Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 271726

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1026 AM MST Mon Feb 27 2017

Issued at 1026 AM MST Mon Feb 27 2017

Current surface analysis shows nearly stationary frontal boundary
across far southern MT and northern SD. An area of low pressure is
located across southern WY. Upper level analysis shows
southwesterly flow across the region, with strong jet from the
Great Basin region through the Northern Plains. Upper level
trough is moving into the Northern Rockies. Current KUDX radar is
showing snow showers over the southern Black Hills and parts of
the southwest SD plains. The more significant activity is over the
Custer area right now, with some accumulations expected through
the midday hours. Temps are in the mid 20s to upper 30s right now
with south to southwest winds in most areas, southeasterly to the
north of the boundary over northwest SD. Breezy conditions across
south central SD.

Have updated to raise pops and add accumulations across the
southern Black Hills area for the late morning and early afternoon
hours. Amounts of an inch or two are expected in some areas,
especially in the Custer area. Otherwise, some minor adjustments
to high temps, winds, and cloud cover were made for today.


.SHORT TERM...(Today Through Tuesday Night)
Issued at 332 AM MST Mon Feb 27 2017

Upper level analysis has near zonal flow across the CONUS with
upper trof moving into the Northern Rockies. Skies are mostly
cloudy across the Northern Plains with some light echoes across
Northwest SD early this morning. At the surface, weak frontal
boundary is draped east west across central SD with only slightly
higher dewpoints and east to northeast winds to the north of the
boundary. Temperatures at 3am are mainly in the teens to lower

Today...Warmer air will advect into the region ahead of the next
shortwave that moves in tonight. Temperatures will rise into the
30s and 40s, but snowpack will slow warming across southern
portions of the area. Clouds will increase today as the shortwave
approaches, and light snow will move into Northeast Wyoming and
the Black Hills late this afternoon and expand over the area
tonight. Light snow accumulations will be possible late tonight
across portions of northeastern WY and northwestern SD, with
some places receiving around 2 inches of snow. Low temperatures
will fall into the teens to lower 20s.

Tuesday...Upper level trof will slide across the Northern Plains
on Tuesday, with mostly cloudy skies expected. Weak shortwave
energy will keep a chance of snow in the forecast for much of the
day. Best chances will be from the Black Hills area into Northwest
South Dakota. High temperatures will be slightly cooler, in the
upper 20s to mid 30s. Light snow will linger into Tuesday evening
with the area finally clearing out late Tuesday night. Low
temperatures will fall into the teens to lower 20s.

.LONG TERM...(Wednesday Through Sunday)
Issued at 332 AM MST Mon Feb 27 2017

Cool and mainly dry northwest flow will develop over the area
Wednesday and Thursday as the upper trof finally shifts east.
Temperatures will remain slightly below average. The exception to
the dry weather will be Wednesday night, when a fast-moving
clipper will sweep through the Northern Plains, bringing a band
of snow to parts of the area. Upper ridging is then expected
Friday into the weekend, resulting in dry and warmer weather.


.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 1026 AM MST Mon Feb 27 2017

Isolated to scattered rain and snow showers and MVFR/IFR
conditions can be expected across southwest SD through the
afternoon. Local LIFR conditions are likely over the southern
Black Hills through early afternoon. Otherwise, VFR conditions
elsewhere today into this evening. Another disturbance will bring
a good chance for snow showers across northeast WY, the Black
Hills, and northwest SD overnight into early Tuesday. Areas of
MVFR/IFR conditions can be expected, with local LIFR conditions
possible as well.




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