146
FXUS63 KABR 010746
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
246 AM CDT Mon Sep 1 2025

.KEY MESSAGES...

- Fog is expected to develop over portions of the area tonight into
Monday morning. Best chances to see fog are over northern South
Dakota and west central Minnesota.

- A cold front will move through on Tuesday, bringing the potential
for severe weather. A Marginal Risk, level 1 of 5, is in effect from
the Missouri River and east.

- 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.

&&

.DISCUSSION...
Issued at 236 AM CDT Mon Sep 1 2025

With storms moving off, fog will be the main concern this morning.
Coverage will be more widespread this morning, but there is still
some uncertainty as to the coverage and density. In general hi-res
models are resolving visibilities in the 2-4 mile range, but the
potential is certainly there for visibility to drop below a mile.
There is also much more areal coverage in the models than would be
expected due to the cloud cover over central South Dakota this
morning. Confidence is higher in the fog potential over northeastern
South Dakota and west central Minnesota, where more effective
radiational cooling can take place. A Dense Fog Advisory is not
expected at this time, but will have a close eye on trends and
observations through the morning today.

Frontal passage is still expected over the forecast area Tuesday,
and we have now reached the time frame where the CAMs pick up on
this potential at the end of their runs. CAMs show that coverage of
these storms is expected to be scattered, and the threat is still
fairly marginal. Machine learning guidance has pinged hail as the
main potential threat, but still with a low chance of occurring.
This matches up with model trends, as an increase in both surface
based and MUCAPE has been observed in the latest runs, as has an
increase in 0-6km shear. Mid-level lapse rates are still not
fantastic, but being close to moist adiabatic is likely sufficient
to get some hail growth in the largest storms. Wind is also a threat
with soundings showing some potential for dry air aloft along with
strong low-level lapse rates. SPC has placed a Marginal Risk from
the Missouri River and east for this event.

Behind the front and associated storms, strong cold air advection
aloft will push surface high temperatures down into the 60s through
Friday, 10-15 degrees below normal for early September. Low
temperatures may dip into the upper 30s on Thursday morning. The
passage of this front may also allow for smoke from Canadian
wildfires to move into the ABR area. Hi-res models are still on the
outer fringes of this time period, but there is a fairly strong
signal for near-surface smoke being present across the Northern
Plains.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1213 AM CDT Mon Sep 1 2025

Terminals KABR,KATY,KPIR,KMBG

Fog will be the main aviation concern over the next 6-12 hours.
Breaks in cloud cover, light winds and cooling temperatures tonight
will combine to produce a favorable environment for fog development.
Far northeast South Dakota and west central Minnesota (including the
KATY TAF site) have the highest probability of seeing IFR
CIGS/VSBYS, but the forecast is for at least MVFR CIGS/VSBYs at all
TAF sites. The worst conditions are expected before sunrise and then
quickly improving once the sun can help mix out the fog.


&&

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

$$

DISCUSSION...BC
AVIATION...Serr