Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 110430
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1030 PM MDT Thu Aug 10 2017

.SHORT TERM...(This evening through Sunday)
Issued at 235 PM MDT Thu Aug 10 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.

.LONG TERM...(Sunday night through Thursday)
Issued at 235 PM MDT Thu Aug 10 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 Thursday.   This will significantly decrease
the afternoon and evening convection but not eliminate it
completely.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1030 PM MDT Thu Aug 10 2017

Isolated showers and thunderstorms have essentially diminished late
this evening, but cannot rule out some activity continuing over the
western mountains overnight as nocturnal activity continues in
eastern ID and SW MT.  Relatively light winds expected overnight
with some mid-level scattered clouds through the morning.  A weak
disturbance will move southeastward into Montana and NE WY in the
afternoon hours Friday.  West-NW breezy wind expected across SW WY,
while a northerly push will come down east of the divide.  The weak
front should focus shower and thunderstorm activity north of a line
from YNP to the Wind River Basin and over to the KCPR area. KCOD and
KBYG should see the biggest impact from the storms after 18z/Fri.
Most of the storminess will diminish by 02Z/Sat, with some residual
showers into Friday night.  The storms are likely to produce brief
heavy rain and wind gusts over 30 kts.

&&

.FIRE WEATHER...
Issued AT 235 PM MDT Thu Aug 10 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.
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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