798 
FXUS63 KABR 090717
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
217 AM CDT Thu Oct 9 2025

.KEY MESSAGES...

- Strong south winds during the morning hours will top out between 
25 and 35 mph with some local gusts over 40 mph in the favored 
downslope areas. Winds will slowly diminish through the afternoon. 

- Light rain this weekend, mainly for the James River Valley and 
eastward. Probability of rainfall of a quarter of an inch or more 
ranges from 30 to 60 percent for this area, highest along and east 
of the Sisseton Hills.

- Winds will increase out of the southeast Saturday with gusts of 30 
to 40 mph through Sunday before diminishing Sunday night.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 217 AM CDT Thu Oct 9 2025

This morning there are steady winds (20-30+ mph) across much of the 
forecast area with a tight surface pressure gradient on the west 
side of a broad high pressure system. In that southerly flow there 
is also a shallow stratus layer up around 6kft over the eastern CWA. 
All of this migrates east through the course of the day, so while we 
do have a core of low level winds up around 40kts in the east by 
daybreak, that mixes out and shifts east with slackening winds 
through the afternoon with the passage of a weak front. Another 
broad high pressure system noses into the north central part of the 
state tonight, and sits overhead for Friday.  

Favorable mixing as winds shift with the trough, and mild 
temperatures aloft, with the clouds mainly in the far east, should 
be easy to make NBM temperatures in the low to mid 70s. The core of 
higher humidity is also still in place with low to mid 50 dewpoints 
but will also shift out of the area with the front.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 217 AM CDT Thu Oct 9 2025

Quite an interesting setup aloft this weekend into early next week. 
The best way to put it is that we have a split flow troughing 
pattern over the western CONUS and western Canada with a ridge over 
the region Friday evening. The axis of a shortwave trough, in this 
overall longwave trough pattern over the western CONUS, tracks 
northeastward and over the Northern Plains through the weekend as it 
tracks into Canada. The northern wave over western Canada tracks a 
bit southeast and gets entangled with the southern wave (Fujiwara 
effect!), where a closed low forms over the Pacific Northwest ~early 
Monday morning. This low then slowly tracks south becoming an open 
wave by the middle/end of next week. Clusters overall agree on this -
PNA pattern but do differ on the exact intensity/position of this 
trough towards the end of the long term period.

At the surface Friday evening through Saturday morning, a high 
pressure system will be working its way eastward (and ridge aloft) 
and exiting the region with the center of the Canadian low over 
~Alberta by 12Z Saturday. The low will track east then northeastward 
across Canada as it occludes. Another low pressure system forms over 
~MT Saturday (and deepens) as it tracks east then northeastward 
(over the Northern Plains) into Canada through Sunday evening, where 
it is forecasted to occlude as well. Ensembles agree pretty well 
with the position and track of the low. With this setup, a couple of 
rounds of precip is possible over the CWA. The first round will be 
light as NBM pops only have a 15-25% Saturday through Saturday 
evening associated with the warm front. As this broad low is then 
positioned over western Dakotas early Sunday, ensembles are in 
better agreement, with NBM pops increasing to 40-65% (excluding 
south central SD) through the day as the low crosses over the 
region, with the highest pops east of the James River. Pops decrease 
southwest to northeast over the CWA Sunday evening as the low tracks 
out of the region. Probability of rainfall>0.25" is 30-55%, highest 
Coteau and eastward. Light pops do return to the forecast area Tues-
Thurs (20-30%) as another system could affect the area, however, 
confidence is low on exact timing and setup this far out.

With steepening pressure gradients ahead of the incoming low, 
southerly winds will increase aloft with 850mb winds by Saturday 
afternoon ranging from 30-45kts and 700 mb winds 20-30kts. Mixing 
heights, per GFS soundings, are forecasted around ~2-3K feet with 
momentum transfer at the top of the mixed layer ranging from 25-
35kts, highest over central SD. This will lead to winds at the 
surface to increase, with gusts of 30-40 mph, highest over central 
SD by Saturday afternoon. Winds will remain breezy Saturday night, 
per LLJ/mixing and ongoing steeper pressure gradients, with gusts of 
25-35 mph, highest over and along the Coteau. Winds will continue to 
be gusty Sunday, with gusts up to 35 mph and more widespread over 
the CWA. Highs will range in the 60s on Saturday and 70s to near 80 
on Sunday. However, the NBM 25-75th spread is quite large (7 to 12 
degree). It does cool down early next week with the incoming high 
pressure system, with forecasted highs only in the mid 50s to the 
lower 60s Monday and Tuesday and lows in the 30s and 40s.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1208 AM CDT Thu Oct 9 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the TAF period. Occasionally 
breezy southerly winds/gusts throughout the forecast area early this 
morning, with some LLWS for the morning hours, but these will be 
shifting over to northeast South Dakota and west central Minnesota
and increasing during the day, out ahead of a dry cold frontal 
passage. Behind the fropa, winds will diminish and veer 
northwesterly.


&&

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

$$

SHORT TERM...07
LONG TERM...MMM
AVIATION...07