818
FXUS63 KABR 092046
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
346 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.

&&

.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 /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1241 PM CDT Wed Jul 9 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions across the region through much of the afternoon.
Will be watching potential for TSRA/+TSRA across central SD
(KPIR/KMBG) late afternoon into early evening, then spreading
eastward towards KABR/KATY later in the evening/nighttime. Still
some questions in regards to areal coverage and placement of said
storms, so will handle with PROB30 for the time being until radar
activity lights up and we can get an idea of where storms will
track. Heavier downpours have the potential for MVFR/IFR VSBY.
Severe storms are possible, with large hail (GR) and squall (SQ)
conditions in strong surface wind gusts from some westerly
component perhaps in excess of 60 knots.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 8 PM CDT /7 PM MDT/ this evening for
     SDZ003>006-009-010-015>018-033>037-045-048-051.

MN...None.
&&

$$

DISCUSSION...TMT
AVIATION...TMT