811
FXUS63 KUNR 181810
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1210 PM MDT Thu Jul 18 2024

.KEY MESSAGES...

- Near average temperatures with a daily chance of thunderstorms
  through the weekend. Isolated severe storms possible Friday

- Trending warmer and drier for the first half of next week with
  elevated fire weather conditions.

&&

.DISCUSSION...(Today Through Wednesday)
Issued at 210 AM MDT Thu Jul 18 2024

Current surface map places high pressure across the Upper Midwest
with weak return flow across the high plains. A few mid/high
clouds across the area with temperatures in the 60s on the
plains/50s for the Black Hills. Water vapor shows upper high
across the Intermountain West with shortwave over the Pacific
Northwest. For today, surface high slips southeast with weak
trough developing along the Rockies. Steep lapse rates will result
in a bit of buoyancy across the forecast area this afternoon and
evening. Overall, lack of forcing should limit thunderstorm
development this afternoon to higher terrain of eastern Wyoming
and the Black Hills. With MLCAPE around 1000J/KG and marginal
shear, an isolated severe storm is possible across the
central/southern Black Hills this afternoon/early evening.
Thunderstorm coverage will increase overnight with combination of
shortwave moving into eastern Montana and theta-e advection on
nose of low level jet. Thunderstorms continue through the day
Friday as shortwave moves through western South Dakota mid-day.
Sufficient buoyancy/shear for a few robust updrafts with a severe
wind/hail threat later tonight into Friday.

Upper ridge becomes more amplified over the weekend with
northerly flow aloft over the Plains. Embedded impulses will keep
small chances for thunderstorms in forecast each day. Early next
week, upper trof moves into Pacific northwest, nudging the ridge
into the Northern Plains. This will bring warmer/drier conditions
across the forecast area. With that, elevated fire weather
conditions are expected.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1208 PM MDT Thu Jul 18 2024

Mainly VFR conditions are expected through the valid fcst period.
Isolated showers/thunderstorms will develop this afternoon across
the Black Hills...with localized MVFR vsbys associated with some
of the stronger storms. A stronger upper level disturbance will
move through the region aft 06z...bringing scattered -shra/-tsra
across the region as well.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...Hintz