048
FXUS63 KABR 220909
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
409 AM CDT Fri Aug 22 2025

.KEY MESSAGES...

- Showers and thunderstorms will continue to push eastward across
the region through the early afternoon. There is a marginal risk
(level 1 out of 5) for isolated severe storms over far east central
SD during this time. The main threats are quarter size hail and 60
mph wind gusts.

- Flooding caused by excessive rainfall continues to be possible
over east central South Dakota through the late morning/midday as
soils are already saturated in this area. A Flood Watch continues
for this area.

- Temperatures Saturday through Tuesday of next week will run about
5 to 15 degrees below normal, meaning highs is the 60s and 70s with
lows in the 40s and 50s.

&&

.DISCUSSION...
Issued at 409 AM CDT Fri Aug 22 2025

As of 3am, radar indicates our next round of showers and
thunderstorms are currently over central SD associated with weak
embedded shortwave energy within overall westerly flow aloft.
Through the early morning this energy aloft, along with ongoing
surface to mid level moisture, CAMs indicate this elevated
convection will continue to track east over the CWA (with additional
convection developing). Mid level lapse rates between 7.0-8C/km,
MUCape up to 3000j/kg, and shear of 30-40kts will continue, with the
highest CAPE over east central SD, closer to the front/lee low.
There is also a weak LLJ continuing over south central to east
central SD. Therefore, a few of the storms could grow vertically
enough to dip into the cooler temps and produce quarter size hail
(potentially larger) and wind gusts of 60 mph.

The center of the mid level low will be over central Manitoba by
12Z. This is a fairly stacked system with its elongated surface low
extending from central Manitoba through western Ontario and its cold
front extending south then southwestward through MN and through east
central SD, with the lee low over the southeastern part of SD/NE
border as well. 12Z through 18Z, the precip will continue to shift
east/southeast over the CWA with the bulk of the pops (70-100%) over
east central SD. Due to slow moving storms late last night,
excessive rain led to reports of flooding in this area which led to
the issuance of a FAW over portions of Codington, Grant, and Deuel
Counties. This remains in effect along with a Flood Watch for Spink
County eastward through Grant County as additional rain/slow moving
or training storms could lead to flooding/additional flooding
concerns. This area is also under a marginal risk for severe weather
through the late morning with hail up to quarter size and wind gusts
of 60 mph could be possible. The front will continue to shift
southeastward and exit the southeastern CWA by the noon/early
afternoon along with the last of the precip.

This evening into tonight a ridge will continue to build over the
western CONUS as winds aloft over the region will turn northwesterly
on the downstream side of this ridge. This +PNA pattern will
continue through the weekend with a couple of weak embedded
shortwaves moving down the ridge at this time and over the Northern
Plains/Upper Midwest as we continue in northwest flow. At the
surface, conditions are expected to remain dry as high pressure will
be the dominant. Looking ahead to early to middle parts of next
week, Clusters agree on this +PNA pattern, and northwesterly flow
over the region, continuing with overall dry conditions expected.
NBM also shows this too keeping the forecast mainly dry as well.
The Climate Prediction Center 6-10 day precipitation outlook (8/27-
8/31) indicates near normal (36%) with a 32% chance of both above or
below normal.

Highs for today will be cooler behind the cold front ranging in the
upper 70s to the upper 80s, warmest over central SD with lows
tonight in the lower to mid 50s. We will get a taste of Fall this
weekend as the CWA will be on the southeast side of the high on
Saturday, southerly side on Sunday, and directly overhead on Monday.
NAEFs indicates 700-850mb temps will be around 2 standard deviations
below climo for the entire CWA by Sunday morning through at least
Tuesday morning! Overall highs will range in the mid to upper 60s
east of the James River and in the lower to upper 70s west of here.
This runs about 5 to 15 degrees below average.  EC EFI indicates
values of -0.6 to -0.8 for TMAX Sunday and Monday James River Valley
and eastward. TMIN values of -0.7 to -0.9 are forecasted for the
entire CWA Sunday and Monday night as temps will dip down in the
lower 40s to lower 50s (about 5 to 10 degrees below average)!

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1225 AM CDT Fri Aug 22 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions throughout the TAF valid period, but thunderstorms
are the main focus. Best confidence for overnight into Friday
morning storms is between now and ~14Z Friday, mainly across the
KPIR/KATY terminals. Can`t rule out an isolated shower/storm late
tonight at KMBG/KABR as well. Post-frontal winds will become
northerly at KATY overnight leaving all four TAFS in a northerly
wind with gradually drying conditions Friday morning to around
mid-day.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Flood Watch until 10 AM CDT this morning for SDZ018>023.

MN...None.
&&

$$

DISCUSSION...MMM
AVIATION...MMM