877
FXUS63 KFSD 101118
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
518 AM CST Fri Jan 10 2025

.KEY MESSAGES...

- Cloud cover lingers Friday, with a few flurries through the
  daytime hours.

- Temperatures warm well above normal Saturday as another winter
  system arrives. Highs are likely to push the 75th percentile
  of the NBM (mid 30s to 40s).

- Confidence remains high that precipitation amounts remain
  light with this weekends system. Probabilities of 0.01" are
  only 40-50%, with less than 10% probability of 0.10".

- An arctic front moves in early Sunday, bringing much colder
  air to start next week, with lingering flurries into early
  Monday.

- A few days of dry and colder weather moves in to start next
  week, with 100% probability of below normal temperatures
  (based on ensemble guidance), through Tuesday. A couple
  nights of below zero temperatures possible.

- Above normal temperatures favored into next weekend.

&&

.DISCUSSION...
Issued at 158 AM CST Fri Jan 10 2025

THIS MORNING:  Stratus continues east of I-29 this morning, as
temperatures fall into the teens.  However, the next round of
stratus over northern South Dakota is quickly dropping southeast,
and will likely stability the fall of temperatures by daybreak.

TODAY: The western flank of an upper trough over the Great Lakes
region will pivot eastward and through the area on Friday.  Stratus
will reside in the -12 to -16C range especially east of the James
River, leading to potential flurries through the daytime hours. High
temperatures approach the middle 20s in many areas.

TONIGHT: Winds turn light and variable during the first half of the
overnight hours, gradually turning southwest as low-lvl warm
advection increases.  After an initial drop in temperatures, some
stabilization or even rise in temperatures may be possible into
daybreak.

SATURDAY-SUNDAY: Really no major changes in the ongoing forecast for
this weekend.  A positively tilted upper trough crosses the Rockies
and enters the Plains on Saturday.  Broad warm advection begins in
earnest early in the day, increasing mid-lvl cloud cover. Surface
low pressure develops over central South Dakota and tracks eastward
into Minnesota by Saturday evening and without any snow cover,
temperatures may surge well into the 30s and towards the 40 degree
mark.  However, this system continues to lack sufficient moisture to
produce widespread precipitation into Saturday night. In fact, NBM
probabilities of 0.01" of QPF are only around 40 to 50%, with
probabilities of 0.10" only around 10% along the Highway 14 corridor
and into the Buffalo Ridge.  Any snow accumulation should remain
from a dusting to a half inch. Models remain in strong agreement
that an arctic front begins to move southeast across the area during
the day on Sunday. Flurries to occasional light snow will accompany
this front, and have increased PoPs slightly and these may be
increased further in later updates. Any accumulation Sunday should
remain very light. Soundings suggest a period of wind gusts
approaching 25 to 30 knots behind the front.

MONDAY-THURSDAY:  Sharp northerly flow arrives for the first few
days of the work week.  Ensemble probabilities continues to support
high confidence in below normal temperatures through at least
Tuesday, with below zero temperatures possible both Monday and
Tuesday nights.   It`s not impossible to see a few scattered snow
showers both Monday night and Tuesday evening as subtle shortwaves
move through the sharp northerly mid-lvl flow.    Uncertainty grows
for the middle of the week as medium range guidance struggles on how
quickly to build mid-lvl ridging eastward.  The NBM 25-75th
percentile spread is nearly 15 degrees on Wednesday, and around
10 degrees for Thursday and Friday. The positive is that by
Thursday and Friday the 25th percentile guidance remains 5+
degrees above normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 516 AM CST Fri Jan 10 2025

Stratus will continue to sink southward this morning, gradually
lowering to MVFR levels in most areas east of the James River. A
few flurries may be possible at times late this morning through
the evening hours. However now visibility restrictions are
anticipated.

Stratus lingers along the Buffalo Ridge this evening before
shifting away. However mid-lvl clouds thicken into Saturday
morning as surface winds go from variable to southerly.

&&

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

&&

$$

DISCUSSION...Dux
AVIATION...Dux