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000
FXUS66 KSGX 251636
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
936 AM PDT WED MAY 25 2016

.UPDATE...
Isolated showers affected San Diego County overnight with a few
hundredths of an inch recorded at a few locales. The maximum
rainfall overnight was 0.07" at Hidden Meadows...just N of
Escondido.

Radar this morning now only shows a few showers just off the coast
of San Clemente/San Onofre State Beach. These are weakening and
moving southeast, but a few showers could develop this morning,
especially over the inland valleys where cumulus mediocris is
seen developing right now out our office windows. These showers
will be brief with just a few hundredths of an inch of rain
expected.

An inland transition is expected this afternoon with any showers
focusing over the far inland valleys/Inland Empire and especially
the mountains...where even a thunderstorm or two is possible.
Water vapor imagery shows a nice upper low spinning over the
California Bight and this will move across SoCal this afternoon.
The colder air aloft associated with this low (H5 temps measured
at around -21C on the Vandenberg sounding this morning) could
lead to enough instability for isolated thunderstorms to develop.
Global and hi res model consensus show surface based CAPE
increasing to only 100-300 J/KG...but just enough to support this
tstorm potential. Main tstorm impact would be lightning strikes as
moisture is very limited for any heavy rainfall. PW on both the
San Diego and Vandenberg soundings this morning are near the
median for late May...only at 0.63 inches. /Gregoria

&&

.SYNOPSIS...
Today will be breezy and cool with a low pressure trough moving
through Southern California. Light showers are possible in the
coastal basin this morning with isolated thunderstorms mainly in
the mountains this afternoon. Cool weather with a deep marine
layer will continue this week, but slightly warmer for the
holiday weekend.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

A few showers have developed within our deep and convective
marine layer this morning. This is in response to a low pressure
trough advancing into Southern California. This system has little
moisture to add to the marine layer, but will squeeze out some
light showers in the coastal basin this morning. It will also bring
colder air aloft this afternoon that will coincide with maximum
heating of the surface. This will create enough unstable energy
for a few thunderstorms today. These are expected mainly over the
mountains, but it`s not out of the question for far inland valleys
too. Strong winds will develop in the mountains and deserts. Local
gusts will exceed 40 mph and could produce pockets of blowing
dust in the desert. The trough exits east tonight and takes the
precip threat with it. The marine layer remains rather undaunted
by this brief encounter with unstable air. Low clouds will
continue to predominate nights and mornings in the entire coastal
basin through the holiday weekend. Some half hearted attempt at
higher pressure will result in temperatures getting close to
average over the holiday weekend. The models are beginning to hint
at a legit high pressure ridge next week for a more meaningful
warming trend as we head into June.

&&

.AVIATION...
251515Z...Coast/Valleys...Broken low clouds based around 3500-
5000 feet MSL with tops to near 6500 feet MSL. Locally bkn low
clouds around 1800 feet MSL in heavier showers til 25/19Z. After
25/19Z showers decreasing and clouds mainly scattered 3500-5000
feet MSL. After around 26/02Z low clouds bases re-developing below
3000 feet MSL. Risk of broken low clouds below 3000 feet this
afternoon is low.  Confidence in broken low clouds returning
overnight is moderate to high but timing is low to moderate.

Mountains/Deserts...Mountain slopes obscured at times in clouds.
From 25/19Z til about 26/02Z thunderstorms possible with CB
tops to near 25000 feet MSL. West winds with gusts of 30-40 knots
will produce weak to moderate up/down drafts over and east
of the mountains through tonight.

&&

.MARINE...
800 AM...Wind gusts to around 20 knots this afternoon and evening.
Otherwise, no hazardous marine conditions are expected through
Sun.

&&

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

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...Gregoria
AVIATION/MARINE...Small





000
FXUS66 KSGX 250914
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
214 AM PDT WED MAY 25 2016

.SYNOPSIS...
Today will be breezy and cool with a low pressure trough moving
through Southern California. Light showers are possible in the
coastal basin this morning with isolated thunderstorms mainly in
the mountains this afternoon. Cool weather with a deep marine
layer will continue this week, but slightly warmer for the
holiday weekend.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

A few showers have developed within our deep and convective
marine layer this morning. This is in response to a low pressure
trough advancing into Southern California. This system has little
moisture to add to the marine layer, but will squeeze out some
light showers in the coastal basin this morning. It will also bring
colder air aloft this afternoon that will coincide with maximum
heating of the surface. This will create enough unstable energy
for a few thunderstorms today. These are expected mainly over the
mountains, but it`s not out of the question for far inland valleys
too. Strong winds will develop in the mountains and deserts. Local
gusts will exceed 40 mph and could produce pockets of blowing
dust in the desert. The trough exits east tonight and takes the
precip threat with it. The marine layer remains rather undaunted
by this brief encounter with unstable air. Low clouds will
continue to predominate nights and mornings in the entire coastal
basin through the holiday weekend. Some half hearted attempt at
higher pressure will result in temperatures getting close to
average over the holiday weekend. The models are beginning to hint
at a legit high pressure ridge next week for a more meaningful
warming trend as we head into June.

