Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 260923
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
223 AM MST Sun Feb 26 2017

.SHORT TERM...Sunday through Tuesday night

All is quiet at this time with only a few light showers across the
western mountains. We are also having some gusty winds in the usual
spots but nothing out of the ordinary. The models do show the winds
gradually weakening in the lee of the Absarokas but remaining gusty
across the southwestern Wind Corridor, but not exceeding high wind
criteria except in a place like Camp Creek where there are only deer
this time of year. Some snow showers will continue across the
western mountains today although accumulations through the day
should be fairly inconsequential. Meanwhile, it will be another cold
day with temperatures kept well below MOS guidance with the fresh
snow cover and inversions holding in the basins.

A weak cold front and trough will approach the west Sunday night and
Monday and increase the chance of snow. There is some jet support
with this system but not a ton of moisture to work with. However,
there could be enough for some low level advisories in a few spots.
There is still some time to decide, so we will let the day shift
make the call on that one. Meanwhile, East of the Divide it looks
like more of the same. Temperatures will be below normal again
although maybe a few degrees warmer. A gusty wind will continue
across the southern Wind Corridor as well. As for any chance of
precipitation, there could be a bit of snow with the trough passage
but most of the moisture will be downsloped away. We have some
slight POPS across some areas but any decent POPS are restricted to
the mountains.

At this point, Monday night looks to be a lull in the activity
before another shortwave approaches the west. Again, the system is
not that strong and does not have a ton of moisture to work with.
The POPS in the forecast looked reasonable so we made few changes.
East of the Divide, temperatures will cool off a few degrees once
again but nothing unusual for the end of February. There is a small
chance some moisture could make it over the mountains but at this
point it looks to be nothing of consequence.


.LONG TERM...Wednesday through Monday

Northwest flow aloft Wednesday and Thursday over the region.
Moisture in the flow will keep periods of light snow in the
northwest WY mountains and in the Northern Bighorn mountains. Expect
some light snow at times in the Jackson Valley down to near Afton
both days. The rest of the region will be dry. Breezy to windy areas
will occur. The flow aloft turns more west northwest Friday and a
more west flow aloft for Saturday and Sunday. Models keep periods of
moisture in the this flow pattern. This brings a chance of light
snow to the western mountains and far west valleys. Northern Bighorn
mountains could see light snow at times during these days. Dry
weather for the rest of the region Friday through next Sunday. The
breezy to windy areas will continue. Temperatures will be seasonably
cold Wed, then milder highs Thursday into next weekend. At this
time, do not see a rapid snowmelt situation in the Lander foothills
like what happened a few weeks ago. The 700MB temps are not forecasted
to reach zero degrees Celsius, or above, next Saturday/Sunday.
There will be some melting, and will need to keep an eye on
things as we go through next week in case the models warm those
700MB temps more.

&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

Areas of MVFR ceilings with scattered mainly mountain snow showers,
frequent mountain obscurations, will linger vicinity and west of a
KAFO-KJAC line through 15z Sunday.  Ceilings should lift mid to late
Sunday morning.  A trough of low pressure will dig into the
Intermountain West Sunday night with snow showers increasing in
coverage and intensity across the western mountains, vicinity and
north of a KEMM-KBPI line.

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

Gusty west to northwest wind vicinity KCOD-KDUB-KRIW will gradually
diminish by sunrise Sunday as the upper flow backs west to
southwest.  This change will also increase southwest winds through
the wind corridor, vicinity 50SM NE KRKS-KCPR, Sunday morning with
wind speeds 20 to 30 knots with gusts near 40 knots.  Areas of
blowing snow with some terrain obscurations will accompany these
winds.  These southwest winds will decrease slightly Sunday evening
but remain gusty overnight.  VFR conditions will prevail through the
period with high and mid clouds increasing from the northwest Sunday
afternoon and evening.

&&

.FIRE WEATHER...

Fire Danger low for all of Wyoming today as a good existing snow
pack combines with seasonal to below seasonal temperatures. Gusty
west to southwest can be expected at times across portions of
central and southern WY as well as the Lee of the Absarokas. Smoke
dispersion will be fair to very good across most of the forecast
area each afternoon through at least Monday. The exception would be
some of the deeper basins and valleys which had heavy snow where
inversions may linger through the day. A period of light to moderate
snow will move into the western mountains tonight and Monday.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

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



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