Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 101727

Area Forecast Discussion
National Weather Service Riverton WY
1027 AM MST Sat Mar 10 2018

.SHORT TERM...Today through Monday night

A cold front is currently moving through northern portions of the
state, with wind gusts of 45 to 55 mph occurring behind it. These
gusts appear to be relatively brief, as winds at Sheridan have
already gone down, from close to 50 to 10 to 15 mph. Although
these speeds will be possible, it is not expected to reach that
high as the front passes through the Wind River Basin and Natrona
County this morning. However, gusty NNW winds are expected to
continue over Johnson County through the rest of the day. A band
of showers (that is currently beginning to break up) is also making
its way over northern WY this morning. Isolated showers will be
possible for areas east of the Divide into this afternoon.

Otherwise, conditions will be dry with seasonal temperatures today
and Sunday. A warming trend will begin by Monday and continue into
the next forecast period. Winds are expected to remain light as

.LONG TERM...Tuesday through Saturday

Overview...Dry and mild conditions will prevail across the area
on Tuesday with most highs in the 50s across the lower elevations.
A Pacific storm system will begin to spread rain and snow showers
into the west on Wednesday, while unseasonably warm and breezy-
windy conditions prevail across central Wyoming. The Pacific storm
system will slowly push across the Great Basin and Rockies
Thursday through Saturday spreading chances of showers east of the
Divide with a more significant cooling trend expected Friday and

Discussion...Upper air pattern on Tuesday is expected to feature
high amplitude flow with ridge centered across the Rockies flanked
by troughs along the west coast and NE U.S. This overall pattern
is forecast to progress slowly eastward through the extended
period. Upper trough along the west coast is expected progress
inland and shear out, ejecting a series of shortwaves into strong
downstream ridge over the Plains Wednesday through Friday. Medium
range models continue to show a great deal of spread and poor run
to run consistency with the handling of these smaller scale
features, so forecast continues to take a more broadbrushed
approach spreading PoPs west to east mid to late week.
Temperatures aloft may cool enough to bring snow levels to basin
floors east of the Divide Friday and Saturday. As far as impacts,
split flow pattern will not be especially favorable for sustained
significant snowfall across the west. Locally heavier, but mostly
short-lived snow showers will should be the rule with this system
across the west Wednesday through Friday. Travel impacts east of
the Continental Divide will be of more concern on Friday and
Saturday, when precipitation will fall mainly as snow.


.AVIATION...For the 18Z TAFS through 18Z Sunday

West of the Continental Divide...KJAC, KBPI, KPNA, and KRKS

Shortwave ridge builds across the region later today and tonight
with VFR conditions to prevail. The exception could be some VCFG at
KJAC early Sunday morning as temp-dew point spreads approach zero
under a clear sky.

East of the Continental Divide...KCPR, KCOD, KRIW, KLND, and KWRL

Upper low spinning slowly across northeast Wyoming Saturday morning.
Mid-cloud deck on the backside of this low, particularly at KWRL,
will dissipate this afternoon as the low makes its way farther to
the southeast. A clearing sky and VFR conditions then anticipated
through the remainder of the forecast period.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.



Seasonal temperatures continue across the region today remaining
just slightly below seasonal east, as a cold front moves through
this morning. Isolated showers will be possible across northeast
portions this morning behind the cold front. Otherwise, conditions
will be dry into early next week. Temperatures will gradually warm
over the next several days, with the warmest day so far this year
possible on Wednesday.





LONG TERM...Meunier
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