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Area forecast discussion 
National Weather Service San Diego California
150 PM PDT Wednesday Jun 3 2015

Synopsis...
below normal temperatures and breezy winds in the mountains and
deserts will continue through this weekend as a large upper-level
low pressure approaches the region. A deep marine layer will keep
low clouds along the coast and inland valleys...and create drizzle
at times in the mornings through Friday. Isolated showers are
possible...mainly over portions of the mountains and high deserts
Friday afternoon and evening as the upper level low pressure area
passes over Southern California. Slight warming and a return to a
shallower marine layer is expected early next week.

&&

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

The deep marine cloud layer up to 3000 efet has cleared out...last
near the la County line. 2 eddies in the bight are spinning around
each other and the northern one over Catalina Island drawing clouds
with it. This evening will feature a rather typical return to the
marine layer clouds 03 to 06z and deepen further to 4500-5000 feet
tops due to the cooling and lift associated with the approaching and
digging east Pacific upper low. Tonight will also see an increase in
areas of drizzle into Thursday morning. Cooler air will spill east
into the deserts on Thursday while the air mass cools further. 850
mb temperatures in the desert drop from 20c today to 17-18c today and down
to 14-15c on Thursday. With the approaching upper trough there will
be sustained moderate low level onshore flow and increased for
ridges. Winds in the San Gorgonio Pass exceeding 50 miles per hour during the
peak diurnal downslope time.

Numerical weather prediction continues to depict a significant dry
flow with the upper low arriving late Thursday...north of the
tropical remnants of Andres which get shunted to the east across the
Baja California. However...significant drizzle it expected with the marine
layer and synoptic layer lift with the upper low again Thursday
night and Friday. The core of the upper low is still prognosticated by all
guidance to drop over the northern California bight on Friday before
then lifting northeast Friday night and early Saturday across the
Mojave Desert. This system is cold enough to provide additional
instability and has its own moisture wrapped around the closed
circulation. Thus best chance of additional convective showers
coming off the bight waters and also forced over the northern
mountains will be Friday afternoon and Friday night into early
Saturday. There is slight cape early Saturday in the San Bernardino
high terrain. The system is rather warm with 700 mb temperatures only about
2c and -14c at 500 mb so lapse rates are not steep.

Longer range outlook remains short wave ridging...drier and warming
trend for the weekend into Monday. GFS and European model (ecmwf) guidance continues
to depict another east Pacific trough...though weaker. This draws
remnant tropical moisture from Blanca. The southerly flow and
further offshore position should allow for a better chance to bring
it into Southern California. At this time it does not look
significant and there is considerable spread in timing of the
opening upper low from late Monday to Wednesday. One change on the
European model (ecmwf) was it has backed off on the upper ridging for the rest of
next week.

&&

Aviation...

032030z...low clouds based near 1500-2000 feet mean sea level with tops near
3500 feet mean sea level will continue dissipating through around 04/0200z kont-
ksna area. The low clouds will move inland again at about 04/0200z
ksan area...with confidence in arrival time of overcast clouds at ksan
moderate-high. Low clouds are expected to return to kont around
04/0800z. Visibilities 3-5sm in localized drizzle possible 04/1000z
through 04/1600z. Lower coastal mountain slopes will become obscured
below 3500 feet. Areas of winds 25 knots with local moderate up and
downdrafts near mountains and adjacent desert slopes. Above the
marine layer in the mountains and in the deserts...mostly clear with
visibilities unrestricted.

&&

Marine...

200 PM...no hazardous marine weather is expected through Sunday.

&&

Beaches...

100 PM...southerly swell from Tropical Storm Andres will
continue...but gradually fade Thursday. Expect elevated surf and
strong rip currents into Thursday...particularly in Orange County.
See surf forecast for details...laxsrfsgx.

&&



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



&&

Sgx watches/warnings/advisories...
California...none.
Pz...none.
&&

$$

Public...tardy
aviation/marine...small

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