Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
925 am PDT Thursday may 23 2013
Synopsis...
Gusty northwest winds will continue today across the
mountains...deserts...and portions of the central coast. An area of
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.
&&
Update...
no significant changes to the forecast this morning. Low clouds were
across valleys and coasts of Ventura and Los Angeles counties with
the marine inversion exceeding 4k feet. A couple of sprinkles have
been reported as the clouds lift...but expect continued thinning and
decrease in cloud cover today. Just a few minimal spots of clouds
along the west Santa Barbara coast this morning. Virtually all areas
are running 2-6 degrees cooler than yesterday with 6-10 degrees
cooler across the mountains.
Other story today are the gusty west to northwest winds. Already
gusting to 40 miles per hour across the western av and picking up in the
Lancaster area. Onshore pressure gradients slightly stronger at 16z
compared to yesterday...but model gradients peak at a lower value
today or about 1mb less. Will let all advisories continue as
planned...including the central coast.
First look at marine inversion forecast for Friday morning. WRF
gradient forecasts have been rather poor and missed this morning by
over 3mb...so little confidence in the very weak onshore gradient
for tomorrow. Catalina eddy looks weaker for Friday and 30agl
humidities are less organized but I don't see much mechanism to
reduce the overall marine layer. Will play up similar areas for
clouds in the morning. Likely to see a little deepening of the
marine layer for Saturday.
***From previous discussion***
Long term (sun-wed)...
models agree that on Sunday and Monday the upper low will open up into
a trough and move slightly to the south. Models indicate that the
onshore flow will also decrease and this should be the bigger
weather factor. The decrease in onshore flow will allow earlier
clearing and a few degrees of warming across the coasts and valleys.
Desert and mountain temperatures will likely not change much.
The Tuesday Wednesday forecast is a little murkier. Both models push the
trough southward but the GFS is much faster and the ec is slower the
ec in fact brings 24 hours of light rain to the area. This is a
little extreme especially for this time of the year. Ramped up the clouds
and cooled temperatures some but need to see some model run to run constancy
before jumping on the rain bandwagon.
&&
Aviation...23/1218z.
MVFR to low VFR conditions will continue through at least 16z at
coastal and valley terminals south of ksba. There is a chance of
MVFR conditions at Santa Barbara County terminals. Periods of
moderate to occasionally strong low-level wind shear and turbulence
is possible at ksba after 23z.
Klax...MVFR to low VFR conditions will continue through at least
16z...or 18z at the latest. There is a 60 percent chance of MVFR
conditions after 07z tonight.
Kbur...MVFR to low VFR conditions will continue through at least
13z...or 16z at the latest. There is a 40 percent chance of MVFR
conditions after 10z tonight.
&&
Lox watches/warnings/advisories...
Wind Advisory (see laxnpwlox).
Gale Warning (see laxmwwlox).
Small Craft Advisory (see laxmwwlox).
High surf advisory (see laxcfwlox).
High rip current risk (see laxsrflox).
&&
$$
Public...boldt/rorke
aviation...Hall
synopsis...seto
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