Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 271000
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
300 AM PDT Mon Mar 27 2017

.SYNOPSIS...
A low pressure system moving inland through Southern California
early this morning will bring stronger onshore flow with strong
gusty west winds in the mountains and deserts into early evening.
This will be followed by strong gusty north winds late tonight
into Tuesday. High temperatures will warm into Wednesday with
Wednesday high temperatures 10 to 15 degrees above average. A low
pressure system moving through the Great Basin into the southwest
states will bring inland cooling for Thursday and Friday...gusty
west winds for Thursday...and gusty north winds for Friday into
Saturday. Weaker winds with some warming possible for next
weekend.


&&

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

.SHORT TERM (Today through Wednesday)...
A trough of low pressure will move inland through Southern
California early this morning bringing stronger onshore flow
today. Satellite imagery early this morning shows the most
widespread low cloud coverage in the inland valleys onto the lower
coastal slopes of the mountains with patchier coverage toward the
coast and over the coastal waters. While a few sprinkles are
possible this morning...no precipitation of significance is
expected.

The stronger onshore flow will bring periods of strong gusty west
winds in the mountains and deserts today...weakening during the
evening. As the low pressure system moves into Arizona...strong
gusty north winds will develop in portions of the mountains and
valleys of southwestern San Bernardino and western Riverside
Counties...near the Santa Ana Mountains...and in the northern
Coachella valley late tonight and continue into Tuesday. Winds
will weaken Tuesday night and Wednesday.

High temperatures will warm to near average today...to around 5
degrees above average on Tuesday...and to around 10 to 15 degrees
above average on Wednesday as high pressure aloft moves across
California.

&&

.LONG TERM (Thursday through Sunday)...
A closed low pressure system will move into the Great Basin on
Thursday and into Arizona Friday. The global models begin to
diverge somewhat from Saturday into next week with the movement of
that low pressure system into the plains and upstream low pressure
systems moving across the eastern Pacific.

In advance of this low pressure system...stronger onshore flow
will develop on Thursday with gusty west winds in the mountains
and deserts and cooling to near to slightly above average. High
temperatures will cool to near average on Friday with gusty
north winds for inland areas. Winds will weaken with some warming
for next weekend...though how much and for how long differs
depending on the model.

&&

.AVIATION...
270915Z...Low clouds with bases varying between 1800-3800 feet msl will
continue over most of the coastal basin this morning. Tops about 4000
feet and local terrain obscured at around that level. Scatter out to
occur starting from the coast toward the coastal slopes during the
morning with coastal airports by around 18Z. Some low clouds at around
1800 feet msl redeveloping after 02Z this evening mainly in San Diego
County. Strong westerly winds 20-40 kt through mountains and along
desert slopes and parts of the desert today. Pockets of strong
up/downdrafts and LLWS over and east of the mountains. Winds shifting
toward the northeast tonight after 04Z and becoming quite strong,
resulting in strong up/downdrafts and LLWS over and west of the
mountains and immediately below the canyons and passes.

&&

.MARINE...
Strong northwest winds and rough seas will make boating conditions
hazardous today into Tuesday. A Small Craft Advisory remains in effect
and contains the details. Northwest winds will increase again Thursday
and continue through Friday leading to more choppy and hazardous
boating conditions.

&&

.BEACHES...
Occasional surf sets could reach 7 feet during the middle of the
week.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 10 PM PDT this evening for Apple and Lucerne
     Valleys-San Diego County Deserts-San Diego County Mountains.

     Wind Advisory from 10 PM this evening to 2 PM PDT Tuesday for
     San Bernardino and Riverside County Valleys-The Inland
     Empire-Santa Ana Mountains and Foothills.

     Wind Advisory until 2 PM PDT Tuesday for Riverside County
     Mountains-San Bernardino County Mountains-San Gorgonio Pass
     Near Banning.

PZ...Small Craft Advisory until 8 PM PDT Tuesday for Waters from San
     Mateo point to the Mexican Border Extending 30 to 60 nm out
     including San Clemente Island.

     Small Craft Advisory from 1 PM this afternoon to 8 PM PDT
     Tuesday for Coastal Waters from San Mateo Point to the
     Mexican Border and out to 30 nm.

&&

$$

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



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