Area Forecast Discussion
Issued by NWS Rapid City, SD

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852
FXUS63 KUNR 151721
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1021 AM MST Sun Jan 15 2017

.SHORT TERM...(Today Through Monday Night)
Issued at 224 AM MST Sun Jan 15 2017

09z surface analysis had high over the Great Lakes with weak
return flow over the CWA ahead of lee trough in place from central
MT into central CO. Two systems of interest on water vapour -
upper low over northern Mexico and shortwave hitting the coast of
BC.

Today and tonight, upper low moves into the southern plains as
shortwave moves into south central Canada. Low level flow becomes
increasingly westerly with weak warm air advection. Pesky arctic air
over entrenched snow cover will play havoc with temperatures again.
Highest readings over the Black Hills given lower tropospheric
thermal profiles. Lift ahead of upper low will bring small chances
for a wintry mix over south central SD late tonight.

Monday, northern stream shortwave pushes a cold front through the
CWA with breezy northwest winds behind it. Upper low swings into the
Midwest with lingering -SN ending over south central SD early. Weak
cold air advection expected. However, well-mixed boundary layer over
northwest SD may actually allow higher temperatures behind the cold
front compared to today.

.LONG TERM...(Tuesday Through Saturday)
Issued at 224 AM MST Sun Jan 15 2017

A dry and mild weather pattern can be expected for much of next
week. Ridging will help to bring above average temperatures across
the CWA by midweek. Snow cover will limit temperature potential in
some areas, especially to the northeast of the Black Hills, where
deeper snowpack is in place. However the warmest days still appear
to be Wednesday and Thursday. Highs these days will reach the
upper 30s to upper 40s...with some 50 across the downsloping
eastern foothills. The next chance for precip will be toward the
end of the week as cyclonic flow redevelops across the western
CONUS. There is still uncertainty exactly how this will play out,
but overall better chance for snow and cooler temperatures closer
to or just below seasonal averages.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1020 AM MST Sun Jan 15 2017

VFR conditions will continue across much of the area through
Monday morning. MVFR/IFR conditions are possible over far south
central SD late tonight and Monday morning, with patchy light
freezing rain or light snow possible as well.

&&

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

$$

SHORT TERM...Helgeson
LONG TERM...13
AVIATION...26



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