065
FXUS63 KABR 231126 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
526 AM CST Sun Feb 23 2025

.KEY MESSAGES...

- A warming trend will continue with high temperatures 10 to 30
  degrees above normal through the middle of next week.

- Expect elevated fire weather conditions Monday afternoon, mainly
  over areas of central South Dakota that are currently snow free.

- Up to a 50 percent chance of rain Monday for far north central
  and all of northeast South Dakota. Isolated pockets of a mix in
  the morning, but overall mainly rain. Accumulations up to one
  tenth of an inch of rain are possible, but most areas will see
  less.

&&

.UPDATE...
Issued at 523 AM CST Sun Feb 23 2025

See updated aviation discussion below.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 308 AM CST Sun Feb 23 2025

Upper level northwest flow behind an exiting shortwave will be in
place over the region today. This flow will continue tonight, then a
fairly potent shortwave will approach Monday morning and track
across the CWA Monday afternoon.

At the surface, a low pressure trough will extend from central
Canada to New Mexico today, keeping warm west to southwest flow over
the region. The trough will track eastward tonight, leaving the CWA
between it and high pressure over the southern Rockies. Winds will
favor a westerly direction during the night. A secondary frontal
boundary associated with the same Canadian low, which will then be
over Hudson Bay, will track across the CWA on Monday, and in
association with the aforementioned upper shortwave, may be the
focus for precipitation. The best chances (35 to 55 percent) look to
be over central and eastern portions of the CWA. The precipitation
may start off as a bit of light snow or light freezing rain early
Monday morning, but that will be short lived as temperatures rise
and change it over to just rain from mid morning into the afternoon.
The other concern for Monday afternoon will be fire danger, mainly
across central South Dakota. Wind speeds will increase behind the
frontal boundary, with gusts of 30 to 40 mph possible along and west
of the Missouri River. Temperatures will be fairly warm for this
time of year, and in combination with a lack of snow cover and
relative humidity values of 30 to 40 percent, could see some fire
danger issues.

High temperatures today will range from the mid to upper 40s across
west central Minnesota and far northeastern South Dakota, to the
lower to mid 60s across south central South Dakota. Low temperatures
tonight will be in the lower to mid 30s. Highs on Monday will range
from the upper 40s across west central Minnesota, to the lower 60s
across south central South Dakota.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 308 AM CST Sun Feb 23 2025

NBM is showing a cool bias, especially after yesterday, and its
evident in the box and whisker plots for temperatures moving forward
so will take that into account with respect to temperatures in the
extended.  We start with one clipper system moving away from the
Dakotas and a second developing over the Northern Rockies. This will
make a beeline into South Dakota late Wednesday. Ahead of this
feature, low level flow shifts to southerly. 850mb temperatures
approach a standard deviation above climo, with the NBM probability
of exceeding 60 degrees at 70 percent along I-90 to about 20 percent
along highway 12.   The passage of a surface low will also cause a
shift in winds during the afternoon with a favorable southwest
component, and as such will apply about an across the board 3 degree
increase to the deterministic NBM for highs. The only caveat is the
cloud cover will also be on the increase in association with the
aforementioned shortwave. There will also be some light showers, but
were only running POPs at about 20-30%, even with a 50-50 shot at
exceeding 0.01 inches of moisture.

A cooler airmass moves overhead for Wednesday, however low level flow
is westerly/northwesterly and as such we can again expect
temperatures to overachieve.  Westerly flow continues into Thursday,
with milder air coming in from the Rockies. Timing is tricky, with
850mb temperatures increasing to a standard deviation above climo,
eventually, though the warmest of that may in fact be overnight.
Either way, we should again overachieve Thursday and again Friday
with a shift to weak cold air advection also aiding in mixing.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 523 AM CST Sun Feb 23 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area today and tonight. Low
level wind shear is possible from central South Dakota to the
James River Valley late this afternoon and tonight.

&&

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

$$

SHORT TERM...Parkin
LONG TERM...Connelly
AVIATION...Parkin