687
FXUS63 KABR 281944
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
244 PM CDT Fri Aug 28 2026

.KEY MESSAGES...

- Storms develop this evening and continue overnight tonight. A
Marginal Risk (level 1 of 5) for severe weather is in place. Hail of
one inch in diameter and wind gusts of 60 to 70 miles per hour will
be the main severe hazards.

- Saturday evening, A Slight Risk (level 2 out of 5) for severe
weather is in place across north central SD, with a Marginal Risk
for areas along and west of the James River Valley. Hail of one inch
in diameter and wind gusts of 60 to 70 miles per hour are once again
the expected severe threats.

- Storm chances return once again Sunday, where another Marginal
Risk for severe weather is in place, this time covering the entire
forecast area. Hail of one inch in diameter and wind gusts of 60 to
70 miles per hour will be the main severe threats. The best chances
for severe weather will be during the evening hours over north
central South Dakota.

&&

.DISCUSSION...
Issued at 232 PM CDT Fri Aug 28 2026

As of roughly 19Z this afternoon, some scattered light rain showers
are moving over the forecast area. Expectations over the next few
hours are that these rain showers will maintain their current
strength as they move eastward, producing light rain. No severe
weather is expected with these showers, although can`t quite rule
out a stray pulse of lightning or two in the strongest showers.

This evening, an upper-level shortwave along with a developing low-
level jet will move over the region, helping to develop the next
round of showers and storms. Expectations for tonight are that
storms will develop over central South Dakota this evening and
progress eastward through the overnight period. There is also some
signal in CAMs showing additional develop in North Dakota late this
evening that will drop south into northeastern South Dakota and
western Minnesota. Comparing the latest CAM guidance, it seems that
individual models show a signal for storms in either central or
northeastern South Dakota, but very few show both. Ensembles trend
towards the central South Dakota scenario, and for that reason
forecaster confidence is a bit higher in that area seeing severe
weather tonight. Currently, a Marginal Risk for severe weather is in
effect for the entire forecast area tonight.

High-resolution ensemble models indicate that the hail threat today
will most likely be confined to central South Dakota. There, MUCAPE
of 1000-2000 J/kg is expected, along with shear of 30-40 knots and
mid-level lapse rates between 7 and 8 C/km providing additional
support for the hail threat. As storms progress beyond central South
Dakota, the signal in the Updraft Helicity tracks drops off
significantly, thereby reducing the hail potential moving into the
overnight period. Wind will also be a severe threat from these
storms, and likely becomes the dominant threat as storms progress
into northeastern South Dakota. However, there is still some
significant uncertainty as to how exactly storms will evolve during
the overnight period and if storms will maintain their strength as
the threat moves east.

Another shortwave aloft and associated vorticity maximum is set to
move into the region Saturday evening, thereby creating another
chance for storm development. North central South Dakota is the main
area of concern on Saturday, and a Slight Risk has been issued.
Storms will once again be expected during the evening to overnight
time frame, although there is still a bit of uncertainty on how far
south storms will reach during the overnight period. For storms that
do develop over and/or move into northern South Dakota, highest
confidence is currently in the potential hail threat. Similar MUCAPE
values of 1000-2000 J/kg are expected, with perhaps a slight
increase in shear from today`s setup to 40-50 knots. A bit less
confidence in the wind threat currently, but with pockets of 1000
J/kg of DCAPE potentially present along with some CAMs resolving a
quasi-linear storm mode, severe wind will likely also be a threat.

Starting Sunday and into next week, the broad upper-level ridge that
has been in place will shift eastward. As a result multiple upper-
level jet streaks are set to pass over the region through early next
week. This setup will be conducive to additional rain chances, with
the best chances generally located along the North Dakota/South
Dakota border. On Sunday in particular, another Marginal Risk for
severe weather is in place. Beyond that point, confidence drops in
the severe weather potential over the Aberdeen forecast area.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1215 PM CDT Fri Aug 28 2026

Terminals KABR,KATY,KPIR,KMBG

Main aviation concern today are showers and storms moving across the
area. As of 17Z, afternoon showers appear to be fairly weak and are
scattered in nature, creating some minor visibility reductions at
worst. An occasional pulse of lightning was observed in these
showers earlier this morning, but over the hour no lightning has
occurred. This evening, another round of showers and storms will
move into the forecast area from the west. These storms will be much
more organized than the ongoing system, and may be severe. Storms are
expected to track into central and north central South Dakota during
the evening time frame, continuing through northeastern South Dakota
and western Minnesota during the overnight period. Due to some
lingering uncertainty, have kept these storms within PROB30 groups
in the 18Z TAFs. In general ceiling are expected to remain above
MVFR thresholds despite the storms, but visibility reductions due to
the rain will be the primary cause for category reductions through
the TAF period. Storms are expected to exit the forecast area and
continue into Minnesota by sunrise Saturday morning at the
latest.

&&

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

&&

$$

DISCUSSION...BC
AVIATION...BC