474
FXUS63 KUNR 050850
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
250 AM MDT Sun May 5 2024

.KEY MESSAGES...

-Windy across the western SD plains today.

-Cool, windy, and unsettled for much of this week.

&&

.DISCUSSION...(Today Through Saturday)
Issued at 203 AM MDT Sun May 5 2024

08Z upper level analysis has shortwave ridge across the Central
Plains, with deep upper low across northern California. Skies are
mainly clear across the Northern Plains at the moment. At the
surface, high pressure resides across the Northern and Central
Plains, with strong low pressure over Idaho. Temperatures at 2am
across the forecast area are in the 40s, with southerly winds.

Transient upper ridge will quickly shift east today as large upper
low shifts into the Great Basin area. Surface low pressure over
Idaho will move into western Wyoming today, producing a strong
pressure gradient across the Northern Plains. Southerly winds
around 30 mph with gusts to 45 mph will develop across the
forecast area by mid day, and persist into the evening hours. As
the surface low approaches the area, some showers and
thunderstorms could develop over northeast Wyoming late in the
afternoon, with precip chances shifting into western South Dakota
this evening. Widespread severe storms are not anticipated at this
time.

Upper low crosses the Rockies late tonight into Monday, with more
widespread rain showers and thunderstorms expected across
northeast Wyoming and far western SD. Rainfall amounts across
northeast WY, the Black Hills, and northwest South Dakota will
likely be half an inch to an inch on Monday. More scattered
showers and storms are expected south and east of the Black
Hills. As the strong surface trof shifts through the area, gusty
west to northwest winds are expected, which may require another
wind advisory across the SD plains. Temperatures should be cool
enough Monday night for some light snow accumulations across the
higher elevations of the Black Hills.

Strong system becomes stacked across western North Dakota by
Tuesday, with blustery conditions continuing across the area.
Precip chances become lighter and more scattered on Tuesday as the
main weather system resides north of the area. Once again, wind
highlights will likely be needed on Tuesday, especially across
northwestern South Dakota.

Upper low and main upper trof finally shifts southeast on
Wednesday, dropping back through central SD on its way out of the
Northern Plains. Unsettled weather continues with better chances
for precipitation across the SD plains. West to northwest winds
remain very breezy. Thursday will be slightly warmer with
continued chances of light rain showers and isolated
thunderstorms, along with breezy north winds.

Weather will slowly warm up and dry out toward the weekend as the
upper low finally exits the region and a ridge of high pressure
builds across the western CONUS.



&&

.AVIATION...(For the 06Z TAFS Through 06Z Sunday Night)
Issued At 1049 PM MDT Sat May 4 2024

Low-level wind shear is possible after 06-08z tonight, especially
over the foothills and western SD plains. Gusty south-
southeasterly winds will increase in coverage from KGCC after 06z,
spreading westward into the morning hours for western SD/KRAP.
These winds will persist through Sunday afternoon; gusts 30-40
knots are likely. Chances of showers and storms after 18z across
NE WY, with spotty showers/storms spreading into western SD Sunday
afternoon and evening. Outside of transient MVFR/IFR conditions in
heavier showers, VFR conditions will prevail through the forecast
period.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from noon MDT /1 PM CDT/ today to 11 PM MDT
     /midnight CDT/ this evening for SDZ001-002-012>014-030>032-
     042>044-046-047-049-073-075>078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...15
AVIATION...SE