&&

.AVIATION...
250900Z...Coast/Valleys...SCT to BKN low clouds with bases 2000 to
4000 ft and tops to 6000 ft. Bases most persistent between 12-16z
this morning, and could temporarily lower to 1500 ft under scattered
rain showers. The chance of rain showers will come to an end this
afternoon. Partial clearing this afternoon, but the exact timing is
uncertain, but most likely to be between about 19-21z.

Mountains/Deserts...Coastal slopes below 6000 feet obscured at times
in low clouds, otherwise mostly clear. West winds with gusts of 30-
40 kts will produce weak to moderate up/down drafts over and east of
the mountains through tonight.

&&

.MARINE...
200 AM...Wind gusts to around 20 knots this afternoon and evening.
Otherwise, no hazardous marine conditions are expected through Sun.

&&

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

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.

&&

$$

PUBLIC...MM
AVIATION/MARINE...JMB





000
FXUS66 KSGX 242059
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
159 PM PDT TUE MAY 24 2016

.SYNOPSIS...
A low pressure trough will continue to deepen over the
west coast through Wednesday. This feature will bring gusty west
winds to the mountains and deserts, well below normal temperatures
inland, and a deep marine layer responsible for night and morning
low clouds. Light rain showers are possible west of the mountains
tonight into Wednesday morning. By Wednesday afternoon, the weak low
pressure disturbance will bring a slight chance of showers and
thunderstorms to the mountains. A trough along the West coast will
remain stagnant over the region through this weekend, maintaining
the night and morning low clouds west of the mountains, onshore
flow, and below normal temperatures.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

AT 2 PM PDT...IR satellite imagery...overlaid with 500 mb heights...
showed a deep trough draped along the west coast with the low center
center west of Monterey. Visible satellite imagery displayed
scattered low clouds filling the local coastal basins and clear
skies in the deserts. Onshore pressure gradients were moderately
strong with +10.0 mb SAN-TPH and +7.2 mb SAN-DAG, driving the gusty
west winds across the mountains an deserts. Through early this
afternoon, radar had been indicating light returns advecting into
coastal San Diego county, but no measurable precipitation has
been reported.

As the aforementioned low pressure feature sags south tonight and
draws closer to the region, strengthening west winds in the
mountains and deserts will stir up patches of blowing dust. Maximum
temperatures along the coast this afternoon are forecast to be near
average for this time of year and up to 10-20 degrees below average
inland. Tonight into tomorrow morning, models agree in pushing a
distinct vort max southeast towards Southern California. A deep
marine layer will once again lead to the formation of light showers
along the coast and over the lower inland valleys. However, not
expecting more than a few hundredths of an inch to accumulate.
Wednesday afternoon, maximum temperatures will be up to 5 degree
below normal along the coast and up to 15-25 degrees below average
inland. As the center of the low pressure sweeps over the region
Wednesday late Wednesday morning 500 mb temps will drop to near -20
C. Additionally, the 12Z GFS20 generates up to 100-200 J/KG of CAPE
over the mountains and a lifted index between -1 and -2. Thus, a
slight chance of thunderstorms is warranted, mainly over the
mountains and higher terrain.

A rather stagnant weather pattern holds in place through the weekend
and into early next as the west coast trough remains in place. So
Cal residents can expect more night and morning low clouds west of
the mountains, onshore flow, and below normal temperatures. &&

.AVIATION...
242030Z...Coast/Valleys...SCT-BKN025-035 and SCT-BKN040-050. Brief
bases to around 2000 feet are possible. Tops to around 6000 feet.
MVFR ceilings are most likely to prevail after dark tonight through
early morning on Wednesday. Isolated light showers could re-develop
overnight and move inland along the coast, but with minimal impacts
expected.

Mountains/Deserts...Coastal slopes below 6000 feet locally obscured,
otherwise mostly clear. West winds with local gusts of 30-40 mph
will produce weak to moderate up/down drafts over and east of the
mountains through tonight.

&&

.MARINE...
130 PM...Winds could gust to around 20 knots Wed afternoon and
evening. Otherwise, no hazardous conditions are forecast through
the week.

&&

.SKYWARN...
Skywarn activation will not be needed today.

