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721
FXUS63 KUNR 231914
AFDUNR

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

.KEY MESSAGES...

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

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

.DISCUSSION...
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(This Evening Through Sunday)
Issued at 112 PM MDT Sun Jun 23 2024

Upper level ridge continues to build into the region today with
temps responding across the area. Several fast moving impulses on
the northern side of the ridge will keep it subdued, flattening
out as sfc trough wavers over/near the region this week. Dry conds
expected most places today, with perhaps an isolated TS or two in
the evening over NE WY as another weak impulse traverses the
region. Associated sfc trough will settle over the region Monday,
stalling across the far SW. Continued warm on Monday, esp the far
SW FA where a few lower 100s are expected, in addition to
scentral SD where higher humidity will be in place, supporting
near adv levels there. Another impulse will advect through the
flow later Monday, supporting chances for TS in the afternoon and
evening, with convection likely initiating over the higher terrain
along/south of the trough in the far SW. As the wave moves across
the region, elevated showers and storms may develop across NW SD
overnight. Main threat from any storms Monday will be strong wind
gusts given inverted V profiles, but a few rotating storms will be
possible capable of producing large hail. Slightly cooler with
much drier profiles Tues as the the bulk of low level moisture
shifts SE of the region. Have left things dry over the Hills Tue
afternoon given meager moisture, but an isolated shower could
develop over the higher terrain, but would likely stay confined to
the Hills. Warmer and more humid Wed-Thur with return flow per
shortwave ridging. Chances for storms will then return and persist
through the rest of the week most days. A deeper upper trough
will then progress through the flow Thur, supporting more
widespread chances for showers/storms, some potentially severe. It
will also trend cooler Fri-Sat with less humidity.
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&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1139 AM MDT Sun Jun 23 2024

Isolated thunderstorms will be possible across NE WY late this
afternoon and early this evening. Otherwise, VFR conditions will
prevail through the forecast period.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...13