Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 101710
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
Issued by National Weather Service Flagstaff AZ
910 AM PST Sat Dec 10 2016

.SYNOPSIS...Dry and mild weather is expected over most of the
area through the middle of next week with considerable high
cloudiness at times. Showers will develop over the Sierra and far
northern Lincoln County today and tonight with mainly light snow
accumulations expected.
&&

.UPDATE...Minor forecast update to cool today`s high temperatures a
few degrees, otherwise currect forecasts are in good shape.

&&

.PREV DISCUSSION...
Issued at 319 AM PST Sat Dec 10 2016

.SHORT TERM...Through Monday Night...

First off, the morning lows for this morning were adjusted down
based on cooler observed temperatures. High clouds are on the
increase this morning and this should limit further cooling through
the early morning hours in most areas.

For today, a moist Pacific flow extending the length of California
will primarily impact the coast, coastal mountains and points east
to the western Sierra slopes as the deeper PWAT airmass moves north
to south through California. Expect showers to develop over the
Sierra crest with some spill over onto the higher elevations of the
eastern side. Snow levels are forecast to remain above 9000 feet
today lowering to around 8000 feet Sunday morning. 4-7 inches of
snow are possible along the crest through tonight with 2-4 inches
possible around the Aspendell and South Lake area. The increased
moisture across the Sierra should limit any downslope potential and
keep the stronger winds near ridgetop. Windy conditions will develop
across the western Mojave Desert this afternoon through tonight but
continues to look marginal for wind advisory level winds. Gusts
should generally be 30-40 mph with localized gusts over 40 mph.

Northwest to west flow aloft is forecast over the area Sunday and
Monday for dry conditions, lighter winds and periods of mid and high
clouds.

Temperatures today through Monday will be unseasonably warm running
about 8-10 degrees above normal.

.LONG TERM...Tuesday through Saturday.

The medium range models are indicating the potential for a
significant change in the weather pattern Thursday through Saturday,
but confidence is low in the details due to model differences. A
zonal flow with a weak mean ridge is forecast to be over our region
Tuesday and Wednesday which will keep us largely dry with continued
relatively mild temperatures. Substantial subtropical moisture is
forecast to stream into northern California and northern Nevada and
there is a chance precipitation could make over to the east slopes
of the southern Sierra but it would be intercepted mostly by the
western slopes. The main change begins Thursday as a trough slides
down over over California and Nevada and pushes the moisture plume
to the southeast across our region. The GFS is a little sharper with
the trough than the ECMWF and more bullish on precipitation
chances...especially Thursday night. This is followed by a much
colder trough dropping down from Canada over the Great Basin late
Friday into Saturday. These trends were already indicated in the
inherited grids and only minor changes were made with more weight
given to the ECMWF solution.
&&

.AVIATION...For McCarran...Varying amounts of high clouds are
expected today. Light and variable winds will continue through the
day possibly favoring and easterly direction this afternoon before
transitioning to southwest up to 10 kts this evening.

For the rest of southern Nevada...northwest Arizona...and southeast
California...Variable winds under 10 kts will continue through mid
day today, but will increase during the afternoon. West winds 20-30
kts are possible across western San Bernardino County with generally
10-20 kts elsewhere. Some enhanced downslope winds will also be
possible Saturday afternoon and night across the eastern Sierra
slopes where gusts to 50 mph will be possible.
&&

$$

UPDATE...Morgan / JJ
SHORT TERM/AVIATION...Salmen
LONG TERM...Adair

For more forecast information...see us on our webpage:


&&

$$

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