775
FXUS65 KREV 092135
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
135 PM PST Sat Nov 9 2024

.SYNOPSIS...

* Smoky and hazy conditions continue within the region today
  before improving by tomorrow.

* Gusty winds, mountain snow and valley rain arrive Monday with
  possible impacts to travel along the Sierra passes late Monday
  into Tuesday morning.

* Following a brief break in active weather midweek, another system
  is in the forecast later in the week which looks to keep the
  region showery, cool, and breezy.

&&

.DISCUSSION...

With an upper air ridge over the region this afternoon, the CWA
continues to see high pressure dominate its weather pattern by
keeping winds relatively calm. Smoke and haze caused by area
prescribed burns will linger within the region due to the poor
mixing and ventilation in the current stable atmosphere. Please
continue to monitor the air quality in your area by visiting
airnow.gov especially if you are sensitive to smoke in the air.
Forecast guidance shows an upper air trough behind the upper air
ridge moving towards the CWA on Sunday morning and passing over
the CWA during the day. With this pattern change, the CWA should
see adequate mixing and better ventilation into Sierra and far
western valleys that clear-out most of this unwanted smoky air.

On Monday, forecast guidance depicts another yet stronger upper
air trough moving towards the CWA during the day before passing
over the CWA going into Monday night and departing Tuesday
morning. At the surface, this system looks to bring a period of
gusty southwesterly winds, mountain snowfall, and valley rain to
the region for the Veterans Day holiday. Upon looking at NBM wind
probabilities, the Sierra ridges see around a 40-50% chance for
afternoon wind gusts of 70+ mph with valley portions of the CWA
seeing a 40-60% chance for afternoon wind gusts of 40+ mph. There
may be potential for a Lake Wind Advisory for Lake Tahoe, but not
enough confidence at this time to issue one just yet. As for the
expected wintry precipitation, models show shower chances moving
into the Sierra Mountains beginning on Monday morning before
spreading over the remainder of the CWA going through the day and
moving out of the region by Tuesday morning. When looking at the
Sierra Mountain snow situation, forecast guidance shows the bulk
of the expected snowfall coming in the late afternoon and evening
hours of Monday. The latest NBM probabilities show around a 50-70%
chance of 6 inches or more of snow for the highest elevations of
the Sierra Mountains by Tuesday morning. The latest Winter Storm
Severity Index (WSSI) shows minor to moderate impacts along the
Sierra Passes on Monday going into Tuesday as a result. There is
still some uncertainty at this time for a potential winter product
as run-to-run snowfall totals have been waffling up and down a
bit, but will continue monitoring the situation as the system
approaches. It would be advised to check the road conditions via
state DOT websites such as Caltrans Quickmap (quickmap.dot.ca.gov)
and Nevada 511 (nvroads.com) if you plan on traveling through the
expected snow impacted areas on Monday and Tuesday. Snow levels
look to drop to around 5500 ft on Monday night which may allow for
some lower elevations to see snow mix in following rain showers
during the day. Little to no snowfall accumulations are expected
at lower elevations should snow occur with minimal impacts seen
at this time.

A trailing upper air ridge is then seen moving over the CWA by
Tuesday afternoon allowing for dry conditions to return to the
region. But by Wednesday afternoon, ensemble guidance forecasts
wintry precipitation chances starting to return to the region that
might last through the late week with yet another Pacific trough
moving into the western CONUS behind the aforementioned ridge.
There is some good uncertainty with timing of this trough`s
progression currently. Therefore, details of this late week
system are not very clear outside of the potential for some
enhanced winds on Wednesday afternoon for the region along with a
cooling temperature trend going into the weekend. Will continue to
monitor this situation as it develops and will have more
information in future forecast packages. -078

&&

.AVIATION...

* Today we will continue to see clouds filter in from the incoming
  trough, with light winds for all terminals. Smoke and haze is
  possible for KTRK and KRNO, which may affect slantwise visibility
  through the afternoon hours. Better mixing is expected Sunday
  ahead of the incoming system.

* Southwest winds will increase along ridges Sunday afternoon and
  into the evening. This will introduce LLWS, and turbulence along
  the Sierra, affecting KTRK, KTVL, KMMH late Sunday into
  Monday morning. Ridge gusts Monday morning could approach 70+ kts.

* Clouds and showers increasing for Monday, bringing concerns for
  mountain obscuration through early Tuesday morning. HRICH

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$