Heavy Snow in Nevada, December 15 to 16, 2021

Area Forecast Discussion
National Weather Service Elko NV
247 PM PST Wed Dec 15 2021

.SYNOPSIS...The next winter storm moves across the region tonight
and Thursday with widespread snow, particularly across northern
Nevada. Colder arrives for the upcoming weekend with many area
have sub-freezing daytime temperatures. The next winter storm
arrives next Tuesday and Wednesday.

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.SHORT TERM...Tonight through Friday.

The next upstream short wave, which appears slightly negatively
tilted, is currently spreading cloud cover over northwest Nevada.
Short wave digs into northern Nevada with modest upwards forcing,
supported by a jet that cuts across central Nevada. The I80
corridor will be the primary beneficiary of this winter weather
maker as snow develops west to east this evening. Later tonight,
the snow spreads southward and impacts US50 from Austin to the
western portion of White Pine County. The short wave loses some
cohesiveness as it gets to east central Nevada. Light snow becomes
widespread overnight across the northern valleys with the
potential of 1-4 inches, particularly over southwest Elko County.
No changes to the current Winter Weather Advisory.

Trough will be moving downstream by Thursday night with a
northerly component to gradient flow aloft. Air mass turns colder
with fresh snow cover, meaning Friday morning will by chilly
although some lingering cloud cloud inhibits the radiational
cooling. Partial clearing is expected with no snow on Friday, but
daytime temperatures stay below freezing all areas.

.LONG TERM...Friday night through next Wednesday.

Model agreement continues the progression of the trough eastward
from the region over the course of Friday. By that night, much
drier conditions will look to settle over Northern and Central
Nevada for the night and following day thanks to a quick building
ridge and high pressure. As flow shifts to northwesterly and skies
clear for the night, expect temperatures to drop bring the
coldest temperatures of the week that Saturday. Look for most
locations to wake up that morning to temperatures in the teens and
single digits with few places dropping below zero. Afternoon high
temperatures aren’t expected to warm up that much either with
locations only reaching into mid to low 20s.

As we enter Sunday and the start of Christmas week, conditions
start to transition as the synoptic pattern shifts to our
northwest. Currently, latest model guidance predicts the onset of
another more robust trough making its way down from the Gulf of
Alaska Sunday before stalling off the coast and deepening. From
here things become a bit muddied as models try to get a handle on
the closed upper-level low that is expected to develop and its
deformations zones. However, general consensus expects the system
to shift further south over the next two days. As the system
continues to ride down the coast, look for pockets of moisture to
sneak through the Sierra Nevadas and bring in some light isolated
showers to the mountains of Northern Nevada Sunday night through
Monday.

By Tuesday, showers will look to spread across the region as
general model agreement begins the advance of the advance of the
trough into California. While still quite a bit of uncertainty in
the models, latest guidance doesn’t expected much amount wise
for the day. However, the next few day may be able to assist
further as the slow moving nature of the trough could bring daily
showers clear into Christmas Eve.

Temperatures are expected to stay pretty chilly for the week of
Christmas. Afternoon temperature are expected to stay settled in
the low 20s to 30s for most locations. Meanwhile, overnight
temperatures prefer to stay closer to the teens and single digits
with a slight warm up into the low 20s during the mid-week.

&&

.AVIATION...VFR conditions are expected to continue into the early
evening hours with CIG lowering for the oncoming storm from the
west. Latest high resolution models and ensembles are still in
agreement for the onset time of showers with KWMC seeing them
start sometime around 01 to 03 UTC. Trends continue to also keep
these showers initally to the northern sites with KEKO seeing the
latest start time around 02 to 04 UTC. Look for showers to spread
to the south and into KELY in the early morning hours. Some MVFR
VIS and CIGS are expected clear through the overnight and majority
of tomorrow with the potential for IFR conditions under heavier
and/or steadier snowfall. To the south at KELY and KTPH conditions
will be much drier in the evening and nightly, but winds are
expected to pick up for KELY with potential 32 kt gusts in the
evening and overnight.

&&

.LKN WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM PST Thursday for Humboldt
County-Northern Elko County-Northern Lander County and Northern
Eureka County-Ruby Mountains and East Humboldt Range-South
Central Elko County-Southwest Elko County.

Winter Weather Advisory from 10 PM this evening to 10 AM PST
Thursday for Southern Lander County and Southern Eureka County.

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