485
FXUS63 KUNR 091119
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
519 AM MDT Thu May 9 2024

.KEY MESSAGES...

- Unsettled again today with scattered showers and a few
  thunderstorms.

- Warmer and drier conditions for the weekend.

- Showers and thunderstorms Monday through Wednesday

&&

.DISCUSSION...(Today Through Wednesday)
Issued at 214 AM MDT Thu May 9 2024

The upper low is currently located along the SD/Neb border in an
E-W oriented trough. A W-E oriented upper ridge is flopping
southward out of the Canadian prairie provinces into MT/ND.

Shortwave energy will move westward across the forecast area
producing scattered showers again today. Diurnal heating will
push MUCAPE values to 300-600J/kg over and near the Black Hills,
and southwestern into south central South Dakota this afternoon so
a few thunderstorms will also be possible along with the showers,
mainly near and to the south of I-90. Showers will gradually
decrease in coverage this evening. Breezy northerly winds are
expected today and on Friday.

The upper ridge will continue to sag southward into the northern
plains on Friday which will push the upper low southwest to the
Four Corners region where it will remain relatively stationary
through the weekend as it gets cut off from the flow. Northwest
flow aloft will then develop over the forecast area as an upper
trough drops southward across the Great Lakes region.

With the surface high dropping southward into the forecast area,
winds will be relatively light through the weekend with a warming
westerly downslope component to the surface winds. High
temperatures on the plains are expected to be in the upper 60s to
upper 70s on Saturday and mainly in the 70s on Sunday.

There is a chance of diurnally driven showers over the Black
Hills on Friday afternoon, with dry weather anticipated for
Saturday. A weak wave dropping into the region on Sunday will
then bring slight chances for showers and thunderstorms with
better chances over and near the Black Hills on Sunday afternoon.

The first half of next week will be unsettled again with daily
chances for showers and thunderstorms.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Friday Morning)
Issued At 518 AM MDT Thu May 9 2024

Scattered rain showers will persist through the morning into the
evening hours today before tapering off after 00z Thursday night.
These showers will bring mainly MVFR/IFR conditions over
northeastern WY, the Black Hills, and far western SD. Conditions
will slowly improve throughout the day, and then VFR conditions
should take hold for most places this evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...10
AVIATION...SE