666
FXUS63 KABR 100626
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
126 AM CDT Thu Sep 10 2026

.KEY MESSAGES...

- Above normal high temperatures in the low 80s to low 90s today and
Friday. A sharp cooldown expected Saturday through early next week
with highs in the 60s to low 70s.

- High to very high grassland fire danger expected on Thursday and
Friday with highest concern focused west of the Missouri river.

-There is a slight (level 2 out of 5) to marginal (level 1 out of 5)
risk for severe storms to happen Friday afternoon into the evening
over portions of northeastern SD and west central MN. The primary
hazards will be wind gusts of 60-75 mph and hail up to 2 inches in
diameter. Additionally, the development of a tornado or two cannot
be ruled out.

&&

.DISCUSSION...
Issued at 126 AM CDT Thu Sep 10 2026

A small upper-level ridge will be moving over SD today which helps
to push a high pressure out of the state. The southerly flow along
the backside of the high pressure will push warm, dry air into SD.
The warm air moving in will help to warm temperatures today and
Friday about 5-15 degrees warmer than normal, with highs in the low
80s to low 90s. The drier air moving in will lower the humidity over
central and northeastern SD, with areas west of the Missouri River
seeing the humidity drop down between 15-25 percent. This dryness
along with the dry fuels in areas west of the Missouri River is
leading to elevated fire concerns. One of the things lowering the
concern is that winds will be fairly marginal, with low chances of
the winds gusting up to 25 mph this afternoon when and where the
humidity is the lowest. There is still high grassland fire danger
index values over some of the areas west of the Missouri River
because the dryness will make it fairly easy for something to
ignite.

A low level jet will be developing tonight into Friday over eastern
SD. This jet will be helping to move more moisture and warm air into
northeastern SD Friday as well as strengthen the winds at the
surface over this area, with a 30-60% chance for winds to gust more
than 35 mph early Friday morning, especially along the eastern edge
of the Prairie Coteau (over I-29). A surface low, as well as warm
front and dryline, will be moving over SD Friday morning and will
sit there through most of the day before a cold front comes in
Friday evening to push everything to the southeast. Since
northeastern SD will be in the warm sector of this low, the warm,
moist air will continue moving into the area, helping to increase
the instability. The NAM has CAPE values getting up between 1000-
3000 J/kg over northeastern SD Friday afternoon. This will help
storms to develop as the cold front moves through late Friday
afternoon into the evening. Right now, the models vary how fast the
front moves through, with some models moving it through quicker and
keeping the chance for storms to develop out of northeastern SD,
while other models are a bit slower and have storms developing more
in northeastern SD and sticking around for a bit longer. There is a
slight (level 2 of 5) to marginal (level 1 of 5) risk for these
storms to become severe. The model soundings over northeastern SD
have some drier mid-level air with steep lapse rates of 7-8 C/km.
This will help to drive a strong wind threat in the storms if they
do develop over the area, with gusts of 60-75 mph possible due to
the potential for a microburst or two. Additionally, since the
storms that develop could be elevated with the strong lapse rates,
there could be hail up to 2 inches that falls from the storms. The
model sounding`s hodographs show some directional low level shear
that could cause some turning in the storms. While the storms do
appear to be elevated in nature, if a storm or two were to develop
closer to the ground, the development of a tornado or two cannot be
ruled out.

Behind the dry line moving in Friday with the weak surface low,
relative humidities will drop down again, with values of 15-25%
possible over portions of south central SD. As the cold front moves
in Friday afternoon, the wind speeds behind it will pick up and will
start to affect the areas with lower humidity values. Wind speeds
over central SD will be able to gust up around 30-40 mph Friday
afternoon into the evening. This creates even higher fire weather
concerns than today, especially over portions of south central SD.
With the winds, low humidity, and dry fuels, there is high to very
high grassland fire danger index values. An eye will need to be kept
on the mixing potential needed to get the strong winds to the
surface as well as the fire weather concerns as the components are
there for a Red Flag Warning. If a fire were to ignite, it would
become difficult to suppress or control, and with the shifting winds
from the frontal passage it could cause changes in fire behavior if
something were to be burning.

High surface pressure will be moving in behind the cold front as
well some cooler temperatures. The temperatures over central and
northeastern SD and west central MN will be slightly below normal,
with highs this weekend in the 60s to low 70s. The high pressure
will help to keep showers and storms from developing Saturday.
Models are forecasting another frontal boundary moving through Sunday
into Monday, which will likely cause showers and storms to occur
over central and northeastern SD, though models do vary the
starting time of the showers and storms.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1215 AM CDT Thu Sep 10 2026

Terminals KABR,KATY,KPIR,KMBG

Prevailing VFR conditions can be expected for all terminals
through the valid TAF period. Wind will become southerly later
today and through the overnight hours.

&&

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

&&

$$

DISCUSSION...12
AVIATION...07