Scientific Forecaster Discussion
fxus65 kvef 192154
Area forecast discussion
National Weather Service Las Vegas Nevada
154 PM PST sun Feb 19 2017
Synopsis...a storm system moving into central and northern
California will bring snow to the Sierra beginning tonight with
precipitation spreading east across the White Mountains of Inyo
County and the southern Great Basin Monday and Tuesday. Breezy
conditions are expected at times through mid-week with cooler
temperatures reaching the area later in the week.
Short term...through Monday night.
As yesterday's significant rain and snow producer moves continues
east today, tonight brings the next potent system to California.
This one is forecast to impact mainly central California and
northward through Tuesday but our portion of the southern Sierra
could see decent, if not significant snowfall. A Winter Weather
Advisory GOES into effect after 10 PM this evening for the Sierra
and White Mountains of Inyo County where up to 2 feet of snow and
strong winds are forecast. It is possible the advisory will need to
be upgraded to a warning at some point if models come together on
the higher amounts forecast to spillover onto the eastern Sierra
slopes by the GFS/NAM. Accumulating snow over the White Mountains
will likely wait until the morning daytime hours on Monday and the
amounts will likely be less than what falls on the Sierra. Look for
precipitation to spread to the southern Great Basin later Monday
with snow showers becoming possible as far south as the Spring
Mountains of Clark County Nevada. Snow amounts for the Spring
Mountains are forecast to be light (2-4 inches) and confined to the
higher elevations (above 8000 feet).
Other than rain/snow showers, the southern Great Basin could see
windy conditions on Monday and Tuesday as well. Winds are not
expected to be significant across the deserts with this system. We
will also see warmer temperatures Monday with highs around 5 degrees
Long term...Tuesday through Sunday. As the shortwave trough rotates
northward into the Oregon coast Tuesday morning and minors out
thereafter, good orographic lift will continue over the Sierra but
spillover will decrease. The better precip chances should remain
confined to the Sierra until the next wave rotates in on Wednesday.
This wave should spread precip chances across the southern Great
Basin on Wednesday and the northern Mojave Desert Wednesday night
before it exits to the east on Thursday and precip chances come to
an end. This break may not last very long as there are some hints of
another storm possibly reaching the West Coast Saturday, although
there is a lot of model spread and confidence is below average.
Tuesday should see above normal temperatures thanks to the
retreating shortwave trough and associated clouds and rain, then
temperatures will come down some on Wednesday as the next wave moves
in, and should be below normal Thursday through Saturday as cooler
air comes in the wake of the second wave.
Aviation...for McCarran...sct-bkn 5-6k feet. SW winds 10-15kts with
gusts to around 20kts through the afternoon then SW winds around
10kts overnight. Clouds increasing again Monday morning with ceilings
around 5k feet.
For the rest of southern Nevada...northwest Arizona...and southeast
California...southerly winds 10-15kts with higher gusts today. Scattered-
broken clouds 4-5k feet scattering out tonight and then becoming broken
again Monday morning. Showers will develop over the Sierra tonight
and spread east across the White Mountains and southern Great Basin
Spotter information statement...spotters are encouraged to report
any significant weather or impacts according to Standard operating