Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
903 am PDT Wednesday Sep 2 2015
fair...cooler and dry weather this week...with night and morning
coastal low clouds extending to the coastal mountain slopes
through Saturday. Locally gusty west winds will develop each
afternoon and evening along Desert Mountain slopes and through
mountain passes. Closer to seasonal high temperatures and dry next
week...with a more shallow marine layer.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
The 02/0000 UTC European model (ecmwf) and 02/0600 GFS are in good agreement in
the short-term...and differ slightly in the long-term.
At 9 am PDT...water vapor satellite imagery displayed an upper-
level trough along the West Coast...a weak low around 150 miles
SW of Point Conception...and an upper-level ridge over western Texas.
Visible satellite showed a deep marine layer...with low clouds
beginning to clear over inland areas...and some high clouds over
the region. The 02/1200 UTC knkx sounding showed an 9 degree c
marine layer inversion...and a calculated precipitable water of
Lower heights across the region will continue the cooling trend
through Friday. High temperatures will be between 5 and 15 degree f
below normal for inland areas...and near normal along the coast
and high deserts. A deep marine layer will help develop
night/morning low clouds inland to the coastal mountain slopes
each night through the end of the week. Onshore surface pressure
gradients of 5 to 7 mb from the coast to the lower deserts will
create afternoon/evening westerly wind gusts near 40 miles per hour through
mountain passes and along adjacent Desert Mountain slopes.
Heights will build slightly early next week...with a weak trough
to almost zonal pattern developing along the West Coast. This
will create near seasonal high temperatures...a moderate marine
layer with night/morning low clouds/fog along the coast and
coastal valleys...and weak to moderate onshore flow through the
period. Dry weather is expected to continue through next week.
021509z...coast/valleys...bkn-ovc stratus 30-50 sm inland with bases
2500-3000 feet mean sea level and tops 3000-3500 feet mean sea level...will likely clear out
through 1900 UTC...with broken-scattered clouds at or above 20000 feet mean sea level and
unrestricted visible prevailing through 03/0000 UTC. Marine layer
inversion strength of 9 degree c this morning. 03/0000-1500 UTC...overcast
stratus filling in 30-50 sm inland...with bases 2000-3000 feet mean sea level and
tops 3500-4000 feet mean sea level. Forecast confidence in ceiling heights/visible is
moderate-to-high...with low-to-moderate confidence in timing.
Mountains/deserts...bkn-sct clouds at or above 20000 feet with unrestricted
visible through Thursday morning.
809 am...no hazardous marine weather is expected through Sunday.
809 am...southwest swells from tropical cyclones will continue at
the so-cal beaches today...producing local 3 to 5 foot surf and
strong rip currents. The south swells will subside Thursday through
early Saturday..before a long period southern hemisphere swell
arrives at the beaches early next week.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.