161
FXUS63 KABR 020221 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
921 PM CDT Mon Sep 1 2025

.KEY MESSAGES...

- Fog is expected to develop over portions of the area early
Tuesday morning. Best chances for fog are across central SD.

- A cold front will move through on Tuesday, bringing the potential
for severe weather. A Marginal Risk, level 1 of 5, is in effect east
of the Missouri River. Main threats are large hail and strong winds.

- Below normal temperatures are expected for mid week. Highs will be
in the 60s, 10 to 15 degrees below normal. Low temperatures Thursday
morning may dip into the upper 30s.

&&

.UPDATE...
Issued at 918 PM CDT Mon Sep 1 2025

Almost all the hi-res models are overdoing their respective modeled
reflectivity compared to current radar trends. The HRRR and RAP
are currently most representative and so forecast updates used
these two as the highest weighted guidance. As such, POPs have
been trimmed back significantly before 9Z tonight. That may even
still be an overestimate, it may be closer to 15-18Z when we see
the frontal boundary sag into our CWA before we see the return of
shower/thunderstorm activity over parts of northeast South Dakota
and west central Minnesota. The other concern through the
overnight hours is fog. Definitely not expecting as
widespread/dense fog as the last couple of mornings, primarily due
to slightly stronger winds across the region. However, did leave
the general "patchy" mention in the forecast for now, but
confidence in development is low.


UPDATE Issued at 625 PM CDT Mon Sep 1 2025

See the updated aviation discussion below.

&&

.DISCUSSION...
Issued at 259 PM CDT Mon Sep 1 2025

A 700 mb low continues to spin in Nebraska today, helping to pull
some clouds into central SD, but mostly out of the picture. The
moisture associated with it, though, persists across eastern SD and
west central MN. Coupled with some weak shortwave energy, showers
and thunderstorms have developed from around the James valley
eastward this afternoon. The atmosphere is again supportive of some
cold air funnels with any otherwise weak thunderstorms. There has
already been one spotted in ND. These showers and thunderstorms will
slowly exit late this evening.

Another round of storms is expected Tuesday as a cold front swings
through. Instability increases with the front in the east during the
evening as a shortwave trough also works its way southeast. There
is a marginal risk for severe storms east of the Missouri River
with large hail and strong winds the main concerns. Some models
show the chance even farther east from the Coteau into west
central MN.

Two other things to note in the short term. Winds will still be
light enough and llm moisture ample enough for fog development early
Tuesday morning, especially across central SD. As winds aloft shift
to the northwest and sfc winds shift to the north behind the front,
smoke will be drawn back into the region late Tuesday.

Temperatures will be 10 to 15 degrees below average Wednesday as an
upper trough digs into the northern Plains and Great Lakes. Some
moderation occurs Thursday before another, dry cold front pushes
through. The latter half of the week looks dry but hazy/smoky and
breezy.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 625 PM CDT Mon Sep 1 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to prevail at all TAF sites. However,
a few things we will be monitoring tonight include shower and
thunderstorm activity across far northeast South Dakota and west
central Minnesota through the overnight hours. Currently models
keep all this activity east of the KATY TAF site. The second thing
we will monitor for is for fog development. As it stands now,
wind gusts of 10-15 mph through the night should help limit any
type of widespread fog development.


&&

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

$$

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