836
FXUS63 KUNR 141854
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1254 PM MDT Tue May 14 2024

.KEY MESSAGES...

-Unsettled through the weekend with periodic chances for showers
 and thunderstorms, with best chances now through Wednesday
 morning.

-A few strong storms are possible this afternoon and early evening
 in south central SD.

-Seasonal temps through the weekend, with Friday the warmest day.

&&

.DISCUSSION...(This Evening Through Tuesday)
Issued at 1231 PM MDT Tue May 14 2024

Water vapor shows upper trof over the Northern Rockies/Northern
Plains region with upper ridge over the Pac NW. First upper low
within the trof is over southwest SD with the second over
southeast ID. At the surface, trof extends from eastern CO
northward through the western Dakotas, more specifically in our
area extending from just east of Porcupine to northeast of KPHP.
Scattered to numerous showers/storms cover northeast WY through
the Black Hills into southwest SD early this afternoon.

Current upper low over southwest SD will migrate slowly east the
rest of this afternoon and evening, with scattered to numerous
showers/storms continuing. There is some chance for a few stronger
to severe storms across southwest into south-central SD through
the afternoon, with the better chance over south-central SD in
closer proximity to the surface trof where MLCAPE up to around
1000J/kg exists. Shear is marginal for rotating updrafts, but
inverted-V profiles suggest some wind threat. Much of the threat
should push east of our area by early evening.

Next upper low moves in overnight and Wednesday morning,
bringing another round of showers/storms. This activity should
decrease from northwest to southwest during the afternoon
Wednesday as low shifts east and drier/breezy northwest winds
develop.

Weak upper ridge in the northwest flow moves through the Northern
Plains Thursday/Friday for somewhat drier and warmer temps. Friday
looks to be the warmest day as thermal ridge peaks overhead, with
many locations climbing into the 80s especially east of the Black
Hills. Some showers/thunderstorms will remain possible, mostly
diurnally driven and over higher terrain.

A series of upper trofs will move through from the weekend
through mid next week, typical of springtime weather. An
unsettled pattern will result with a swing up/down of temps, but
temps will remain relatively close to seasonal averages.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 1126 AM MDT Tue May 14 2024

Showers and storms are expected across the region today. MVFR/IFR
conditions are possible in and near any stronger cores. IFR
ceilings (even transient LIFR) are expected at KGCC and NE WY
overnight tonight, beginning around 08-12z and continue into
Wednesday morning.

&&

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

$$

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