915
FXUS63 KFSD 230401
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1101 PM CDT Fri Aug 22 2025

.KEY MESSAGES...

- The first taste of Fall arrives tomorrow, bringing cooler
  temperatures, lower humidity and dry conditions through the
  first half of next week. Highs mostly in the 60s and 70s are
  likely along with lows falling to the 40s and 50s.

&&

.DISCUSSION...
Issued at 257 PM CDT Fri Aug 22 2025

Showers and a few thunderstorms persist this afternoon. The surface
cold front continues to push through the area and is roughly along a
line from Jackson, MN to Le Mars, Ia to Wayne, NE. A shortwave
trough is also pushing through the area from the northwest. This
wave is interacting with this boundary and has developed an isolated
storm currently over Sioux City. This storm will continue its
southeastward trajectory and looks to exit the area over the next
hour or so. While today`s 12z guidance initially suggested
additional convective development this afternoon, think that is
trending to be more and more unlikely. With the cold front pushing
through the area and the best ascent from the previously mentioned
shortwave trough also pushing south and east of the area, think that
the latest trends of the HRRR are on the right track that little if
any additional development is expected. If new storms develop, they
would would generally take place east of I-29 in parts of southwest
Minnesota and northwest Iowa. BUFKIT soundings show tall skinny CAPE
profiles with magnitudes of about 1,000 J/kg. Though do think that
this could potentially be a bit overdone, especially with dew points
beginning to fall behind the front. Should new convection develop,
think that it would be sub severe though small hail, gusty winds,
and brief heavy rain being the main threats. Any chance for rain
will come to an end around 7 pm or so leaving dry conditions for
tonight. Low temperatures will finally drop out of the 60s as dew
points lower behind the cold front tonight with lows bottoming out
in the 50s.

Saturday begins the first day of our first taste of Fall as dew
points will lower to the 50s across the region. 850 mb temperatures
will cool to the upper single digits to low teens aloft. Mixing
these temperatures to the surface will result in high temperatures
in the upper 60s and 70s, coldest across the Buffalo Ridge in
southwest Minnesota. Surface ridging will be spilling into the
Northern Plains, keeping only marginally breezy winds for the
afternoon hours. Winds will be out of the northwest with gusts up to
20-25 mph expected. Low temperatures will fall to the 40s and 50s
overnight. Sunday will be another Fall like day with highs remaining
in the 60s to low to mid 70s. Winds will be a bit weaker than on
Saturday thanks to the surface pressure gradient loosening a little
bit. Thus, Sunday will be another beautiful day! Low temperatures
will fall to the 40s overnight.

The first half of next week looks to remain dry as surface high
pressure slowly drifts through the Northern Plains. This will keep
highs in the 60s, 70s, and 80s while dew points remain in the 40s
and 50s. Lows will start out in the 40s Monday night before slowly
warming to the 50s Tuesday and Wednesday nights.

Southerly return flow sets up by Thursday which may bring rain
chances back to the forecast. Highs will warm back to near
seasonable in the 70s to low 80s while dew points moisten to the 50s
to potentially the 60s again. As of now, the ensembles paint a
picture of an upper level ridge sitting over the Central Plains with
potentially a weak mid level shortwave trough rounding the ridge.
Low level winds will become southerly, thus increasing the chance
for rain. The ensembles do somewhat support this potential as they
show a 20-30% chance for rainfall totals to exceed a tenth of an
inch. However, details can certainly change this far out so have
stuck with model blended PoPs at this time.

This same pattern continues through Friday yielding the same
probabilities for exceeding a tenth of an inch of rain. Uncertainty
persists in this possibility though given that specific details will
likely change over the coming days. Temperatures however will remain
in the 70s to possibly the 80s though. Will continue to monitor
trends over the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1057 PM CDT Fri Aug 22 2025

VFR conditions are expected to prevail through the TAF period,
though there is a low probability of MVFR visibility in fog
ahead of a cold front which could impact KSUX and portions of
northwest IA prior to sunrise. Confidence too low to include in
the KSUX TAF at this time, but will monitor trends and amend if
needed.

North winds behind the cold front may briefly gust 20-25kt early
in the TAF period. Otherwise more widespread gusts 20-25kt are
expected with mixing late morning and afternoon Saturday.

&&

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

&&

$$

DISCUSSION...Meyers
AVIATION...JH