027
FXUS63 KUNR 210425
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1025 PM MDT Mon May 20 2024

.KEY MESSAGES...

- Widespread showers/isolated thunderstorms continue through
  Tuesday.

- Potential for light snow accumulations for higher elevations of
  the Black Hills tonight.

- Active pattern continues through the Memorial Day holiday
  weekend.

&&

.DISCUSSION...(This Evening Through Monday)
Issued at 1225 PM MDT Mon May 20 2024

Water vapor shows upper trof over the northwestern CONUS with lead
short wave ejecting into the Northern Plains. At the surface,
broad high covers the Northern Plains with early afternoon temps
in the 40s/50s under mostly cloudy skies. Showers are shifting
north/east across our southern zones, mainly south of I-90 at this
time.

Showers and an isolated thunderstorm or two will continue to shift
north/east through the region this afternoon and tonight, with all
but possibly far northwest SD receiving beneficial rain.
Precipitation will continue through Tuesday across much of the
area as main upper trof shifts into the Northern Plains. Fairly
high probability that areas near and south of I-90 will receive
near or a little more than 0.50 inches, with substantially less
than that further north. Thermal profiles do suggest some
accumulating snow at higher elevations, but amounts will be light.
Temperatures will remain below average through Tuesday.

Upper trof departs Tuesday night, with drier conditions expected
Wednesday and Wednesday night as short wave ridge builds in. Highs
will be in the 60s/70s with small chances for diurnal
showers/storms mainly around the Black Hills.

Next upper trof crosses the Northern Rockies on Thursday, with
increasing chances for precip across our area in the
afternoon/evening. Slightly drier for Friday/Saturday before next
trof moves in Sunday. Temperatures late week into the weekend
should be close to seasonal averages.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1021 PM MDT Mon May 20 2024

Periods of rain will continue through tomorrow, especially along
and south of Interstate 90. MVFR/IFR conditions are expected
mainly along and south of I90. Conds will improve NW-SE Tue
afternoon as rain ends and drier air moves into the region, with
conds trending VFR all places Tue evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...Johnson
AVIATION...JC