Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/05/21

Area Forecast Discussion

National Weather Service Reno NV

 233 PM PDT Thu Nov 4 2021

.SYNOPSIS...

A trough of low pressure remains over the northeast Pacific through
the middle of next week. This will bring unsettled weather to northeast
California and western Nevada. The next system arrives Saturday with
breezes and chances for light rain and mountain snow; some Sierra pass
impacts are possible. Late Monday and Tuesday another system arrives
with winds along with the potential for Sierra travel impacts due to
mountain snow.

&&

.SHORT TERM...

Low pressure is moving into the Pacific Northwest today. While
precipitation impacts have been minimal given lighter precipitation
and snow levels above ~8,500 feet in the northern Sierra, winds kicked
up as the light precipitation hit the west side of the Sierra. Peak
gusts today have been widespread in the 35-45 mph range, with 50-70
mph (and even an 80 mph gust near the Galena Bridge on 580) for wind
prone areas along Highway 395/I-580. By mid-late afternoon and into
the evening, winds are expected to ease down as winds aloft come
down as the upper trough axis moves away. Expect a colder start to
Friday as skies clear and winds diminish (at least in valleys)
tonight.

Lighter winds prevail overall Friday; however, ridgetop winds will
remain gusty with peak gusts up to 80 mph still possible Friday
afternoon through Saturday as the next weak shortwave affects the
region. This wave will also provide a period of rain and mountain
snow showers across NE California and the Sierra Saturday afternoon
and evening. Snow levels will be around 6,000`-7,000` (lowest
Lassen/Plumas) during this period so a couple of inches of snow
accumulation is not out of the question Saturday evening on the
main Tahoe area passes. Travel slow downs along with wet and slick
roads are possible. Be sure to keep tabs on the forecast if you
have travel planned across the Sierra. -Snyder/Fuentes

.LONG TERM...Sunday onward...

Monitor road conditions through the weekend as there will be
intermittent chances for snow along the Sierra passes.

A large trough positioned off the Pacific Northwest coast will
direct shortwaves into the West early next week. There has been some
variability with the timing and the location of the incoming waves
of moisture. A weak shortwave passage will occur late Sunday into
Monday and then the primary storm will push through late Monday into
Tuesday. During this time, Sierra locations may see little to no
breaks in the shower activity.

The best chances for moderate to heavy precipitation rates still
appear to be Monday evening through Tuesday morning for locations
west of Highway 395. Spillover potential in recent simulations is
very limited with forecast soundings showing the possibility of
downslope winds for Monday afternoon ahead of the main moisture
push. Snow levels will start around 6000 to 7000 feet for much of
the storm with impacts to Sierra passes probable. The main storm
pushes through rather quickly from Monday night through Tuesday
afternoon, especially as the southwest ridge ramps up.

Wednesday onward...Ensemble clusters are leaning pretty heavily
towards a drier and mild 8-10 day outlook across much of the West.
Highs are forecast to climb back into the 60s for western NV and
into the 50s for the Sierra. While we are fairly confident in the
return of the ridge with the trend for warming and drying, there
are a handful of simulations that maintain a flatter, less
impressive ridge stationed near Baja CA for end of next week.

-Edan

&&


.AVIATION...

Strong turbulence and numerous LLWS reports have been noted in the
immediate lee of the Sierra per PIREP and AMDAR data as a sharp
trough axis and front push through the region. As far as CIGS/VIS,
they are no longer of any concern (VFR) as earlier frontal showers
in the Sierra and northeast CA have dissipated with just some residual
stratocumulus above the terrain in far northeast CA.

Winds will diminish below ridges tonight with lighter speeds (peak
gusts 15-25 kts) for Friday. However, winds aloft and over Sierra
ridges will remain elevated through tomorrow as a northeast Pacific
trough remains in place. With this in mind, some turbulence is likely
over and downwind from the Sierra crest through Friday.

Another wave approaches northeast CA and western NV on Saturday.
Besides breezy conditions and turbulence, higher terrain obscuration
with light mountain snow is likely, especially near the Sierra crest.

-Snyder

&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until 5 PM PDT this afternoon for Pyramid
     Lake in NVZ004.

     Wind Advisory until 5 PM PDT this afternoon for Pyramid Lake in
     NVZ005.

     Lake Wind Advisory until 5 PM PDT this afternoon for Lake Tahoe
     in NVZ002.

CA...Wind Advisory until 5 PM PDT this afternoon for Pyramid Lake in
     CAZ070-071.

     Lake Wind Advisory until 5 PM PDT this afternoon for Lake Tahoe
     in CAZ072.

&&

$$

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