069
FXUS63 KABR 081504 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1004 AM CDT Tue Sep 8 2026

.KEY MESSAGES...

- Northwest wind 15 to 25 mph with gusts of 30 to 40 mph, low
  relative humidity, and dry cured fuels will create elevated
  fire weather conditions mainly over north central SD today. A
  Red Flag Warning has been issued for north central SD.

- Temperatures closer to normal (highs mid 70s to mid 80s) are
  forecast for Today and Wednesday, with below normal
  temperatures, in the 60s to low 70s, forecast Sunday and
  Monday.

&&

.UPDATE...
Issued at 1000 AM CDT Tue Sep 8 2026

A Red Flag Warning has been issued for north central South
Dakota from noon CDT to 7 PM CDT today, due to northwest wind
gusts in excess of 25 mph and relative humidity values between
15 to 25 percent combined with the amount of available dry/cured
fine fuels in place. No other changes planned to the today
period forecast.

UPDATE Issued at 622 AM CDT Tue Sep 8 2026

See below for an update to the 12Z aviation discussion.

&&

.DISCUSSION...
Issued at 122 AM CDT Tue Sep 8 2026

As an upper-level trough continues to push east today, it will be
suppressing the upper-level ridge that has be stuck over SD. This
upper-level trough will continue to help a cold front at the surface
finish moving through northeastern SD during the morning. There is a
little bit of warm air and moisture trying to advect into portions
of south central and northeastern SD in front of the the cold front
early this morning. The warm air and moisture advecting in as well
as a weak low level jet sitting over the area again is creating some
more of the elevated scattered showers and storms, similar to what
has been happening the past few mornings. These showers and storms
will have a little bit of shear and some lapse rates, around 5-6
C/km, to strengthen a bit, though they should stay below severe
criteria. As the cold front moves through this morning, these
showers and storms should dissipate as dry air moves in.

Behind the cold front, some high surface pressure will move through
southwestern SD while a low pressure sits over Manitoba and
Saskatchewan, which will help to create a tight pressure gradient
over ND and northern SD. This tight pressure gradient will cause
stronger winds to develop aloft, and with stronger lapse rates and
cold air advection occurring, there will be a fair bit of mixing in
the atmosphere to get these winds down to the surface over
north central SD. The ensembles have a 30-50% chance for the
northwest winds to gust around and greater than 40 mph, and 50-80%
chance for 35+ mph wind gusts over mainly Corson and Dewey counties.
The HREF models has slightly weaker winds chances over north central
SD, with a 40-80% chance for winds to gust greater than 30 mph.
While these winds are weaker than wind advisory criteria, they are a
big point of concern for fire weather in portions of north central
SD. There is a 20-40% chance that conditions mainly in Dewey county
but also other portions of north central SD will reach Red Flag
criteria, which is wind gusts greater than 25 mph and relative
humidity values less than 20% in addition to dry fuels. The main
cause for these lower chances is because the humidity values will be
slightly above 20%. When checking the models for wind gusts greater
than 25 mph and humidity less than 25%, then the chances shoot up to
50-80% over Dewey county and slightly lower over other portions of
north central SD. While the conditions do not reach Red Flag
criteria, there is still Very High to High Grassland Fire Danger
Index Values and some fire weather concerns for Dewey, Corson, and
other portions of north central SD this afternoon. With the dry
fuels in these areas in combination with the weather conditions, if
a fire were to ignite, it would become difficult to suppress or
control.

Temperatures today behind the cold front will be around to just
slightly above normal for this time of the year, in the upper 70s to
mid 80s. Another surface cold front is forecast to move through SD
again tonight into early Wednesday morning. The RAP model shows
there to be a little bit of instability over portions of northern SD
tonight, with CAPE values less than 1000 J/kg, as well as a little
bit of lingering moisture aloft. The cold front could interact with
this environment during the overnight hours into Wednesday morning
to create some isolated to scattered showers and storms over
portions of central and northeastern SD. While there will be a fair
bit of shear from the frontal boundaries, the lapse rates will be a
bit weaker. This will help the showers and storms from becoming
severe. However, with the stronger shear, around 45-60 kts, even
some weaker lapse rates could get strong winds to the surface and
the storms could have gusts up around 50 mph.

The second cold front will help to cool temperatures even more on
Wednesday, with highs in the 70s possible. A weak upper-level ridge
will be moving over SD Thursday and Friday, which will help to move
some warm, drier air in again, with highs these day in the low 80s
to low 90s. A surface high pressure moving in Wednesday afternoon
through Thursday night along with the drier air aloft will help to
keep showers and storms from developing for a couple of days. The
next chances for precipitation will be during the day and evening
Friday as another frontal boundary moves through.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 622 AM CDT Tue Sep 8 2026

Terminals KABR,KATY,KPIR,KMBG

A cold front sliding across the region may produce periods of
MVFR and IFR conditions with low cigs and patchy fog. Once the
front pushes through, flying conditions will become VFR. The
winds will also shift to the west-northwest behind the frontal
passage.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning until 7 PM CDT /6 PM MDT/ this evening for
     SDZ003-004-009-015-016-034.
MN...None.

&&

$$

UPDATE...10
DISCUSSION...12
AVIATION...17