763
FXUS63 KABR 061739 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1239 PM CDT Sun Sep 6 2026

.KEY MESSAGES...

- There is a Marginal risk (level 1 out of 5) for severe storms
  over the region today and Monday. Main hazards will be 1 inch
  diameter hail and 60 mph wind gusts.

- Hot temperatures will persist into Monday. Highs in the low
  80s over northeastern SD to mid 90s over central SD are
  expected for the next couple of days.

- Northwest wind 15 to 30 mph and gusts of 30 to 45 mph, low
  relative humidity, and dry cured fuels may result in fire
  weather concerns on Tuesday.

&&

.UPDATE...
Issued at 1230 PM CDT Sun Sep 6 2026

Aviation discussion updated below for the 18Z TAFs.

UPDATE Issued at 1045 AM CDT Sun Sep 6 2026

No changes planned to the today period forecast. Scattered to
numerous showers/storms over the Missouri River valley should
eventually loose steam and dissipate over the next few hours.
However, the available instability and strength of mid-level
lapse rates over northeast South Dakota into west central
Minnesota may get tapped by a shortwave circulation over north
central Nebraska as it moves into southeast/east-central South
Dakota this afternoon. Short-range CAM guidance would have
convection developing across northeast South Dakota within the
next 3-5 hours.

UPDATE Issued at 630 AM CDT Sun Sep 6 2026

Aviation discussion updated below for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 126 AM CDT Sun Sep 6 2026

The upper-level ridge continues to sit over SD today and into
Monday, with multiple rounds of shortwave moving over the state
during that time. At the same time, a surface trough continues to
sit over western SD with an attached stationary front stretching from
northwest to southeast SD. Scattered showers and storms look to
continue to develop as the shortwaves move over the boundaries this
morning through Monday morning. Some models are hinting at showers
and storms developing early this morning from a low level jet, which
then move into northeastern SD where they continue to stay into the
early afternoon. CAPE values in northeastern SD this morning into
the afternoon will be between 1000-3000 J/kg, which will help with
the continue development over the area as the low level jet and
shortwaves provide some upper-level support. With very little shear
over northeastern SD, the storms will have a hard time becoming
supercellular and severe. However, with stronger lapse rates, they
could develop hail and some strong winds. There is a marginal risk
(level 1 out of 5) for these storms to become severe, and if they
do, the wind gusts could get up to 60 mph and hail up around 1 inch
in diameter.

The warm, moist air moving in today will help to support the storms
this morning and early afternoon, as well as helping to warm the
temperatures at the surface and aloft. 850 temperatures this
afternoon and evening will be between 20-24 degrees C, which will
help to place a decent cap over central and northeastern SD. This
cap will help the early afternoon storms to taper off and keep
strong storms from developing late this afternoon and into the
evening, though there could be some weak scattered pulsy showers and
storms that develop and try to break through the cap. As
temperatures cool slightly overnight into Monday morning weakening
the cap, as well as another nocturnal low level jet developing over
central and northeastern SD, some more isolated showers and storms
could try to develop overnight into Monday morning. While there will
be some instability to help them develop, the stronger lapse rates
and shear will not be there to help them become severe.

An upper-level low and trough over the Pacific Northwest will be
pushing east Monday and Tuesday, which will finally cause the ridge
to move out of the state Monday night. This upper-level trough will
be supporting a cold front pushing through SD Monday night. This
front will be moving into an environment that has had warm, moist
air being pushed into it through the day. The NAM shows CAPE values
of 1000-3000 J/kg building over central and northeastern SD through
the day. Storms will be able to develop as the front moves through
late Monday afternoon into the nighttime hours. Lapse rate values of
5-7 C/km as well as shear values of 30-40 kts could help hail and
strong winds to occur in the storms that do develop. There is a
marginal risk (level 1 out of 5) for storms to become severe, with
the primary threats of 60 mph wind gusts and hail up around 1 inch
in diameter.

Early Monday morning and through the day, as the front is
developing, the pressure gradient over SD strengthens. This will
cause the winds to strengthen aloft and get to the surface as the
lapse rates start to pull the winds down during the day. Winds will
pick up during the afternoon, with models showing a 30-50% chance
for gusts to be above 40 mph Monday afternoon over portions of
northeastern SD. The winds look to pick up again Tuesday over north
central SD with a 40-60% chance for gusts the get above 45 mph.
These winds, as well as the relative humidity, will need to be
watched over the coming days to see if the models continue to show
strong winds and lower humidity. If it does, there could be some
wind and fire weather concerns. Temperatures behind the front will
cool to be around normal for this time of the year Tuesday and
Wednesday. Highs Tuesday look to be in the 80s and highs Wednesday
in the 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1230 PM CDT Sun Sep 6 2026

Terminals KABR,KATY,KPIR,KMBG

A slow moving storm system will produce showers and
thunderstorms through the afternoon and evening hours. The
strongest storm activities will cause IFR/MVFR conditions due to
heavy rainfall. Wind gusts will also be sporadic with
thunderstorms. The storm activity has push east of KPIR with
prevailing VFR conditions expected through tonight.

Another round of showers and storms will progress eastward
across the region on Monday morning, mainly between 12-18Z. Will
add PRO30 to account for some uncertainty with storm track.

&&

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

&&

$$

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