Wildfire and Heavy Snow in Nevada, November 17 to 18, 2020

Area Forecast Discussion
National Weather Service Reno NV
222 PM PST Mon Nov 16 2020

.SYNOPSIS...

A storm moves in Tuesday for strong winds, especially in eastern
California and far western Nevada. Some wind damage is possible
in the immediate lee of the Sierra. Rain and higher elevation snow
are likely later Tuesday and Wednesday with travel in the Sierra
affected. Mild temperatures through Tuesday will fall closer to
average mid-week through the weekend.

&&

.SHORT TERM...

Forecast thinking now supports a bit stronger winds Tuesday with a
solid high wind event now expected for eastern CA and far western
NV. As far as snowfall amounts for the Sierra from Alpine County
northward and above valley floors across northeast CA, a good number
of simulations have increased their QPF with snow levels possibly a
bit lower than previously expected. In any case, there is high
confidence that travel over Sierra passes and the higher roads across
northeast CA will be affected by snow Tuesday night and Wednesday.
Let's break the weather elements down...

* WIND...

  Wind projections for Tuesday from blended model guidance have
  come up a bit more this morning. Also, now that short-term
  guidance from the HRRR is available to add confidence, concern
  has increased for a solid high wind event (more widespread peak
  gusts to 60+ mph) for eastern CA and far western and northwestern
  NV. More damage is possible than with the last round of wind (last
  Friday) as fencing/trees could have been weakened from those
  winds and this event could feature a good 8-12 hours of strong
  wind ahead of the cold front. See our wind statements for more
  details of the expected wind speeds and impacts.

  Farther east into the west-central NV basin and range, given
  that good mixing is expected with 700 mb winds 40-55 kts ahead
  of a cold front, we now expect wind gusts to peak out in the
  40-55 mph range Tuesday afternoon-evening. Thusly, a wind
  advisory has been issued for Pyramid Lake and Pershing and
  Churchill counties.

  Blustery conditions with gusts to ~25-40 mph are expected Wednesday
  as the region remains under the influence of troughing with winds
  aloft remaining elevated.

* PRECIPITATION...

  Many simulations have come in with heavier precipitation totals
  Tuesday-Wednesday, especially in eastern California from Alpine
  County northward but also possibly out into portions of western and
  northwestern NV. Models now show a secondary wave moving over northern
  California Wednesday morning which, with the moist westerly flow on
  the unstable side of the cold front (hung up in Alpine County
  and out into the Basin and Range), should result in another push
  of rain and higher elevation snow. This feature, along with the
  main period of heavier precipitation Tuesday night, have pushed
  confidence in higher QPF upwards with a winter storm warning to be
  issued for Lake Tahoe. Also, a bit colder air may filter into
  northeast CA and northwest NV than expected previously due to the
  more defined secondary wave. This may allow for more snowfall down
  to between 5500-6000 feet (affecting Truckee and the Lake Tahoe
  Basin) than was previously expected through Wednesday. See the
  latest winter statements to be issued this afternoon for more
  details.

  With heavier precipitation still appearing to hang up in Alpine County
  as the upper jet and cold front stall in their southward propagation,
  precipitation totals for Mono County remain rather unimpressive with
  the bulk limited to west of Highway 395. Still, there should still be
  some relief for drier timber.

-Snyder

.LONG TERM...Thursday onward...

A weak trough over the western U.S. Thursday will maintain cool
temperatures, with mostly cloudy skies and chances for light showers.
Snow levels within these showers could come down to below 5,000
feet, but any snow accumulations are expected to be localized and
fairly light. Clouds should be on the decrease by Thursday night
as the trough exits to the east and then a weak high-pressure
ridge builds Friday though the weekend. With this ridging,
overnight inversions will return leading to cold morning
temperatures in valleys (single digits in the typically colder
spots) and as a result afternoon temperatures may warm only a
degree or two.

For next week, the pattern continues to be progressive but there are
some indications the weather systems could be weaker compared to
tomorrow's storm and that the deeper moisture may stream more into
the Pacific Northwest. That said, there is still potential for snow
(especially at mountain passes) which could impact Thanksgiving
holiday travel. Make sure to stay tuned to the forecast if you have
travel plans next week. JCM

&&

.AVIATION...

After fairly light surface winds through this evening (southeast-
south around 10 kts) winds increase overnight tonight and become
very strong tomorrow as a strong jet aloft move over the Sierra
and western Great Basin.

* WINDS: Winds aloft will increase significantly 06-12Z Tuesday
  with ridge level winds 40-55 kts, gusts to 70+ kts. These winds
  get even stronger Tuesday after 12z with ridge level winds 50-70
  kts with gusts up to 100+ kts. South-southwest winds will
  develop at the Tahoe terminals early Tuesday morning and then
  expand to all of the eastern Sierra and western NV, intensifying
  during the morning and afternoon Tuesday. Moderate to severe
  turbulence, LLWS and rotors will be common with widespread
  surface wind gusts 40-55 kts, locally stronger to 60-70 kts in
  wind prone areas along the Highway 395 corridor from Susanville
  to Lee Vining. Surface winds will back off in these areas
  Tuesday night as precipitation arrives, but turbulence will
  likely continue Tuesday night and Wednesday as winds aloft
  remain strong. Surface winds will likely stay strong from Lee
  Vining south into KMMH well into the night Tuesday night (gusts
  45+ kts at KMMH).

* RAIN/SNOW: Rain and high elevation snow will bring mountain
  obscurement to the Tahoe Basin northward into Lassen County
  beginning Tuesday evening and continuing overnight and Wednesday
  morning. Snow levels will start above area terminals but there
  is a chance for rain to change to snow at KTRK and KTVL with up
  to 3 inches of wet snow possible. Precipitation and terrain
  obscuration will spread into western NV Tuesday evening and
  Tuesday night, but fewer impacts are expected for locations east
  of Highway 95. JCM

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 10 AM Tuesday to 4 AM PST Wednesday NVZ001.

     Winter Storm Warning from 4 PM Tuesday to 6 PM PST Wednesday
     NVZ002.

     High Wind Warning from 9 AM to 7 PM PST Tuesday NVZ005.

     High Wind Warning from 7 AM to 4 PM PST Tuesday NVZ002.

     High Wind Warning from 10 AM to 7 PM PST Tuesday NVZ003.

     Wind Advisory from 10 AM to 10 PM PST Tuesday NVZ004.

CA...Winter Weather Advisory from 1 PM Tuesday to 6 PM PST Wednesday
     above 5500 feet in CAZ071.

     Winter Storm Warning from 4 PM Tuesday to 6 PM PST Wednesday
     CAZ072.

     High Wind Warning from 9 AM to 7 PM PST Tuesday CAZ070-071.

     High Wind Warning from 10 AM Tuesday to 4 AM PST Wednesday
     CAZ073.

     High Wind Warning from 7 AM to 4 PM PST Tuesday CAZ072.

&&

For more information from the National Weather Service visit...
http://weather.gov/reno