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...JT
AVIATION/MARINE...Gregoria





000
FXUS66 KSGX 241126
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
426 AM PDT TUE MAY 24 2016

.SYNOPSIS...
A pair of upper disturbances within the broad trough of low
pressure over the western states will bring a few light showers
early this morning and again late tonight into early Wednesday for
coastal areas to the coastal mountain slopes...with a slight
chance of thunderstorms near the mountains Wednesday afternoon. A
deep marine layer through mid week will become a little less deep
for late in the week through early next week with areas of night
and morning low clouds and patchy fog extending into the far
inland valleys and sometimes the lower coastal mountain slopes.
Well below average high temperatures for far inland areas will
warm slowly for Thursday and Friday...cool slightly for the
weekend...then resume warming early next week.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

A broad trough of low pressure remains across the western states.
Within this broad trough of low pressure one shortwave is moving
inland through central California today with a second moving
inland through Southern California on Wednesday. A few light
showers have been spreading inland into far southern
California...mainly near the coast of Orange and San Diego
Counties and near the coastal slopes of the San Bernardino County
mountains. Similar conditions are expected for late tonight into
early Wednesday morning. As the coldest mid level air moves across
Southern California Wednesday...there is a slight chance of
thunderstorms near mountains...inland valleys...and upper deserts
for Wednesday afternoon. A deep marine layer will continue and
high temperatures Will remain near average near the coast...to
around 15 degrees below average in the deserts through Wednesday.

The trough of low pressure over the West will weaken a little
across Southern California for late in the week into next weekend.
Inland high temperatures will warm slowly for Thursday and
Friday...cool slightly for the weekend...then resume warming early
next week. Warming aloft will result in a stronger marine
inversion for Thursday into early next week for greater
persistence to the night and morning coastal low clouds. The
marine layer will remain fairly deep...sufficiently deep for low
clouds to extend into the far inland valleys...if not the lower
coastal mountain slopes at times.

Onshore flow will continue to bring periods of gusty west winds to
the mountains and deserts each late afternoon through
evening...mostly below advisory strength.

&&

.AVIATION...
240900Z...Coast/Valleys...Low clouds will fill the coastal basin
this morning through 18z. Bases will be vary between 2000-3500 feet
msl with tops around 6000 feet. Visibility below 3SM is likely where
clouds and terrain intersect. Scattered drizzle or light showers are
possible between 11-16z. Mainly scattered clouds for 18-01z. After
01z low clouds will gradually gather once again in the coastal basin
with similar bases and tops.

Mountains/Deserts...Coastal slopes below 6000 feet locally obscured,
otherwise mostly clear. West winds with local gusts of 30-40 mph
will produce weak to moderate up/down drafts over and East of the
mountains today through tonight.

&&

.MARINE...
200 AM...Wind gusts near 20 knots in the outer waters during the
evenings through Thursday. Otherwise, no hazardous marine weather is
expected through Saturday.

&&

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

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...17
AVIATION/MARINE...MM





000
FXUS66 KSGX 231636
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
936 AM PDT MON MAY 23 2016

.SYNOPSIS...
A low pressure trough will continue to deepen over the
west coast today. This feature will bring onshore flow, below normal
inland temperatures, and a deep marine layer responsible for the
night and morning low clouds. Light rain or drizzle is possible west
of the mountains tonight into Tuesday morning, then again Tuesday
night into Wednesday morning. On Wednesday, a weak low pressure
disturbance will bring a slight chance of showers and thunderstorms
to the inland valleys and mountains. A trough along the West coast
will remain stagnant over the region through this weekend,
maintaining the low clouds west of the mountains, onshore flow,
and below normal temperatures.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

AT 8 AM PDT...Water vapor imagery showed broad troughing draped
along the west coast with the center of low pressure located over
northern California. The 12z KNKX sounding indicated the marine
temperature inversion at 2600 ft msl with dry air aloft. Onshore
surface pressure gradients have nearly doubled in strength as
compared to 24-hours ago with SAN-TPH now +5.7 mb and SAN-DAG +5.4
mb.

As the west coast trough deepens today, scattered low clouds will
persist west of the mountains and breezy westerly winds will develop
in the mountains and deserts. Temperatures along the coast are
forecast around 5 degrees below normal with inland temperatures 10
to 15 degrees below normal for this time of year. Tonight, the local
WRF model depicts the stratus marine layer deepening to around 4000
ft msl and generates patchy light rain or drizzle west of the
mountains. Synoptically little changes on Tuesday. Breezy westerly
winds will continue across the mountain tops and desert slopes with
inland temperatures on the cool side, 10 to 20 degrees below normal.

