267
FXUS63 KFSD 032256
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
556 PM CDT Fri Oct 3 2025

.KEY MESSAGES...

- Well above normal temperatures continue through Saturday. A
  few record high temperatures and warm low temperatures are
  possible today-Saturday. Widespread moderate to very locally
  major Heat Risk due to the unseasonable heat.

- Hot, dry and breezy to windy afternoons will lead to elevated
  fire weather conditions today (localized) and Saturday (more
  widespread with stronger wind). Use caution to avoid sparking
  fire in dry crops and grasses as rapid spread is possible.

- Rain chances for the latter half of the weekend are trending
  lower/farther west, with <20% chance of rainfall exceeding
  0.10" in our forecast area through Sunday night.

- Near normal daytime highs return early-mid next week. Low-
  moderate rain chances (20-30%) focused toward Sioux City to
  Storm Lake Monday morning and across the entire area Wednesday
  night into Thursday.

&&

.DISCUSSION...
Issued at 231 PM CDT Fri Oct 3 2025

Breezy conditions continue through the night which will keep
overnight lows near or above record warm lows. Expect lows to only
drop to 65 to 70. A strong low level jet and increasing southerly
gradient will bring about a windy day on Saturday with gusts of 35
to 45 mph expected. A few locations will likely see gusts around 50
mph. This will lead to potentially dangerous fire weather conditions
with highs climbing into the upper 80s to lower 90s and after
relative humidity falling to around 35 percent.

Showers will be possible Saturday evening into the night with the
better chances west of the James River. This is in response to a
fairly strong wave moving from western SD into eastern ND. Soundings
do not suggest much in the way of instability, but with the lack of
moisture below about 10 kft, some gusty winds will be possible with
these showers mainly west of the James River. Otherwise, dry air and
a general lack of instability will keep precipitation chances to a
minimum Saturday night through Sunday night. The cold frontal and
cold air advection settle in through the day Sunday with soundings
indicating the chance for any thunderstorms close to zero. Some
isolated shallow showers will be possible with some very weak
instability within the mixed layer to around the top of the mixed
layer. Confidence in this activity is low.

Model consensus for the Saturday night into Sunday night continues
to bring lower chances with all but south central SD seeing the
chance for a tenth of an inch or more about 10 percent or less.

Once this wave moves by to the north another wave is expected to
move into KS and NE and interact with the boundary that was sent
southward by the northern wave. For now the majority of any showers
and thunderstorms that can develop will remain in Nebraska and Iowa.
There are some hints that some of this activity will sneak northward
towards Woodbury and Ida counties with the GEFS showing a 10-20
percent chance for a half an inch of rain. This is likely in
response to mid level warm air advection as the wave to the south
moves by.

The big story for next week will be the return to seasonal normal
with highs from the 60s early in the week to the 70s mid to late
week. While meaningful precipitation is not expected next week,
there does appear to be some agreement to a wave swinging out on
Thursday and bringing the next better chance for rainfall.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 555 PM CDT Fri Oct 3 2025

VFR conditions are expected through the TAF period. Wind gusts
will ease a bit this evening and overnight, and with an
increasing low level jet there will be a period of LLWS at all
TAF sites. Winds increase again on Saturday morning, gusting 30
to 35 kts into Saturday evening.

&&

.FIRE WEATHER...
Issued at 231 PM CDT Fri Oct 3 2025

Gusty southerly winds today and Saturday will bring some fire
weather concerns to the area as we head into the first weekend
of October. Today will see winds gusting 20-30 MPH in most areas
by this afternoon, with some higher gusts near 35 MPH west of
the James River Valley. Well above normal temperatures
approaching 90F this afternoon modest humidity levels (as low as
30-40%) will generally lead to Moderate to High Grassland Fire
Danger. However, fully cured crops and/or grasses could see
localized Very High fire danger conditions and caution is
advised when working in these drier areas.

Saturday brings greater concerns as the south-southwest winds
strengthen further. Late morning to early evening gusts of 35 to 45
MPH will be more common, with humidity levels falling as low as 25
to 35 percent (perhaps lower if mixing is even more efficient). This
will lead to more widespread High to Very High Grassland Fire Danger
in the greener grasses. However, the drier grasses and especially
crops would be susceptible to rapid fire spread (localized Red Flag
conditions possible), as marginal humidity levels could easily be
overcome by the stronger winds currently forecast. With this in
mind, farmers and others working outdoors will need to be mindful of
their equipment usage to avoid sparking a fire in the dry fuels.
Next week provides dry conditions and much cooler temperatures with
much less dangerous harvesting conditions.

&&

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

&&

$$

DISCUSSION...08
AVIATION...JM
FIRE WEATHER...08