860
FXUS63 KABR 020629
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
129 AM CDT Wed Sep 2 2026

.KEY MESSAGES...

- Low chances, 10-20%, for an isolated shower or storm to develop
this evening into Thursday morning.

-There is a Slight (level 2 of 5) to a Marginal (level 1 of 5) risk
for severe storms to develop over northeastern SD and west central
MN late Thursday afternoon into the nighttime. The primary threats
will be hail up to 2 inches in diameter and wind gusts of 60 to 75
mph.

- Above normal temperatures (5 to 15 degrees) continue through the
week, peaking at 10 to 20 degrees above normal Friday and Saturday.

&&

.DISCUSSION...
Issued at 128 AM CDT Wed Sep 2 2026

As of 1 am CDT, there are some lingering showers over portions of
northeastern SD and west central MN. These showers will be
dissipating and moving out into the early morning. Other than the
lingering showers this morning, there could be some localized areas
of patchy fog. The easterly flow this morning could create upslope
fog where the flow tries to move up over the terrain in areas of
higher humidity. This fog will dissipate during the morning once the
sun rises and the atmosphere starts to mix things up.

The moisture will be sticking around, as relative humidity values
will stay above 55 percent for most of central and northeastern SD
and west central MN today. This moisture as well as some higher
instability, between 1000-2000 J/kg possible late this afternoon
into the evening, will help to create a decent environment for storm
and shower development. The one thing that will be lacking is a
source of lift. Some models show a shortwave moving over SD late
this evening and overnight, which would help with the development as
a source of lift. However, there is variability in the models with
the shortwave, as some of them don`t have it moving over until
Thursday evening and other models don`t have any shortwave move
over. Without the shortwave as a source of lift, the showers and
storms will struggle to develop. There is also variability in the
models as to how long the storms will be able to last if they do
form. This is because some of the models hint at a low level jet
developing overnight to support the showers and storms, while other
models don`t have the jet develop and the storms don`t last. If
things line up just right, there could be some isolated showers and
storms late this evening and overnight into early Thursday morning.
Models show lapse rates between 6-7 C/km and bulk shear up around 35
kts, which could help with some hail development and occasional
strong wind gust tonight if the storms are able to happen, though
there is lower confidence in this happening.

Southerly flow Thursday will help to warm the temperatures to be in
the mid 80s into the low 90s, which is 10-15 degrees warmer than
normal. These southerly winds will also help to push moist air into
central and northeastern SD and west central MN. A frontal boundary
is forecast to move through SD Thursday and overnight, which will
help to provide the lift needed for storms and showers to develop in
the moist environment. The models show the instability developing
through the day mainly over eastern SD and west central MN, which is
in front of the frontal boundary, with CAPE values of 1000-3000
J/kg. Depending on how fast or slow the boundary moves into and
through SD during the day, there could be a smaller or larger area
with chances for showers and storms to develop. The NAM shows some
higher mid-level lapse rates between 6-7 C/km and bulk shear of 30-
45 kts, which could help with the development of some hail and
stronger winds if anything were to develop. There does not look to
be the development of a low level jet Thursday night, which might
also limit the ability for the storms to stay alive through the
night. There is a Slight (level 2 of 5) to a Marginal (level 1 of 5)
risk for these storms to become severe. The primary threats
initially look to be hail up to 2 inches in diameter and wind gusts
of 60 to 75 mph. As the evening progresses, the storms will likely
transition to more of a wind threat as they could become more
linear.

After Thursday, an upper-level ridge looks to build over and
slightly to the east of SD. This will help warm air to build in
Friday and Saturday, causing temperatures to be 10-20 degrees warmer
than normal. High temperatures Friday and Saturday are forecast to
be in the upper 80s to mid 90s, warmest over central SD. The ridge
should also help to keep showers and storm from developing, though
some models have a shortwave pushing through Friday night into
Saturday morning, which could support an isolated shower/storm or
two to developing.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1228 AM CDT Wed Sep 2 2026

Terminals KABR,KATY,KPIR,KMBG

There are a few showers near/in vicinity of the KABR terminal
right now. By 07Z, precipitation should be clear of said
terminal, with all four terminals expected to be dry for the TAF
valid period. KPIR could see some (MVFR) light fog or (MVFR) low
clouds develop by sunrise on light east-component winds. Beyond
that, VFR conditions are forecast at all four terminals
throughout the TAF valid period.

&&

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

&&

$$

DISCUSSION...12
AVIATION...10