788
FXUS63 KABR 130215 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
915 PM CDT Wed Aug 12 2026

.KEY MESSAGES...

- There is a Slight (level 2 of 5) to Marginal (level 1 of 5)
  risk for severe storms to develop this afternoon west river,
  migrating east through the evening and overnight. Main threats
  include wind gusts of 60 to 70 mph and hail up to 1 inch in
  diameter. Additionally, heavy rainfall could lead to localized
  flooding in a few areas.

- Next chance for showers and storms will be Thursday night
  into Friday morning over central and northeastern SD. These
  storms are forecast to stay below severe criteria.

&&

.UPDATE...
Issued at 911 PM CDT Wed Aug 12 2026

Largest area of moderate to heavy rainfall is over the northern
CWA from Brown county westward towards MBG. Updated PoPs to
reflect very high chances over this area. Severe storm threat
for the remainder of the night is very low. Will watch for
pockets of heavy rainfall in the next hour, mainly in Brown
county and the Aberdeen vicinity where an inch+ is not out of
the question.

UPDATE Issued at 622 PM CDT Wed Aug 12 2026

Updated PoPs across the region to better align with radar trends
and be in better collaboration with neighbors. Continue to watch
showers and embedded thunderstorms move slowly east across
central SD and starting to approach the James River valley. A
few cores spike up at times, but having trouble sustaining
anything significant. Severe storms not out of the question, but
overall threat seems somewhat low for anything larger than
quarter inch hail and 60 mph gusts or greater. Could see a
couple isolated cases of this though. Will continue to monitor
trends through the evening.

&&

.DISCUSSION...
Issued at 130 PM CDT Wed Aug 12 2026

Wildfire smoke will continue to move in today. While most of this
smoke will stay above the surface, portions of northeastern SD could
see some of this smoke get to the surface. The concentration of
smoke will not be enough to cause a decrease in visibilities, though
the air quality will drop into the moderate Air Quality Index
category. Those who are sensitive to air pollutants could be
impacted slightly. Temperatures today are on track to be around
normal, with highs in the 80s.

As a weak upper-level shortwave moves over SD this afternoon into
the evening, a surface boundary will be moving into central and
northeastern SD. This shortwave and surface boundary will help to
provide some forcing for shower and storm development today as they
move over an area with some instability. The models are showing CAPE
values of 1000-2000 J/kg over central and portions of northeast SD
this afternoon into the evening, decreasing as the surface boundary
moves in. Mid-level flow from the intermountain west will help to
move in moisture in the mid-levels and create a bit of an inverted-V
sounding. The inverted-V sounding indicates 2 things: that the
convection will likely be elevated, and that strong winds from
microbursts will be possible in the storms. There is a slight (level
2 of 5) to marginal (level 1 of 5) risk that any storms that
develops could become severe, with the highest risk for severe
storms over south central SD. The main hazard will be strong wind
gusts of 60-70 mph. Even though there will be weaker lapse rates, if
any isolated cell does develop in front of the boundary, there is a
risk for hail up around 1 inch. Additionally, with the moisture
moving in from the intermountain west helping to feed the storms,
there could be heavy rainfall at times. If multiple cells were to
move over the same area, that rainfall could add up and create
localized flooding at times. These storms should move out of central
and northeastern SD during the early overnight hours, with the
potential for a few lingering showers into early Thursday morning.

Behind the surface boundary, cooler air will be moving in Thursday.
This will cause temperatures to fall slightly, to be about 5 to 10
degrees below normal through the weekend. High temperatures will be
in the 70s during this time. There is a little bit of variability in
the models as to precipitation chances Thursday. Some models keep
some isolated showers and storms over central and northeastern SD
Thursday morning and afternoon, while other models keep the showers
and storms out of the area. The next larger chance for showers and
storms to move in will be Thursday night into Friday as the Lee of
the Rockies surface trough starts to move over and through SD.
Models show very weak instability over northeastern and central SD
as well as weak lapse rates and shear. Because of this, these
showers and storms will likely stay as weak storms with little
chance to become severe.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 622 PM CDT Wed Aug 12 2026

Terminals KABR,KATY,KPIR,KMBG

SHRA/TSRA continue to move eastward across the region, with all
TAF sites likely affected at some point this evening/tonight.
Heavier downpours that manage to move over a TAF site could
bring brief MVFR/IFR VSBY. Potential also exists for areas of
MVFR/IFR CIGs across the region as well, especially in the wake
of this system late tonight into Thursday morning.

&&

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

&&

$$

UPDATE...TMT
DISCUSSION...12
AVIATION...TMT