Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 111053

Area Forecast Discussion
National Weather Service Reno NV
253 AM PST Sat Nov 11 2017


High pressure will provide lighter winds and drier conditions for
the rest of the weekend before the next system arrives late Monday
and into Tuesday morning. Gusty winds along with rain and high
elevation snowfall will be possible across northeast California
and the northern Sierra Monday evening. An active pattern remains
next week as additional wetter systems are possible by midweek
and next weekend.



A shortwave ridge will provide a break from gusty conditions and
precipitation today. Temperatures will remain seasonable through
the weekend with highs in the upper 50s to low 60s for western
Nevada and lower 50s for Sierra valleys. Sunday will see
increasing clouds and breezes as a weak low pressure system
arrives. The biggest increase in winds will occur across the
ridgetops from the Tahoe Basin northward as an upper jet
approaches the northern Sierra.

Did make some adjustments to the forecast for Monday mainly to
slow the arrival of the incoming precipitation, decrease expected
precipitation totals, and raise snow levels. Overall, this system
has shown signs of slowing with little precipitation reaching
into western Nevada due to shadowing or into Mono County due to a
lack of dynamics and deep moisture.

Precipitation onset looks to occur Monday morning across Plumas
and far western Lassen County and reaching the Tahoe Basin by late
Monday afternoon. Late Monday afternoon and evening looks to be
the main window to see precipitation through the northern Sierra
with precipitation amounts generally in 0.25-0.50" range west of
highway 89 to the crest with localized amounts along the crest
getting around 0.75". Best chances for snow should remain above
7,500-8,000` late Monday night into early Tuesday morning, so
impacts on passes looks to be mainly from wet roadways.

Gusty winds are also expected mainly north of I-80 Monday
afternoon with the highway 395 corridor from Reno to Susanville
seeing the best potential of seeing wind gusts in the 40-50 mph
range. Restrictions are possible for high profile vehicles where
crosswinds are present. Hazardous boating conditions are also likely
across Tahoe and Pyramid lake. The bulk of the system moves east
by Tuesday morning with lingering showers and decreasing winds.

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

After a quiet day Tuesday, another storm will roll into the region
Wed-Thu. Medium range models are in a little better agreement
although the ECMWF continues to be slower than the deterministic GFS
and various ensemble means including its own. The GFS has shown
quite a bit of consistency over the past couple nights and with
support from the ensemble mean we are giving it a lot more weight in
the forecast. So we have bumped up pops Wednesday night when the
main trough/frontal passage is expected to occur. Then we should see
relatively quiet weather late Thursday through Friday with seasonal
temperatures and lighter winds.

For the storm Wed-Thu, winds will increase Wednesday ahead of the
front with gusts approaching 100 mph over the Sierra ridges and
around 50 mph for lower valleys. This will result in increased
turbulence for aviation, impacts to high profile vehicles and rough
lake waters. Precipitation will arrive at the northern Sierra Crest
Wednesday afternoon and then spread south and east Wednesday night
as the front rolls through the region.

It does not look like this will be a major precipitation producer
due to its progressive nature, but it is colder than previous
systems and snow levels will likely fall enough so that passes
around the Tahoe Basin will be impacted Wednesday night into early
Thursday morning with snow accumulations down to lake level as the
storm winds down late Wednesday night and Thursday morning. There
will also be a brief period of spillover with the front across
western NV mainly north of Highway 50 where rain may change over to
snow or mix with snow down to 5000 feet behind the front. The band
weakens considerably as it pushes south, so QPF/snow amounts will be
less south of Highway 50. A first guess at snow amounts suggest 10-
18" above 7000 feet in the Tahoe Basin tapering to 6" toward Mammoth
Mountain, up to 6" at lake level and higher passes of northeast CA,
and a couple of inches down to 5000 feet around the Tahoe Basin
northward into Plumas...Sierra and western Lassen Counties. If you
have travel plans through the northern Sierra/northeast CA Thursday
morning, be prepared for hazardous winter driving conditions. Hohmann



Low clouds have mitigated freezing fog at KTRK so far this morning
but are currently just starting to clear which will promote
freezing fog development. Otherwise, VFR today with light winds.

The next storm is set to arrive Sunday night through Monday night
with gusty winds the main concern. Mtn wave turbulence along with
local LLWS is expected along with areas of reduced CIGS/VIS north of
I-80. Another colder storm with another round of wind and possible
runway snow accumulation at Sierra airports is expected Wednesday
into Thursday. Hohmann


.REV Watches/Warnings/Advisories...



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