494
FXUS63 KUNR 011913
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
113 PM MDT Sat Jun 1 2024

.KEY MESSAGES...

- Warming up through weekend with chances of showers and
  thunderstorms at times across the Black Hills and areas to the
  south/east. Some storms could be strong to severe this weekend.


- Warm weather expected for much of next week with drier
  conditions mid to late week.

&&

.DISCUSSION...(This Evening Through Saturday)
Issued at 1238 PM MDT Sat Jun 1 2024

Water vapor shows upper trof axis over the far eastern Dakotas,
weak ridge over the Northern Rockies, and next trof over the far
western CONUS. At the surface, high is over southern ND with weak
surface trof near I-90 across western SD. Early afternoon temps in
the 60s/70s with weak easterly flow resulting in some towering
cu and a developing thunderstorm over the northern Black Hills.

Even though there is ample CAPE/shear near and south of I-90
across western SD, short wave ridging building in is trying to
keep a lid on development this afternoon (outside of the Black
Hills) and may limit overall coverage. The best locations for
development this afternoon/early evening would be across the Black
Hills into southwest/south-central SD where a stronger storm or
two is possible. Better chance for activity arrives later this
evening and overnight as jet streak moves through the weak ridge
and modest low level jet develops.

On Sunday, upper trof works through the Rockies with a cold front
working eastward across our zones. The cold front will likely push
through all but central SD by about noon. Given the timing of the
front, best severe threat will be across our south-central SD
zones in the afternoon to early evening where CAPE/shear
will be ample for supercells. This looks to be depicted well by
most CAMs. Highs will likely range from the lower/mid 70s in
northeast WY to the west of the front, and well into the 80s
south/east of the Black Hills.

Much of Monday looks mostly dry behind departing upper trof, but
temps should rebound quickly as return flow gets going early in
the day. However, storms will be possible again by late Monday in
our western zones as next trof dives quickly into the Northern
Rockies. Storms may linger into Tuesday before trof pushes east.

For the rest of the week, a building ridge over the western CONUS
and a large scale trough over the eastern CONUS will likely keep
our area at least seasonably warm and mostly dry. There is
uncertainty with the temp forecast for mid to late week, depending
on whether the ridge can eventually progress eastward into the
Plains toward the end of the week.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1124 AM MDT Sat Jun 1 2024

Isolated to scattered thunderstorms are expected to develop this
afternoon and evening. MVFR conditions are possible near any
showers and thunderstorms, otherwise VFR conditions will prevail
through the forecast period.

&&

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

$$

DISCUSSION/KEY MESSAGES...Johnson
AVIATION...Dye