000
FXUS66 KSGX 152130
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
230 PM PDT Sun Oct 15 2017

.SYNOPSIS...
High pressure aloft and weak offshore flow will continue hot and
very dry weather west of the mountains through Tuesday with high
temperatures in the valleys and inland coastal areas in the 90s to
around 100. Cooling will begin to spread inland with onshore flow
Tuesday afternoon and Wednesday with greater cooling on Thursday and
Friday as a trough of low pressure moves inland along the West
Coast. This will bring more cloud cover...gusty west winds in the
mountains and deserts...and a slight chance of showers for Thursday
night and Friday. Dry with a warming trend for next weekend with
strengthening high pressure aloft and moderate offshore flow.

&&

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

A day of extremes across our small slice of SW California today
with a low of 22 degrees at Baldwin Lake this morning, and now
near 100 degrees just away from the coast, due to very dry
airmass and persistent but light offshore flow. These conditions
will continue through Monday with cold temperatures across the
higher elevations and the high desert of San Bernardino County,
and very dry air west of the mountains bringing temperatures just
as hot on Monday to areas just away from the immediate coast.

The red flag warning was allowed to expire at Noon today. The
reason for that is because the gusty Santa Ana winds are not quite
as strong at this point and not close to meeting the forecast
thresholds for red flag criteria to be met.

Onshore flow will begin to kick in on Tuesday. Inland areas will
remain very dry and hot on Tuesday. Some patchy fog and
low clouds will be possible by Tuesday night and into Wednesday
morning. in the morning. Onshore flow will become
more pronounced Wednesday and Thursday as the upper level ridge
over SoCal breaks down. More widespread low clouds and fog will
arrive Wednesday night into Thursday morning with some gusty
winds through the mountain passes and into the deserts with
blowing dust and sand possible there.

A strong low pressure trough will move through California
Thursday night and Friday. Widespread precipitation is forecast
for the northern portion of the state, with just some isolated
showers possible this far south with a decaying frontal boundary.

For next weekend the models are coming into some agreement that a
strong high will build over the region and create conditions for
strong offshore flow to develop and much warmer weather once again.
This pattern will have the potential to bring another round of
critical fire weather conditions to Southern California.

&&

.AVIATION...
152100Z...Clear skies, unrestricted visibility and light winds will
continue through Monday. Patchy fog is possible over the coastal
waters and beaches between 03Z and 16Z Monday.

&&

.MARINE...
No hazardous marine weather is expected through Thursday.

&&

.BEACHES...
A long period south swell will arrive in the Bight late Monday
evening and continue through Thursday. This will produce 3-6 ft
surf with sets to 7 ft north of Del Mar. Highest surf will occur
along southwest facing beaches. Strong rip and longshore currents
will accompany the elevated surf.

&&

.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...Brotherton
AVIATION/MARINE...Albright