Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
857 am PST Tuesday Mar 3 2015
Synopsis...cool conditions with scattered rain and mountain snow
showers will persist today as a trough pushes through the region.
Drier conditions and slightly warmer weather is expected Thursday
before a marked warming trend commences Friday. Over the weekend
high temperatures will rise above normal thanks to high pressure
building across the West Coast...and staying put through early next
Update...increasing clouds and chances for precipitation today as a system
moves in from the north. Morning models continue to highlight
Lincoln and northern Mohave counties as the most favorable areas for
shower activity producing light rain/snow accumulations. Will be on
the lookout for developing thunderstorms which will be capable of
producing brief moderate rain, gusty winds and small hail. Forecast
in good shape and no updates currently needed. -Salmen-
Aviation...for McCarran...mostly clear conditions through 19z when
the atmosphere begins to destabilize and isolated vicinity showers
break out. Ceilings in the 5-6kft range will be possible with any
activity in the immediate vicinity of the airfield but broken ceilings in
the 7-8kft range will be predominant. West to southwest winds of 9
to 12 kts favored in the afternoon but direction and speed may be
variable at times due to shower activity in the area. Improving
conditions expected after 00z with a push of northerly winds
expected after 3z.
For the rest of southern Nevada...northwest Arizona...and southeast
California...scattered showers possible today especially east of a
line from kdag-kdra-kely. Isolated thunderstorms are possible with
strong updrafts and gusty surface winds. Ceilings near shower activity
will range from 4-6kft. A push of northerly winds expected Tuesday
night into Wednesday with winds of 15-25kts possible down the
Colorado River valley.
Previous discussion...145 am PST...
Short term...today through Wednesday night.
Shower activity has diminished this morning across most of the
forecast area with the exception of some light returns showing up on
radar across northern Mohave County. I expect that with return of
daytime heating after sunrise this morning things will quickly liven
up again as the trough axis remains overhead and an additional
shortwave pushes through the Great Basin. With the trough axis
passing directly overhead and 500mb temperatures in the -25c to -28c
range...there will once again be marginal instability present to
support a few lightning strikes and perhaps a stronger updraft or
two may produce some small hail.
The shortwave driving this activity along with the entire trough
axis which stretches all the way down into the Baja California will begin to
shift eastward by late afternoon. Drier and more stable air will
invade from northwest to southeast with shower and thunderstorm
chances becoming limited to Mohave County by late in the evening
where a few lingering showers will be possible through the early
overnight period. As the trough exits...a push of northerly winds
will follow as high pressure builds in behind the storm system.
These northerly winds will be strongest down the Colorado River late
Wednesday night through early Thursday morning before slowly
subsiding by early Thursday morning.
Long term...Thursday through Monday.
The medium range models continue to show an amplified ridge along
the West Coast Thursday that will slowly migrate inland over the
weekend and early next week providing dry and mild weather for our
forecast area. A weak upper low is forecast to develop near the base
of the ridge over northern Baja California Thursday through Friday/Saturday
which will lead to periods of north breezes...especially down the
Colorado River valley near Laughlin and Bullhead City. Temperatures
will begin a noticeable warming trend with highs climbing back into
the 70s across the Mojave Desert region for the weekend.
Spotter information statement...spotters are requested to report
any significant weather according to Standard operating procedures.
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