280
FXUS63 KABR 110853
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
353 AM CDT Tue Mar 11 2025

.KEY MESSAGES...

- Temperatures warming back to above average Wednesday and Thursday,
with highs on Thursday around 30 to 35 degrees above normal.

- A storm system will be moving through the central plains into the
northern plains Friday and Saturday. The eastern half of the
forecast area, generally from the James River valley eastward, may
be experiencing rain changing to snow and windy conditions too. The
system`s track and timing are still being refined. This will
determine precipitation type/change-over from one type to another as
well as strength of wind component.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
Issued at 353 AM CDT Tue Mar 11 2025

As of 330AM north winds are sustained between 10-15mph and temps in
the upper teens to the mid 20s over the CWA. Slight northwest flow
aloft this morning will switch to zonal flow as a slight negative
tilted ridge sets up to our west, with the crest of the ridge over
the western Canadian territories and southeastward through the PacNW
by 00Z Wednesday. This ridge will gradually amplify over western
Canada and shift a bit east through the short term, bringing in
warmer air for Wednesday. At the surface a 1020mb high pressure
system will be the dominant over the region, with the center of the
high over northern ND/MN border by 12Z. It will then push east
through the day as it is forecasted to be over the Great Lakes
Region by 00Z Wednesday. Pressure gradients steepen up a bit over
western to central SD as a weak lee low forms over southwest
SD/northwestern NE this evening. With this and weak mixing, winds
will increase a bit over central SD with gusts between 15-25kts out
of the south, highest over Corson/Dewey Counties. This low will
shift ever so slightly northeast through the night before fizzling
out. It does look like winds pick up a bit over and downslope of the
Coteau overnight as winds will be out of the south/southwest, with
gusts up to 20kts before diminishing by 12Z. A surface ridge builds
over the area for Wednesday into Wednesday evening in conjunction
with the upper level ridge.

What a difference it will be between today and yesterday! We broke
record high temps Monday at KABR/K8D3/KMBG/KATY and tied at KPIR as
temps were in the upper 60s to the mid 70s. With the high and CAA,
925mb temps by this afternoon will range from -1C over far
northeastern SD up to +11C over south central SD (more WAA and
further away from the high). As the high moves out, a bit warmer air
over northeastern SD moves in tonight with temps at this height
around +4 to +5C by 12Z Wednesday. With daytime heating and some
mixing (mixing levels are much lower) highs will range in the 40s to
lower to mid 50s, warmest over south centrals SD with lows in the
upper 20s to around 30. This runs about 5-8 degrees above. Warmer
air from the ridge will allow temps to recover nicely for Wednesday
at 925mb, which range from +8 to 15C, again warmest over central SD.
Highs will jump back up in the upper 50s to the lower 60s, running
about 15 to 20 degrees above average.

&&

.LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/...
Issued at 353 AM CDT Tue Mar 11 2025

The period opens Wednesday night with a return flow surface pressure
pattern unfolding across the region, continuing into Thursday
night/early Friday morning. There`s an upper level ridge aloft
working through the region during this time as well, with west-
northwest flow Wednesday night eventually becoming nearly meridional
southerly flow rolling into Friday in response to the large upper
level longwave trof that is progged to be making steady progress
moving onto the west coast (Wednesday night) and over the desert
southwest/intermountain west (Thursday/Thursday night) before
lifting out onto the plains Friday.

The probability of seeing measurable precipitation happen over this
CWA prior to 00Z Saturday continues to decrease. QPF clusters
analysis has pretty much taken qpf off the board for Friday,
although, still can`t rule out a renegade pocket or two of showery-
type precipitation developing within the preliminary deformation
zone. Still carrying a 35 to 50 percent chance of precipitation on
Friday. With the upper level low track/timing looking quite similar
to the low track/timing of 24 hours ago, it appears that a more
potentially significant deformation zone-forced banded precipitation
event is setting up across eastern Nebraska up into far eastern
South Dakota Friday night into Saturday morning. But, again, with
temperatures warm enough for p-type to start out as rain, not
looking at snow accum potential as high as there could be if the
whole system was starting out colder and p-type Friday night into
Saturday were all snow. QPF clusters is highlighting a general 0.25
to 0.50+ in of water equivalent across the far eastern forecast
zones under this deformation zone precipitation area. There is still
some indication in the NBM ensemble that a moving corridor of
transition p-type from rain to (briefly) freezing rain and then snow
Friday night into Saturday morning. The probability of 3 or more
inches of snow is currently highlighting far northeast South Dakota
(east of the James River valley) into west central Minnesota between
7 PM CDT Friday and 7 PM CDT Saturday with an appx 30-60 percent
chance. Timing it out, it would be more like from between 4 AM CDT
Saturday and 7 PM CDT Saturday for the eastern portion of the CWA to
see p-type as snow and any snow accumulation.

As for wind, models and guidance do continue to showcase something
on the order of 20 to 35 mph with gusts to 45 to 50 mph developing
throughout the Missouri River valley by late Friday afternoon and
slowly expanding over into west central Minnesota Saturday morning,
before a west to east decrease in winds from late Saturday afternoon
through early Sunday morning. Without much in the way for
precipitation across the CWA on Friday, it just looks like a windy
day developing out west, but then at some point Friday night windy
rain is supposed to become wind-blown falling/blowing snow. And that
would be when/where (between the Missouri and James river valleys?)
hazardous traveling conditions/weather would start and maintain
until some point Saturday evening/night. Falling snow is expected to
be done by late Saturday afternoon/early evening, but the wind will
take longer to diminish.

Behind this system, Sunday and Monday look dry and cool with a ridge
of high pressure aloft setting up. Models indicate some low level
WAA trying to establish, once more, across the region, but will have
to deal with any fresh new snow on the ground first.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1218 AM CDT Tue Mar 11 2025

Terminals KABR,KATY,KPIR,KMBG

Broken to scattered mid to high clouds are positioned west to
east over the ND/SD border and will gradually shift east to
southeast. More clouds will move in from the west this afternoon
and evening. VFR conditions will continue through the TAF period.


&&

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

$$

SHORT TERM...MMM
LONG TERM...Dorn
AVIATION...MMM