High Wind in South Dakota, December 8, 2023

Area Forecast Discussion
National Weather Service Aberdeen SD
333 AM CST Fri Dec 8 2023

.KEY MESSAGES...

- Windy tonight through Saturday morning (peak gusts 45-50 mph).

- No change in overall snow totals from yesterday afternoon forecast
package which included a potential range of trace to over 3 inches
(peak in the northwest Sisseton hills).

- Snowfall timing ranges from late this afternoon (Mobridge area) to
overnight (Sisseton hills) with a duration of about 6-8 hours.

- Combined wind and falling snow may have an impact on travel
Tonight/Saturday morning (low visibility/icy roads).

- Quiet extended right now. Warmer more often than it's cold between
Saturday night and Thursday.

&&

.SHORT TERM /Today through Saturday Afternoon/...
Issued at 332 AM CST Fri Dec 8 2023

Showers extend to just about the ND/SD state line north of Mobridge,
otherwise winds are the main story this morning. Peak winds were
58mph at Pierre, with low 50s/upper 40 mph gusts over the last 6
hours. Model winds show a trend of a slight diminishment through the
remainder of the morning, after which we'll see a slight enhancement
thanks to favorable mixing in cold advection/steep low level lapse
rates and a persistent pressure gradient (12-14mb from northeast to
southwest) and weak pressure rises. A secondary trough rotates
around the surface low later this afternoon/evening, with an
enhancement of the gradient (now up to 16mb across the state from
northeast to southwest) which also slightly enhances the already
modest pressure rises (up to 8mb/6 hours). CAMS and particularly the
NBM show high enough probabilities for exceeding advisory criteria
under a favorable environment to support continuation of the wind
advisory through tonight into Saturday.

The main wrinkle in the forecast comes from a TROWAL that migrates
out of North Dakota later today, and across the CWA from west to
east before weakening as it reaches western Minnesota. GEFS mean QPF
for most stations is around 0.1 to 0.2 inches liquid. BUFKIT
profiles show lift in the dendritic growth zone, though peak lift is
somewhat below that, along with relatively deep dendritic grow zones
of about 6kft. Not completely ideal collocation of lift and
breakup/impaction from wind will probably undercut the NBM snow
ratios of 14-16:1 overall NBM really doesn't much change forecast
snowfall amounts, and neither does the suite of CAMS.  With winds in
the 40-50mph range and light/moderate snow, travel impacts are the
main concern. Added a winter weather advisory to highlight travel
impacts from the combination of winds and falling snow, though snow
totals should be low enough that catch in grass/ditches will keep
any snow on the ground from continuing to blow enough to present a
hazard.

&&

.LONG TERM /Saturday Evening through Thursday/...
Issued at 332 AM CST Fri Dec 8 2023

Right now, the extended is a dry forecast. Northwest flow over the
CWA persists through Wednesday. The latest 500hpa height progs
suggest that some sort of Rex block pattern takes over beyond that,
developing out over the Rockies by mid-week and then eventually
making its way over into the nation's mid-section by week's end.

With surface high pressure quickly taking over Saturday night,
dropping winds to calm or light and variable by daybreak on Sunday,
if skies are clear, low temperatures dipping into the teens may be
too warm, particularly for areas with a fresh, albeit light, coating
of snow on the ground, especially further north in the CWA closer to
the border of the Dakotas.

Weak low level WAA begins on Sunday and persists into Monday before
the next clipper system's cold front comes barreling south into the
CWA, turning things colder again for Tuesday. But, models are
progging low level WAA to start back up again for Wednesday and
Thursday.

&&

.AVIATION /06Z TAFS through 06Z Friday/...
Issued at 1125 PM CST Thu Dec 7 2023

Terminals KABR,KATY,KPIR,KMBG

MVFR CIGs will gradually increase across the region, especially
during the daylight hours on Friday. Strong westerly surface winds
will also occur through the period, more so across KPIR/KMBG. Will
also be watching an area of -SN/SN moving east into the area
Friday afternoon and evening, with IFR/MVFR VSBY.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 6 AM CST /5 AM MST/ Saturday for SDZ003-015-
     033>037-045-048-051.

     Wind Advisory until 6 PM CST this evening for SDZ004-005-009-010-
     016-017.

     Winter Weather Advisory from 6 PM this evening to 6 AM CST
     Saturday for SDZ004-005-009-010-016-017.

     Wind Advisory until 9 PM CST this evening for SDZ006>008-011-018-
     019.

     Winter Weather Advisory from 9 PM this evening to 9 AM CST
     Saturday for SDZ006>008-011-018-019.

     Wind Advisory until 9 AM CST Saturday for SDZ020>023.

MN...None.
&&

SHORT TERM...Connelly
LONG TERM...Dorn
AVIATION...TMT

Hazardous Weather Outlook
National Weather Service Aberdeen SD
400 AM CST Fri Dec 8 2023

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-091000-
Traverse-Big Stone-Corson-Campbell-McPherson-Brown-Marshall-Roberts-
Walworth-Edmunds-Day-Dewey-Potter-Faulk-Spink-Clark-Codington-Grant-
Hamlin-Deuel-Stanley-Sully-Hughes-Hyde-Hand-Jones-Lyman-Buffalo-
400 AM CST Fri Dec 8 2023 /300 AM MST Fri Dec 8 2023/

This Hazardous Weather Outlook is for west central Minnesota,
central South Dakota, north central South Dakota and northeast
South Dakota.

.DAY ONE...Today and tonight.

Gusty winds will persist today, on the order of 40 to 55mph. An area
of snow will follow for tonight. The combination of light to
moderate snow and strong winds could potential result in hazardous
travel conditions along and to the north of Highway 212 from the
Missouri river to the Sisseton hills. The main threats consist of
low visibility and the combination of icy roads and winds.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Winds and snow diminish during the day Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be requested. Weather spotters are encouraged
to submit reports to the National Weather Service in Aberdeen. The
public can submit reports on our web page, Facebook page, or our
Twitter feed.

Connelly