Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 312327
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
527 PM MDT WED AUG 31 2016

.SHORT TERM...This Evening Through Thursday Night
Issued at 211 PM MDT Wed Aug 31 2016

Upper level analysis has amplified flow with large ridge across
the central CONUS and trof across the west coast. Skies are mostly
sunny across the forecast area. At the surface, high pressure is
located across Minnesota with low pressure developing across
central Montana. In between, breezy southerly winds have allowed
temperatures to rise into the 80s this afternoon.

Tonight...Upper ridge will remain across the central CONUS with
surface low deepening across central Montana. Southerly winds will
remain breezy across much of Northeast Wyoming, but should drop
off across the South Dakota plains. Under mostly clear skies,
temperatures will fall into the 50s and lower 60s.

Thursday...Upper ridge axis will cross the Northern Plains with
very warm and dry conditions continuing. Surface low pressure
across central Montana with further strengthen, producing a very
tight north/south pressure gradient across the South Dakota
plains. South to southeast winds will increase during the morning
to 20 to 35 mph with gusts to 40 mph across much of the plains,
strongest across northwest SD where a wind advisory may be needed.
Temperatures will remain above average, with highs in the 80s to
lower 90s expected.

Clear and mild conditions are expected Thursday night with breezy
south winds continuing across the SD plains. Temperatures will
only fall into the upper 50s to mid 60s.

.LONG TERM...Friday Through Wednesday
Issued at 211 PM MDT Wed Aug 31 2016

The upper ridge will shift off to the east on Friday as the upper
low/trough approaches from the west, leading to southwesterly flow
aloft over the northern plains. A N-S elongated surface low will
move into ern MT/WT and wrn ND/SD on Friday. Dry downslope
southwesterly winds will lead to very low relative humidity over
northeastern Wyoming on Friday afternoon. The tight sfc pressure
gradient is expected to create gusty winds with deeply mixed
boundary layer conditions, especially over northeastern Wyoming.
Fire weather headlines may be needed there for Friday aftn. A cool
front will cross the area Saturday beginning a cooling trend that
will continue through early next week. There will be a chance of
showers and thunderstorms each day from Saturday through Tuesday
as a series of impulses in the upper trough cross the northern
plains. The best chances for more widespread precipitation will
occur on Sunday and Monday.

&&

.AVIATION...For the 00Z TAFS Through 00Z Thursday Evening
Issued At 517 PM MDT Wed Aug 31 2016

Gusty southerly winds will persist through Thursday afternoon. VFR
conditions will continue through the period.

&&

.UNR Watches/Warnings/Advisories...
SD...WY...None.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...55



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