Tuesday night into Wednesday, both the 12Z GFS and 00Z ECMWF drop a
distinct vort max southward towards Southern California. This
feature will once again act to deepen the marine layer Tuesday night
and maintain gusty westerly winds in the mountains and deserts.
Patchy light rain or drizzle will again be a possibility west of the
mountains. As the center of the low moves overhead on Wednesday, 500
mb temps lower to near -20 C. This cold and marginally unstable air
aloft, combined with limited moisture, will generate a slight chance
of showers and thunderstorms in the mountains and inland valleys
through the afternoon. Temperatures on Wednesday will be well below
normal, especially inland and over the mountains with a handful of
mountain locations forecast 20-25 degrees below normal.

A rather stagnant weather pattern holds in place through the end of
the weekend and into early next as the west coast trough remains in
place. So Cal residents can expect more night and morning low clouds
west of the mountains, onshore flow, and below normal temperatures.

&&

.AVIATION...
231515Z...Coast/Valleys...Areas of bkn low clouds based
mainly 2000-3000 ft MSL with tops to near 3500 ft MSL.
After about 23/19Z becoming mostly scattered. Confidence in
conditions becoming scattered by afternoon today is high. After
about 24/02Z this evening scattered clouds will become more broken
into the night with bases mainly around 2000-3000 feet MSL and tops
around 3500 ft MSL. Risk of bkn low clouds with bases below 2000
feet MSL at times tonight is moderate-high at KSAN.

Mountains/Deserts...Lower coastal slopes below 3500 ft locally
obscured before 23/18Z otherwise mostly clear. West winds with local
gusts of 30-40 mph will produce weak to moderate up/down drafts over
and east of the mountains through tonight.

&&

.MARINE...
815 AM...Wind gusts near 20 knots at times through this evening
over the outer waters. Otherwise, no hazardous marine weather
is expected through Friday.

&&

.SKYWARN...
Skywarn activation will not be needed today.

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...JT
AVIATION/MARINE...Small





000
FXUS66 KSGX 231045
AFDSGX

AREA FORECAST DISCUSSION
National Weather Service San Diego CA
345 AM PDT MON MAY 23 2016

.SYNOPSIS...
A trough of low pressure over the western states
will strengthen a little through Wednesday...then weaken again for
next weekend. High temperatures will remain below average for
inland areas through much of the week...then warm towards the end
of the week into next weekend. A deep marine layer will bring
areas of night and morning low clouds and patchy fog for coastal
areas inland to the coastal mountain slopes. There are small
chances for light precipitation along and west of the mountains
for late tonight into Tuesday morning and again late Tuesday night
into Wednesday morning with a slight chance of thunderstorms near
the mountains Wednesday afternoon. There will continue to be
periods of gusty west winds in the mountains and deserts...stronger
during the late afternoon and evening each day.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

.SHORT TERM (Today through Wednesday)...
Broad low pressure extends across the western states. Within that
broader low pressure...a shortwave off the California coast will
move inland through Southern California tonight and Tuesday. This
will bring deepening of the marine layer with a slight chance of
light showers along and west of the coastal slopes of the
mountains for late tonight into Tuesday morning. A second
shortwave moving southward just off the West Coast will move
inland through Southern California Tuesday night and Wednesday as
a closed low pressure system. This will bring a slight chance of
light showers along and west of the coastal slopes of the
mountains late Tuesday night into Wednesday morning. With the
coldest mid level air moving across Southern California
Wednesday...there is a slight chance of thunderstorms Wednesday
afternoon...mainly near the mountains and inland valleys. Inland
high temperatures will cool slightly through Wednesday with gusty
west winds in the mountains and deserts...strongest during the
late afternoon and evening each day.

&&

.LONG TERM (Thursday through Sunday)...
The trough of low pressure will weaken for Thursday and Friday. A
low pressure system moving into the Pacific Northwest on Saturday
will maintain the low pressure trough into Southern California
through the Memorial Day weekend. Areas of night and morning
coastal low clouds and patchy fog will continue with slow warming
of inland high temperatures.

&&

.AVIATION... 230900Z...Coast/Valleys...Mostly scattered, but
occasionally broken low clouds will continue through 18z. Cigs would
be around 2500 feet msl with tops to 3200 feet. After 02z scattered
clouds will become more broken overnight with bases around 2500 feet
msl.

Mountains/Deserts...West winds with local gusts of 30-40 mph will
produce weak to moderate up/down drafts over and east of the
mountains through tonight. Otherwise, mostly clear.

&&

.MARINE...
200 AM...Wind gusts near 20 knots at times this evening over the
outer waters. Otherwise, no hazardous marine weather is expected
through Friday.

&&

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

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...17
AVIATION/MARINE...MM





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