565
FXUS63 KFSD 151105
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
605 AM CDT Wed Oct 15 2025

.KEY MESSAGES...

- Areas of fog, some locally dense, through mid morning.

- Low shower/drizzle chances remain through today and tonight,
  though additional rainfall amounts will be less than a tenth
  of an inch through the period.

- Warm and breezy on Thursday ahead of an incoming system that
  will bring additional showers along a cold front Thursday
  night into Friday.

- Temperatures fall back to near seasonal averages for the
  upcoming weekend, with only low rain chances - mainly on
  Saturday.

&&

.DISCUSSION...
Issued at 340 AM CDT Wed Oct 15 2025

Seeing spotty light showers and drizzle remaining across the area
very early this morning, with hi-res guidance suggesting this
continuing through at least mid to late morning. The overall trend
through the remainder of the day, however, will be for lessening
coverage with increasing subsidence as an upper level ridge
amplifies over the region. Additional rainfall amounts will average
less than 0.05" - and this would mainly occur during the morning.
Developing low pressure over CO will begin to usher warmer air
northward through the day, and temperatures this afternoon will be
15 to 20 degrees warmer than yesterday. Highs will range from the
lower to mid 60s north, to the 70s through the MO River corridor
where there may be more breaks in the clouds by afternoon.

Low pressure continues to deepen into western NE/SD tonight, and in
an increasing surface pressure gradient southeasterly winds will
begin to pick up overnight. Rainfall chances will remain low (20% or
less) for the much of tonight, though may bump up a bit (30-40%)
through our north and west later in the night as an elevated warm
front lifts to the north and a LLJ develops through central NE and
SD. It will be a milder night in response to the warm air advection
with lows in the 50s to lower 60s.

For Thursday through Friday, an upper level trough oriented through
the Rockies lifts into the Northern Plains through the period. At
the surface, the low pressure to our west lifts into ND and finally
into south central Canada by Friday, pulling a cold front through
our area as it does so. Out ahead of the front, a strong southerly
flow will result in a breezy day on Thursday, along with
temperatures climbing into the mid and upper 70s. Ensembles and
deterministic models continue to indicate the better rain chances
with this front occurring on Thursday evening as the main upper
level low ejects northward out of the trough - tracking over the
western Dakotas during this time frame and enhancing midlevel
frontogenesis west of Interstate 29. Current rainfall amounts during
this period are projected to average 0.2" to 0.3" west of I-29, with
ensembles on the lower end of this amount. Rainfall chances may
linger into Friday as the front finally sweeps through the area,
though rainfall amounts will most likely be less with appreciable
forcing weakening. With cold air advection behind the front,
temperatures will cool slightly for Friday with highs into the 60s
and lower 70s.

Much cooler temperatures push into the region for the upcoming
weekend as the upper level trough deepens over the Plains and
Mississippi Valley through the period. Could again see some low rain
chances for Saturday, with both the GFS and ECMWF showing upper
level energy tracking southeastward on the backside of the trough,
ending up in the Central Plains on Saturday. Temperatures for the
weekend look to be in the 60s, with lows in the 30s.

As we move into next week, confidence in the forecast becomes low
with increasing model divergence in solutions. While  the GFS would
indicate an upper level ridge building back over our region, both
the ECMWF and Canadian have a deepening trough through the Northern
Plains for the beginning of next week. Temperatures over our area
will be dependent on which solution verifies, though it does look
like a drier period for Monday and Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 600 AM CDT Wed Oct 15 2025

Widespread IFR/LIFR stratus expected through at least early
afternoon, with some improvement possible by late afternoon and
evening. Otherwise, areas of MVFR/IFR fog will persist through
mid to late morning, then improving by early afternoon. While
spotty showers and drizzle will occur through the morning,
chances will lessen during the afternoon into early tonight.

Although cloud coverage will lessen tonight, there could still
be areas of IFR ceilings. With a low level jet developing west
of Interstate 29 tonight, there will be a period of LLWS at KHON
overnight.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Dense Fog Advisory until 10 AM CDT this morning for SDZ050-052-
     057>059-063-064.
MN...Dense Fog Advisory until 10 AM CDT this morning for MNZ071-072-
     080-081-089-090-097.
IA...None.
NE...None.

&&

$$

DISCUSSION...JM
AVIATION...JM