Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 261105

Area Forecast Discussion
National Weather Service Las Vegas NV
305 AM PST Sun Feb 26 2017

.SYNOPSIS...A pair of weather systems will keep cool and unsettled
weather in the forecast through Tuesday before higher pressure
returns warmer temperatures to the region later in the week.

.SHORT TERM...Sunday through Tuesday Night.

Low pressure was centered just west of Point Conception at 2 AM
Pacific time with denser cloud cover spreading across San Bernardino
and Mohave counties. Models forecast the tightly wound low pressure
center to weaken and open up this morning as it moves into southern
California. Models generally agree with the best chance of showers
over the deserts of San Bernardino and southern Mohave counties this
morning. Amounts should be light and range from a trace to a couple
of hundreths where showers occur. The system is east of the forecast
area by this afternoon with only a small chance a few showers could
wrap around the back side into far eastern Mohave County. Winds, for
the most part, should be light today with temperatures remaining on
the cool side or about 6-10 degrees below normal.

The next system is on its way with water vapor imagery showing it
sliding south along the British Columbia and Washington coastline
this morning. This one if forecast to rapidly weaken as it sinks
into the Pacific NW and Great Basin. As the trough approaches,
strong westerly flow will move across the forecast area setting up
nearly perpendicular to the Sierra. Downslope wind signatures along
the eastern Sierra slopes are not real impressive however it is
possible a Wind Advisory may be needed for overnight Sunday into
early Monday. As the trough continues southward on Monday, breezy to
windy conditions set up across a large portion of the southern CWA.
by the afternoon hours on Monday. Other than the Spring Mountains,
wind speeds look sub-advisory level.

Some decent moisture is available with this system and rain/snow
chances will be on the increase across a large chunk of the area
Monday and Monday night...then lingering in Mohave County into
Tuesday. Models are currently targeting far southern Mohave County
with the highest precipitation amounts...locally an inch or
better...where a tropical moisture tap develops and higher
precipitable water values briefly surge northward into that area.
Elsewhere models are less generous giving less than a quarter
inch. As model QPF forecasts now stand, the Las Vegas Valley and
Spring Mountains would lie between the better moisture associated
with energy passing by to the north and the deeper moisture to the
south. Light rain/snow showers producing sprinkles/flurries
amounting to a trace or a few hundreths is all that is currently
expected. A dry northwest flow sets up behind the system late
Tuesday bringing an end to shower chances Tuesday night.
Temperatures Monday and Tuesday are expected to remain well below

.LONG TERM...Wednesday through Saturday.

Generally dry and quiet for the long term. Dry northwesterly flow on
Wednesday will transition to dry zonal flow by the weekend as
heights begin to rise. This will result in temperatures warming back
up to seasonal normals, if not slightly above, by the weekend. A few
ripples in the flow will lead to periods of breezy winds, but
nothing at this time looks anywhere near even advisory levels. &&

.AVIATION...For McCarran...Light and variable winds will continue
to favor typical diurnal trends through mid-day. A passing system
may bring CIGs down to 8-10k feet and a slight chance of showers to
the mountains surrounding the valley this morning. Otherwise, dry
conditions are expected. Southwest winds will increase by late this
afternoon with gusts of 15-25kts. Gusty southwest winds will persist
through Monday.

For the rest of southern Nevada...northwest Arizona...and southeast
California...A passing system will bring lower CIGs and a slight
chance of showers to the high terrain across the region and perhaps
across areas south of Las Vegas through this morning. Southwest
winds will increase areawide by late this afternoon/evening with
gusts of 15-25kts across much of the region. Winds are expected to
strengthen tonight and last through Monday.

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating


Short term/Aviation...Salmen
Long term...Steele

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