Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 150404 AAA

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
904 PM PDT Wed Mar 14 2018


All winter headlines for the current weather system will be
dropped with this update. Aside from a few snow showers possibly
spreading into parts of northeast CA and west of Tahoe with only
sparse accumulations, this first event looks finished based on the
latest satellite and radar trends. Farther east, most of the rain
has also diminished with the final band likely to exit far eastern
Pershing County in the next hour or so. All mentions of thunder
will also go away with this update.

Looking into Thursday, we will start the next warning for the
Tahoe basin a few hours earlier at 2 PM. Even though this is
typically time of peak heating, highs will not be very warm to
begin with, then temperatures fall as snow picks up in intensity
during the afternoon. For those with flexible travel plans, the
best bet for avoiding snow over the main passes (including I-80
and US-50) is to complete the trip by 12 noon. Otherwise there
will be a 24-36 hour period of continuous moderate to heavy snow
with poor visibility, possible whiteout conditions (especially
Thursday late afternoon through much of the night) and long delays
over these main passes. MJD



A stronger and colder storm moves into the region by Thursday
afternoon and continues through Saturday morning. This storm will
produce additional periods of heavy snow in the Sierra with snow
accumulation also possible for lower elevations. Lighter showers
may continue through the rest of the weekend, then dry weather is
likely through Tuesday morning ahead of the next storm system.


.PREVIOUS DISCUSSION... /Issued 317 PM PDT Wed Mar 14 2018/


Another round of light to moderate snow is expected in the Sierra
this evening. A stronger and colder storm moves into the region
by Thursday evening and continues through Saturday morning. This
storm will produce additional periods of heavy snow in the Sierra
with snow accumulation also possible for lower elevations.
Showers continue through Sunday, then conditions become much
drier through Tuesday morning ahead of the next storm system.



Bottom line up front... Winter conditions remain in the Sierra
through Saturday with additional rounds of snow and wind. There
is a brief break in the action on Thursday morning, but then the
main event comes into the Sierra late Thursday afternoon into
Friday and then shifting south of Highway 50 Friday afternoon and
Friday night. Widespread travel impacts are expected for the
Sierra, northeast California, and western Nevada during this time.
Anyone with travel plans over the Sierra or around the Tahoe
Basin Thursday night into Friday morning should be prepared for
rapidly deteriorating conditions and high likelihood for gusty
winds, blowing snow and near zero visibilities in the mountains
Thursday evening. There is even a good potential for snow "down
here" in the valleys of western Nevada Thursday night into Friday
morning with potential impacts for the Friday morning commute.

For tonight...light to moderate snow showers are currently
ongoing across the Sierra and western Nevada with some snow
pellet showers currently around the Reno-Sparks area. This
increased instability (evidenced by the snow pellets) could also
result in isolated thunder through this evening. We extended out
the winter weather advisory for Lassen-Plumas through this evening
as well, mainly to cover for these convective showers developing
over the western slopes of the Sierra and will bring additional
snow to the Sierra tonight.

There is a break in the action Thursday morning, ahead of the next
shortwave moving in Thursday afternoon. Winter storm is still on
track for Thursday night into Friday, bringing widespread heavy
snow to the Sierra. Winter storm warnings remain in place for
Lassen-Plumas and Lake Tahoe Basin. For the Tahoe Basin above
7000 feet, 2-3 feet of snow are most likely, with some locations
along the Sierra Crest around Tahoe potentially seeing up to 4
feet between Thursday afternoon and Saturday morning. For the
Sierra valleys below 7000 feet, roughly 1 to 2 feet are expected,
including around Lake Tahoe, Truckee, and Portola. There is a high
confidence for heavy snow in around the Tahoe Basin and through
Lassen-Plumas during this time.

