Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 221038
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
238 AM PST Wed Feb 22 2017

.SYNOPSIS...
A low pressure trough moving through California today will bring cooler
and partly cloudy weather and areas of strong winds in the mountains
and deserts. Mostly clear skies will follow Thursday and Friday,
but it will continue cool. A storm is currently forecast to bring
rain and wind Sunday into Monday, with showers continuing into
Tuesday.

&&

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

High clouds are on the decrease while coastal low clouds are on
the increase this morning. Skies will be partly cloudy today as a
low pressure trough moves through California to our north. This
will bring cooler weather and wind, but not precipitation. Winds
in parts of the mountains and deserts will gust over 50 mph this
afternoon through tonight. As the trough moves out Thursday, dry
northwest flow will keep our weather fair but on the cool side
through Saturday. Then things get interesting. A cutoff low
pressure system in the ocean a long way west of San Diego will
grab some subtropical moisture from southern latitudes. A separate
low pressure trough coming down the coast will grab and absorb
that southern system and move into Southern California. This will
bring a relatively warm rain event Sunday into Monday morning. It
will also bring some brisk winds to all areas. The trough will
move fully into Southern California Monday bringing colder but
drier air with it. That will mean steady precip will turn to
showers, and in the mountains rain will turn to snow showers. Of
course there are differences in model solutions, but it appears
the showers will end Tuesday morning. Over the next few days we
will get a better focus on the details of timing/amount of
precipitation and strength of winds so stay tuned. It looks like
a high pressure ridge develops by midweek to start off March dry
and warm.

&&

.AVIATION...
221030Z...Coasts/Valleys...Stratus with bases 700-1000 ft MSL will
gradually lift to around 1000-1500 ft MSL through the morning,
becoming mostly scattered by 16Z. Areas of vis 3-5 SM likely over
higher coastal terrain and mesas through 16Z. Otherwise SCT-BKN
cloud layers above 3500 ft MSL continuing through this evening,
clearing out by early Thursday morning.

Mountains/Deserts...West to northwest winds strengthening through
the day and peaking during the late afternoon and evening with sfc
gusts 35-45 kt. Strongest winds will occur on the ridges/upper
desert slopes of the mountains, below passes and canyons, and where
mountain waves surface in the deserts. STG-SVR UDDFS and areas of
LLWS likely over and E of the mountains. Winds will slowly weaken
late tonight into Thursday morning.

&&

.MARINE...
Northwest winds and seas will increase today and continue through
Thursday. A swell from 275-285 degrees will build peak at 8-12
feet/14 sec late this afternoon and evening. Winds will peak this
afternoon and evening with gusts 25-30 kt. Gusty winds and
large/steep seas will result in hazardous boating conditions...and a
Small Craft Advisory remains in effect this morning through early
Friday.

&&

.BEACHES...
A building swell will bring high surf today and Thursday. The
swell will peak later today into Thursday morning at 11-12 ft/14
sec/285 degrees. This will result in surf of 5-8 ft with sets to 10
ft. A High Surf Advisory remains in effect from this morning through
early Friday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 1 PM this afternoon to 1 AM PST Thursday for
     Apple and Lucerne Valleys-Riverside County Mountains-San
     Bernardino County Mountains-San Diego County Deserts-San
     Diego County Mountains-San Gorgonio Pass Near Banning.

     High Surf Advisory from 7 AM this morning to 2 AM PST Friday for
     Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...Small Craft Advisory from 7 AM this morning to 2 AM PST Friday
     for Coastal Waters from San Mateo Point to the Mexican
     Border and out to 30 nm-Waters from San Mateo point to the
     Mexican Border Extending 30 to 60 nm out including San
     Clemente Island.

&&

$$

PUBLIC...MM
AVIATION/MARINE/BEACHES...SS


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