067
FXUS63 KFSD 241136
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
536 AM CST Mon Nov 24 2025

.KEY MESSAGES...

- Patchy to areas of fog is possible over far southeastern South
  Dakota through northwestern Iowa through Tuesday morning.

- Light rain will continue mainly south of a line from Lake
  Andes through Sioux Falls and Westbrook and end west to east
  through the day today.

- Much colder temperatures will move into the region on Tuesday,
  leading to temperatures being 10 degrees below normal through
  next weekend.

- light rain returns to east central South Dakota Tuesday, and
  changes over to light snow during the daytime hours. There is
  a 30 percent chance of 1 inch of snow or greater Tuesday
  through Tuesday night near and north of a line from Huron to
  Brookings and Marshall.

- Winds gusts of 30 to near 50 mph are expected Tuesday.
  Stronger winds gusting up to 60 mph will be possible over
  Gregory County of south central South Dakota, where the strong
  winds and little to no precipitation will result in High
  Grassland Fire Danger Index values Tuesday.

&&

.DISCUSSION...
Issued at 437 AM CST Mon Nov 24 2025

The surface weather map shows low pressure over western KS.
Farther to the north there is a cold front draped over the
northern half of SD, stretching to a low across Ontario. Light
rain will continue mainly south of a line from Lake Andes
through Sioux Falls and Westbrook and end west to east through
the day today. Total rainfall amounts of around a tenth to a
quarter of an inch will be possible from Yankton through far
northeastern Nebraska and northwestern Iowa.

Mainly dry weather is forecast this evening before light rain
returns to east central South Dakota by daybreak Tuesday, and
much of the rest of the area during the day Tuesday. This will
be as the next low over MT/WY shifts across SD and deepens over
MN/WI Tuesday. Dry weather is currently expected for our far
northeastern NE counties. Cold air pushing in will result in
rain changing over to light snow during the daytime hours
Tuesday. There is a 30 percent chance of 1 inch of snow or
greater Tuesday through Tuesday night near and north of a line
from Huron to Brookings and Marshall. Winds will increase
Tuesday, with gusts of 30 to near 50 mph. Stronger winds gusting
up to 60 mph will be possible over Gregory County of south
central South Dakota Tuesday. As a result, a High Wind Watch has
been issued for portions of south central SD Tuesday (Gregory
County). The strong winds and little to no precipitation will
result in High Grassland Fire Danger Index values Tuesday for
portions of south central South Dakota.

Snow is forecast to move out of eastern SD, southwest MN, and
northwest IA Tuesday night, with some patchy areas of blowing snow
having to potential to continue into Wednesday morning over
northeastern SD. In the upper-level, northwest flow will be over the
area Wednesday and Thursday, which will continue to advect cold air
through the atmosphere into central and eastern SD, northeast NE,
southwest MN, and northwest IA. This CAA will cause temperatures to
drop to be 5-10 degrees below normal by Thanksgiving and stay cold
through the weekend. At the surface, high pressure is forecast to
move over the area Wednesday and stay through the day Thursday,
helping to keep precipitation out during that time. The stronger
winds Tuesday will slowly move over eastern SD, southwest MN,
northeast NE, and northwest IA Tuesday night while decreasing its
speed. The winds will continue to decrease through the day
Wednesday, though some stronger wind gusts along the eastern edge of
the Prairie Coteau from some downslope winds and to the east could
be a bit stronger. There is a 30-60% chance for winds to gust over
30mph overnight into Wednesday morning over and east of the Prairie
Coteau (highest long in northeastern SD along the eastern edge of
the Coteau). By the afternoon, the probability for gusts over 30mph
decreases to 20-40% before dropping off after sunset over eastern
SD, southwest MN, and northwest IA.

Starting Thursday night/Friday morning, things become a bit more
uncertain as there is a lot of variability in the models. Thursday
night into Friday morning, some of the models are showing a line of
WAA aloft on the back side of the high pressure. This WAA looks to
help with the development of a band of snow that then moves over
central and eastern SD, northeast NE, southwest MN, and northwest IA
during the day Friday. As with the nature of banded snow event,
there is a lot of variability in location and track of the band as
well as snowfall amounts. After the band of snow moves through, the
variability continues in the models, as some have shortwaves that
push more snow through the area during the weekend and other models
don`t. An eye will need to be kept on this time to see if future
model runs decrease uncertainty for these events as there could be
many traveling after Thanksgiving that could be impacted.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 536 AM CST Mon Nov 24 2025

VFR conditions are forecast to continue at HON and FSD. Light
rain will stay mainly south of FSD this morning, but may be able
to move in from 15-20Z today. Confidence was low on the
potential, so a PROB30 was added. Fog looks to stay mainly south
of the FSD site. At SUX light rain this morning will bring MVFR
ceilings and visibility as early as 15Z, and IFR ceilings by
17Z which will continue through the TAF period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Watch from Tuesday morning through Tuesday afternoon
     for SDZ050.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...06/12
AVIATION...06