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fxus65 kriw 142219 

Area forecast discussion
National Weather Service Riverton Wyoming
319 PM MST Thu Nov 14 2019

Short term...(this evening through Friday night)
issued at 1230 PM MST Thu Nov 14 2019

Northwest flow with some high clouds continues over Wyoming this
afternoon as the ridge axis over the northern Great Basin slowly
moves eastward. A slightly relaxed surface pressure gradient over
the area will decrease afternoon wind speeds slightly compared to
yesterday, and afternoon high temperatures should be close to or
slightly above yesterday's values as well. With shortwave trough
energy moving into the West Coast overnight, the ridge axis will
move more eastward and be over western Wyoming by 6am Friday. This
pattern will allow mid- and low-level temperatures to increase
Friday, with afternoon Max temps reaching the 50s to near 60 in
the lower elevations. Southwest winds should also increase over
the typical windy areas, and with mid-level moisture being
advected from the west, clouds will increase as the day GOES along
as well. Late Friday into Friday night should see the mid-level
flow become more westerly as a shortwave trough moves from eastern
Oregon to around ynp around 6am Saturday. Rain and snow showers
are slightly possible across northwest Wyoming Friday evening as 700 mb
temps start to drop below 0c. Decreasing temperatures and
increasing moisture with this trough will increase the chance of
precipitation across northwest Wyoming by Saturday morning. Southwest
wind should stay breezy overnight from Sweetwater into Natrona
counties as well as over the higher terrain of western Wyoming. A weak
surface front should be on the doorstep from Cody to Buffalo early
Saturday morning. Only light amounts of rain/snow are expected by
Saturday morning.

Long term...(saturday through thursday)
issued at 300 PM MST Thu Nov 14 2019

The shortwave on Saturday will be a quick hitter with activity
over by Saturday evening. The northwest flow is not as favorable
for central and southern areas and therefore west of The Divide
and the Bighorn Basin and mountains eastward will be most
impacted. This system is on the weaker side meaning snow amounts
will be light and low temperatures Sunday morning only 5 to 10
degrees cooler than on Saturday morning before the passage of the
front. All snow will fall west of The Divide and in the
mountains, with lower elevations east of The Divide starting as
snow in the morning and changing to a mix or possibly all rain
during the afternoon.

Behind saturday's system a ridge builds into the western United
States placing northwest flow back over the region and keeping a
drier and mild pattern in place across the area. In this flow two
things of note: one, a strong jet may set up over the area and
bring strong gusty winds to prone locations, especially the
absaroka and Bighorn Mountains. Two: though conditions will
generally be dry, some moisture will stream into the northwest and
a chance for light snow showers will stay in the forecast Sunday
through Tuesday.

Things begin to change on Tuesday when the ridge axis nudges
eastward, allowing for the next shortwave to approach the area.
Timing with this shortwave is unfortunately still uncertain.
Models are still having trouble pinning its passage down and
continue to push it further back.


Aviation...(for the 00z tafs through 00z friday) issued at 315
PM MST Thu Nov 14 2019

Mostly high level clouds will drift across the area through the
period and slowly increase in coverage tonight into Friday. VFR
conditions will prevail through the forecast period. Gusts at kcpr
have remained under 25 knots and will decrease after sunset. Gusts
are expected to return to kcpr mid-morning Friday, by 16z, but
otherwise, mainly light winds are expected through the period.


Fire weather...
issued at 1240 PM MST Thu Nov 14 2019

Mild conditions continue across western and central Wyoming for the
rest of the day, with breezy conditions continuing from Sweetwater
County NE through central Wyoming into Natrona County. Afternoon high
temps will be about 5 degrees above normal. Winds around 10 mph
are likely to continue overnight from central Wyoming into the Casper
area overnight before increase to 15-20 mph by noon Friday. With
high pressure moving over the area Friday, afternoon Max temps
will be in the 50s to around 60, which is 12-16 degrees above
normal. The higher terrain of western Wyoming will also see breezy to
windy conditions Friday as a weak system moves in Friday night.
Far northwest Wyoming will start with rain/snow showers Friday evening, with
better chance of light snow by Saturday morning. The weak storm
system will move through Saturday, bringing colder temps, breezy
to windy northwest wind, and some precipitation, mainly in the higher
elevations and from Buffalo to Casper.


Riw watches/warnings/advisories...none.



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