068
FXUS63 KFSD 051141
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
641 AM CDT Sun Oct 5 2025

.KEY MESSAGES...

- A cold front will pass through the area today, resulting in
  cooler high temperatures. Early morning light showers will
  give way to another round of showers late this afternoon and
  evening across mainly northwest Iowa. A few rumbles of thunder
  are possible.

- Elevated fire danger is possible today along and southeast of
  a Marshall, Minnesota to Sioux Falls, South Dakota, to
  Yankton, South Dakota line where humidity values will be
  lowest.

- Near seasonable temperatures return on Monday before highs
  slowly warm back to above average through the rest of the
  week.

&&

.DISCUSSION...
Issued at 339 AM CDT Sun Oct 5 2025

Light showers begin the day today as a cold front continues to push
through the forecast area early this morning. These showers have
been encountering drier air as they push eastwards. Some may survive
as they push eastwards with the front but should see coverage overall
decrease, especially as the better forcing for ascent pushes
northwest of the area. Breezy winds will persist through the morning
hours thanks to the cold advective push right behind the surface
front. Winds will turn westerly for the morning hours with gusts up
to 25-40 mph. Winds will be decreasing through the afternoon hours
as the front pushes southeast of the area while high temperatures
warm to the upper 60s to low 80s from northwest to southeast. That
said, elevated fire danger remains possible, mainly along and
southeast of a Marshall, Minnesota to Sioux Falls, South Dakota, to
Yankton, South Dakota line where humidity values will be lowest
around 30% thanks to dew points falling to the upper 40s to low 50s.
At the same time, this is the same area where winds will be weakest
with gusts weakening to just about 25 mph. While elevated fire
danger is still possible in this area, have decided to hold off on
issuing a Special Weather Statement (SPS) at this time given the
marginal fire danger conditions. At the same time, light showers may
develop across portions of northwest Iowa during the late afternoon
to early evening hours behind the main cold front. The bulk of the
showers and thunderstorms look to develop along to just barely ahead
of the front southeast of the area. With lingering instability
behind the front, could see a few rumbles of thunder in the light
showers that do develop. Showers across northwest Iowa should end by
about midnight. Mainly quiet conditions are expected through the
overnight hours with low temperatures falling to 40s. The exception
will be another round of showers developing across northern Nebraska
and southerly South Dakota just before daybreak tomorrow.

These showers will kick off the day on Monday as strong
frontogenesis (FGEN) takes place between 700-600 mb. The lift from
the front will cool the mid levels to saturation, especially in the
dendritic growth zone (DGZ). With sufficient omega in the DGZ, light
rain showers will persist along the Missouri River Valley and into
adjacent portions of northwest Iowa throughout the day on Monday.
With forcing for ascent slowly weakening throughout the day, only
light rainfall amounts are expected on the order of a few
hundredths. Cloud cover will blanket the area for the majority of
the day, keeping high temperatures near seasonable in the 60s across
the area. Low temperatures will fall to the 40s overnight.

Tuesday and Wednesday will be quiet days with high temperatures
slowly warming from the 60s on Tuesday to the low 70s on Wednesday
thanks to weak ridging aloft. Wind remain light on Tuesday but
strengthen again on Wednesday as the surface pressure gradient will
re-tighten, bringing breezy winds back to the area. This could
result in some elevated fire danger but the strongest winds look to
be offset from the lower humidity at this time. Lows will fall to
the 40s Tuesday night before warming back to the 40s and 50s
Wednesday night.

Temperatures remain in the 70s for Thursday and Friday but could
potentially see some very light rain on Thursday as a weak shortwave
trough passes through the Northern Plains. The ensembles are in
decent agreement as they show a broad 20-60% chance for exceeding a
mere hundredth of an inch, mainly on Thursday. Once the wave pushes
southeast of the area, Friday looks to be a more quiet day.

Uncertainty increases in the upper level patterns evolution for the
weekend. Medium range guidance shows a rather large trough pushing
into the Northern Plains. The ensembles paint a similar picture but
are slower with the upper trough. They also diverge in how the
trough evolves into next week with some ensembles developing a
cutoff low and others keep it as a progressive wave. Too early to
say what evolution will occur at this time but will monitor over the
next week. Otherwise, high temperatures will remain in the 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 639 AM CDT Sun Oct 5 2025

Light showers begin the TAF period early this morning. The showers
are currently located just west of I-29 and eastward through
northwest Iowa and parts of southwest Minnesota. These showers will
persist through the next couple of hours before pushing east of the
area. Ceilings and visibilities remain at VFR levels in the showers.
A stray rumble of thunder is possible as well. As the showers move
out, there could be a small area of MVFR stratus that pushes into
KHON. Have left ceilings scattered at this time but will monitor
trends.

A second round of showers looks to develop late this afternoon and
evening across parts of northwest Iowa. This could impact KSUX but
confidence is too low in the location of the showers to include in
KSUX`s TAF at this time. A few rumbles of thunder are also possible
in this second round of showers before they move out around
midnight.

Aside from rain, a cold front is pushing through the area this
morning, turning southerly winds ahead of it to westerly behind the
front. Winds will continue to veer through the afternoon hours to
northwesterly with gusts up to 20-30 knots. The winds will continue
to slowly veer while weakening through the evening and overnight
hours.

&&

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

&&

$$

DISCUSSION...Meyers
AVIATION...Meyers