845
FXUS63 KUNR 021125
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
525 AM MDT Sun Jun 2 2024

.KEY MESSAGES...

- Warm today with chances for showers and thunderstorms. Severe
  storms possible, mainly east of the Black Hills.

- Warm weather expected for much of the upcoming week, with drier
  conditions developing mid to late week.

&&

.DISCUSSION...(Today Through Saturday)
Issued at 230 AM MDT Sun Jun 2 2024

Current surface analysis shows warm front across the central
Plains, with a cold front across the northern Rockies into the
northern Great Basin region. A surface trough is in place from
north to south across the central and southern high Plains. Upper
level analysis still shows low pressure over central Canada, with
west-southwest flow across the Plains and Rockies. Embedded
disturbances aloft, combined with a low level southerly jet across
western NE and much of the western Dakotas has helped to produce
isolated to scattered showers and thunderstorms across a good
portion of the area overnight. Right now, most of the activity is
north and east of the Black Hills. Temps are mostly in the 50s and
lower 60s with south to southeast winds.

Chances for showers and thunderstorms will persist across much of
the area today, mainly early this morning and then in the afternoon
and early evening, as cold front pushes slowly southeast across the
area during the day. The front should make it to far western SD and
the Black Hills toward midday and into far eastern portions of the
CWA during the mid to late afternoon. High temperatures will range
from the upper 60s to mid 70s over northeast WY and the Black Hills
to the mid 80s toward south central SD. The highest risk for severe
storms in our area should be along the front as it crosses south
central SD later in the afternoon, with steep lapse rates ahead of
the front helping to produce MLCAPE of 1500 to 2500 j/kg during this
time, along with moderate shear. Large hail and strong wind gusts
would be the main threats before storms move east of the area. Post
frontal showers and storms are expected further west as well during
the afternoon. There looks to be sufficient CAPE and shear to
support isolated strong to severe storms across much of western SD.
Activity will dissipate and exit the area during the evening.

The cold front washes out south and east of the area later tonight,
with warm air returning for Monday, ahead of the next cold front.
Highs will mostly be in the 80s, with 70s over the higher Black
Hills. A few places across the southwest SD plains could approach 90
degrees. A developing upper trough over the northern Rockies will
push east over south central Canada and the northern Plains late
Monday into Tuesday. Accompanying cold front will slide through the
area Monday night. Chances for showers and some thunderstorms will
increase again late Monday and especially Monday night, with the
better chances generally from northeast WY to northwest SD. MUCAPE
values are forecast to be minimal, so the threat for any stronger
storms will be very low Monday and Tuesday. The rest of the week
looks to be mainly dry as ridge builds over the western US and large
trough develops over the eastern US mid to late week. After a more
seasonable day on Tuesday, temps look to be at least slightly above
average for the rest of the week and into next weekend. There is
more uncertainty on temps ranges toward the end of the forecast
period, depending on where the western ridge ultimately sets up late
in the week.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 520 AM MDT Sun Jun 2 2024

Isolated thunderstorms are expected to develop after 21Z this
afternoon and increase in coverage early this evening, especially
toward central South Dakota. Severe thunderstorms are possible.
Thunderstorms are expected to move off to the east of the forecast
area by 05Z this evening. LCL MVFR conditions are possible near
any precipitation, otherwise VFR conditions will prevail through
the forecast period.

&&

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

$$

DISCUSSION/KEY MESSAGES...26
AVIATION...10