Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 122022
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
222 PM MDT Sat Aug 12 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 216 PM MDT Sat Aug 12 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 to 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 through Tuesday, west to southwest flow aloft will
move over the area with warming and drying Monday night and Tuesday.
Showers and thunderstorms will be possible with decreasing coverage.
Areas of west to southwest winds will spread from west to east
and become gusty.

.LONG TERM...(Tuesday night through Saturday)
Issued at 216 PM MDT Sat Aug 12 2017

Tuesday night and Wednesday the Pacific low pressure trough will
pass through the area with scattered showers and thunderstorms.
winds will be gusty.  Thursday northwest flow aloft will return
to the area.  drying is expected at this time with much less
convection expected through Saturday.  Temperatures will cool
Thursday and slowly rise into the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 216 PM MDT Sat Aug 12 2017

Isolated to widely scattered thunderstorms continue to develop
and move east southeast at 25 to 30 mph along and west of the
Divide...just starting to enter portions of central Wyoming this
afternoon. Brief heavy rain, small hail, wind gusts from 20 to 35
kts with some fleeting low VFR cigs will all be possible at times
through the rest of the afternoon.

Otherwise, VFR conditions to prevail through the forecast period.
VCTS at all TAF sites through 02z this evening. Additionally,
outflow boundaries from this convective activity east of the
divide...particularly across Fremont and Natrona counties will cause
erratic gusty winds for brief periods through 02z this evening.
Later, isolated showers with a thunderstorm or two will re-occur 08z-
18z Sunday morning vcnty KJAC, KBPI, KPNA and KRKS...then 12z-18z
Sunday morning for KCOD. After 19z Sunday afternoon, most sites have
vcnty thunder in the forecast as another upper level disturbance
moves across the region.

Note: 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.

&&

.FIRE WEATHER...
Issued AT 216 PM MDT Sat Aug 12 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 to 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 through Tuesday, west to southwest flow aloft will
move over the area with warming and drying Monday night and Tuesday.
Showers and thunderstorms will be possible with decreasing 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...Braun
FIRE WEATHER...Baker



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