583
FXUS63 KFSD 120855
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
255 AM CST Wed Nov 12 2025

.KEY MESSAGES...

- Fog may develop in river valleys this morning, with a 40%
  chance or less of visibility below one mile. Valley fog is
  possible again Thursday and Friday mornings.

- Well above average temperatures continue into the weekend with
  the warmest temperatures Friday. Temperatures moderate near
  seasonal early next week.

- Drier conditions will persist into the weekend with our next
  precipitation chances (20%-40%) returning early next week.

&&

.DISCUSSION...
Issued at 251 AM CST Wed Nov 12 2025

THROUGH TONIGHT: Cirrus clouds continue to stream southeast this
morning across central SD and across eastern SD into northwestern
IA. Temperatures through 3 AM are in the 30s, and we should drop a
few more degrees before daybreak. Will be watching for fog
development in river valleys through the mid morning hours. HREF
probability of visibility below 1 mile is 40% or less. Be prepared
for some patchy fog during the morning commute.

A little breezy this afternoon, mainly along the higher elevations
of the Buffalo Ridge where we mix into the stronger LLJ. Not quite
as warm today with northwesterly flow and cooler temperatures aloft;
however, warmed highs by a few degrees across the area given how
dramatically we exceeded forecast highs yesterday even with snow
pack. Highs today in the 50s. Expect a mix of clouds and sun through
the day, with clouds increasing tonight. Lows fall into 30s. Can`t
rule out some patchy valley fog tonight as well.

THURSDAY-FRIDAY: Ridging moves east through the end of the week,
with the ridge axis overhead Friday. A couple weak perturbations
track through the synoptic flow, but conditions remain dry with a
lack of moisture. Prevailing southerly low level flow and WAA with
the building ridge allows for well above average temperatures. Highs
by Friday warm into the 60s and even 70s with overnight lows in the
upper 30s to mid 40s (averages are the mid 40s for highs and mid 20s
for lows).

May see some valley fog Thursday and Friday mornings if winds remain
on the lighter side. Breezy Friday with the compressed surface
pressure gradient and more efficient mixing. This may lead to some
areas of elevated fire danger especially for south central SD given
we`ll have had a few days to dry out and our well above average
temperatures.

FRIDAY NIGHT-TUESDAY: More active pattern returns for the weekend
and into early next week, although guidance continues to vary on
timing/track of troughs/low pressures. Surface cold front and wave
aloft move through late Friday night into Saturday, with the 12.00z
ECMWF the quickest in moving this through. Probability of measurable
precipitation during this time is low (less than 20%) and confined
to north of I-90 toward US Hwy 14. Saturday may also see elevated
fire danger due to breezy winds, although RH values remain above
critical.

Short lived ridge builds in for Saturday night through Sunday with
troughing sweeping through the Midwest. 12.00z guidance has
continued to trend slower with the wave early next week, with the
GFS/ECMWF leaning toward an open wave with the Canadian bringing a
closed low into the Plains Monday evening. This continues to be our
next best chance of precipitation, with NBM pops now in the 20-40%
range late Sunday night into Monday. At this time, measurable
precipitation is likely (probability over 60%), with moderate (40-
60%) chances of more than a tenth of an inch. Temperatures may be
cold enough for some light accumulation of snow, although confidence
in p-type is low at this time given the differences in model track.
Temperatures through early next week moderate back to near seasonal
normals.


&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1037 PM CST Tue Nov 11 2025

VFR conditions are expected for the TAF period. Light west/northwest
winds will persist through the night. Confidence has increased in
fog developing along the James River and Missouri River valley`s,
along with other bodies of water. Thus, have included reduced
visibility and BR in KHON and KSUX`s TAFs. Will keep an eye on
trends to see if the timing of onset of fog/mist needs to be
adjusted. Any fog that does develop will burn off during the morning
hours. Winds will go light and variable during the afternoon hours
tomorrow and remain that way for the rest of the TAF period.

&&

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

&&

$$

DISCUSSION...SG
AVIATION...Meyers