351
FXUS63 KABR 172322 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
622 PM CDT Sat Oct 17 2026

.KEY MESSAGES...

- Downslope winds along the east side of the Coteau will ease
  slightly this evening before ramping back up overnight with a
  40 to 60 percent chance of gusts exceeding 45 mph through
  Sunday morning.

- Dry conditions and temperatures roughly 5 to 10 degrees above average
  continue from Sunday through early next week, with Monday
  being the exception as temperatures dip closer to average.

&&

.UPDATE...
Issued at 619 PM CDT Sat Oct 17 2026

The forecast remains on track this evening. No major changes are
planned. Continuing to monitor wind gusts along the Coteau and
the I-29 corridor. They remain between 30 and 40 mph this
evening as we approach sunset.

&&

.DISCUSSION...
Issued at 1254 PM CDT Sat Oct 17 2026

Northwest flow continues aloft as a ridge remains over the region
through this evening with 850mb winds out of the southwest with the
highest speeds of 25-35kts over the James Valley and eastward. This
along with steeper pressure gradients, a southwesterly surface wind
within a shallow mixing layer under a strong inversion just off the
surface has led to gusty downsloping winds along the eastern slopes
of the Coteau. Peak gusts have ranged from 40 to 60 mph over this
area with the highest gust in Peever earlier this morning.
Through the rest of the afternoon and evening winds will remain
breezy with this setup James Valley and eastward with gusts of
25 to 50 mph, with the highest gusts of 40 to 50 mph along the
eastern slopes of the Coteau. Winds over and along the Coteau
will diminish a bit this evening before strengthening again late
tonight and overnight as the inversion becomes stronger and
warmer. For example Peever soundings warms to +22C at 950mb
around 06Z! HREF ensemble does indicate gusts of 40 to
potentially 50 mph with winds diminishing through Sunday
morning. Probability of wind gusts>45 mph tops out at 80%
between 00Z-06Z or so. Prob of gusts>50 mph is 45-60%. However,
REFs and NBM are much lower with a prob of winds>45 mph up to
about 50% REFS and less than 20% NBM, so this leads to lower
confidence in maximum wind gusts. HRRR Peever sounding shows the
top of the momentum transfer (again right off the ground due to
strong inversion) about 20-25kts and around 15kts per RAP
overnight. Went ahead and used HRRR from 00-12Z Sunday to show
for potential higher gusts. Wind gusts will need to be monitored
later on this evening and tonight.

With this ridge overhead and high pressure so the south and
southeast, models continue to indicate very dry air over the region
with RAP 1000-500mb RH below 20% into tonight! This ridge will
track eastward this evening as a shortwave, and its surface low
strengthen, as it tracks eastward across central Canada. By 12Z
Sunday, models indicate the center of the ~984mb low is forecast
to be over northern Manitoba with its cold front extending
southward over east central ND through central SD. As the front
tracks southeastward, winds will continue to shift out of the
northwest behind it, then north/northeast, across the CWA with
the region behind the cold front by late Sunday afternoon.
Again, with the ongoing dry air over the region no precipitation
is expected with this fropa passage. Otherwise, high pressure
moves in behind it through Monday.

With this return flow tonight, overnight temps will be warmer
ranging in the 40s. Highs for Sunday will be a few degrees cooler
mainly along and west of the Mo River behind the fropa with highs in
the upper 60s. While east of the River temps will be able to warm up
with temps similar to today or a few degrees warmer with highs in
the mid to upper 60s to around 70 with the warmest temps far
NESD/western MN. With high pressure moving in and light northeast
winds, temps will drop into the upper 30s to the lower to mid 40s,
coldest over north central SD and warmest over the Coteau per
inversion. This results in the potential for patchy frost over
portions of north central SD late Sunday night into early Monday
morning. Temps will remain cooler (still above average) with overall
highs in the upper 50s to the lower 60s per high over the region
Monday.

Looking ahead Tuesday through the end of next week, a -PNA pattern
sets up with a broad ridge east of the Rockies which results in
overall dry conditions and temperatures above average. Confidence is
increasing for precipitation to move back in towards the end of next
week as Clusters are in agreement on a mid level closed low moving
in off the southern CA coast and a weaker open wave over the
northern Pacific/western Canada as they potentially phase together
into an open wave and tracking east/northeast into the central and
northern CONUS. Beyond Day 5, there are differences between the
ensembles on exact placement and intensity of the wave resulting in
a difference in QPF placement and timing. With this setup, the
Climate Prediction Center indicates a 50 to 65% chance of above
normal precipitation 10/22 to 10/26. During this time, there is a 65-
75% chance of above normal temperatures resulting in ptype to stay
as rain as temps are forecast to range in the 60s and 70s before
cooler air moves in behind the system next weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 619 PM CDT Sat Oct 17 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Sunday afternoon.

&&

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

&&

$$

UPDATE...20
DISCUSSION...MMM
AVIATION...20