Area forecast discussion
National Weather Service San Diego California
200 PM PDT Thursday may 23 2013
Synopsis...
daytime temperatures will remain a little below seasonal averages
through Memorial Day...with areas of night and morning low clouds
extending into the inland valleys. Strong onshore flow will continue
for gusty southwest to west winds in the mountains and deserts.
Stronger southwest to west winds with increasing clouds and a chance
for rain and showers next Tuesday into early Wednesday...tapering
off late Wednesday. Gradually warmer and dry for Thursday.
&&
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...
This afternoon...satellite imagery shows clearing of the low clouds
in most areas...except for a few patches over Orange County and the
inland Empire. Surface pressure gradients remain strongly onshore...with
+9 mb san-tph.
The large-scale low/trough over the western U.S. Is expected to
remain in place and dominate our weather for the foreseeable future.
Through Memorial Day... a series of shortwaves progressing through
the mean cyclonic flow aloft will cause minor day-to-day
variations...but we can expect generally cooler conditions with
extensive night and morning low clouds west of the mountains...as well as
strong onshore pressure gradients for gusty SW to west winds in the
mountains and deserts. The onshore flow will peak this afternoon/tonight
with wind gusts around 45 miles per hour in favored locations.
For late Monday through Wednesday...for 2 cycles in a row...the
global deterministic models continue to indicate precipitation associated
with a vigorous shortwave moving in from the northwest and forming a closed
low over central/Southern California by Monday night. Some differences
in the timing and positioning of the low remain...making the details
somewhat uncertain. However...it is likely that we will at least see
increasing clouds and noticeably lower temperatures. West to SW winds will
also increase...especially in the mountains and deserts...and confidence
is increasing that some precipitation will materialize. This will likely be
followed by gradual warming and drying Wednesday and Thursday.
&&
Aviation...
232000z...coast/valleys...low clouds have cleared in most
areas...but scattered-broken clouds with bases 2500-3500ft mean sea level are lingering
in Orange County and the northern inland Empire...as well as just
offshore in southern San Diego County. Expect another early return
of low clouds to ksan and kcrq this evening between 01-04z. Low
clouds will arrive late at ksna...around 06-10z...if at all. The
same holds for kont...though chances for low clouds are even smaller
there. In general...bases will be around 2500-3000 feet mean sea level with
patchy and less extensive coverage tonight. Earlier clearing
expected Friday morning between 15-17z.
Mts/deserts...mostly clear with unrestricted visible through Friday.
&&
Marine...
a short period northwest swell and an increase in northwest winds
will create choppy seas around San Clemente Island late today into
early Friday. Isolated conditions may be hazardous to small craft in
that area. The highest/lowest tides of the month...with swings of
8.9 feet...will combine with surf for potential minor coastal
flooding Friday through Memorial Day. Strong rip currents are
expected through the Holiday weekend.
&&
Sgx watches/warnings/advisories...
California...Wind Advisory from 3 PM this afternoon to 3 am PDT Friday for
the Coachella Valley...Riverside County mountains...San
Diego County deserts...San Diego County mountains.
Pz...none.
&&
$$
Public...pg
aviation/marine...ts
