607
FXUS63 KUNR 180052
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
652 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.

&&

.UPDATE...
Issued at 649 PM MDT Fri May 17 2024

Thunderstorms have weakened, so have canceled the Severe
Thunderstorm Watch. Northwesterly winds are becoming strong behind
the cold front, and will remain strong overnight.

UPDATE Issued at 355 PM MDT Fri May 17 2024

With the cold front already entering far northwest SD, will start
the wind advisory now for that area.

&&



.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 00Z TAFS Through 00Z Saturday Evening)
Issued At 425 PM MDT Fri May 17 2024

A strong cold front will continue to move across the CWA tonight,
behind which there will be strong northwesterly winds (gusts up to
45 kts) across northwestern SD tonight. Thunderstorms have
developed along the cold front and will shift into central SD
early this evening; these storms are producing strong wind gusts
as well (over 50 kts). Another round of showers could move
through northwestern SD overnight. MVFR conditions will be
possible in any showers/storms; otherwise, VFR conditions are
expected through the TAF period. Skies will clear on Saturday
morning, and winds will decrease through the day.

&&

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

$$

UPDATE...Pojorlie
DISCUSSION/KEY MESSAGES...7
AVIATION...Pojorlie