371
FXUS63 KABR 101723 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1223 PM CDT Mon Aug 10 2026

.KEY MESSAGES...

- A Slight Risk (Level 2 of 5) has been issued for storms that
  are expected to organize across central/north central South
  Dakota during this evening, and then spread rapidly east to
  southeast through the overnight hours. Large hail (1 to 2
  inches) and winds in excess of 60-70 mph are possible with
  these storms.

&&

.UPDATE...
Issued at 1214 PM CDT Mon Aug 10 2026

Updated discussion for the 18Z TAFS below.

UPDATE Issued at 1013 AM CDT Mon Aug 10 2026

Satellite indicates a lower stratus deck, around 1000ft, over
south central SD producing some MVFR cigs there. With continuing
daytime heating, this should erode over the next few hours.
Otherwise, smoke aloft continues over the region creating an
ongoing hazy sky. Current temperatures and in the upper 60s to
the lower 70s with dewpoints in the upper 50s to the lower 60s
with overall light winds as high pressure is over the area.
Quiet weather expected before the threat of showers and
thunderstorms move into the region late this afternoon/evening
and continue through the overnight per shortwave and surface
trough. Forecast remains on track.

UPDATE Issued at 614 AM CDT Mon Aug 10 2026

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 1247 AM CDT Mon Aug 10 2026

Northwest flow with a weak trough passage across the state during
the early morning hours. Just a weak low level jet across the area
at about 20kts. Given the rather nebulous setup for weak forcing
aloft and at the surface, CAMS are likewise struggling to come up
with a unified solution and thus will maintain a rather low chance
for POPs through the early morning hours. NAM BUFKIT profiles aren`t
even that unstable with minimal mid level CAPE. Then again, we
remain in this northwest flow regime with a unidirectional shear
environment so can`t rule out a stronger storm or two but the
overall prognosis is for mainly sub-severe type storms and isolated
coverage.

Shift to this evening with a low pressure system developing out west
and an inverted trough extending up across northeast South Dakota. A
weak wave arrives late in the day, supporting convection in
southeasterly low level flow with westerly unidirectional flow
aloft. CAMS for the most part organize into  a complex that drives
across central/north central South Dakota in the evening/early
overnight with an overall rapid progression east southeast across
the state. HREF 0-3km helicity peaks around 300m2/s2 and the 4-hour
max ensemble winds indicate 60+ kt potential with ensembles
highlighting central South Dakota.

In regards to smoke, no real change. The Pacific Northwest and
British Columbia continue to generate a broad expanse of thick smoke
aloft which will continue to track across the region until we get a
pattern change. Flow around the current surface high even as it
moves off to the east currently has no low level smoke to advect
into the area.  The one impact smoke is most likely to have is
influence on high temperatures. While I`ll stick with NBM highs,
realize that initial surface based thunderstorm intensity is
contingent on temperatures and if the expected thick sheen of smoke
knocks down temperatures 2-4F then the resulting convective
evolution may not stick to the current CAM consensus.

The only major change to the pattern and forecast for the next few
days is a much cooler airmass coming in for the latter half of the
work week, as we see an eastern Canadian upper low strengthen, with
a broad high across central Canada which dribbles slightly cooler
air into the Northern Plains.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1214 PM CDT Mon Aug 10 2026

Terminals KABR,KATY,KPIR,KMBG

MVFR cigs continue at KPIR per low stratus around 1000ft,
otherwise VFR cigs for the rest of the terminal sites and hazy
skies due to ongoing smoke aloft. Thunderstorms are forecast to
develop or move in over central SD this evening before merging
and growing upscale into a potential cluster/MCS as the system
tracks east/southeast. Between the individual CAMs, there are
differences in where these storms initially develop, exact
timing/location of upscale growth, and and exact track the
cluster. Consensus seems to highlight mainly central through
east central SD for this convection. Due to this, confidence is
very low on which scenario will play out at this time. Some of
the storms could become severe with large hail (potentially 2"+
in diameter) especially early on this evening with more of a
wind threat tonight/overnight if the MCS develops with wind
gusts in excess of 58kts.

&&

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

&&

$$

UPDATE...MMM
DISCUSSION...07
AVIATION...MMM