Scientific Forecaster Discussion
fxus66 klox 180410
Area forecast discussion...updated
National Weather Service Los Angeles/Oxnard California
910 PM PDT Fri Aug 17 2018
Near to above normal temperatures and onshore flow will continue
through this weekend and into next week, as high pressure
continues to move west. Night to morning low clouds will return to
some coastal areas and valleys through Sunday.
Short term (fri-mon)...17/908 PM.
An upper-level ridge center can be seen over southern Arizona in
the latest satellite imagery this evening, while an upper-level
trough continues to move through the Pacific northwest. The ridge
will build west into the state through Sunday, while the trough
centered along the Oregon-Washington border exits. A warming trend
will take shape over the weekend as the high pressure system
builds in. A brief cool down will likely materialize for Saturday
as onshore flow increases slightly, then warming should take a hold
by Sunday. 500 mb heights and 1000-500 mb thickness values climb
into the weekend, which should thin the marine layer and weaken
onshore flow. A few cloud build-ups cannot be ruled out over the
mountains each afternoon and evening through the weekend, but
moisture is rather limited and pops will remain under mentionable
The flow aloft should turn southwest on Monday and increase into
Tuesday. This should allow for a better marine intrusion to start
the work week and possibly some cooling.
***From previous discussion***
Long term (tue-fri)...17/122 PM.
The Monday trough will linger into Tuesday then lift out Wed/Thu.
As this happens onshore gradients will weaken and high pressure
will rebuild from the east again. This will lead to a 2-5 degree
warm up and push temps to their warmest in this seven day period
with valley highs up to 105 and inland coastal areas into the
lower 90s. Another trough hitting Washington/or later in the week will
again push the ridge east and lead to cooling area-wide, but still
a few degrees above normal at least. Models keep the monsoon
moisture east of la County so for now no threat of convection
through next week.
At 00z, the marine layer depth was around 1200 feet deep at klax.
The top of the inversion was near 2100 feet with a temperature of
around 25 degrees celsius.
At coastal terminals, IFR to MVFR conditions will likely spread in
through 13z. There is a chance of LIFR conditions at coastal terminals
north of Point Conception between 08z and 16z. There is a chance
that IFR to MVFR conditions could linger confidence in VFR
conditions developing between 16z and 19z.
At inland terminals, VFR conditions are expected throughout the
period, except for a chance of IFR to MVFR conditions between 07z
and 16z at valley terminals. There is a chance of LIFR conditions
at valley terminals north of Point Conception, mainly between and
10z and 15z.
Klax...there is a 80 percent chance of IFR to MVFR conditions
spreading in through 07z. Any IFR conditions should lift into the
MVFR category as early as 05z or as late as 11z. MVFR conditions
could linger throughout the day on Saturday.
Kbur...VFR conditions are expected throughout the period, except
for a 50 percent chance of IFR to MVFR conditions between 07z and
16z. Conditions should improve to VFR between 16z and 18z.
For the outer waters, local Small Craft Advisory level winds will
continue through this evening near Point Conception, then
diminish. There is a 20 to 30 percent chance of Small Craft
Advisory level winds on Saturday evening near Point Conception,
increasing to 50 percent chance Sunday night. Winds will increase
through early next week and into midweek next week for pzz673 and
For the inner waters, conditions will likely remain below Small
Craft Advisory level through midweek next week.
There is a 30 percent chance of patchy dense fog in the overnight
and morning hours in portions of the coastal waters through
Increased south swell will result in hazardous conditions for
mariners through Saturday evening, particularly near the surf
Elevated surf will continue at Southern California beaches through
Saturday as a long-period southerly swell moves across the coastal
waters. Strong rip currents and sneaker waves will be common,
especially at south-facing beaches.
Moderate to strong rip currents and sneaker waves could linger
into Sunday as the southerly swell will be slow to diminish.
Swimmers and anyone in the surf zone should remain vigilant
through the weekend.
California...beach hazards statement in effect through Saturday evening
for zones 40-41-87. (See laxcfwlox).
Hazard potential outlook (mon-fri).
No significant hazards expected.