Area Forecast Discussion
Issued by NWS Elko, NV

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FXUS65 KLKN 102207

Area Forecast Discussion
National Weather Service Elko NV
207 PM PST Sat Dec 10 2016

.SYNOPSIS...A long stream of tropical moisture will penetrate into
the Great Basin for the next several days with little breaks
between snow and rain periods. Valleys rains and wet snows will
turn to heavy mountain snows in central and northern Nevada. Some
mountains could get over two feet of additional snow...with
valleys experiencing minor flooding.


.SHORT TERM...Tonight through Tuesday. A steady stream of tropical
moisture originating in the ITCZ south of Hawaii is streaming into
northern Nevada Saturday afternoon. With cool air at the surface
and freezing levels around 6500 to 7000 feet, valleys have been
getting all cold rains with occasional snowflakes. Mountains have
been receiving snow above about the 7000 foot level. This
precludes many passes or well traveled summits, but cooler air
into the night will drop snow levels a bit and affect these
routes. Therefore, the current Winter Storm Warning for Northern
Elko County, South Central Elko County, and the Ruby/East Humboldt
Range remains in effect until 12z Sunday. Likewise, the Winter Wx
Advisory for White Pine County remains in effect for the same

The moisture plume shows little signs of stopping with the very
strong jet (160 knots) progged by all models to drop slightly
south and the trajectories keeping the moisture source in their
rear view mirrors.

A small break occurs Sunday before the mid-Pacific trajectory
picks up more subtropical moisture from the western ocean and
advects it strongly into the Basin for later Monday and Tuesday.

Temps/dewpoints remain fairly well fixed with steady cloud cover
and little movement by the jet, and H10-H5 thicknesses remaining
fairly high, generally.

Winds do not appear to want to increase much even with the strong
H250 jet, due to utter lack of downward mixing.

Expecting rainfall amounts to reach daily records in many
locations, with bodacious snows in west facing mountains,
especially ones such as Jarbidge, Independence, Santa Rosa,
Ruby/East Humboldt, possible Pinon, Great Basin NP massif, and
outside chance for the northern Toiyabes.

.LONG TERM...Tuesday night through Saturday.
ANother atmospheric river scenario is expected to impact the Great
Basin bringing wintry mix to northern NEvada Tuesday night into
Wednesday. A relatively warm air mass will maintain a valley
rain/higher elevation snow setup Wednesday and Thursday. Appears
that this event will not be as robust as ongoing event.
However, antecedent ground moisture will factor into potential for
some flooding if it becomes apparent that Wed-Thu system will be
stronger than current forecast. Nonetheless, models are in fairly
good agreement in bringing 0.75 to 1.25 inches of LWE to a large
swath of northern Nevada for the middle part of next week.

Models show a big change occurring later next week with colder air
moving into the state as trough moves into the Pacific Northwest.
Below normal temperatures are expected by the end of next week
with lows in the single digits and highs in the teens by next
weekend. Lingering precip Friday and Saturday associated with the
trough should change over to all snow across the CWA as colder
air settles into the Great Basin. Snow will continue to pile up in
higher elevations with another 1 to 2 feet accumulation over a
several day period next week with light accumulations in the
valleys beginning early Friday.


.AVIATION....MVFR to occasionally IFR conditions will persist
through the early afternoon hours at KWMC and KEKO as a large
area of valley rain and higher elevation snow continues to move
through the state. Conditions are expected to improve at these
terminals tonight with rising CIGs and diminishing showers but
mountain obscurations will linger into tomorrow morning. Expect
deteriorating conditions at KELY later this afternoon and evening
as lower CIGs, increasing showers and reduced visibilities affect
the terminal area. Freezing temperatures overnight will pose a
risk of ice formation on runways at all but KTPH.

KTPH will remain relatively quiet. Cloud cover will increase this
evening with the advancing storm system but precip should stay
largely to the north of the terminal.


Winter Storm Warning until 4 AM PST Sunday for Northern Elko
County-Ruby Mountains/East Humboldt Range-South Central Elko

Winter Weather Advisory until 4 AM PST Sunday for White Pine



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