236
FXUS63 KFSD 160838
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
338 AM CDT Thu Oct 16 2025

.KEY MESSAGES...

- Although some fog remains across the area very early this
  morning, visibilities continue to improve across the area.

- Warm and breezy today ahead of an incoming cold front. This
  front will bring a chance for rain showers west of the James
  River today, then moving west to east for tonight. Total
  rainfall accumulation will generally range from 0.2" to 0.4".

- Temperatures Friday drop to more seasonable values, with
  highs by this weekend in the mid 50s to mid 60s.

- There is a 20 to 40 percent chance for additional rain showers
  Saturday before a drier period Sunday into early next week.

&&

.DISCUSSION...
Issued at 335 AM CDT Thu Oct 16 2025

A warm front continues to lift northward across our area very early
this morning, resulting in rapid improvement in visibilities with
the passage of the front. Was able to cancel the southern tier of
our Dense Fog Advisory earlier, and will continue to monitor
conditions for possible early cancellation of the remaining advisory
through east central SD and southwestern MN. Showers and isolated
thunderstorms which developed along the front earlier are now
pushing out of our area, though may continue to see scattered light
activity west of the James River through the morning - this in
association with midlevel theta e advection related to a LLJ
streaming through central SD. Temperatures have been slowly rising
across the area through the night as the front lifted northward,
with current readings in the upper 50s to mid 60s, and we are on
track to a breezy and much warmer day with highs in the upper 70s to
lower 80s.

Synoptically, a closed upper level low presently situated over UT
tracks northward into the western Dakotas by this evening, while
surface low pressure deepens from CO northward through the central
portions of NE and the Dakotas. This will keep low rain chances (20-
30%) from the James River Valley and westward into later this
afternoon as an associated frontal boundary slowly pushes eastward
through central SD. Rainfall chances then increase by later this
afternoon into this evening as the front pushes into our area and
lifts increases in response to the aforementioned upper level low
approaching from the west. Although isolated to scattered
thunderstorms will be possible through this time period, not
expecting anything severe with CAPE values generally running less
than 500 J/KG. Shower and thunderstorm chances then wane later
tonight as the better forcing lifts off to the north. In terms of
rainfall amounts for today into the first half of tonight, looking
at average amounts of 0.2" to 0.4" west of Interstate 29 - with only
minor amounts to the east of there.

The front continues to push across our area on Friday - exiting to
the east by Friday evening. Little additional rainfall is expected
with the front. Cooler air will begin to feed into the region behind
the front, with highs in the 60s and 70s.

Almost all guidance brings another chance of light rain on Saturday
as upper level energy over the Northern Rockies dives southward into
the Northern/Central Plains during the day, and a secondary frontal
boundary pushes across our area. Any rainfall amounts look light,
with ensembles supporting only a few hundredths of an inch at best.
Temperatures continue to cool on Saturday with highs only in the 50s
and 60s.

Models are now in a little better agreement on the The weather
pattern for the beginning of next week, with brief upper level
ridging moving across the region for Sunday into early Monday. This
will bring temperatures back into the 60s to near 70 on those days.
It looks to be dry through the period. Behind this, another upper
level trough dives southward for mid week, bringing cooler
temperatures for Tuesday and Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1029 PM CDT Wed Oct 15 2025

Scattered light showers are ongoing over northwestern Iowa. Showers
gradually taper off over the next few hours. Additional chances
for scattered showers west of Highway 81 Thursday morning. Another
round of showers and possibly an isolated thunderstorm is possible
Thursday afternoon beginning over central South Dakota and
moving east into the late afternoon.

Dense fog has developed across much of the region, especially areas
along and north of I-90. Visibility and ceilings are down to LIFR to
IFR in this area as well. To the south fog is patchy and in low
laying areas. Fog is expected to burn off by about 16.15Z from south
to north.

Southeasterly winds will be breezy overnight, then increase and
become southerly after daybreak. Gusts of 20-24 kts will
increase to 25-29 kts. LLWS is possible at all three sites.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Dense Fog Advisory until 10 AM CDT this morning for SDZ039-040-
     054>056.
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...AJP