Scientific Forecaster Discussion
Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
1012 am PST Friday Dec 20 2013
..updated aviation discussion...
A cold storm system will continue to exit the region this
morning. Otherwise...high pressure and offshore flow will bring a
gradual warming trend to the area through the middle of next week.
A slight cooling trend could occur on Christmas day.
The storm system will exit the region this morning as its center
moves south and east into the Gulf of California. Very few clouds
remain over the mountains this morning and the gusty north to
northeast winds have lessened to below advisory levels. Icy roads
may still persist at higher elevations until around noon. Removed
precipitation from the forecast as all indications are that the event is
***From previous discussion***
A cold air mass will likely remain in place across the area
through tonight. Many locations across the interior will see low
temperatures at or below freezing tonight. Frost headlines may
need to be considered for the central coast and Santa Ynez Valley
tonight as it will a close call. Patchy frost is still possible
tonight across the interior portions of the central coast and
through the Santa Ynez Valley.
High pressure building in across the region should bring a warming
trend through the weekend and into next week. A weak disturbance
could clip the area this weekend and mainly bring clouds to the
mountains. Patchy marine layer is also possible for the coastal
areas south of Point Mugu.
Long term (monday-thursday)...
A warming trend should persist into Tuesday as high pressure
remains over the area. With a northerly flow component rather
northeasterly between Monday and Wednesday...the air mass has
been cooled slightly.
Model solutions continue to hint at better cooling for Christmas
day across the area as a weak trough brushes the area as it moves
through the Central Valley and into the desert. Partly cloudy
skies are possible for Christmas day with most of the cloudiness
occurring over the mountains.
Overall high confidence in 18z tafs with VFR conditions expected for
most sites...except the l.A. Coast sites where low clouds with IFR
ceilings/visibility are expected after 10z. There is uncertainty in the timing
and height of the low clouds. There is a 20% chance that low clouds
could affect koxr and the San Fernando Valley.
Klax...moderate to high confidence in 18z taf. VFR conditions are
expected through 10z...with IFR ceilings/visibility from 12z-18z. The timing
could differ by 2 hours from taf times...and 10% chance ceilings heights
will differ by a category.
Kbur...high confidence in 18z taf. VFR conditions are expected
through the forecast period...but there is a 10% chance of IFR/LIFR
ceilings/visibility after 12z.
Small Craft Advisory (see laxmwwlox).
High rip current risk (see laxsrflox).