Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
800 PM PDT sun Aug 30 2015
Synopsis...a broad low pressure trough along the West Coast will
bring dry southwest flow with cooler and breezy conditions through
the coming week and into the Labor Day weekend. Isolated
thunderstorms over eastern Mohave County will diminish each day
Update...skies have cleared out for the most part across the
forecast area but another batch of high clouds are pushing into the
Southern California coast this evening. These clouds will shift
eastward tonight bringing another round of high clouds overnight. I
updated the grids to better reflect this but otherwise the forecast
is in good shape.
Short term...tonight through Tuesday.
Isolated thunderstorms were firing over eastern Mohave County this
afternoon as expected while the rest of the region was experiencing
dry conditions with gusty south-southwest winds. A stubborn swath of
high clouds along the leading edge of the trough over southern
Nevada has been filtering sunshine much of the day and may have
limited temperatures a degree or so. The overall pattern will not change
too much through Wednesday as a mean trough hangs over the Great
Basin and Mojave Desert region. Winds speeds will be 5-10 miles per hour less
Monday then pick up again Tuesday as additional short wave energy
moves enhances the trough. Moisture and instability will gradually
decrease over eastern Mohave County each day Monday and Tuesday.
High temperatures will continue trending downward 1-2 degrees f each day.
Long term...Wednesday through Sunday.
Numerous shortwaves will move through a longwave trough which will
remain over the Pacific northwest/northern rockies during much of the period. This
will keep the southern Great Basin/Mojave Desert under a southwest
flow. Look for breezy to locally windy afternoon/evening hours with
slightly below normal temperatures.
Something to monitor will be the potential development of a tropical
system in the eastern Pacific. Both the GFS/European model (ecmwf) develop a system
well southwest of Cabo San Lucas Wednesday. The feature moves north
but looks to get sheared apart west of the Baja California peninsula Friday
with remnant middle level energy getting caught in the southwest flow
and moving over Arizona Saturday. The associated moisture bears
watching as some of it may get pulled northward up the Colorado
River and into western Arizona Saturday night or Sunday.
Aviation...for McCarran...gusty south-southwest winds will decrease
after sunset and persist overnight. A light east-southeast component
may develop middle-late Monday morning then transition to south with
gusts around 20 knots Monday afternoon. Isolated thunderstorms near
the Peach Springs corridor will dissipate early this evening.
For the rest of southern Nevada...northwest Arizona...and southeast
California...south-southwest gusting 20-30 knots will diminish this
evening. Fair weather is expected across most of the region with
only isolated thunderstorms in northwest Arizona Monday afternoon.
Areas of smoke can be expected in the Owens Valley and near kbih. &&
Spotter information statement...spotter activation will not be
necessary. However...spotters are encouraged to report any
significant weather conditions according to Standard operating
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