Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
215 PM PDT Sat may 25 2013
Synopsis...
Low pressure to the north will result slightly below normal
temperatures through early next week...along with night through
morning low clouds and patchy fog for the coastal plain and valleys.
A trough of low pressure will move through the area Monday night and
Tuesday...bringing a chance of showers as well as gusty north to
northwest winds. A warming trend is then expected late next week.
&&
Short term (tonight-tue)...main concerns in the forecast are the
anticipated winds and light showers. Upper level trough remains
parked across the Pacific northwest with little change in conditions
for southern cal today. Temperatures remained similar to yesterday
or a few degrees cooler. Occasional wind gusts over 35 miles per hour across
the western av but nothing out of the Ordinary today.
Heights go up slightly on Sunday so there will be some warming for
inland areas. Low clouds should plague the coastal regions Sunday
morning and may only burn off to the beaches in the afternoon. Cloud
cover will hold down temperatures for these areas. West to southwest
winds will increase and become more widespread across the av Sunday
afternoon and continue into Sunday night. This is mainly due to a
tighter pressure gradient and bump up in upper level winds tomorrow.
Offshore flow develops for southern Santa Barbara County Sunday
night so a weak sundowner is expected for western sections near
canyon mouths.
On Monday...a stronger low pressure system drops into the Pacific
northwest accompanied by a 100+kt northwesterly jet. Clouds will
start to increase across all areas Monday afternoon and winds will
become gusty for many areas...especially the mountains and deserts.
Would expect solid wind advisories for these areas on Monday and
Tuesday. The front associated with this system weakens as it
approaches the central coast Monday night/Tuesday morning...but will
continue with a chance of showers north of pt Conception. The other
areas with the highest risk of showers will be the North Slope of
the mountains. It will be hard to get much of anything rain-wise for
the south coastal slopes and coasts of Ventura and Los Angeles
counties due to the strong northwest flow. Would expect decreasing
cloud cover in the wake of this system by Tuesday afternoon.
Long term (wed-sat)...continuing windy conditions on Wednesday but
removed any mention of showers by then. Temperatures will remain
below normal on Wednesday. A high pressure ridge will build into the
West Coast starting Thursday and linger through Saturday. A dry
offshore flow will squash any low cloud development and expect
temperatures to push well into the 80s and 90s late in the week for
inland valleys. The European model (ecmwf) model hints at some backbuilding of the
central states trough by Saturday which would drop heights
some...but GFS stays more progressive and on the warmer side.
&&
Aviation...25/1800z...
Moderate confidence in 18z tafs...with a deep marine layer expected
to bring somewhat more widespread stratus clouds to the coast and
valleys overnight into Sunday morning. Expect ksba to remain clear
overnight...but there is a 10% chance of IFR ceilings forming overnight.
Expect IFR/MVFR ceilings to form overnight for the central coast sites
and kprb...although lower confidence in the timing and height of low
clouds for kprb.
S of pt Conception...expect fairly similar marine layer depth and
coverage...but pushing further north along the Ventura coast to
koxr. The timing of stratus clouds arriving at the airfields may
differ up to 2 hours from taf times.
Klax...moderate to high confidence in 18z taf. The moderate
confidence is for timing of stratus return tonight...which may
differ up to 2 hours from taf time of 07z.
Kbur...moderate confidence in 18z taf. The timing of MVFR ceilings
scattering out this afternoon is uncertain... and the timing of
stratus return tonight is lower confidence.
$$
Lox watches/warnings/advisories...
Wind Advisory (see laxnpwlox).
Small Craft Advisory (see laxmwwlox).
Gale watch (see laxmwwlox).
&&
$$
Public...boldt
aviation...Smith
synopsis...sukup
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