Heavy Snow and High Wind in Nevada, January 11 to 13, 2017

Area Forecast Discussion
National Weather Service Las Vegas NV
645 PM PST Tue Jan 10 2017

.SYNOPSIS...Unsettled weather expected through Friday with
precipitation moving into the area early Wednesday and again on
Thursday night into Friday. Conditions improve over the weekend with
clear skies and below normal temperatures.
&&

.UPDATE...Winds have lulled a bit in portions of the
advisory/warning areas but winds should pick back up again across
the Mojave Desert. Winds in the Sierra and Owens Valley may continue
to decrease as precipitation moves in this evening and should be
able to expire the High Wind Warning by 06z. I tweaked sky grids a
bit for tonight to jive with the latest satellite and model trends.
No other updates anticipated this evening. -Harrison-
&&

.PREV DISCUSSION...
334 PM PST Tue Jan 10 2017

.SHORT TERM...Tonight through Wednesday Night
Another atmospheric river event is currently affecting most of
central California this afternoon. The associated plume of moisture
is expected to continue sagging south toward our area. Conditions
have begun deteriorating in the higher terrain of the Sierra in Inyo
County. Likewise, wind speeds from rotor activity have also started
again in earnest bringing high winds to the lower elevations of the
Owens Valley. The wind advisory for Owens Valley has been upgraded
to a High Wind Warning given the wind speeds we are seeing roll in
from that area. These stronger west to east winds will continue to
trek south and affect the lower deserts in San Bernardino County and
areas east like southern Nevada later tonight. The previous forecast
issuance expanded the Wind Advisories to most of Southern Nevada.
No changes with these headlines. It was however, decided to add
California Zone 525 into the Advisory as well, which includes the
Twentynine Palms, Yucca Valley area of San Bernardino County. Gap
flow into the Morongo Valley could produce winds in excess of
advisory criteria in that area. Thus the reason for inclusion.
Later tonight we should see winds kick up in earnest for southern
Nevada. Higher terrain areas like the Spring Mountains will begin
first. However, most the high resolution models we utilize show
higher winds rolling off the higher terrain after midnight. It may
get quite gusty overnight in the Las Vegas Valley and environs with
winds up to 50 mph for much of western and southern parts of the
valley.

.LONG TERM...Thursday through Monday.
Thursday through Monday. Still on track for one final storm to roll
through the area before a drying trend takes hold. Picking up
Thursday morning, the storm is forecast to be centered over northern
California, with precip chances beginning to spread southeast across
the Mojave Desert. Precip chances should spread areawide in the
afternoon and overnight hours as the storm tracks southeast. One
noticeable model trend is to track the low a bit farther southwest
to near Ensenada by Friday afternoon, and then eject it more slowly
as it gets nearly cut off from the main flow. Thus, pulled precip
chances back to the west for Friday night and Saturday, delaying a
dry forecast for the whole CWA until Saturday night. Dry northerly
flow is still expected thereafter as ridging develops near 130W.
After days of trending downward, MOS temperature forecasts have
trended upward several degrees for the weekend. Nudged the forecast
part way toward the new MOS and will see what the next run brings.
&&

.AVIATION...For McCarran...Southwest winds will prevail through
tomorrow. Current gusts to 20kts will give way to stronger
persistent winds after 08 UTC tonight. Gusts to 30-35 kts remain
possible. This could create crosswind issues on 01/19 runway and
possible low level wind shear as well. There will be some rain
shower activity early in the morning on Wednesday. Then a small
break in activity until Thursday when another storm system moves in
and increases chances for low cloud ceilings and rain.

For the rest of southern Nevada...northwest Arizona...and
southeast California...High winds and associated turbulence are a
widespread problem for area terminals through tonight as the first
of two storm systems move through the area. Wind conditions are
particularly high impact along the lee of the Sierra in California.
A brief break between system on Wed afternoon through Thursday
morning before a wetter storm system moves in late Thursday into
Friday. Low ceiling and strong winds expected with that system.
&&

Short Term/Aviation: Lericos
Long Term: Morgan

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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
905 PM PST TUE JAN 10 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0222 PM     NON-TSTM WND GST 5 NW INDEPENDENCE       36.84N 118.27W
01/10/2017  M71 MPH          INYO               CA   MESONET

            WIND GUST RECORDED AT THE OAK CREEK RAWS.

&&

JH