971 
FXUS63 KUNR 062025
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
225 PM MDT SAT AUG 6 2016

.SHORT TERM...(This Evening Through Sunday Night)
Issued at 207 PM MDT Sat Aug 6 2016

Upper level analysis has upper ridge over the central CONUS with
closed low over Vancouver Island off the Washington coast. Weak
shortwave moving through the ridge is producing cloud cover and
some weak showers across south central South Dakota. At the
surface, high pressure resides across southern Minnesota with
breezy east-southeast boundary layer flow across much of the
area. Temperatures at 2 pm are in the 70s and 80s.

This afternoon - tonight...Weak upper shortwave moving across
Nebraska will continue to produce light showers across south
central SD through early evening. Isolated showers and storms are
possible from portions of northeast WY into the Black Hills very
late in the afternoon and into the evening. Instability is rather
weak, so threat for any stronger storms looks minimal at best.
Any activity that develops should taper off by late evening, but
clouds will hang around overnight. Lows will be in the 50s and
lower 60s.

Sunday...More sunshine is expected on Sunday, especially by the
afternoon. It will also be a bit warmer, with highs in the 80s
across the plains, some 70s across the Black Hills. South to
southeast winds will again be breezy across portions of the
plains, especially northwest SD. There looks to be at least a
little better chance for thunderstorms in the afternoon and
evening across northeast WY and the Black Hills compared to today
as moisture and instability increases, and southwest flow develops
behind slowly exiting ridge. Isolated stronger storms look
possible if they develop, especially over northeast WY. Best
chances for storms will persist across northeast WY and northwest
SD into the evening, diminishing by midnight. Low temperatures
will fall into the mid 50s to mid 60s.

.LONG TERM...(Monday Through Saturday)
Issued at 207 PM MDT Sat Aug 6 2016

The upper level trough/low will remain over the western CONUS
into the middle of the week. The upper low will eject to the
northeast into the Canadian prairie provinces on Wednesday with
the upper trough gradually washing out by Friday. The upper ridge
over the central CONUS will shift east on Monday developing
southwesterly upper flow over the forecast area. A series of
disturbances in the flow will produce chances of showers and
thunderstorms. The upper ridge will redevelop over the northern
plains on Tuesday with hot temperatures expected on Tuesday and
Wednesday which is expected to create very dry relative humidity
readings over northeastern Wyoming and southwestern South Dakota.
Temperatures will cool slightly for the end of the week and
unsettled weather will return as southwesterly flow aloft
redevelops ahead of the ejecting but weakening upper trough.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Sunday afternoon)
Issued At 207 PM MDT Sat Aug 6 2016

MVFR cigs with local IFR conditions are expected to develop over
the Black Hills, parts of northeastern Wyoming and southwestern
South Dakota after 06Z tonight. Conditions will improve to VFR
again after 15Z Sunday morning. Isolated to scattered
thunderstorms are possible over northeastern Wyoming, the Black
Hills and southwestern South Dakota late this afternoon and
evening, with isolated showers possible overnight. There is
another chance of thunderstorms over northeastern Wyoming and far
western South Dakota on Sunday afternoon and evening.

&&

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

$$

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