763
FXUS63 KUNR 171845
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1245 PM MDT Fri May 17 2024

.KEY MESSAGES...

- Cold front this evening with gusty northwest winds.

- Strong to severe thunderstorms late this afternoon and evening
  across northwestern South Dakota with the main threat damaging
  wind gusts.

- Unsettled pattern continues through much of next week.

&&

.DISCUSSION...(Today Through Thursday)
Issued at 222 AM MDT Fri May 17 2024

Water vapor shows upper low over the Northern Rockies with short
wave ejecting into eastern MT. At the surface, cold front extends
from far northwest ND through southeast MT. Temps in the warm
sector across our area early this afternoon area well into the
70s/80s. Skies are mostly clear across our area, but thunderstorms
are developing along the cold front over southeast MT.

Later this afternoon and evening, robust cold front will cross our
western zones and should be all but through our far south-central
SD zones by midnight. Showers/storms will continue to develop
along the front this afternoon as it sweeps southeast. MLCAPE in
the 500-1000J/kg range and inverted-v soundings will support high
based thunderstorms with a damaging wind threat, mainly north of
the Black Hills, into early evening, with activity shifting east
of the forecast area by later tonight. In addition, pressure rises
behind the front in the 3-6mb/3hr range will support a period of
very gusty northwest winds, which may also aid the severe gust
potential with thunderstorms. Current wind advisory looks good.

Dry, cooler, and breezy conditions expected Saturday. Next
shortwave impacts the area late Sunday with a chance of showers
and thunderstorms. Upper trough lingers across the Pacific
Northwest/Northern Rockies through much of next week with a series
of impulses crossing the area. This will result in daily chances
for showers and thunderstorms and temperatures near seasonal
averages.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1233 PM MDT Fri May 17 2024

Thunderstorms will develop this afternoon across far northeast
Wyoming, the Black Hills area, and northwest South Dakota. Strong
winds will be possible with these storms, along with hail and
MVFR conditions. While there is the potential for a storm or two
to impact the KRAP or KGCC terminals later this afternoon and
evening, confidence is low in this occurring and therefore left
mention out of the TAFs. Otherwise VFR conditions are expected
through the TAF period. A cold front moving from northwest to
southeast will bring strong northwest winds to the area after 00z,
with gusts to 45 kt possible.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 6 PM this evening to 3 AM MDT Saturday for
     SDZ001-002-012>014-025-026-031-032-072-073-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...Johnson