Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 210635 AAA
AFDREV

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
1135 PM PDT FRI MAY 20 2016

.UPDATE...

All of the wind headlines were allowed to expire earlier this
evening. Some localized gusty winds in the 30-40 mph range
continued until around 10 pm but overall the speeds should slowly
decrease. Sierra ridge gusts have also begun trending down with
gusts on Slide Mtn. dropping from near 80 mph to 50 mph between 9
and 11 pm.

The band of snow that affected I-80 earlier this evening brought
some impressive totals over 1 foot west of the crest...with some
web camera images near the crest appearing to indicate around 6
inches of new snow. A few inches may have also accumulated down to
near Truckee. Although chain restrictions were still in effect, road
conditions over Donner Summit are improving based on the latest
web camera images. Farther north in the advisory area, satellite
images still show some enhancement although tops have been slowly
warming. Cedar Pass is still snow covered and weather sensors in
the Surprise Valley are reporting temps in the 30s with measured
precip during the evening, which may be yielding some slushy
accumulations down to the 4500-5000 foot level. No changes to this
advisory are planned. MJD

&&

.PREVIOUS DISCUSSION... /Issued 220 PM PDT FRI MAY 20 2016/

SYNOPSIS...
Low pressure will keep the chance for showers and isolated
thunderstorms going through the first half of next week.
Temperatures will start out well below normal this weekend and
then gradually rise to near normal by the middle of next week.

SHORT TERM...

Upper low over northern CA/NV will gradually weaken and lift out
of the of the region on Sunday. The best chances for showers and
isolated thunderstorms will be tonight and Saturday with a
general decrease in activity Saturday night into Sunday. Winds
will also be lighter although typical afternoon/evening breezes
can still be expected Sat-Sun.

For tonight-Saturday, upper trough/area of deformation will swing
through northern areas. The 12z GFS and 12z/18z NAM are in good
agreement and have support from ensemble QPF members regarding a
period of moderate to heavy precipitation overnight and early
Saturday morning across far northeast CA and northwest NV. Some of
the members indicate rather impressive QPF. Snow levels will be
near valley floors and this will promote accumulating snowfall
with several inches likely near Surprise Valley and across
northern Washoe County. So we have hoisted a snow advisory for
snowpacked and slushy roadways north of Gerlach and across far
northeast CA. Some model solutions bring several inches down into
pars of northern and western Lassen County, so that will have to
be watched this evening. A tight westerly gradient will also keep
winds going in these areas which will result in poor visibility
where snow falls.

Isolated-scattered showers will continue across the northern
Sierra and western NV north of Hwy 50 tonight with best chances
north of I-80. We have seen a few lightning strikes so we will
keep a mention of isolated thunder this evening. Where heating has
occurred in the Basin and Range, there could be a few stronger
storms capable of small hail. The gusty winds will gradually
diminish through the night for much of the region south of I-80.

Isolated to scattered showers and thunderstorms will spread to
most areas for Saturday as upper low will be over the region.
Southern areas of Mono-Mineral Counties are in a better position
for showers and thunderstorms as shortwave rotates through upper
low into central NV Sat afternoon-evening. There could be some
brief but light snow accumulations over higher passes along Hwy
395 through Mono County as the sun drops Sat evening. Less shower
coverage and slightly warmer for Sunday as west flow aloft
develops ahead of another trough dropping in from the northwest.
Expect more typical breezy afternoon and evening winds both Sat-
Sun.

LONG TERM...Monday through Friday...
No major changes in the forecast for next week. Still appears that
the Sierra and western Nevada will be in a relatively active weather
pattern. Multiple upper level shortwaves drop out of the Gulf of
Alaska down the west coast which will keep chances for showers and
thunderstorms in the forecast at least for the first half of the
week.

Winds will be relatively light with some afternoon/evening breezy
conditions possible. Temperatures will be relatively cool for the
first part of the week with highs between 60 to 70 degrees for the
lower valleys and in the 50s/60s for the higher elevations. Model
agreement diverges by later in the week with the ECMWF showing a
ridge building in, while the GFS keeps another trough over the west.
Accordingly, forecaster confidence with the chances for continued
showers/thunderstorms beyond Wednesday is low. -Edan

AVIATION...

Gusts up to 30-35 kts will continue through this evening along
the Sierra front range and along the I-80/hwy 50 corridors
including at KRNO/KCXP/KLOL. Wind gusts will be a bit stronger
south of hwy 50 at KMMH/KHTH through this evening.

Mostly VFR conditions expected through Saturday morning except for
local MVFR conditions under scattered showers and isolated
thunderstorms. Our ongoing shower and thunderstorm threat will
continue this weekend and into next week. -Edan

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 9 AM PDT Saturday NVZ005.

CA...Winter Weather Advisory until 9 AM PDT Saturday CAZ070.

&&

$$

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



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