041
FXUS63 KFSD 220431
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1031 PM CST Thu Nov 21 2024

.KEY MESSAGES...

- Some patchy dense fog is possible this morning. Any fog that
  forms is expected to be shallow, and burn off shortly after
  sunrise.

- Dry conditions are expected for the rest of the week and
  weekend. High temperatures will warm back to the 30s and 40s
  Friday through Sunday.

- A colder holiday week is expected with high temperatures very
  likely (90%+ chance) to remain below 32 degrees F. Light
  precipitation is possible (40-70% chance) Wednesday and
  Thursday, though this chance can change with time.

&&

.DISCUSSION...
Issued at 236 PM CST Thu Nov 21 2024

Quiet conditions persist across the forecast area this afternoon.
Surface ridging is sliding through the Northern Plains, which is
pushing the tightest surface pressure gradient (SPG) east of the
area. This will put an end to the breezy conditions that locations
east of I-29 are currently seeing by this evening. Overnight low
temperatures look to fall to the teens to low 20s but could fall
further if efficient radiational cooling is achieved. The main
caveat stopping this is upper level cirrus that will push into the
Northern Plains tonight. IF efficient radiation cooling is achieved
tonight, fog will also be possible. Think that it will most likely
be west of I-29 due to the recent snowpack that fell yesterday.

Friday will see a continuation of quiet conditions as the previously
mentioned surface ridging sits over the area. With upper level
ridging aloft, high temperatures will warm to the mid 30s to upper
40s, warmest across south central South Dakota. With the riding in
place, winds will be light and variable throughout the day. Low
temperatures will fall to upper teens and 20s overnight.

Dry conditions look to persist through the weekend due to lacking
moisture across the area. However, an upper level jet will push into
the region, resulting in warm air advection (WAA) aloft. The WAA
will push 850 mb temperatures up to the single digits on Saturday
and may reach up to the low teens on Sunday. Winds will be light,
out of the southeast on Saturday but a surface trough will push
through the area on Sunday, turning the winds to out of the
northwest. This will bring a return of breezy winds with gusts up to
about 30 mph possible. Low temperatures will fall to 20s and 30s
Saturday night and teens to 20s Sunday night.

A colder airmass looks to usher into the Northern Plains for the
majority of next week. This airmass may be the first one to feel
much more winter like as below average high temperatures are likely.
Ensembles support this as they show a near 100% chance for
temperatures to be below 32 degrees F Monday through Thursday. Winds
look to be on the lighter side but any wind will result in cold wind
chills, potential down to the teens F. While the beginning of next
week looks dry, could see a return of precipitation on Wednesday and
Thursday. As of now, any precipitation that may fall looks to be
light, with only a 40-70% chance for exceeding a hundredth of an
inch per ensemble analysis. Will certainly keep an eye on any light
precipitation for this period of time. All in all, the holiday week
looks to be cold with some potential for light precipitation right
before and on Thanksgiving day.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1030 PM CST Thu Nov 21 2024

Winds will be light and variable with VFR conditions for the period
at the three TAF sites. A narrow north/south oriented deck of
stratus is present over western Minnesota and Iowa. Under this deck
MVFR ceilings around 2000 ft AGL are present. These clouds
should slowly erode over the next few hours.

Patchy dense fog is possible this morning, but confidence in
formation is low due to a cirrus deck that looks to move into the
area after 22.08Z. These high clouds may be enough to prevent fog
formation. If any fog should develop, it is expected to be shallow
and burn off shortly after sunrise.

&&

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

&&

$$

DISCUSSION...AJP
AVIATION...Meyers