816
FXUS63 KUNR 020842
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
242 AM MDT Thu May 2 2024

.KEY MESSAGES...

-Cool and unsettled through Friday

-Breezy/windy and warmer this weekend

-Strong storm early next week with windy/wet conditions.


&&

.DISCUSSION...(Today Through Wednesday)
Issued at 240 AM MDT Thu May 2 2024

Current surface map places weak cold front across western South
Dakota. Scattered rain showers continue east of the Black Hills
into northwestern South Dakota with some light snow in the Black
Hills. Showers associated with shortwave rotating around southern
Saskatchewan upper low. As shortwave continues to move east, most
shower activity will be out of the area early this morning. With
cyclonic flow around upper low and steep lapse rates with cold air
aloft, shower activity returns this afternoon. Drying in low
levels will limit rainfall amounts and promote gusty winds with
the showers. Upper low shifts eastward today/tonight with another
impulse rotating through Friday.

Upper ridge builds across the Northern Plains this weekend as
strong low digs through the western CONUS. Strong pressure
gradient/pressure falls will favor gusty south winds over the
weekend. Warmest day will be Sunday with highs mainly in the 70s.

Low deepens across the Intermountain West and lifts into the
Northern Plains early next week. Decent agreement with
deterministic GFS/ECMWF/GEM with low over western North Dakota on
Tuesday. Ensemble cluster analysis suggest above average
confidence with that solution. Chance for shower/thunderstorms
increase late Sunday into Monday when best QG forcing lifts
through the area. With upper low north of the forecast area,
the longer duration widespread precipitation will be further
north/northwest. Tight pressure gradient should result in a period
of strong winds Tuesday/Wednesday.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Thursday Night)
Issued At 1042 PM MDT Wed May 1 2024

Areas of -SHRA/-TSRA with associated MVFR conditions will
continue to slowly move out of western SD through the overnight
hours with most of the precip out of the forecast area by 10z.
Areas of MVFR/IFR cigs will also develop towards south central SD
overnight. Conditions will gradually improve to VFR from west to
east with VFR area wide by around 16z.

&&

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

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...Wong