Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 162239
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
239 PM PST Fri Feb 16 2018

.SYNOPSIS...
Temperatures will warm with dry conditions expected for Saturday.
Another strong cold front will move through the region Sunday
into Sunday night bringing snow showers and much colder
temperatures for the start of next week. The temperatures early
next week will be the coldest of the season with dangerous wind
chills in the Sierra.

&&

.SHORT TERM...
Models continue to come into much better agreement with the cold
trough for late in the holiday weekend. They have all come over to
the EC solution with the EC continuing to be the coldest (with the
NAM not far behind). Leaning more toward the EC for the short
term, but aside from temps they are all pretty close with timing
and precip amounts.

Quiet for the next 24 hours with mild temps expected Saturday.
Winds will begin to pick up late in the day, but only to around 10
mph or so. The big change then begins Saturday night with winds,
followed by snow then bitter cold.

WINDS: 700 mb winds are now expected to peak at near 60 kts by 15Z
Sunday, and continue at 40-50 kts through 06Z Monday. Some
downslope winds will occur Sunday morning for the 395 corridor
with the peak around 15Z for the Sierra Front. As the afternoon
progresses, the winds will become more widespread as the surface
pressure and thermal gradients increase ahead of the front.
However, peak gusts won`t be quite as strong. With the more
widespread nature to the winds, we are issuing a wind advisory for
Sunday for all areas I-80 south. North of I-80, it will be closer
to being behind the front where the winds aloft are not quite as
strong. Peak gusts there of around 40 mph versus 50-60 mph to the
south.

SNOW: A band of snow is expected to form in the cold air behind
the front, within a few hours of frontal passage. Confidence is
still only low-moderate because it is a slider after all. Assuming
it follows a typical slider evolution, the band will only be 25
miles wide or so. The best chance of snow will be in the Sierra to
about 40 miles east. Amounts will be light with only up to 2
inches, but locally higher amounts are possible, especially on the
Eastern Sierra slopes. Timing for the band is Sunday afternoon in
the north, Sunday evening for Sierra Front/Tahoe and overnight for
Mono/Mineral. Snow showers will linger into Monday with a chance
of lake effect off of Pyramid during the morning, and to a lesser
extent Tahoe/Walker.

COLD: Very cold air arrives with the front, with winds continuing
to be gusty Monday from the northwest. Highs Monday will struggle
to reach the freezing mark in Wrn NV with teens and 20s. The wind
will also contribute to wind chills in the single digits. Winds
back off with some clearing Monday night with temps the coldest of
the season so far (although Wed morning may be colder, see below).
Below zero temps in Sierra valleys with single digits widespread
in Western NV.

Bottom line, there will be some travel issues Sunday
afternoon/night. However, the bigger issue is the cold, especially
after such a mild winter thus far. Bundle up if you must be
outside. X

.LONG TERM...Tuesday through Friday...

Frigid conditions continue into Tuesday as winds continue to
diminish. Although temperatures warm a little by Wednesday, expect
colder than average temperatures for the remainder of the forecast.
The main forecast changes were to increase precipitation chances
Thursday, mainly towards the Oregon border, and for Friday.

Medium range models continue to favor cold, northerly flow that will
remain open to passing troughs. High pressure continues to be
depicted well offshore in the eastern Pacific with the storm track
running down the Cascades into the Sierra. Still, this is a drier
track than tracks that originate more offshore. Therefore, any
passing waves will not bring very large quantities of moisture into
the region, but will continue to add a little to the weak Sierra
snowpack. Reinforcing cold air from each successive wave will keep
snow in the forecast for all valley floors.

A passing slider will move through the region Wednesday night and
early Thursday. Precipitation chances were increased although models
remain mostly dry. Sliders this season have tended to produce higher
chances than models guidance has forecast. Precipitation totals are
likely to be very light and more directed towards the Oregon border
and eastern Nevada for this wave.

Also, the ECMWF has been verifying well with these systems of
late; the forecast has largely been nudged to the EC due to its
better performance. As such, precipitation chances were increase
with a stronger wave moving into the region Friday. Winds will
increase ahead of this wave bringing wind chill concerns back for
western Nevada and the Sierra. This system`s trajectory seems to
have a slightly westward track and could tap into a slight
moisture feed off the Pacific. If this verifies, we could see a
few inches of snow across the region. Confidence remains very low
for this scenario, but this system will be watched with greater
interest than the mid- week slider. Boyd

&&

&&

.AVIATION...
VFR with light winds through 21Z Saturday. Winds begin to increase
during the afternoon, but issues really begin Saturday night.
After 09Z Sunday, sfc wind gusts to 45 kts at some terminals along
with LLWS and mtn wave turbulence are expected. LLWS may abate
some after 18Z Sunday as better mixing occurs, but the mountain
waves will remain strong.

As for precip, a quick shot of snow is expected Sunday afternoon
to Sunday night progressing north to south. It will only last 1-3
hours or so with IFR conditions and light runway accumulations
possible. X

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 2 AM to 6 PM PST Sunday NVZ002>004.

     Wind Advisory from 7 AM to 10 PM PST Sunday NVZ001.

CA...Wind Advisory from 2 AM to 6 PM PST Sunday CAZ072.

     Wind Advisory from 7 AM to 10 PM PST Sunday CAZ073.

&&

$$

For more information from the National Weather Service visit...
http://weather.gov/reno



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