Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service San Diego California
300 am PDT Thursday Apr 17 2014

Synopsis...
seasonal weather today with increasing high clouds. A low pressure
trough will move across Southern California Friday...bringing
extensive low clouds and a small chance of a shower in the
mountains. Higher pressure returns Saturday through Monday with
warmer weather and less extensive coastal clouds. A stronger trough
of low pressure will bring cooler...windy weather next Tuesday and
Wednesday.

&&

Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...

Low clouds are gathering and slowly migrating inland early this
morning. The clouds will probably get into the coastal corners
of the inland Empire before sunrise. These clouds will clear by late
morning...but as they do some higher clouds will arrive and then
thicken this afternoon across the region. A mixture of these thicker
high clouds and thicker low clouds will be with US tonight and
Friday morning. All these clouds are brought to you by a weak low
pressure trough moving eastward through Southern California. Drizzle
is possible but not likely Friday morning. There is some decent
moisture aloft...but little in the way of dynamics; what little
there are could produce elevated showers and virga above a dry layer
of atmosphere. The evaporating rain below these clouds could send an
isolated gust of wind to the ground. This is a remote possibility
only in the mountains and would be very isolated were it to occur.
High clouds will clear Friday night while low clouds west of the
mountains will lag into Saturday. High pressure aloft briefly
rebuilds Sunday and Monday for a warming trend and a marine layer
more coastal in coverage. After a couple days of models coming
together...confidence has grown for a pretty robust trough of low
pressure moving through California Tuesday. Primarily...this will be
a wind maker mainly for the mountains and deserts...with the
potential for some damaging wind. Moisture and any chance of rain
stay in northern California. The marine layer will respond by
deepening and extending low clouds inland...but overall not too
gloomy. Just cool and windy. The trough moves out Wednesday for
improving weather by Thursday.

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Aviation...
170930z...coast/valleys...stratus with bases 1300-1600 feet mean sea level and
tops around 2000 feet will continue to move 15-20 sm inland through
early this morning. This cloud deck may affect kont between
17/1100z-1400z. Most visible will remain above 5 Michigan...except locally
lower where terrain is obscured. These low clouds will erode back to
the coast between 17/1500z-1700z. A few beach locations will have
broken conditions through this afternoon. Stratus clouds with bases
and tops a few hundred feet higher than this mornings will move up
to 20 miles inland between 18/0300z-18/0600z this evening.

Mtns/deserts.....Unrestricted visible with increasing high clouds
through tonight.

&&

Marine...
no significant marine weather conditions through Monday.

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Skywarn...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

Sgx watches/warnings/advisories...none.

&&

$$

Public...mm
aviation/marine...jt