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Area forecast discussion
National Weather Service San Diego California
928 am PDT Fri Jun 23 2017

Synopsis...
strong high pressure will continue to bring hot weather to the
Southern California interior while the marine layer will dominate
near the coast. There is a slight warming trend and less
extensive coastal cloudiness for the weekend. A very welcome but
gradual cooling trend will develop for much next week.

&&

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

The marine layer is deeper this morning and there was patchy
drizzle reported along the coast. There was no measurable precip
from the drizzle this morning. Clearing is occurring inland, but
will be a challenge along the immediate coast today as the
inversion strength on the morning San Diego sounding is at an
impressive +15c.

Temps today will be similar to yesterday, but a couple degrees
warmer in the deserts as the ridge becomes a little better
oriented with a slight westward shift, and very similar temps
elsewhere compared to yesterday.

Weak mid level moist S flow around the high will bring some thin
moisture into Southern California through today with a few cu
buildups likely over the mountains but not enough of the prime
ingredients to generate showers or storms.

For this weekend the ridge strengthens a bit and will bring a
warmup for well inland, mountain, and desert locations. The
hottest temperatures are still slated for Sunday when the lower
deserts could touch 120 degrees again. The excessive heat warnings
continue there. It will heat up over the inland Empire as well with
triple digits there at many locales Sunday and in the mid 90s to
around 100f in the mountains below 5000 feet and across the inland
valleys of San Diego County. A heat advisory continues in effect
Sunday for these locales. The western valleys and the coast will
continue to be influenced by the marine layer, although it should
become a bit shallower due to the decreasing onshore component.

For next week, the ridge will gradually weaken, with some break in
the heat wave finally for the deserts. Tuesday through Wednesday
we're actually along the southernmost flank of an area of
increased zonal flow which should bring the greatest cooling along
with some periods of gusty winds. Temperatures will settle to
near normal to slightly above normal for the remainder of next
week. Medium range models are starting to hint at some rebuilding
of the 4 corners high by next weekend which would bring another
warmup for inland areas.

&&

Aviation...
231541z...coast/valleys...stratus 15-25 sm inland, with bases 1000-
1200 ft msl, tops 1700-2000 ft msl, and areas of vis 2-5 sm, will
clear to near the coast through 1900 UTC. Marine layer inversion
strength of around 15 deg c. 1900-24/0000 UTC, mostly p6sm vis and
few-scattered clouds at or above 15000 ft msl, except within 3 sm of the coast
where broken-overcast stratus clouds around 1500-2000 ft msl and 5 sm vis
may linger. Chance that ksan and kcrq will not clear today. 24/0000-
1600 UTC, stratus re-developing 15-25 sm inland, with bases around
600-900 ft msl, tops around 1300-1800 ft msl, areas of vis 1-5 sm
and local vis down to 1/4 sm over inland mesas/higher coastal
terrain. Low confidence that kont will be impacted with stratus/fog.

Mountains/deserts...p6sm vis through Saturday morning. Increasing
clouds at or above 15000 ft msl through tonight. Scattered cumulus may develop
over the mountains during the afternoon, dissipating by sunset.

&&

Marine...
northwest wind gusts over the outer waters may reach 25 kt during
the afternoons and evenings from Sunday through Tuesday, potentially
resulting in conditions hazardous to small craft. Otherwise, no
hazardous marine weather conditions expected through Tuesday.

&&

Beaches...
a south swell of 3 ft/13-14 seconds/165-170 degrees combined with
large tidal swings will result in strong and dangerous rip and
longshore currents through this evening. This swell will also
produce surf of 3 to 6 ft at Orange County beaches and San Diego
County beaches north of Carlsbad. Also, the high tides will likely
reach 7+ ft during the evenings through Saturday. Tides this high
may result in minor tidal overflow at low lying beaches. The beach
hazards statement continues through late Saturday evening. High tide
will fall below 7 feet Sunday, lowering the tidal overflow threat.

&&

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



&&

Sgx watches/warnings/advisories...
California...excessive heat warning until 9 PM PDT Monday for Coachella
Valley-San Diego County deserts-San Gorgonio Pass near
Banning.

Heat advisory from 10 am to 9 PM PDT Sunday for Riverside County
mountains-San Bernardino County mountains-San Bernardino
and Riverside County valleys-the inland Empire-San Diego
County mountains-San Diego County valleys-Santa Ana
Mountains and foothills.

Excessive heat warning until 9 PM PDT Sunday for apple and
Lucerne valleys.

Pz...none.
&&

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