Winter Weather Advisory 21, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
1249 PM PST Sun Nov 5 2023

.SYNOPSIS...

Strong winds will continue through the night and Monday, with
rain showers becoming more numerous during the day Monday. Some
snow may cause travel impacts over the Sierra Monday late
afternoon and night. From Tuesday afternoon onward, including the
Veteran's Day weekend, relatively quiet weather is expected for
most areas. A few mountain snow showers are possible Friday.

&&

.DISCUSSION...

* Areawide strong winds will continue through tonight and into
  Monday in response to 140 knot upper jet and 50 knot mountain
  top flow. Slight increase in the wind forecast, but overall a
  just under advisory event with most areas seeing gusts 30-45 mph
  with the typical wind prone spots seeing gusts 50-60 mph for
  periods of time. This includes Washoe Valley, 395 in Lassen &
  Mono Counties, and maybe 95 at Walker Lake. Winds will likely
  not let up much tonight except in the most sheltered of valleys.

* Rain and snow showers will increase in coverage Monday into
  Monday night. We're within the time horizon of the HRRR/HREF and
  both of those are showing potential for a period of up to
  1"/hour snow rates near the Sierra crest from Donner southward
  into the E Sierra late Monday afternoon into the night. Very
  convective looking environment too, so that limits
  predictability but also creates a larger boom/bust scenario.
  Either way we're messaging potential snow travel impacts over
  the Sierra passes late Monday into the night, including the
  evening commute (earlier sunset too). A few light flurries/snow
  showers may persist into Tues morning, even down to about 5500'
  in W Nevada foothills.

* Tuesday afternoon onward looking relatively cool and quiet with
  more limited valley mixing and ventilation. Still potential for
  a very quick/weak storm to bring light snow showers to the
  mountains on Friday. NBM guidance showing about a 10% chance of
  1" in the mountains.

* Storm door remains at least slightly ajar into the week two
  period. CW3E atmospheric river landfall tools, especially the
  GEFS, showing potential for Pacific storms 11/14-18 timeframe.
  ECMWF EPS less so. Based on NBM temperature/snow level
  projections out that far, any storms would be of the average to
  cooler-end on the spectrum.

-Chris

&&

.AVIATION...

* With mountain top flow nearing 50 knots and jet stream speeds
  near 140 knots, expect increased turbulence, wind shear, and
  mountain wave activity through Monday. Already seeing winds
  gusting to 80-95 mph along the ridges.

* Surface winds will ramp this afternoon into early Monday with
  persistent breezes through the night tonight. Gusts on the order
  of 25-35 knots will be common, with a 1 in 4 chance (25%) of
  seeing gusts exceed 40 knots per NBM guidance at RNO and MMH for
  example.

* Precipitation impacts through tonight will be confined to far
  NE California (SVE) with occasional MVFR showers. Rain/snow
  showers become more widespread Monday with a better bet for
  seeing occasional MVFR/IFR conditions and mountain obscuration
  areawide, including RNO/TRK/TVL/CXP/MEV, and even as far south
  as MMH Monday night.

* Snow accumulations can't be ruled out for TRK/TVL Monday
  evening/night with NBM showing 20-40% chance of 1" and even a
  10% chance of 2". Latest HRRR shows a very convective
  environment so snow showers will be hit/miss but if they hit
  then quick accumulations and LIFR conditions are a good bet.
  Snow risk for MMH is less certain but not-zero.

-Chris

&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until 4 PM PST Monday for Lake Tahoe in
     NVZ002.

     Winter Weather Advisory from noon Monday to midnight PST Monday
     night NVZ002.

     Lake Wind Advisory from 1 AM to 4 PM PST Monday for Pyramid Lake
     in NVZ004.

CA...Lake Wind Advisory until 4 PM PST Monday for Lake Tahoe in
     CAZ072.

     Winter Weather Advisory from noon Monday to midnight PST Monday
     night CAZ072.

     Winter Weather Advisory from 3 PM Monday to 3 AM PST Tuesday
     CAZ073.

&&