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000
FXUS63 KUNR 060848
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
248 AM MDT Thu May 6 2021

.DISCUSSION...(Today Through Wednesday)
Issued at 245 AM MDT Thu May 6 2021

Current surface map places high pressure across the Northern
Plains with a few clouds and chilly temperatures. For today into
Friday, upper level ridge shifts into the plains with low level
temperatures peaking Friday afternoon. Will become windy Friday
with tight pressure gradient between surface high over the western
Great Lakes and pressure falls along the Rockies. Upper trough
digging through the Pacific Northwest sends initial impulse into
the western Dakotas Friday night. A few showers/thunderstorms
possible with 850-700mb theta-e advection combined with some mid
level instability. Upper low cuts off Saturday over the northern
Rockies. Good chance for precipitation across northwest South
Dakota with sustained frontogenesis/upper level diffluent flow.
Thermal profiles cool Saturday night, with 0C wet bulb
temperatures near the surface across northwest South
Dakota...supporting some rain/snow mix.

Upper low weakens Sunday, with reinforcing impulse digging through
the central Rockies Monday/Tuesday. Chance of showers continue,
with best lift shifting into southern portions of forecast area.
Thermal profiles support rain/snow mix for higher elevations,
especially at night.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Thursday Night)
Issued At 1031 PM MDT Wed May 5 2021

VFR conditions are expected through the TAF period.

&&

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

$$

DISCUSSION...7
AVIATION...15