Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 180042

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
642 PM MDT Mon Oct 17 2016

Issued at 641 PM MDT Mon Oct 17 2016

Showers and isolated thunderstorms currently north and east of
the Black Hills will continue to move northeast this evening.
Forecast updated to adjust POPS through the remainder of the


.SHORT TERM...(This Evening Through Tuesday Night)
Issued at 210 PM MDT Mon Oct 17 2016

1930z surface analysis reveals 996mb low over southwestern South
Dakota. 30mph to 40mph gusts have been observed in the wake of the
low and associated surface trough in northeastern Wyoming and
southwestern South Dakota. Rain showers from this morning have
dissipated over most of the CWA, but high-res short term model
guidance suggest showers and thunderstorms developing in
northeastern Wyoming and pushing into Western South Dakota this
evening. NWP guidance does have anywhere from 300-500J/Kg of CAPE
this afternoon across northeastern Wyoming and western South
Dakota, so will include thunderstorms in the forecast. Should see
precipitation taper down across the CWA by midnight.

By Tuesday, high pressure over the CO/WY rockies will slide over the
central plains resulting mostly sunny skies and westerly flow at the
surface. Clouds and chances for showers will start to increase late
Tuesday afternoon through Tuesday night as another shortwave moves
in from the west. Current NWP guidance progs the southern portions
of the CWA as the most likely to see precipitation Tuesday
evening while keeping northern portions of the CWA dry. Model
soundings suggest a mixture of rain/snow possible over parts of
northeastern Wyoming and the Black Hills Tuesday night, though
surface temperatures should remain at or just above freezing,
resulting in very little to no snow accumulations.

.LONG TERM...(Wednesday Through Monday)
Issued at 210 PM MDT Mon Oct 17 2016

A weak upper trough will cross the forecast area on Wednesday
creating small chances for showers and low level cold advection on
Wednesday will bring slightly cooler than average temperatures.
Near average temperature are expected on Thursday as an upper
ridge begins to build in from the west. Models are in generally
good agreement showing an upper ridge building over the northern
Plains Friday into early next week, resulting in dry weather and
temperatures 5-10F warmer than average.


.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 509 PM MDT Mon Oct 17 2016

Scattered showers an possibly a few thunderstorms will move
eastward from northeastern Wyoming into western South Dakota
during the late afternoon and evening. Local MVFR conditions are
possible with the showers and thunderstorms. Otherwise, VFR
conditions will prevail.




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