259
FXUS63 KABR 070542 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1242 AM CDT Mon Sep 7 2026

.KEY MESSAGES...

- There is a Marginal risk (level 1 out of 5) for severe storms
  over portions of central SD overnight prior to daybreak. Main
  hazards will be 1 inch in diameter hail and 60 mph wind
  gusts.

- There is a Marginal risk (level 1 out of 5) for severe storms
  over central and northeastern SD and west central MN Monday.
  The primary hazards will be 1 inch in diameter hail and 60 mph
  wind gusts.

- Hot temperatures for September 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 1241 AM CDT Mon Sep 7 2026

Updated for 06Z Aviation Discussion below.

UPDATE Issued at 918 PM CDT Sun Sep 6 2026

The heavy rain and thunderstorms we saw through the late
afternoon hours across our far eastern zones pushed off into MN
and diminished in aerial coverage by early this evening. There
were a few lingering showers across the northeast corner of SD
into west central MN, but those have since fizzled. Cloud cover
in our east cleared out while thickening mid to high level cloud
cover has been drifting in across western SD where there had
been a few isolated evening storms. More convective activity is
developing across the northern High Plains southwest of the
Black Hills and that`ll be part of the next impulse of storms
that heads in our direction toward the early morning hours.

Made some adjustments to PoPs, Sky and Wind grids earlier this
evening to account for the drier conditions expected this
evening into the first half of the overnight along with the
satellite and wind field trends that were observed. These
updates to the forecast have been sent out.

UPDATE Issued at 640 PM CDT Sun Sep 6 2026

The aviation discussion has been updated for the 00Z TAFS.

&&

.DISCUSSION...
Issued at 225 PM CDT Sun Sep 6 2026

At 2 PM CDT, except for portion of the west river counties (edge of
cloud shield, skies are cloudy due to earlier and ongoing
thunderstorms over the region. Temperatures have struggled to warm
up through the cloud-cover, with most of the forecast area
registering temperatures in the 60s and 70s. Those locations across
the far western CWA in sunshine have warmed into the 80s. Outside of
thunderstorms, winds range from the southwest to the southeast
generally in the 10 to 20 mph range with gusts to 30 mph.

The ensembles/deterministic GSM`s all continue to point to the
unfolding of this omega block pattern (a wave pattern change) by mid-
week as western CONUS energy/upper troffing works east across
southern Canada/northern tier states and flattens the flow out to
nearly zonal. This pattern change is forecast to hold into this next
weekend.

A more zonal flow pattern should knock the edge off all the
warmer/more humid than usual conditions of late. Guidance shows a
steady drop in temperatures from 80s/90s to 70s/80s once the first
cold front pushes through the CWA Monday/Monday night.

Showers and thunderstorms are dissipating across north central South
Dakota (at the time of this writing). However, convective coverage
should increase across the far eastern CWA forecast zones from late
this afternoon through late this evening while the best mid/upper
level forcing and lift overlaps the greatest instability/lapse
rates. And the biggest concern/threat through this evening with
convection is heavy rain/flash-flooding potential. With very little
in the way of deep layer shear, and sitting underneath the axis of
the upper level ridge, storm motion is only about 10 to 20 mph. So,
slow-moving heavy rain-capable storms could pose a flooding threat.

Otherwise, convective chances should take a break during the
overnight hours, returning on Monday (potentially as early as Monday
morning in the form of pre-cold-frontal showers/storms) when energy
within the western CONUS upper trof lifts out onto the northern
plains. Storms may be able to form in a pre-frontal surface trof
over the far western Dakotas and race off to the east in the morning
to early afternoon hours. A second round of storms may develop along
the actual cold front, itself, and move eastward into Minnesota
during the afternoon through late evening hours. SPC has the
forecast area in a marginal risk for severe thunderstorm on
Monday/Monday night.

Otherwise, the forecast turns dry and cooler for much of the rest of
the week. PoPs return by the weekend when the next upper trof is set
to work over the region. Still keeping a close eye on Tuesday for
fire weather concerns (low humidity and 15-30 mph northwest winds
with higher gusts).

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1241 AM CDT Mon Sep 7 2026

Terminals KABR,KATY,KPIR,KMBG

Initial concern will be for the potential of low stratus moving
into some of the terminals this morning (primarily KATY, but
KABR too). Already seeing this spread into KATY at TAF time and
models show it potentially reaching KABR (although downsloping
SSE winds off the Coteau could limit it some). Also some hints
it could even make it to the Missouri River, but confidence was
too low to include that far west. Those MVFR conditions will
likely remain into the morning hours. Then the focus is on
convection moving into western SD and expected to slide eastward
across the northern half of the state today. Addressed this in
the TAFs with combined FM/PROB30 groups to best time out the
arrival/departure. Confidence is fairly high in rain occurrence
and should see some embedded thunderstorms too. Should have a
better feel for the convection timing for the 12Z TAFs.

&&

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

&&

$$

UPDATE...SRF
DISCUSSION...10
AVIATION...SRF