505
FXUS63 KABR 310520 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1220 AM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Showers and weak thunderstorms will continue through the weekend.
Severe weather is not expected with this system, though cold air
funnels are possible in the afternoon. Heavier rain or stationary
storms may also pose an isolated flooding threat.

- A cold front will move through on Tuesday, with a 20 to 40 percent
chance of rain. The remainder of the week is expected to stay dry.

- Below normal temperatures are expected for mid week. Highs will be
in the upper 50s to mid 60, 10 to 20 degrees below normal.

&&

.UPDATE...
Issued at 1218 AM CDT Sun Aug 31 2025

Aviation discussion has been updated in accordance with the 06Z
TAF issuance.

UPDATE Issued at 902 PM CDT Sat Aug 30 2025

Forecast updates mainly revolve around lingering showers and
thunderstorms this evening. There is just enough instability to
maintain a couple of thunderstorms from Huron to Mobridge, but
loss of daytime heating and hi res model trends all suggest
thunder should be ending in the next hour or two. Meanwhile the
stratiform rainfall in the Pierre area should become less
widespread overnight, but on and off showers are expected to
persist through the night in this region. 24-hour precipitation
estimates show 2 to 3 inches of rain over far western Stanley
County, but rain rates have been slow enough and soil moisture dry
enough in this area that there are no flood concerns at this time.
The last concern going into the overnight hours is fog
potential. Plenty of low level moisture, light winds and cooling
temperatures will provide a favorable set up. How widespread fog
becomes is still uncertain at this time.

UPDATE Issued at 635 PM CDT Sat Aug 30 2025

See the updated aviation discussion below.

&&

.DISCUSSION...
Issued at 221 PM CDT Sat Aug 30 2025

No big changes to the last few forecast discussions. An upper level
low continues to spin over central SD and churn up showers and
thunderstorms. This system will linger through Sunday. The colder
air aloft and weak daytime heating induced thunderstorms east of the
upper low may generate some cold air funnels this afternoon and
evening before the sun sets. Otherwise, no severe weather is
anticipated. Localized flooding is the only other concern with
prolonged rainfall over the same areas or short, intense bursts in
thunderstorms over more saturated soils.

If clouds scatter out a bit tonight or Sunday night, there may be a
little morning fog around, but confidence is too low to pinpoint an
area. Mentioned patchy/areas of fog based on forecast dewpoint
depressions for now.

Once this upper low meanders out of the region, a cold front swings
through Tuesday bringing additional chances for showers and weak
thunderstorms. It also ushers in fall-like temperatures for mid week
with overnight lows possibly dipping into the 30s Wednesday night
and daytime highs 10 to 20 degrees below climo norms for early
September. Some areas east of the James Valley may not climb out of
the 50s on Wednesday. Cooler temperatures continue for Thursday
under northwest flow aloft as a strong upper low digs into the Great
Lakes. Ridging over the Rockies may translate far enough east on
Friday to allow for a little waa.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1218 AM CDT Sun Aug 31 2025

Terminals KABR,KATY,KPIR,KMBG

Scattered showers continue in and around the KPIR region and are
expected to persist though the TAF period. CIGS may fluctuate between
VFR/MVFR with passing showers, but minimal visibility reduction
is expected.

The other concern going into the overnight and early morning hours
will be fog. Some west central Minnesota obs are now reporting fog
and satellite trends are showing the development of fog/stratus over
parts of northeast South Dakota. Models suggest this will continue
to spread across parts north central/northeast South Dakota with
density/coverage peaking around the sunrise hours. Fog is mostly
likely to influence the KABR/KATY TAF sites. IFR CIGS and VSBYS are
possible roughly around 9-15Z hours. Cloud cover should help limit
fog development further west toward the Missouri River.

&&

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

$$

UPDATE...BC
DISCUSSION...20
AVIATION...Serr