Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 180744
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
144 AM MDT Sun Jun 18 2017

.SHORT TERM...Sunday through Tuesday night

We look to be entering a quiet period in the weather over the next
couple of days. Ridging will build across the area and bring mainly
dry weather along with a warming trend. As for today, expect a
warmer day with a mixture of clouds and sunshine. There will still
be a bit of an afternoon breeze but certainly nothing to strong.
A weak shortwave will pass to the north of the state. Most areas
will see nothing but some cumulus build up this afternoon. We can`t
rule out a stray shower over the northern mountains, the chance is
so small we kept the forecast mainly dry.

With heights rising over the area, temperatures will average 5 to 10
degrees warmer on Monday than on Sunday. Winds will also be much
lighter. With the axis of the ridge on the closest approach except
dry conditions for all areas along with lighter winds.

Temperatures will likely peak on Tuesday with the highest
thicknesses across the area. 90s will be a good possibility across
many of the lower elevations. In the afternoon, a combination of
a weak shortwave and an increase in moisture will bring the chance
of a few afternoon and evening thunderstorms, mainly to western and
northern areas. However, most areas will likely see nothing. The
shortwave will increase the pressure gradient however and as a
result we will see a return of a gusty breeze across the area,
especially across areas favored by southwesterly flow.

.LONG TERM...Wednesday though Sunday

Largely zonal flow will dominate the area through Thursday. Another
week shortwave will swing through the area with another chance of
mainly diurnal showers and thunderstorms. The models do differ on
the position of the storms, however. So for the most part we went
with continuity. With slightly lower thicknesses, temperatures will
be a bit cooler although still above normal for most locations.
Decent 700 millibar winds will also continue across the area,
especially the southwestern half of the area so a gusty breeze looks
to continue. Expect similar conditions for Thursday although maybe a
few degrees cooler.

There is more uncertainty for Friday and the upcoming weekend
however. The latest GFS has trended MUCH cooler for Saturday and
Sunday with a deep trough digging across the northern Plains.
Meanwhile, the European is a little less troughy. Both models have
some convection moving into the state however, especially across
northern and eastern areas. Again, given the uncertainty we made few
changes. As for temperatures, we did trend them down a bit for
Friday and Saturday but did not go all the way given dramatic drop
and the potential for a flip flop.
&&

.AVIATION...12Z Issuance

VFR conditions will prevail through 12z Monday.  Surface N-NW winds
10-20kts will prevail across the area Sunday afternoon, with these
winds diminishing around sunset.  SCT-BKN FL120-140 will be found
across the northern and eastern Wyoming through Sunday afternoon
with clearing Sunday evening.&&

.FIRE WEATHER...

Mainly dry conditions will dominate today with sunshine mixing with
some clouds. Expect warmer temperatures than yesterday. A gusty
breeze will continue across portions of the area as well, especially
across western and southern Wyoming. Relative humidity may fall to
around 15 percent in portions of Sweetwater County, but should
remain above critical levels elsewhere. Mixing and smoke dispersal
will range from fair in some of the basins to good to very good in
the normally windier areas. &&

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

$$

SHORT TERM...Hattings
LONG TERM...Hattings
AVIATION...Meunier
FIRE WEATHER...Hattings


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