Area Forecast Discussion
Issued by NWS Riverton, WY

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102
FXUS65 KRIW 150855
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
255 AM MDT Tue Aug 15 2017

.SHORT TERM...Tuesday through Thursday night
Issued at 240 AM MDT Tue Aug 15 2017

At this point there looks to be one more unsettled day before
things begin to dry out. One last shortwave now over Utah will
lift across the area and bring another round of showers and
thunderstorms. And much like yesterday, with a fair amount of
clouds around most of thunderstorms should be of the garden
variety. It will also be a cool day although a bit warmer than the
previous runs of the models thought. Most of these storms should
move out of the area by around midnight with mainly dry conditions
following that time frame.

Starting Wednesday, we will see somewhat of a pattern shift as
ridging begins to build across the area. We went ahead and made
Wednesday completely dry. The models do have some isolated
convection over the mountains but the models, especially the GFS,
are notorious for overdoing high based convection. There could be a
stray shower or thunderstorm but coverage is expected to be so
sparse we left it out. It is the same situation for Thursday.
Temperatures will also be on the rise with high temperatures
returning to near normal levels during the mid week.

.LONG TERM...
Issued at 240 AM MDT Tue Aug 15 2017

Friday will be dry and seasonably warm. Saturday will be dry for
most places with very isolated showers or storms. Warmer high
temps for Saturday. Sunday still looks to see an increase in
shower or thunderstorm coverage, especially in the west and
southwest. High temps still warm.

Monday, eclipse day, looks dry for most places. Models still hint
at isolated showers in NW WY with more clouds there. Still think
some clouds will occur east of the divide, but mainly high clouds.
Temps mainly in the 70s in the total eclipse zone, warming into
the 80s afterwards. There will be isolated afternoon and evening
showers and storms developing Monday after the event is over.

Next Tuesday will see some showers and storms develop in the
afternoon and evening. Temps a little cooler due to more clouds in
the area.

&&

.AVIATION...12Z Issuance
Issued at 240 AM MDT Tue Aug 15 2017

Nocturnal convection will persist across southern Wyoming until
around 12Z/Tue with central areas hanging on until about 15Z/Tue.
Shortwave will rotate north and then linger clouds and light
precipitation across the north through midday. Nonetheless, expect
all terminals to remain VFR through the forecast period. Moist
airmass will keep widespread mountain obscurations above 10K MSL
through 18Z/Tue with additional obscurations around the Bighorn
Range through mid-afternoon. Precipitation will wind down from south-
to-north from 12-18Z/Tue. Less cloud cover across the south will
lead to early afternoon convection, particularly off the Uinta
Mountains and higher terrain to our south. Lingering cloud cover to
the north will limit surface heating and convection will likely not
get underway in earnest until 22Z/Tue. Least likely terminals for
Tuesday showers will be KJAC, KBPI, and KPNA where drier and more
stable air will be nudging in by late in the day. Expect this
airmass to gradually filter east into central areas by 06Z/Wed with
all areas with only scattered mid-clouds by 12Z/Wed.

&&

.FIRE WEATHER...
Issued at 240 AM MDT Tue Aug 15 2017

Fire conditions should remain below critical today. The last in a
series of upper level disturbances will swing through the area today
and bring another round of isolated to scattered showers and
thunderstorms. With cool temperatures and cloud cover, relative
humidity should remain above critical levels for all areas. Other
than in or around any shower or thunderstorm, wind should remain
light to moderate for all areas. Mixing and smoke dispersal will
range from poor in some of the basins to good across southern
Wyoming.

&&

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

&&

$$

SHORT TERM...Hattings
LONG TERM...AR
AVIATION...Jones
FIRE WEATHER...Hattings



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