Area Forecast Discussion
Issued by NWS Reno, NV

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152
FXUS65 KREV 292200
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
300 PM PDT Thu Sep 29 2016

.SYNOPSIS...

High pressure over northeast California and western Nevada will
exit the region tonight with a few showers possible south of
Highway 50 and east of Highway 95. A cold trough moves into the
West Coast this weekend bringing breezy and much cooler
conditions. More widespread precipitation and even some Sierra
snow showers are expected Sunday and Monday.

&&

.SHORT TERM...

Weak low pressure over Southern CA/NV continues to bring up some
moisture into our region today with a few showers and isolated
thunderstorms possible into this evening. Deep low pressure moving
into the Pacific Northwest over the next few days will bring some
major changes to the weather, including gusty winds and chances
for rain and mountain snow by Sunday. While this is not an unusual
trough for this time of year, it will likely bring some of the
coldest temperatures we`ve had so far this season.

Models have trended a bit less wind for Friday, although still
looks gusty for much of the area. Winds aloft will increase
sharply with winds mixing down into the valleys by late Friday
morning. Expect to see widespread gusts 30-35 mph Friday, especially
north of Highway 50, with wind prone areas seeing wind gusts up to
40 mph or so. These stronger winds will create hazardous boating
conditions on Tahoe and Pyramid on Friday, as well as increased
fire danger. See our fire weather discussion below for details.

The cold front will push through the region Friday night into
Saturday with temperatures cooling off nearly 10 degrees each day
through Sunday. High temperatures on Sunday will be around 10
degrees below average for this time of year, with highs around 60
degrees for the desert valleys and highs near 50 in the Sierra.
Breezy conditions on Saturday and Sunday will also make it feel
even cooler.

Snow levels Sunday will drop to around 5500-6500 feet, with light
snow accumulations possible Sunday afternoon/evening over the
passes in the Sierra. Not a significant snowfall for Sierra
standards, but up to 2-3 inches of snow may be possible over the
passes. Anyone traveling in the Sierra late on Sunday should be
prepared for early season winter driving conditions. Hoon

.LONG TERM...Monday through Friday...

Monday the area of low pressure will be slowly moving eastward, but
it will likely be the coldest morning we have seen so far this fall.
Highs will be in the 40s and 50s for the Sierra and western Nevada.
With snow levels near 5000 feet early Monday morning a little
residual moisture we could see some light snow showers down to
valley floors. With these snow levels a couple inches of wet snow is
possible in the higher elevations above 6000 feet, including around
Lake Tahoe. Snow should be quite showery, so widespread impacts to
mountain passes isn`t expected, but localized travel impacts will be
possible through Monday morning.

Tuesday and Wednesday will see a warming trend, but it will be slow
with temperatures still remaining below average in the valleys due
to the northeast flow while the mountains rise closer to average.
-Edan

&&

.AVIATION...

VFR conditions through Friday. Increasing SW winds today with peak
gusts to 25 kts north of I-80. Stronger SW winds Friday 18-03Z with
peak gusts to 35 kts north of Highway 50 and to 25 kts south. Some
mtn wave turbulence is possible in the morning before mixing helps
to alleviate some of it.

Friday night, mtn wave turbulence will be stronger as 700 mb winds
increase to 40-50 kts. LLWS will be possible for higher elevation
terminals such as KMMH and KTVL, with a lower probability for
KRNO/KCXP. Saturday`s winds will weaken with less turbulence
expected.  The next chance of precip is late Sunday into Monday
morning with some restrictions to CIGS/VIS in the Sierra as well as
potential for light snow accumulations as the Sierra terminals.
-Edan

&&


.FIRE WEATHER...

Strong trough moving into the Pacific Northwest over the weekend
will push a strong cold front through the Sierra and western Nevada
Friday night. Winds will begin to pick up near the Oregon Border
this afternoon with localized critical fire weather conditions
possible.

Models have backed off a bit for winds on Friday but we are still
expecting widespread gusts of 30 to 35 mph. Minimum relative
humidities are on the rise and are currently expected to be in the 13
to 20 percent range along the Sierra Front and western Nevada Basin
and Range. In the Sierra and extreme northwest Nevada current
projections show they may only reach as low as 20 to 30 percent,
though confidence in how quickly during the day moisture will move
in is lower. For this reason we left the watch in place where areas
may moisten up first to allow one more forecast shift to look at it.
A Red Flag Warning has been issued for the Sierra Front and the
Basin and Range where forecast confidence is higher that humidities
will lower to at least the 15 to 20 percent range.

A dry slot will move in on Saturday with minimum humidities in
western Nevada quickly dropping back to at least the low teens and
potentially as low as single digits in some areas. Models have
backed off significantly for winds on Saturday with widespread gusts
of 20 to 25 mph currently expected. Sunday gusty winds, wetting
rains, and high elevation snow are expected in the Sierra with much
cooler temperatures for the beginning of next week. -Zach

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 11 AM to 8 PM PDT Friday NVZ450-453.

     Lake Wind Advisory from 11 AM to 8 PM PDT Friday for Pyramid
     Lake in NVZ004.

     Lake Wind Advisory from 11 AM Friday to 11 AM PDT Saturday for
     Lake Tahoe in NVZ002.

     Fire Weather Watch from Friday morning through Friday evening
     NVZ458.

CA...Lake Wind Advisory from 11 AM Friday to 11 AM PDT Saturday for
     Lake Tahoe in CAZ072.

     Fire Weather Watch from Friday morning through Friday evening
     CAZ272.

&&

$$

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



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