Area forecast discussion
National Weather Service San Diego California
300 am PDT Tuesday may 21 2013
Synopsis...
fair but cooler weather is expected the next few days as a trough of
low pressure develops along the West Coast. Low clouds will extend
farther inland each night through Thursday. Gusty west winds will
also develop each afternoon and evening in the mountains and
deserts. The low pressure will weaken slightly Friday...but cooler
than normal weather will continue with fairly extensive low clouds
and fog each night and morning through early next week.
&&
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...
Low clouds have gained some traction early this morning as surface
pressure gradients trend more onshore and a coastal eddy continues
to spin. Even The Corners of the inland Empire will get some fog by
sunrise. The low clouds will clear by late morning and some high
clouds will pass overhead today. Except for the high clouds...the
temperatures and low cloud pattern will be much like yesterday. Change is
coming as a trough of low pressure amplifies and deepens along the
West Coast Wednesday and Thursday. The main action will stay well
north of our area...but it will cause our marine layer to deepen and
the coastal eddy to strengthen. That will mean clouds getting into
almost if not all of the coastal basin up to 3000+ feet by early
Thursday. The thicker clouds could produce spotty drizzle that
morning. Fog along the coastal slopes looks like a good bet for
those freeways going through the mountains. Locally strong winds
will develop each afternoon starting today through those favored
mountain passes and adjacent deserts. These winds will peak during
afternoons and evenings Wednesday and Thursday. A shortwave rotates
through the trough Thursday representing its deepest extent and
leaves behind a weaker baggy trough Friday. This residual cyclonic
flow pattern does not change much for several days through the
Holiday weekend and even beyond. We will keep a relatively deep
marine layer and slightly lower than normal temperatures for a while.
&&
Aviation...
210900z...coasts/valleys...stratus with bases 1100-1400 feet mean sea level will
clear to the coast 16-18z. Stratus returning to the coastal airports
02-05z and spreading into the far western and southern portions of
the inland Empire overnight.
Mtns/deserts...scattered clouds at or above fl200 and unrestricted visibility through
Tuesday night.
&&
Marine...
a 3-4 feet/16-17 second period southwest swell through midweek with
elevated surf and strong rip currents. Highest surf from 3-5 feet on
exposed southwest facing beaches with a infrequent sets to 7 feet.
A 6-8 feet short-period northwest swell will move into the outer
coastal waters Wednesday and Thursday resulting in rough seas near
San Clemente Island. Swell and surf will gradually subside Friday into
the weekend.
&&
Sgx watches/warnings/advisories...none.
&&
$$
Public...mm
aviation/marine...sunset
