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Area forecast discussion 
National Weather Service Riverton Wyoming
1113 PM MDT Tuesday Jul 22 2014

Short term...tonight through Wednesday

Instability lingers in northern Wyoming with Montana thunderstorms
flirting with our northern Wyoming border this evening...especially far
northeast Johnson County as storms move up and over the building
ridge over the area. Increasing southwest flow on the back side of
the ridge will increase the fire danger across portions of central
and southern Wyoming as winds increase...relative humidity drops to critical
levels and temperatures heat up where a Fire Weather Watch has been
issued for Wednesday afternoon and early evening. Expect highs as hot as the
upper 90s Wednesday afternoon in the Big Horn. Winds will probably be
too light to War rent any fire weather hilites north of The Owl
creek mountains

Long term...Wednesday night through Tuesday

Expanding upper 4-corners high will allow for the subtropic plume
that is currently over southeastern Arizona to lift northward towards US over the next
24 hours. Currently trajectory looks like it will impact our southeastern
zones late in the day tomorrow into the evening hours. Isolated high
based gusty thunderstorms are possible anywhere along this plume of
middle level moisture. Probably also enough diurnal heating and low
level moisture to fire a few storms over the western mountains with a
few trying to get off the mountains into the Upper Green and NE to
the Grass Creek area by Wednesday evening. Moist southeast flow will be on
our eastern fringes until early to middle afternoon when the SW winds kick
in pushing the best chance for deeper moisture storms to the east.
Could see a brief storm fire in Johnson...especially eastern before the
SW winds dry them out. Otherwise...hot and breezy to windy with
increasing fire weather concerns. On Thursday...pacnw low moves inland
with increasing hot...westerly flow across the area with even higher fire
weather concerns as more wind and a front will come into play. Could see
an isolated storm along the front and possibly still in the far southeastern
zones if the westerly middle level doesn't sweep all the middle level moisture
out. Dry and quite warm to hot on Friday as front washes out in all
but the northern or northestern zones. Our upper low to the NE will drop into
the eastern U.S. Trough with rising surface pressures to our north and NE
over the weekend. Dry northwest flow with cooler readings. Still warm but
not the intense heat that will see for a few days this week. Ridge
axis is then expected to shift east into western Wyoming on Monday with
monsoonal plume edging into the west late in the day and possible
edging into at least parts of central Wyoming by the evening hours.
Potential for some middle level monsoonal moisture across the entire
area on Tuesday with at least isolated mainly high based gusty
showers and thunderstorms just about anytime from later Monday night
through Tuesday.

&&

Aviation.../06z issuance/

Through 09z...some breezy northerly winds from convection in Montana
will continue to affect or slide south across Johnson/Natrona and
the Big Horn basin. However these winds will subside by around 09z.
Otherwise...sky clear conditions and light winds will be rule for the
remainder of tonight.

Convection will be hard pressed to develop Wednesday...with a mainly
stable atmosphere due to warm middle level temperatures...and meager moisture.
Having said that...there could be some very isolated convection over
the mountains that try to form late Wednesday afternoon and
evening. Chances are too remote to mention at any taf site. Winds
will generally be light through Wednesday morning...becoming breezy
from the southwest/west over the west...and from the wind corridor
from krks-kcpr. Winds more southerly in Jackson Hole.

&&

Fire weather...

Isolated convection will be limited to the northern border of
Wyoming through this evening. A Fire Weather Watch is in effect
for portions of central and southern Wyoming for Wednesday and
Thursday afternoon and early evening. A combination of hot
temperatures ... relative humidity and the return of a gusty
west to southwest wind will likely bring elevated fire danger for
Wednesday and into Thursday.

&&

Riw watches/warnings/advisories...
Fire Weather Watch from Wednesday afternoon through Thursday
evening wyz279-280-283-285-287-300.

&&

$$

Short term...lipson
long term...skrbac
aviation...wm
fire weather...lipson

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