Southwest California area forecast discussion...updated
National Weather Service Los Angeles/Oxnard California
440 PM PDT Thursday may 23 2013
..updated aviation discussion...
Synopsis...
Gusty northwest winds will continue tonight across the
mountains...deserts...and portions of the central coast. Low
pressure will linger over the western United States through early
next week with areas of night through morning low clouds and fog.
Temperatures will stay below normal through early next week...then a
warming trend should begin by midweek as low pressure moves east.
&&
Short term (tonight-sun)...
stratocumulus has hung in there all day across areas of Ventura and
Los Angeles counties...and little change has occurred with the
marine inversion today. Afternoon highs stayed the course of many
degrees cooler than yesterday in most areas. Winds increased along
the central Coast...Mountains...and Antelope Valley this afternoon.
Onshore pressure grads are not as strong as yesterday and speeds are
reflecting this. Expect low-end wind advisories to continue into the
evening/night as planned.
Marine inversion remains above 4k feet this afternoon. Model 30agl
humidity shows low clouds reforming in a similar fashion as last
night across Ventura and Los Angeles counties...although the eddy is
not as robust by Friday morning so there could be a little more
ragged look to the cloud deck. Along the central coast winds turn
slightly offshore so don't expect clouds to form overnight.
Very little changes for the weekend. The low pressure system over
the Pacific northwest remains stationary with heights remaining
static over Southern California through Sunday. Temperatures will be a
couple of degrees higher than today but that's about it. Night and
morning low clouds and patchy fog should return along the South
Coast and reorganize along the central coast over the weekend.
Long term (mon-thu)...
the long range becomes a little more fuzzy with lower forecast
confidence for Monday and Tuesday. With the Pacific northwest low
pressure system stalling out...this allows time for a stronger
northwest jet stream to reach the eastern Pacific and dig down the
backside of the low pressure trough. By Tuesday morning this jet
stream is rapidly pushing 90+kts along the central coast as the
trough amplifies across the Great Basin. The European model (ecmwf) has been the most
aggressive for the past two runs...but the GFS is also showing
enough to warrant a slight chance of showers late Monday night
through Tuesday evening. Gusty northwest winds may turn out to the
bigger story for the central Coast...Mountains...and av during this
time frame. The trough looks progressive and should clear Southern
California by Wednesday but it may remain rather windy in places. Expect
temperatures to be below normal early in the week then warming as a
ridge builds in mid-week.
&&
Aviation...23/2335z.
Satellite imagery showing some stratocumulus clouds lingering across the
la County valleys and mountains this afternoon...otherwise skies are mostly
clear. A persistent eddy circulation is expected to maintain low clouds
across much of the la basin tonight...potentially spreading into portions
of Ventura County late. Only 20 percent chance of low clouds redeveloping
along central coast. Gusty onshore winds continue across central coast
and Antelope Valley...however speeds are not as strong as yesterday.
Klax...high confidence that MVFR ceilings will return at some point
tonight...but low confidence in timing. A 10% chance that VFR conditions
could linger through the night.
Kbur...high confidence that MVFR ceilings will return at some point
tonight...but low confidence in timing. A 10% chance that VFR
conditions could linger through the night.
&&
Lox watches/warnings/advisories...
Wind Advisory (see laxnpwlox).
Gale Warning (see laxmwwlox).
Small Craft Advisory (see laxmwwlox).
High rip current risk (see laxsrflox).
&&
$$
Public...boldt
aviation...Smith
synopsis...sukup
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