Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 120434
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1030 PM MDT Fri Aug 11 2017

.SHORT TERM...(This evening through Monday)
Issued at 206 PM MDT Fri Aug 11 2017

A series of cool low pressure troughs moving across the Pacific
Northwest, the Northern Rockies and Southern Canada will converge
with warmer moist southwest flow on the west side of a flat high
pressure ridge over the Desert Southwest and Great Basin, over
Wyoming.  This will keep clouds and scattered showers with
isolated scattered thunderstorms over the area through Sunday.
Precipitation will be greatest over the mountains.  This will keep
temperatures depressed and relative humidity elevated.  With low
level north to east flow winds will be rather light outside of
thunderstorms which may produce strong erratic wind gusts.
Sunday night and Monday, west to southwest flow aloft will move
over the area with warming and drying.  Isolated showers and
thunderstorms will be possible but with much less coverage.
areas of west to southwest winds will spread from west to east
and become gusty.

.LONG TERM...(Monday night through Friday)
Issued at 206 PM MDT Fri Aug 11 2017

As a large low pressure trough moves inland along the Pacific
Northwest, southwest flow will move inland the high pressure ridge
over the Desert Southwest and Great Basin shifts east.  The Pacific
trough will also produce stronger south southwest flow over
the Northern Rockies and Southern Canada bringing an end to the
cool northwest flow.  Drying and warming will result as the flow
aloft over Wyoming shifts to the west and eventually to the
southwest.  Surface winds from the west and southwest will spread
from the west and southwest into central and eventually eastern
Wyoming through Friday.   This will significantly decrease
the afternoon and evening convection but not eliminate it
completely.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 1030 PM MDT Fri Aug 11 2017

The LND TAF has been NILed as of 00Z/Sat.  ASOS observations have
not been available for a week, and there is no estimated time of
return of service.  With the runway being under construction through
the end of October and no observations, the TAF will be NILed until
further notice.

Scattered showers with isolated thunder continue late this evening
across the central part of the state.  Expecting isolated showers
overnight, but not certain on location.  Models are suggesting west
central WY (KBPI,KPNA) to have best chance of showers after 10Z/Sat.
 Saturday should be a similar day like Friday with isolated to
scattered showers and thunderstorms.  VFR conditions to dominate,
but have included VCTS at all sites after 18Z/Sat; expecting brief
heavy rain, small hail, and gusts over 30 kts with local MVFR
conditions possible. Saturday should see generally west flow west of
the divide, and another weak northerly push with outflow boundaries
east of the divide.

&&

.FIRE WEATHER...
Issued AT 206 PM MDT Fri Aug 11 2017

A series of cool low pressure troughs moving across the Pacific
Northwest, the Northern Rockies and Southern Canada will converge
with warmer moist southwest flow on the west side of a flat high
pressure ridge over the Desert Southwest and Great Basin, over
Wyoming.  This will keep clouds and scattered showers with
isolated scattered thunderstorms over the area through Sunday.
Precipitation will be greatest over the mountains.  This will keep
temperatures depressed and relative humidity elevated.  With low
level north to east flow winds will be rather light outside of
thunderstorms which may produce strong erratic wind gusts.
Sunday night and Monday, west to southwest flow aloft will move
over the area with warming and drying.  Isolated showers and
thunderstorms will be possible but with much less coverage.
areas of west to southwest winds will spread from west to east
and become gusty. Mixing heights and transport winds will combine
for generally very good to excellent smoke dispersal from  late
morning through early evening each day.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Baker
LONG TERM...Baker
AVIATION...McDonald
FIRE WEATHER...Baker



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