144
FXUS63 KABR 131128 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
528 AM CST Mon Jan 13 2025

.KEY MESSAGES...

- Light snow west of the Missouri River late this afternoon and
tonight, with accumulations up to 1.5 inches.

- Roller coaster temperatures next several days, starting below
average by about 10 to 20 degrees through Tuesday. Mild air returns
with average temperatures 10 to 25 degrees above normal until
Friday. The next Arctic blast comes with readings 10 to 25 degrees
below normal for next weekend and well into next week.

&&

.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 420 AM CST Mon Jan 13 2025

A backdoor cold front dives into the northeast with advancing sfc
high pressure and an upper low over northern MN slinging a vort max
into the Dakotas. These features reinforce the cold air over the
region today and Tuesday. On the southwest edge of the sfc high, a
weak baroclinic zone sets up this afternoon into tonight. Locations
in that zone from Eagle Butte to Lyman county will see some light
snow develop. Generally, less than an inch of snow is expected.
However, there is the potential (25 to 50 percent chance) of patchy
higher amounts up to 2.5 inches. Confidence is low on exactly where
those higher amounts could be or if they will actually develop in
this forecast area at all.

Other than west river, dry conditions are expected through Tuesday
with high pressure settling in. Drier air across the east under the
high will lead to few clouds and good radiational cooling overnight.
Lows should easily fall into the negative teens by Tuesday morning
east of the Missouri, especially in areas that have snow on the
ground. There will be a steep temp gradient between west central MN
and areas west river both today and Tuesday with highs topping out
10 to 15 degrees below average, ranging from the single digits to
the lower 20s.

&&

.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 420 AM CST Mon Jan 13 2025

A mostly dry forecast with a clipper that will move well east of the
region, placing a gradient with westerly winds across the area
Wednesday. 1/2km winds are about 20 to 30kts and NBM 25th/75th
percentiles for wind gusts range from 20 to 30mph meaning there is a
high confidence that we`ll mix out this Arctic airmass, though how
warm we can expect to get is still a little uncertain as there is
about a 8 degree spread in the 25th/75th percentiles for high
temperatures. Thursday will remain mild with 850mb temperatures
briefly topping a standard deviation above climo. Only issue here
may be that while it is warm aloft, winds are not as strong and more
of a southerly component, so conceptually that would suggest a
favorable environment for fog/stratus development with all this new
light snow/moisture now on the ground.

For the system on Friday, while there is little model QPF, likely
correlated to the split flow setup, we cant rule out some light
snow. The main story though will be the cold frontal passage that
follows. NBM 25th/75th percentile winds increase to between the
upper 20mph to low 40mph range so already we`ll be looking into the
potential gusty winds but also the degree of cold air that follows.
850mb temperatures drop to a standard deviation below climo Saturday
and 2 standard deviations below for Sunday/Monday. This next Arctic
outbreak runs though the end of the NAEFS and well into the less
reliable past the 7 days range of deterministic models suggesting it
will be colder and longer lived in comparison to some of our more
recent Arctic outbreaks. It may be tempered, however, by the lack of
snow cover since we will have a few days of near/above freezing
temperatures between now and then.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 527 AM CST Mon Jan 13 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail at all sites except KPIR through the
period. MVFR cigs will move into KPIR this afternoon as some snow
develops to the west and south of KPIR. Conditions will then
improve again after 06z Tuesday.

&&

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

$$

SHORT TERM...Wise
LONG TERM...Connelly
AVIATION...Wise