FXUS63 KFSD 281123
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
623 AM CDT Tue Apr 28 2026

.KEY MESSAGES...

- The remainder of the work week features cooler than normal
  temperatures and occasional risks of very light rain.

- Warmer temperatures return by next weekend with high
  temperatures around 10 degrees above normal in the upper 60s
  to 70s.

&&

.UPDATE...
Issued at 329 AM CDT Tue Apr 28 2026

No significant changes to the forecast this morning. Stratus
continues to move off to the east, with a few high clouds moving in
across south central SD and southern MO River Valley, leading to
mostly clear skies. Still can't entirely rule out some patchy fog
with temperatures falling into the 30s; however, winds should remain
just strong enough to preclude fog development. If fog develops,
expect it to be through the MO and James River Valleys, east toward
I-29.

Minor changes early this morning to pops for today into early this
evening, as a mid level wave moves across the southern part of the
area and across northern NE/IA earlier in the day, with a second
wave tonight. Soundings show some weak instability (less than 100
J/kg) which may be enough with weak WAA to get some isolated to
scattered sprinkles/showers to develop. Some question on how quickly
the unstable layer can saturate, so not confident in going any
higher with pops at this time. No impacts expected. Cooler again
today with lower level clouds increasing. Highs in the upper 40s to
upper 50s.

May have to watch for potential patchy fog and/or frost development
tonight if we can see skies clear a bit more than forecast with
temperatures. Winds may also remain just stronger enough again
tonight to prevent any development. For now, will keep mention out
of the forecast given low confidence in occurrence. Temperatures
fall into 30s again.

&&

.DISCUSSION...
Issued at 1215 PM CDT Mon Apr 27 2026

THIS AFTERNOON: Upper level troughing and associated surface low
pressure continues to move east and away from the Tri-State area
this afternoon. At mid-day we're beginning to see 30+ knot wind
develop in central SD, which will begin to extend eastward through
the evening hours. Some gusts over 40 knots could be possible
through the higher elevation of the Ridge. Temperature will continue
to slowly fall as stratus remains in place.

TONIGHT: Subsidence will begin to chew away on lower stratus early
this evening, eventually leading to clear skies throughout the CWA
near or after midnight. Temperatures may fall below freezing in
areas north of I-90. With the recent rainfall and clear skies,
should winds fall off adequately, then areas of fog may
develop.

TUESDAY-FRIDAY: A broad upper trough centered across the eastern
half of the CONUS will keep the region cooler than normal through
the rest of the week. A few weak perturbations passing through the
southern side of this trough will lead to very light rain chances.
These rain chances are focused along the MO river valley Tuesday
afternoon and evening, most of the Tri-State area Wednesday
afternoon and night with these chances continuing into Thursday.
Overall QPF amounts will be light with the 24 hour probability of
QPF over 0.10" no more than 15% ATTM.

SATURDAY-MONDAY:  Confidence in the temperature forecast for the
upcoming weekend remains medium at best.  Guidance remains split on
the potential for the expansion of western CONUS ridging to the
east, increasing overall spread in ensemble guidance. That said, as
compared to 24 hours ago, the spread has narrowed slightly, with an
overall cooling in temperatures in the 25/75th percentile ranges of
the NBM. While PoPs remain below mentionable levels, the passages of
1-2 cool fronts Saturday and Monday could lead to future low end
mentions in future forecasts.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 616 AM CDT Tue Apr 28 2026

Largely VFR conditions through the period with increasing
mid/high clouds this morning. MVFR conditions are expected by
early this afternoon in south central SD, expanding with showers
through the MO River Valley. Maintained the PROB30 groups for
KFSD and KSUX for -SHRA this evening, although recent model
trends are keeping most activity away from KFSD. Otherwise, most
of the area will see some lower end VFR stratus for the latter
half of the period.

Winds remain light and generally northwesterly, becoming
variable overnight.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

UPDATE...SG
DISCUSSION...Dux
AVIATION...SG