Latest model trends have backed off on precipitation amounts for
northern Lassen County, as well as Mono County, as the jet pivots
around and remains pointed at the Tahoe Basin for the majority of
this storm. Don`t worry, Mono will still get it`s share of snow,
but it could limit the snow Thursday night through Friday,
leaving the main snow show for Mono County for Friday night. A
Winter Storm Watch remains in effect for Mono County, with roughly
1 to 2 feet above 7000 feet and west of US-395 and 4-12 inches
below 7000 feet along and east of US-395. Most of this snow will
fall Friday afternoon through Friday night. There is medium
confidence for the snow amounts in Mono County.

As for the valleys of western Nevada and northeast California, we
expect to see good spillover Thursday night into Friday morning,
with snow levels down to all valley floors. Snow amounts along
the Highway 395 corridor will be several inches for the valley
floors, including around the Reno-Carson City and Susanville. Some
of the foothill locations above 5000 feet and west of Highway 395
could see up to 12 inches of snow--including Virginia City and VC
Highlands. Medium confidence for snow amounts in western Nevada.

As for the valleys of west-central Nevada, we could also see light
snow accumulations Thursday Night into Friday morning, up to 1-3
inches in Fernley-Fallon-Lovelock-Yerington-Hawthorne. Should see
some decent instability Thursday and Friday afternoons in western
Nevada and northeast California as well, with potential for an
isolated embedded thunderstorm. -Hoon

LONG TERM...Saturday through Tuesday...

Snow showers will linger on Saturday as the storm slowly migrates
eastward through the day. Some additional accumulations may be
possible, especially in the Sierra but otherwise showers will begin
to taper by late afternoon. Generally drier conditions are expected
for Sunday, but there is a small chance for showers in the Sierra.

Shortwave ridging will really build across the Sierra and western
Nevada for Monday, so you can plan on a quiet commute Monday AM at
least weather-wise. Although the ridge doesn`t take residence for
incredibly long with the next storm just off the west coast by
Tuesday afternoon.

This storm for next week is wet and warm, but the best dynamics and
moisture associated with it will be directed at the southern Sierra.
Atmospheric river tools are also directing the moisture plume into
southern Sierra and central/southern CA. Although snow levels will
be higher with this storm, the eastern Sierra will likely get some
snow Tuesday into Wednesday. Otherwise, anticipate mostly rain for
the lower elevations and valley floors. Keep in mind that this next
storm is a week away, so timing and track will likely change. -Edan


The second wave of this current storm system is making its way
through the region dropping snow levels down to valley floors and
impacting all area terminals with convective snow showers and
gusty winds. These showers will be on and off throughout the rest
of the afternoon into the early evening hours.

Due to their convective nature, the snowfall rates with these
showers can be intense at times reducing flight conditions to IFR or
even lower mainly for KTRK and KTVL where they have the best chance
to see the worse conditions. Additional accumulation of 2-4
inches is possible for these terminals. As for the western Nevada
terminals and KMMH, MVFR restrictions can be expected at times due
to more general snow shower activity. Slick runways and mountain
obscurations will also be an issue.

This ongoing snow shower activity should taper off by 03Z tonight
for KRNO, KCXP, and KMMH with the central Sierra terminals ending by

A brief break in the precipitation will take place Thursday morning
ahead of the next system set to impact the region late Thursday
night into early Saturday morning. Heavy snow is forecast for the
Sierra with accumulation down to valley floors. Stronger winds are
expected for Mono county as recent model trends have the jet taking
a more southerly trajectory. -LaGuardia


.REV Watches/Warnings/Advisories...
NV...Winter Storm Watch from Thursday afternoon through late Friday
     night NVZ003.

     Winter Storm Warning from 2 PM Thursday to 5 AM PDT Saturday

CA...Winter Storm Warning from 2 PM Thursday to 11 PM PDT Friday

     Winter Storm Watch from Thursday afternoon through late Friday
     night CAZ073.

     Winter Storm Warning from 2 PM Thursday to 5 AM PDT Saturday



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