162
FXUS63 KUNR 131114
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
514 AM MDT Mon May 13 2024

.KEY MESSAGES...

-Unsettled this week with periodic chances for showers and
 thunderstorms, best chances late tonight into Tuesday.

-Smoke from Canadian forest fires will slowly push SE out of the
 region and diminish today, although it will likely return later
 in the week.

-Seasonally temps most of the week.

&&

.DISCUSSION...(Today Through Sunday)
Issued at 105 AM MDT Mon May 13 2024

Mean NW flow can be expected through the week, supporting
occasional weak PAC impulses. Each of these impulses will have the
ability to support isold-sct shra/ts as a frontal boundary wavers
over the region. Moisture will continue to be limited with most
of the impulses as the GOMEX remains closed to the region, leaving
the main moisture source as leftover PAC moisture. Slow moving
upper trough will support increasing LSA with mid level moisture
adv across the region today. This will bring increasing low
chances for showers/storms across the western third, starting
first over the Black Hills, then across NE WY. CAPE and shear
remain highly limited with severe weather not expected. As the
upper trough shifts east overnight, pos theta-e adv will support
shower chances across the FA, esp the NW third closest to the
best LSA. Shower chances will shift SE through the day Tues, with
NW winds increasing behind the sfc cool front, possibly bringing
more smoke to the region. Unsettled NW flow will persist through
the remainder of the week with chances for showers each day.
Things trend drier later in the week, with continued low chances
for showers each day. Expect most areas will remain dry toward the
end of the week, with more isolated convection. Overall, temps
will be seasonal with highs generally in the 70s, with Tue-Wed
being the coolest days, given weak CAA and lingering shower
chances. Overall, any appreciable rain will be localized with most
places seeing a few hundredths or less given lack of deep
moisture and convective nature of precip.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 513 AM MDT Mon May 13 2024

Wildfire smoke filtering into the region may cause periods of MVFR
visibilities this morning, mainly across western to central South
Dakota. Expect gradual improvement after 18-20z this afternoon.

Isolated to scattered thunderstorms will develop this afternoon
and push eastward across the area tonight. Lower flight
conditions and erratic and gusty winds are possible near any
storms. Otherwise, VFR conditions are expected through the TAF
period.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...SE