Area forecast discussion
National Weather Service Las Vegas Nevada
342 am PDT Wednesday may 22 2013
Synopsis...a large area of low pressure will remain over the
Pacific northwest through the coming Holiday weekend with a dry
southwest flow over the southern Great Basin and Mojave Desert. This
will lead to mostly clear skies and breezy conditions each afternoon
with temperatures close to normal. Today will be the windiest day
with gusts over 40 miles per hour expected across much of Mohave and northern
San Bernardino counties.
&&
Short term...today through Friday night...the Pacific northwest low
could be seen digging slightly on recent satellite loops as energy
dives into the base of the system. This will lead to increasing
winds today...strongest over northwest San Bernardino and Mohave
counties as indicated in the going Wind Advisory for those areas.
Minor adjustments were made to timing the decreasing trend for winds
this evening based on the latest high resolution models and
consistency across northern Arizona. The advisory for northwest San
Bernardino County was extended until midnight while Mohave County
was trimmed back to end at 7 PM MST. Will need to watch potential
downslope enhancement for winds possibly gusting over 40 miles per hour in
Red Rock Canyon this evening but the latest models indicate a
marginal event.
Breezy to windy conditions will redevelop Thursday afternoon and the
latest model wind fields look stronger than they did 24 hours ago
across much of the region. A vorticity lobe is forecast to swing across
the southern Great Basin and should enhance speeds. Though less
widespread...may see some gusts over 40 miles per hour in similar areas to
today and will have to monitor later runs for a potential extension
of advisories into Thursday. Winds will be noticeably weaker Friday
as the Pacific northwest low is forecast to lift northward.
Temperatures will dip 3-5 degrees Thursday but variations will only
be slightly noticeable during the period.
&&
Long term...Saturday through Tuesday...broad trough is forecast to
remain over the western states through the weekend with periods of
gusty winds and temperatures close to normal. The models are
indicating a couple of pieces of energy pushing into northern Nevada
which is deeper than previous runs. Although there is not a lot of
moisture associated with these systems...did add a slight chance of
showers for the extreme northern portions of the County Warning Area starting Monday
night and continuing through Wednesday as the trough remains firmly
in place. For the southern half of the forecast area this will
translate into locally breezy winds each day. Temperatures will
remain close to normal through the extended period. &&
Aviation...for McCarran...south/southwest winds 13-17 kts with
gusts to 25 kts through 18z before gusts to near 30kts are seen
between 18z and 03z tonight. Mostly clear skies expected.
For the rest of southern Nevada...northwest Arizona...and southeast
California...generally south to southwest winds 10-20 kts with gusts
to between 25-30 kts through middle morning. Winds will then increase
over much of the area late this morning and afternoon with local
gusts to over 40 miles per hour especially in the western Mojave Desert and
northwest Arizona. Mostly clear skies expected.
&&
Fire weather...a dry southwest flow will persist across the region
through the remainder of the week and into the weekend. As a low
pressure system initially deepens over the Pacific northwest
today...breezy to windy conditions will develop...especially across
western San Bernardino County and in Mohave County outside of the
River Valley. Gusts to 40 miles per hour are likely in these areas. The
combination of gusty winds and low relative humidity are expected to
meet red flag criteria in fire weather zone 102 and a red flag
warning is in effect. Conditions will be close to red flag criteria
in some other areas but the either the duration or geographical
extent will not be sufficient to warrant a red flag warning...or
fuels are not reported as critical. Southwest winds will persist
Thursday but wind speeds are expected to be slightly lower then
noticeably lighter Friday.
&&
Nevada...none.
Arizona...red flag warning from noon today to 8 PM MST this evening for
azz102.
Wind Advisory from noon today to 7 PM MST this evening for
azz001-003.
California...Wind Advisory from noon today to midnight PDT tonight for caz523.
&&
$$
Adair/gorelow
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