465
FXUS63 KABR 081912
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
112 PM CST Wed Jan 8 2025

.KEY MESSAGES...

- A clipper system will move across the area tonight through
Thursday delivering a round of light snow and pockets of freezing
rain. Accumulations of both will be minor.

- A system affecting the region Friday night through Saturday night
looks to bring snowfall to the area, with forecast accumulations
generally around 2 inches or less.

- An arctic blast (short-lived) returns Monday, with highs back down
into the single digits for many areas.

&&

.UPDATE...
Issued at 112 PM CST Wed Jan 8 2025

Light snow and fog were concerns during the morning hours, with
lesser concern this afternoon. Our focus is on temperatures,
winds, and precipitation chances tonight into Thursday. Area
webcams are showing little to no snow drifting across area
roadways over central SD. Little changes have been made to the
ongoing forecast.

&&

.SHORT TERM /TODAY THROUGH THURSDAY AFTERNOON/...
Issued at 415 AM CST Wed Jan 8 2025

The main focus in this term will be on an incoming clipper system
that will affect the forecast area tonight into tomorrow. Currently
still out ahead of that system now and during most of the daytime
hours today. Sfc high pressure will continue shifting away to the
south while a warm front traverses west to east across the Dakotas
today. Warm air advection shifts into our CWA with 925mb temps
warming into the single digits either side of zero C. Daytime highs
at the surface will get back to near/around normal with readings in
the mid 20s to mid 30s. If we can get some of that warmer air to set
up across parts of our western zones, it will be helpful in putting
a crust on some of the new snow pack. This will be important in
something we`ll get to in just a bit. Thickening high level
cloudiness will begin to filter out the sunshine as the day wears
on.

More of the deterministic/ensemble guidance along with some CAMs
have latched on to a speedier solution into the arrival of this
clipper system. We`ll begin to see some light perception enter our
northwest zones as early as this evening before it progresses south
and east through the overnight hours tonight. That warmer air just
off the surface, a shallow layer of the atmosphere above freezing
will pose some p-type issues for parts of our zones this evening
into the overnight. Currently anticipating some pockets of freezing
rain or a wintry mix to fall, which obviously could pose some
issues. NAM BUFKIT profiles at KPIR indicate that once we get the
column to saturate and precipitate, that shallow warm layer aloft
will be brief before cooling, thus curtailing the time freezing rain
would be possible. The ENS vertical profile data also more or less
confirms that scenario as well. Eventually, the cooler air will win
out and we should round out this system with all light snow
overnight through Thursday afternoon. Increasing northwesterly winds
behind the associated cold front passage will pose some blowing and
drifting snow issues, at least with respect to the snow that falls
during the event. The previously mentioned older snowpack could also
potentially blow around if we don`t get a crust on it from either
from the warm temps today or the initial period of some ice with the
clipper. This system is again another one of these higher PoP/low
QPF events. Not expecting much in the way of precip. Snowfall
amounts look minor for most(1 inch or less). However, portions of
the windward side of the Prairie Coteau could see some uphill
enhancement flow resulting in a pocket of 2-3 inches.

&&

.LONG TERM /THURSDAY EVENING THROUGH TUESDAY/...
Issued at 415 AM CST Wed Jan 8 2025

Shortwave energy looks to be passing off to our east Thursday night
into Friday. At the surface, a high pressure ridge quickly moves
eastward over the region on Friday. During this time, weather looks
to be rather benign with near average temperatures.

Main area of focus in the extended enters the picture Friday night
and Saturday as a surface low drops southeast out of Canada and
across the Dakotas. There`s now fairly good agreement amongst the
ensemble camps (and even deterministic solutions) in regards to the
surface low track, which takes it southeast right through the CWA.
Overall, QPF still seems rather light with this event, generally
under 0.25in. Although, there are some signs for potentially higher
amounts across the eastern CWA as the NBM shows about 20-25% chance
for greater than 0.25in. Grand Ensemble probs for >0.25in are a bit
lower, around 5-10%. Generally looking at all snow with this system,
but initially during the day Saturday there could be a mix across
central SD depending on the exact track of the low and just how far
east the warm air advection push advances into the central part of
the state.

Still rather good agreement noted in regards to the cold air
returning Sunday into Monday. At 18Z Monday, GEPS/GEFS/ENS all show
925mb temps ranging from around -17C to -22C across the eastern CWA
where the coldest of the air looks to reside. Forecast high temps on
Monday have come down several degrees compared to 24 hours ago, with
readings now only in the low/mid single digits across the eastern
CWA.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 112 PM CST Wed Jan 8 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are occurring at all locations, and will stay that
way until around 07Z when light snow (with freezing rain or rain
also possible as temperatures hover near freezing until around
15Z). Patchy blowing snow will be possible while snow is falling,
and may be added to the TAFs as the time nears. Winds will gust
out of the northwest 25-35mph during the day Thursday over central
SD (PIR/MBG). MVFR to IFR conditions with lower ceilings will
shift across ABR/ATY too after 12Z.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...KF
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...KF