Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service San Diego California
900 am PDT Wednesday Apr 16 2014

Synopsis...
fair and seasonal weather will continue today through
Thursday...with low clouds and fog in the coastal areas and inland
valleys during the nights and mornings. Cooler on Friday and
Saturday with more clouds...along with locally gusty winds in the
mountains and deserts. Warmer inland Sunday and Monday under weak
high pressure aloft. A deeper trough of low pressure will bring
cooler weather and gusty southwest to west winds for next Tuesday
and Wednesday.

&&

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

Onshore flow...a coastal eddy and a 2000 foot deep marine layer
allowed low clouds and fog to cover the coastal areas and spread
25-30 miles inland. The clouds and fog are now beginning to burn
off. However...a 7-degree celsius inversion could result in slow
clearing today...with some low clouds lingering at the beaches into
the afternoon. Otherwise...fair with seasonal temperatures today. Surface
pressure gradients are +4.1 san-dag and +5.9 san-ipl...producing
locally gusty winds...mainly in the northern Coachella Valley.

A weak high pressure ridge aloft...onshore flow...and a coastal eddy
will continue the seasonal weather through Thursday. Coastal low clouds
and fog tonight into Thursday morning will burn off by late
morning...with daytime temperatures in the 60s and 70s west of the mountains a
weak low pressure trough approaching from the west will bring some
high clouds and southerly winds in the deserts as large-scale
cyclonic flow reflects down to the surface.

For Friday and Sat...the low pressure trough moving in from the west
will bring increasing high clouds...lower temperatures...stronger onshore
flow...and a deeper marine layer allowing low clouds to spread
inland to the coastal slopes. There is a chance that weak upper
level dynamics could produce some elevated convection on Friday as the
trough begins to move inland...but a lack of deep-layer moisture
will likely prevent any precipitation from reaching the ground.

For sun and Monday...a weak high pressure ridge builds over socal. This
will bring some warming...mainly inland...along with a shallower
marine layer for less extensive low clouds during the nights and
mornings.

For Tuesday and Wednesday...global deterministic models indicate that a low
pressure system developing over the Gulf of Alaska will move inland
to the north...with a front extending southward into socal. Most of
the moisture and cold air will likely remain to our north...but this
system will bring noticeable cooling and could bring strong and
gusty west to northwest winds in the mountains and deserts. It may even
be strong enough to produce some precipitation on Wednesday. However...that is
still very uncertain.

&&

Aviation...
161439z...coast/valleys...stratus 20-35 sm inland...with bases
1300-1600 feet mean sea level and tops 2100-2300 feet mean sea level...will clear to the
coastal waters through 1800 UTC. 1800-17/0000 UTC...unrestricted visible
and mostly sky clear. 17/0000-0300 UTC...stratus moving back inland 10-15
sm...eventually reaching 20-35 sm inland by 17/1200 UTC. Bases will
be 1400-1700 feet mean sea level...tops 2200-2400 feet mean sea level...and stratus is
expected to make it into kont again. Also...expect areas of visible
3-5sm...with local visible 1-2sm in the vicinity of kont/kcno/kral and
krnm.

Mtns/deserts.....Unrestricted visible and mostly sky clear through Thursday
morning.

&&

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

The wave watch 3 shows possible large short-period swells and strong
coastal water winds next Tuesday due a trough of low pressure moving
through California. Confidence in this occurring is low at the
moment.

&&

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

&&

Sgx watches/warnings/advisories...none.

&&

$$

Public...pg
aviation/marine...Harrison