPERATURES
WILL WARM INTO THE UPPER 70S TO LOW 80S. THIS IS RIGHT AROUND TO
SLIGHTLY ABOVE AVERAGE FOR THIS TIME OF THE YEAR, WHICH IS THE MID
70S.
THE WEEKEND: WARMER TEMPERATURES ARE ON THE WAY FOR THIS WEEKEND.
HIGHS FOR SATURDAY WILL REACH THE UPPER 70S TO LOW 80S, AND FOR
SUNDAY THE LOW TO MID 80S. THERE IS ONE SMALL HITCH IN THE NICER
WEEKEND WEATHER SATURDAY MORNING. A FAST MOVING SHORT WAVE WILL
MOVE THROUGH THE REGION EARLY SATURDAY MORNING. WE WILL FIND
OURSELVES IN THE LEFT EXIT REGION OF A MODEST UPPER JET STREAK,
WHICH WILL RESULT IN SOME SYNOPTIC LIFT. MLCAPE WILL GENERALLY BE
LESS THAN 400 J/KG, WITH VERY LITTLE 0-6 KM BULK SHEAR. CONSIDERING
THIS, SEVERE WEATHER IS NOT EXPECTED AT THIS TIME, BUT A FEW RUMBLES
OF THUNDER ARE POSSIBLE. DUE TO VARIANCE IN GUIDANCE, COVERAGE
AT THIS TIME IS UNCERTAIN. SHOWERS DRY OUT BY SATURDAY NIGHT.
NEXT WEEK: THE FIRST HALF OF NEXT WEEK LOOKS TO BE UNSETTLED AS A
NEGATIVELY TILTED UPPER TROUGH MOVES OUT OF THE CENTRAL ROCKIES AND
ACCELERATES NORTHEAST THROUGH OUR REGION. DETAILS ARE UNCERTAIN WITH
HIGH MODEL DISAGREEMENT. BUT SHOWER CHANCES LOOK TO CONTINUE
THROUGH AT LEAST WEDNESDAY OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 614 PM CDT TUE MAY 27 2025
MOSTLY VFR CONDITIONS THIS EVENING WILL TRANSITION TO MOSTLY
MVFR AND LOWER OVERNIGHT AS PATCHY AREAS OF FOG DEVELOP. TAKING
A LOOK AT SATELLITE IMAGERY, AREAS OF DEVELOPING SHOWERS THIS
EVENING SHOULD GRADUALLY DIMINISH AFTER SUNSET GIVING WAY TO
OVERCAST SKIES WITH LIGHT AND VARIABLE WINDS. THIS COMBINED
WITH LINGERING MOISTURE IN THE LOWER LEVELS OF THE ATMOSPHERE
SHOULD LEAD TO THE DEVELOPMENT OF MVFR/IFR FOG BETWEEN 3 AM TO
7 AM ON WEDNESDAY MORNING. WHILE SOME PATCHY AREAS OF LIFR FOG
WILL BE POSSIBLE, SHOULD SEE MOST OF THIS ACTIVITY GRADUALLY
DIMINISH BY MID-MORNING. OTHERWISE, A FEW MORE SHOWERS WILL BE
POSSIBLE BY WEDNESDAY AFTERNOON. LASTLY, LIGHT AND VARIABLE
WINDS WILL BECOME LIGHT NORTHEASTERLY DURING THE DAY ON
WEDNESDAY TO END THE TAF PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...AJP
AVIATION...05
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