562 
FXUS63 KUNR 010515
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1015 PM MST Mon Nov 30 2020

.UPDATE...
Issued at 704 PM MST Mon Nov 30 2020

Breezy conds continue across portions of the nern WY plains this 
evening. Some stronger winds are also expanding to the Black 
Hills and foothills, particularly the northern foothills and
southern to Hermosa foothills. Suspect stronger winds will 
persist across the southern/Hermosa foothills over the next 
several hours with sfc low progged to shift east, then southeast, 
of the hills while pressure rises associated with cold front 
approach. 

Downslope winds in these areas, coupled with dry prefrontal air 
mass, could produce occasional critical fire wx conds thru the 
night, though obs across the Black Hills indicate some modest 
cooling and moistening since the 00z UNR RAOB. RH will improve 
later in the night, particularly after the cold frontal passage 
around midnight.

&&

.DISCUSSION...This Evening Through Monday
Issued at 227 PM MST Mon Nov 30 2020

Upper ridge overhead will move east as an upper low crosses the
northern US. Light snow showers are possible over northeastern WY
and the northern Black Hills after midnight through Wed morning, 
with some snow showers possible over southwestern SD Tues night-
Wed morning as the upper low deepens over the central Plains. A
cold front will cross the area after midnight tonight, bringing
strong northwest winds to the area during the day Tue. Forecast 
soundings show momentum transfer winds over 30kt reaching the
surface over the SD plains, so will issue a wind advisory for the
afternoon. Upper ridge builds after low moves away, with warm and
dry conditions returning toward the end of the week.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1015 PM MST Mon Nov 30 2020

MVFR to IFR cigs and vsbys in SHSN will gradually overspread nern
WY and the Black Hills late tonight into Tuesday AM behind a cold
front. By the afternoon, these SHSN and associated reduced cigs/vsbys
should be concentrated over the nrn Black Hills. Meanwhile, breezy
NW winds will develop behind the front, increasing after daybreak.
Gusts to 40-45 kt will be possible from late morning thru the 
afternoon, particularly over the far wrn SD plains. Winds will
diminish after 00z Tuesday.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 10 AM to 5 PM MST Tuesday for SDZ001-002-
     012>014-025-026-030>032-043-072-073.

WY...None.
&&

$$

Update...Sherburn
DISCUSSION...55
AVIATION...Sherburn