Area Forecast Discussion
Issued by NWS San Diego, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
FXUS66 KSGX 171032

Area Forecast Discussion
National Weather Service San Diego CA
332 AM PDT Sat Mar 17 2018

Mostly light showers will decrease this morning with another round
of showers for the late afternoon and evening ending late tonight
with snow levels of 4000 to 4500 feet. It will also be cooler
today with gusty southwest to west winds to 45 mph on the desert
slopes of the mountains. Dry with warming for Sunday through
Tuesday. A low pressure system over the eastern Pacific could
bring rain to areas bordering Los Angeles County on Wednesday with
greater chances for rainfall across much of southwest California
for Thursday into early Friday.



A low pressure system centered across southern Oregon and northern
California will move slowly inland today and into the Rockies on
Sunday. Mostly light showers with a weak cold front continue to
move across southwest California along and west of the mountains
early this morning. Showers may linger near the mountains into the
afternoon. Another round of scattered showers will move across
the area during the late afternoon and evening, decreasing from
the northwest and ending by morning. Total rainfall will range
from one tenth to one quarter inch near the coast to one half to
one inch in the mountains with locally greater amounts.

In the mountains, snow levels near 4000 to 4500 feet early this
morning will rise to 4500 to 5000 feet this afternoon, then lower
to around 4000 feet late tonight. Total snow accumulations of a
trace to 1 inch are expected between 4000 and 5000 feet, 2 to 5
inches from 5000 to 6000 feet, and 5 to 7 inches above 6000 feet
with isolated accumulations to 10 inches on the highest peaks of
the mountains in San Bernardino and Riverside Counties.

There will be gusty southwest to west winds from the mountain
ridge top onto the desert slopes into tonight with gusts to 45
mph. Strongest gusts to 55 mph are expected for this evening along
the east slopes of the mountains from the San Bernardino Mountains

For Sunday through Tuesday...high pressure aloft will be across
California with a low pressure system farther off the coast
centered along 140W. This will bring dry weather with a warming

For Wednesday through Friday...the forecast leans toward
the ECMWF and Canadian models. This would bring an initial round
of more significant precipitation for central and northwestern
portions of Southern California for Tuesday night into Wednesday.
Some of that precipitation might extend into areas bordering Los
Angeles County on Wednesday. As the upper trough off the West
Coast begins to move eastward...more significant precipitation
would spread across much of Southern California Wednesday night
and Thursday...decreasing early Friday.


171000Z...Mountains westward...Isolated to scattered showers
continuing through about 10Z Sunday, heaviest and most widespread
through 16Z this morning. Local vis 2-4 SM in heavier showers.
Otherwise SCT-BKN cloud layers 1500-5000 ft MSL and tops 8000-10000
ft MSL through Sunday morning.

Desert mountain slopes/deserts...west winds 20-30 kt with gusts to
45 kt through 23Z-18/06Z with strong UDDFS/LLWS.


West-northwest winds 15-25 kt developing this evening through Sunday
morning. A Small Craft Advisory is in effect from 7 PM this evening
through 4 AM Sunday.

Showers will continue at times today through Sunday morning.


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


CA...Winter Weather Advisory until 3 AM PDT Sunday for Riverside
     County Mountains-San Bernardino County Mountains-San Diego
     County Mountains.

PZ...Small Craft Advisory from 7 PM this evening to 4 AM PDT Sunday
     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.



AVIATION/MARINE...SS is the U.S. government's official web portal to all federal, state and local government web resources and services.