Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 170222 AAA

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
722 PM PDT Fri Mar 16 2018


The cold front was exiting Mono-Mineral-Churchill Counties this
evening with associated forcing from upper jet/front shifting
eastward into central and northeast NV. Snow showers were mainly
impacting the Sierra locations as convection on the west side of
the Sierra continued to flare in the unstable airmass there and
work eastward into the higher terrain. Snow showers will continue
to put down several inches of snow along and west of Highway 89
as well as Highway 395 through Mono County with locally a foot or
more right at the crest in heavier convective snow showers through
Saturday morning. Travel is strongly discouraged across the
Sierra tonight and the warnings will remain in place.

For lower elevations, isolated to scattered snow showers will
bring an inch or two of local accumulation but the threat of
widespread snowfall has diminished for the night. We have allowed
the warnings and advisories to drop for these areas. However with
the setting of the sun and temperatures already near or below
freezing, any light snow or remaining water on roadways, sidewalks
and driveways will result in icy conditions and caution is
advised. Hohmann


.PREVIOUS DISCUSSION... /Issued 322 PM PDT Fri Mar 16 2018/


A winter storm will continue to impact the region into early
Saturday morning with dangerous travel conditions in the Sierra.
Snow showers and well below normal temperatures Saturday will
give way to a drying and warming trend for early next week. The
next storm system is forecast to bring rain and heavy mountain
snow for Wednesday and Thursday.


The current potent storm has performed as expected in the northern
Sierra (storm just spreading over Mono County), with anywhere
from 1.5 to 3 feet reported thus far in the Tahoe Basin. Out into
far western Nevada, the storm actually over-performed with
generally twice what was called for (8-16") as the system`s low-
level frontal band got stuck just in the right place to keep
moderate to heavy snow going through this morning. On the opposite
side, west-central Nevada has seen a delay in snow with the
Lovelock area just now seeing accumulating snowfall, and Fallon
still a mix of rain and snow as the front is just pushing south in
the past couple hours.

Late this afternoon into the evening, a cold front stretching from
near Coleville east to between Hawthorne and Schurz will continue
to push south and east. The heaviest and most widespread snow east
of the Sierra will mainly be north of the front, generally south
of Interstate 80, with more sporadic snow showers northward. In
the Sierra, unstable and moist upslope flow will keep showers
going overnight, with the heaviest snowfall this evening south of
Highway 50. As far as main roads, they should remain mostly wet
(the heaviest showers could bring brief slushy conditions) in the
lower valleys through most of the evening commute. The warnings
and advisories for western NV have been left up thus far to cover
slick evening conditions if showers persist after 6 PM; however,
they COULD BE dropped after further review this afternoon with
the main period of accumulating snow finished. In the Sierra,
continued showers and colder temperatures will keep the threat for
road impacts intact through tonight so the warnings will be
continued as scheduled.

Some residual snow showers under the cold upper low will persist
on Saturday, with high temperatures remaining well below average.
Any light snowfall accumulations should generally remain in the
Sierra with snow showers in the lower valleys unlikely to be
sufficient to cause travel issues/road accumulations. Drier and
warmer weather returns Sunday and Monday ahead of another
significant storm for the middle of next week. -Snyder

LONG TERM...Tuesday through Saturday...

Simulations continue to trend wetter with the a potentially
significant storm for next week. Atmospheric river detection tools
are showing the moisture plume directed at areas from the Tahoe
Basin and southward from Tuesday through the end of the week.
Multiple shortwaves dropping through the main trough will tap into
the moisture and swing it into the Sierra and western Nevada for
multiple rounds of rain, snow and gusty winds.

Snow levels will start off fairly high at the onset of the event on
late Tuesday into Wednesday (~7000-8000 ft), but some simulations
drop the snow levels to all valley floors by Thursday night into
Friday morning. The high Sierra, especially above 8000 ft, will
likely pick up another couple feet of snow depending on where the AR
centers from north to south, while this may be a decent heavy rain
event for lower elevations including the foothills and western
Nevada. This will be a storm to keep an eye on, especially with
the high snow levels and the subtropical moisture tap. -Edan


Widespread IFR CIGS/VIS to continue with snow in the Sierra into
early Saturday morning, with some improvement with more scattered
-shsn by late morning and afternoon. Another few inches of
 snowfall is possible for northern Sierra terminals, with higher
 amounts for KMMH as a cold front keeps higher snowfall rates
 going there through evening.

For western Nevada, areas north of Highway 50 should see overall
improvement (occasional lowered CIGS/VIS in -shsn) by this
evening, although higher terrain obscuration could persist
overnight. South of Highway 50, conditions will likely deteriorate
this evening as a cold front moves through and CIGS lower with
increasing coverage of -sn/sn. Minimal snowfall accumulations are
expected for terminals south of Highway 50, especially on paved
areas, as ground temperatures remain above freezing.

Winter storm will clear out by Saturday with lingering snow or
pellet showers. Dry conditions return Sunday with fog potential at
KTRK. The next system of note is forecast to move through the
region Wednesday and Thursday. -Snyder/JCM


.REV Watches/Warnings/Advisories...
NV...Winter Storm Warning until 5 AM PDT Saturday NVZ002.

CA...Winter Storm Warning until 11 PM PDT this evening CAZ071.

     Winter Storm Warning until 11 AM PDT Saturday for Lake Tahoe in

     Winter Storm Warning until 5 AM PDT Saturday CAZ072.



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