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137
FXUS63 KUNR 231054
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
454 AM MDT Sun Jun 23 2024

.KEY MESSAGES...

- Warm and mainly dry for the first half of the week.

- Cooler for the end of the week with an uptick in thunderstorm
  activity.

&&

.DISCUSSION...(Today Through Saturday)
Issued at 151 AM MDT Sun Jun 23 2024

Current surface map places high pressure across the Dakotas. Flat
upper level ridge is located across the Rockies. As ridge shifts
eastward today, low level thermal ridge surges north and east.
Surface trof will be located along the South Dakota/Wyoming border
this afternoon, dividing the warm/dry and well mixed boundary
layer to the west and slightly cooler/more humid southeasterly
flow on the South Dakota plains. Decent amount of buoyancy across
the western South Dakota plains but strong cap and lack of
forcing should limit thunderstorm development. A few high based,
mostly dry, thunderstorms are possible across northeastern Wyoming
late this afternoon and early evening. High DCAPE will result in
locally strong winds in any storm that does develop there.

Strong shortwave track across southern Canada on Monday with
surface trough sliding through the forecast area. Trough stalls
out along southern forecast area. Monday will be the warmest day
with highs in the upper 90s across southwest and south central
South Dakota. A few thunderstorms are possible Monday afternoon,
mainly across the Black Hills. Weak 750-600mb theta-e advection
Monday night will keep small chances for thunderstorms, mainly
across northwest South Dakota.

Upper trough moves across the northern Rockies into the plains
late in the week with cooler temperatures and increasing chances
of thunderstorms.

&&

.AVIATION...
-- Changed Discussion --
(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 452 AM MDT Sun Jun 23 2024

VFR conditions will prevail through the forecast period.
There is a slight chance for a thunderstorm over northeastern
Wyoming from 23Z to 03Z this evening.
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&&

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

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...10