Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
930 am PDT Sat Oct 25 2014
a trough of low pressure will move inland across the West Coast this
weekend...bringing cooler conditions to Southern California as well
as some gusty west winds to the mountains and deserts. A deep
marine layer will reform and push inland tonight as well. High
pressure will then rebuild over the west...with dry and warmer
conditions developing for the work week.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Water vapor imagery shows a trough of low pressure moving inland
across the West Coast this morning...with the upper level low
lifting towards the Washington coast and the associated cold front
extending southward across Oregon and northern California. A few
middle and high clouds ahead of this cold front moved into Southern
California a little earlier this morning...disrupting our shallow
marine layer. As a result...the dense fog that formed along the
immediate coast quickly mixed out...with just partly to mostly
cloudy skies prevailing at this time. Temperatures are also running
up to 4 degrees cooler than this time yesterday most locations...and
expect this kind of trend to continue through the afternoon...with
daytime highs today running 3 to 7 degrees cooler than yesterday.
This cooling trend will continue into Sunday as well...as this
trough pushes inland across the West Coast and deepens across
Southern California. The marine layer will likely reform and deepen
as well tonight. At this point in time though...it appears that the
marine layer may be somewhat disorganized...and the chances for
drizzle are even less than yesterday. Otherwise...just expect some
locally gusty west winds to develop in the mountains and deserts
each afternoon and evening.
High pressure will slowly rebuild along the West Coast for the first
part of the work week...with dry and warmer conditions developing.
Some weak offshore winds will also develop each morning across the
inland areas...with some locally gusty conditions possible in the
favored passes and canyons.
Although the extended models are in good agreement with each other
for the latter part of the work week and next weekend...there is
very poor run to run consistency between the models.
Yesterday...the 12z models all showed high pressure dominating our
pattern through Friday...with a trough potentially moving inland for
the latter part of the weekend. Now...the 00z European model (ecmwf) and Gem as well
as the 06z GFS...show a weak disturbance pushing inland across
Southern California on Thursday...followed by the long wave trough
on Saturday. If these latter solutions were to come to
pass...onshore flow...the marine layer...and cooler conditions would
likely return starting on Thursday. There might even be enough
moisture for some light precipitation on Saturday.
However...confidence is low in these solutions given the lack of run
to run consistency. For now...will keep dry conditions
prevailing...but may start trending cooler...depending on what the
12z runs show today.
251506z...coast/valleys...areas of scattered-broken ceilings at or above fl100...with
isolated patches of lower clouds around 1500 feet mean sea level along the coast
and unrestricted visible through 04z. After 04z through 08z widespread
ceilings developing 1500-2000 feet mean sea level...with tops from around 2000-2500
feet mean sea level spreading inland 25-30sm with areas of 3-5sm visible in br/haze and
locally lower inland where the stratus deck intersects and obscures
higher terrain. Low to moderate confidence for arrival and height of
ceilings at individual taf sites.
Mountains/deserts...areas of scattered-broken ceilings at or above fl100 with
unrestricted visible through Sun morning.
200 am...no hazardous marine weather conditions are expected through
800 am...a northwest swell peaking at about 9 feet in the outer waters with a
14 second period...combined with a 2 feet south swell at 17 seconds
will create above normal surf of 3-5 feet...with local sets of 7
feet or more along exposed west-facing beaches on Sunday. Highest
sets will be near Huntington Beach and the beaches of southern San
Diego County. A beach hazard statement for elevated surf and a high
risk of rip currents GOES into effect Sunday morning.
Skywarn activation will not be needed today.
California...beach hazards statement from Sunday morning through Sunday
evening for the Orange County coastal areas...San Diego
County coastal areas.