Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 262051
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
251 PM MDT FRI AUG 26 2016

.SHORT TERM...(This Evening Through Saturday Night)
Issued at 250 PM MDT Fri Aug 26 2016

Current surface analysis shows low pressure over eastern CO, with
trough stretching northward across eastern WY into MT. Upper level
analysis shows broad trough across the Rockies and high plains,
with numerous disturbances within the trough across the region.
Skies are variably cloudy across the area. KUDX radar shows
isolated to scattered showers and thunderstorms from northeast WY
and southeast MT to northwest SD, with some showers lingering
across south central SD. Clouds are beginning to build across the
northern and central Black Hills as well. Temps are mostly in the
60s, with 50s across the higher Black Hills. Winds are generally
from the south to southeast.

Unsettled weather will continue through much of tonight, then dry
and warmer weather will return for the weekend as the upper trough
shifts east of the region on Saturday. Above average temperatures
will return on Sunday.

For late today through the overnight, isolated to scattered showers
and thunderstorms can be expected. The better chances for showers
and storms should be across far northeast WY and the Black Hills
area as another disturbance passes through a moderately unstable
airmass in place over these areas. Shear is on the weaker side, but
could be sufficient for a supercell or two. Isolated strong to
severe storms are possible with hail and gusty winds. Activity
should begin to exit the area and dissipate from west to east
overnight, with decreasing clouds as well. With near saturated low
levels expected, will put some patchy fog in late tonight/early
Saturday for most of the area. Lows will be in the 50s, with some
40s over northeast WY and the Black Hills.

Skies will be or become mostly sunny across the area on Saturday,
with temps rising to the low to mid 80s across much of the plains,
70s over the Black Hills. Winds will be southerly at 5 to 15 mph.
Clear to partly cloudy skies Saturday night with lows in the 50s and
lower 60s.

.LONG TERM...(Sunday Through Friday)
Issued at 250 PM MDT Fri Aug 26 2016

An upper level ridge of high pressure will quickly rebuild across
the central and western US through the long term period. This will
bring mostly dry conditions and warm temperatures. High
temperatures Sunday through Friday will be above average, with
highs in the 80s and 90s. As the holiday weekend approaches, the
chance for thunderstorms will increase as the upper ridge axis
slides to our east and southwest flow aloft returns.

This type of weather pattern may lead to an increased fire risk
next week, due to low minimum relative humidity values, poor
overnight recovery, and gusty winds; especially across northeastern
Wyoming.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 250 PM MDT Fri Aug 26 2016

Scattered showers with isolated thunderstorms are now exiting the
region to the east, but MVFR/IFR cigs still persist across
portions of Western South Dakota and extreme Northeast Wyoming.
The MVFR/IFR cigs will be slow to dissipate and expect them to
last the majority of the afternoon across Western South Dakota.
Scattered showers and thunderstorms will redevelop late this
afternoon across Northeast Wyoming and Southeast Montana before
moving into Western South Dakota. Could see brief MVFR cigs/vis
with some of the stronger storms. Patchy fog is possible late
tonight after storms push east of the region, otherwise VFR
cigs/vis expected.

&&

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

$$

SHORT TERM...26
LONG TERM...Johnson
AVIATION...Johnson



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