Lake Wind Advisory 59, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
201 AM PST Thu Nov 30 2017

.SYNOPSIS...

Weak high pressure will remain over the area into Friday favoring
weak to moderate valley inversions each morning. Air quality will
deteriorate through Friday morning. A weak brush-by system will
increase clouds near the Oregon border tonight, but no
significant weather is expected. Another Pacific storm is possible
this weekend with an increase in winds along with some light rain
and snow. Dry weather returns next week.

&&

.SHORT TERM...

There were only minimal changes made to the forecast through the
daytime hours Saturday...and most of those were during the
Saturday time frame.

Weak flat ridging over the region today will result in morning
inversions. But these inversions should dissipate during the
afternoon allowing at least moderate mixing in the lowest valleys.
The atmosphere should mix up to about 2000-2500 feet off the
valley floors. Highs will be seasonal both today and Friday. A
weak short wave trough passes by to the north tonight. That could
bring an increase in sky cover north of I-80 and a moderate
increase in winds near the Oregon border...but no significant
weather.

Mixing starts to increase a little more Friday...but valley
inversions remain until the late morning. The ridge begins to
drift east as a trough starts to dig off the west coast.

This trough edges a little closer to the forecast area Saturday.
Ahead of the trough winds increase aloft so ridge winds become
quite gusty. By late in the day increased winds will begin to
materialize in the valleys...but gusts should not exceed 40-45 mph
most areas. The timing of this system has slowed just a bit so it
is possible the strongest winds will be Saturday night and early
Sunday morning east of the Sierra. The slightly slower nature of
the system has also led us to delay the start of pcpn. We trimmed
back pops for Saturday and they are mainly confined to areas north
and west of Susanville and north of Gerlach by late in the day.
More of this system will be covered in the long term part of the
discussion.

.LONG TERM...

We continue to keep an eye on a pesky upper level trough for the
weekend that will likely bring some gusty winds and increased chances
for rain and snow. If you have travel plans across northeastern
California or northwest Nevada this weekend, continue to monitor the
forecast for updates through the end of the week.

The storm is not looking as impressive as it was a few days ago. The
storm and associated cold front still appear to be pretty cold,
especially once the cold front moves through late Saturday night
into early Sunday morning, but moisture appears to be limited.
Potential remains for a quick burst of light, lower elevations snows
late Saturday into Sunday, but forecaster confidence is fairly low
considering the variance in the model simulations the past few days.

Impacts with this storm may begin on Saturday afternoon with some
gusty winds around 40 to 50 mph. Although the trajectory of the
system won't be great for producing significant rain and snow we
will likely see some snow shower potential. Main areas of concern
for snow will be for passes roughly from the Tahoe Basin northward
as snow levels fall with the passing cold front Saturday evening
into Sunday morning. Also, can't rule out a few snow showers down to
the lowest valleys by early Sunday morning, but the best chances for
this will be north of Interstate 80. Continue to monitor the
forecast for updates if you have travel plans for this weekend.

Much colder air will inundate the Sierra and western Nevada as the
system exits the area and high pressure returns Sunday. It does
appear there could be a period of gusty east winds, especially along
the foothills and the ridges for Sunday night into Monday night.
High pressure will also amplify along the coast allowing higher
elevations to warm and strengthen valley inversions for much of
next week. Inversion development would produce an increased
potential for pollution to be trapped in valleys and air quality
degradation. Edan

&&

.AVIATION...

VFR with light valley winds today and Friday. Winds aloft start to
increase Friday...but really start to ramp up Saturday ahead of
an approaching storm system. The only exception to VFR at any
terminals will be this morning and again tonight at KTRK where
freezing fog is likely to reduce the visibility to less than 1/2
mile at times.

As stated above...winds begin to increase Friday at the ridge
lines...but really increase Saturday. By late day Saturday valley
winds will also begin to increase. Turbulence aloft is likely
late Friday into Friday night with turbulence extending into the
lower levels...along with low level wind shear...Saturday
afternoon.

The storm is likely to bring lower cigs/vsbys to the Sierra...
northeast California...and northwest Nevada Saturday night and
Sunday.

&&

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

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