Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 301718
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1118 AM MDT Fri Sep 30 2016

.SHORT TERM...(Today Through Saturday Night)
Issued at 229 AM MDT Fri Sep 30 2016

08Z analysis places a low pressure center over southeastern
Montana with a trough extending southward across eastern WY/CO.
High pressure was located over MN/IA resulting in a relatively
tight sfc pressure gradient and breezy southerly winds across the
SD part of the forecast area. An upper shortwave, combined with
mid-level instability is currently producing scattered showers
over parts of far nern WY and nwrn SD. A period of increased
cloud cover will lead to high temperatures slightly cooler than
yesterday, in the lower 70s to lower 80s. Diurnal heating will
help to push the MLCAPE to 500-700J/KG over the Black Hills area
this aftn so may see a few showers and thunderstorms develop in
the convergence zone along the sfc trough. Mainly clear skies are
expected overnight with lows in the mid 40s to lower 50s. Saturday
will be mostly sunny and warm again with highs in the mid 70s to
lower 80s and a slight chance of aftn T-storms over the Blkhls.

.LONG TERM...(Sunday Through Thursday)
Issued at 229 AM MDT Fri Sep 30 2016

Southwest flow aloft, ahead of strong upper level
system over the western US, will bring increasing chances for
showers and thunderstorms, especially early next week. Warm
temperatures will persist Sunday and Monday before a cold front
crosses the area Monday Night and Tuesday. Upper level system will
move across the Great Basin and Rockies Monday and Tuesday, then
across the plains midweek. The latest EC remains faster and further
north with track of the low than the GFS. Latest EC brings upper low
across northern WY, southeast MT and ND, while GFS tracks it across
southern WY, western Neb and SD. Until solutions come into better
agreement, will keep widespread chances for rainfall across the area
through Wednesday and into Wednesday night. There is some potential
for snow across the higher elevations of the cwa on the back side of
the system Wednesday night if the storm track is favorable. Gusty
northwest winds are likely Wednesday through Thursday on the back
side of the system as well. Drier weather is expected late week with
temperatures a bit below average.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1117 AM MDT Fri Sep 30 2016

VFR conditions are generally expected through this afternoon and
into this evening. An isolated shower or thunderstorm is possible
this afternoon across the Black Hills area.

&&

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

$$

SHORT TERM...10
LONG TERM...26
AVIATION...15


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