016
FXUS63 KABR 100309 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1009 PM CDT Wed Jul 9 2025

.KEY MESSAGES...

- Enhanced/Slight risk (level 3/2 of 5) for severe storms across
  the region into the evening hours. Hail up to 2 inches in
  diameter possible over central/north central SD late this
  afternoon, with gusts up to 75 mph into this evening.

- Heat and humidity today and Thursday (especially over central
  South Dakota), with highs in the 90s and heat indices
  approaching 100 degrees.

- Marginal Risk (level 1 of 5) for severe storms
  Thursday/Thursday night. Main risks are hail up to around
  quarter size and wind gusts of 60 mph.

&&

.UPDATE...
Issued at 957 PM CDT Wed Jul 9 2025

Continuing to track a line of thunderstorms of which some have
been severe. This line has had the history of producing strong
wind gusts between 60-70 mph with localized stronger gusts in some
areas. Heavy rainfall has also been observed with one inch or more
an hour rainfall rates. Good news on the front is that this line
continues to progressively shift eastward with rain coming to an
end relatively quickly. Severe weather threat will continue for
northeast SD through the next 2-3 hours or so before this activity
begins to weaken as it approaches the MN border.

UPDATE Issued at 640 PM CDT Wed Jul 9 2025

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

&&

.DISCUSSION...
Issued at 345 PM CDT Wed Jul 9 2025

Convection is beginning to fire along the surface boundary across
northwest SD into southwest ND. Swath of very unstable air with
MLCAPE values in excess of 4000 J/KG lies from central ND, southeast
into the James River valley. Bulk shear values are around 30 knots
over western SD. So, although the current storms are not developing
over the most unstable air, anything that moves closer to central SD
will be approaching very buoyant air. Parameters continue to support
potential for large hail up to 2 inches in diameter across central
SD, plus a strong wind threat up to around 75mph also over central
SD eastward into the James River valley. Severe watch 498 is already
in effect across central SD into the evening hours.

Also for this afternoon/evening, went ahead and issued a Heat
Advisory as several locations were in that 100-108 heat index range,
a bit higher and more expansive than what the forecast looked like
this morning. Dewpoints are a bit higher than forecast in some
areas, leading to the higher heat indices. Also, actual air
temperatures are flirting with 100 over central SD.

More potential for precipitation and perhaps strong/severe storms
arrives Thursday/Thursday night. Although, the timing of the mid-
level wave and associated best lift/ascent may be later in the
evening, thus leaving more widespread coverage to hold off until the
overnight hours.

Cold front moves through the region on Friday, bringing in cooler
air as 850mb temps drop into the low to mid teens C. High
temperatures drop back into the upper 70s to low 80s on Friday,
along with lowering dewpoints.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 640 PM CDT Wed Jul 9 2025

Terminals KABR,KATY,KPIR,KMBG

An overall prevailing condition of VFR can be expected at all
terminals through this forecast cycle. Continuing to monitor
TSRA/+TSRA entering central sections of South Dakota early this
evening. KMBG is the only site that will imminently be affected by
this activity. So, included VCTS mention right at the beginning of
the TAF valid period with a TEMPO group for +TSRA that will be
capable of producing vsbys down to at least MVFR or potentially
lower into IFR depending on the intensity of the activity. KPIR
will have the potential to see similar conditions later this
evening. Farther east, a little more uncertain but retained PROB30
groups at KABR/KATY by late evening. Some of the stronger cells
will still be capable of producing large hail and strong
thunderstorm wind gusts in excess of 60 knots.


&&

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

$$

UPDATE...Vipond
DISCUSSION...TMT
AVIATION...Vipond