Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 041724
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
924 AM PST Sun Dec 4 2016

.SYNOPSIS...Mostly quiet and dry weather is expected across the
region as northwest flow sets up aloft.  A few weak disturbances may
bring periodic high clouds through the middle of next week.  A
stronger system moving through the Great Basin Wednesday will bring
the coolest air of the season so far to the region by Thursday
morning.
&&

.UPDATE...

Updated the wind grids this morning based on recent trends.  Main
changes were to increase the winds in the Colorado River Valley
through early afternoon and to increase speeds in the higher terrain
of the Sierra and White Mountains this afternoon and this evening as
a weak perturbation moves southeast through the area.  Other than
that, forecast looks in good shape.
&&

.AVIATION...For McCarran...Light, diurnally-driven winds and VFR
conditions are expected the next 24 hours.  High clouds should be on
the increase late this afternoon through tonight.

For the rest of southern Nevada...northwest Arizona...and southeast
California...Aside from stronger northerly breezes near KIFP and
KEED through this afternoon, light/diurnally-driven winds are
expected across the area for the next 24 hours.  High clouds should
be increasing this afternoon and tonight from north to south across
the area, but VFR conditions will prevail.
&&

.PREV DISCUSSION...
Issued at 246 PM PST Sun Dec 4 2016

.SHORT TERM...through Tuesday night.

Anticyclonic northwest flow transitioning to cyclonic northwest
flow is the main feature of the short term. This will result in
little sensible weather other than some bouts of high clouds
courtesy of some weak disturbances clipping the area.

.LONG TERM...Wednesday through Sunday.

Period starts out with area under dry northwest flow on backside of
trough over the Utah/Colorado Wednesday morning. Models not as sharp
or deep with trough but just how cold the temperatures become
Wednesday, Thursday and Friday becoming less clear. As has been the
case the past several days Operational GFS/Ensemble GFS MOS guidance
running consistently warmer than the ECMWF. But even the latest
ECMWF is not as cold as what I was looking at last night. Instead of
low 20s for Nellis AFB and Henderson it now shows mid 20s with
McCarran around 32 Thursday morning. Of course away from the valley
temperatures in Pahrump and Kingman would be closer to 20 degrees.
This period will need to be watched for hard freeze products
in future forecasts.

Temperatures set to slowly modify late in the week into next weekend
as heights rise and flow aloft becomes more westerly. There are some
differences with extent of precipitation associated in an area of
warm air advection associated with disturbances passing by to our
north. Did keep a mention for showers along the eastern Sierra
slopes of Inyo County Thursday night and Friday. Dry elsewhere
although RH progs indicate a decent swath of cloudiness passing over
the area Thursday night and Friday.
&&

.SPOTTER INFORMATION STATEMENT...Spotter activation will not be
needed.
&&

$$

Update/Aviation:  Shafer
Short Term:  Steele
Long Term:  Pierce

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