Duarte Weather

000
FXUS66 KLOX 161203
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
403 AM PST Fri Nov 16 2018

.SYNOPSIS...16/315 AM.

Weak offshore flow will keep dry and fairly warm weather across
the region today. Onshore flow will return Saturday, bringing
some cooling and a return of night through morning low clouds and
fog to coastal and some valley areas. Temperatures will be near
normal in most areas Sunday through Monday. Cooler weather is
expected for Tuesday and Wednesday. A couple of upper level
troughs moving into the West Coast could bring some rain to
portions of the region late Wednesday into Thanksgiving Day.

&&

.SHORT TERM (TDY-SUN)...16/335 AM.

A fair amount of high cloudiness was spreading across the region
this morning, and will continue for much of the day. Partly cloudy
wording should cover the expected cloud conditions today. Some
patches of low clouds were developing off the Central Coast and to
the west of VTU County, but weak offshore gradients this morning
should keep clouds from moving onshore. Gradients between KLAX and
KDAG are forecast to turn onshore this afternoon, for the first
time in over a week, since last Wednesday night. This should bring
some cooling to most areas today, especially to coastal and valley
areas. However, max temps should still be slightly above normal.

Heights and thicknesses will lower across the region tonight and
Saturday as a weak trough drifts into the region. Pressure
gradients will become increasingly onshore, from west to east and
also from south to north. Models show somewhat of a southerly
surge across the coastal waters tonight and Sat morning, and show
low level moisture increasing in coastal and some valley areas.
Expect low clouds and fog to push into coastal sections south of
Pt. Conception tonight, and, at least initially, the fog may be
dense in some areas. Southerly flow should help push clouds around
Pt. Conception and into the Central Coast, and possibly into the
San Gabriel Valley. After low clouds dissipate on Sat, there
should be enough high clouds to make for a partly cloudy day. Max
temps should be down a few degrees in most areas.

An upper ridge will push into the West Coast Sat night and Sunday,
causing heights to rise again. Low level gradients will turn
offshore again by Sun morning. Do not expect much in the way of
wind, but it may reduce any low cloud coverage Sat night/Sun
morning, and allow for a few degrees of warming in many areas Sun.

.LONG TERM (MON-THU)...16/403 AM.

The upper pattern is forecast to undergo fairly rapid changes
next week, with timing differences between models. This is leading
to below normal confidence in the forecast for much of next week.

It looks as though the upper ridge will hold across the region
Sun night and early Mon and gradients will remain offshore. An
upper low will race toward the region Mon afternoon passing to the
south of the area Mon night, then moving into Arizona on Tue.
Models show surprisingly little moisture from this system across
the region, with mainly some mid and high level clouds Mon through
Tue. The low cloud pattern will be tricky to forecast, and may be
totally wiped out by this fast moving system. Still, lowering
heights should bring a bit of cooling across northern areas for
Mon, with little change elsewhere. Minor changes in max temps are
expected for Tue, except there may be some warming in northern
areas due to height rises.

A stronger upper trough will move across the eastern Pacific
and into the West Coast Wed through Thu. The EC is sharper and
faster with this system, bringing the trough axis through the
region Wed night. The 06Z GFS shows a broader trough, with the
trough axis remaining well off the coast through Thu. This is
different from the 00Z run which was more similar to the EC. Have
introduced slight chance to chance pops to much of SLO and SBA
Counties for late Wed through Thu morning, with a slight chance
extending into VTU County and much of L.A. County Wed night and
early Thu. As mentioned, confidence is below normal, and the GFS
maintains dry weather through Thu, but there is at least a slight
chance of rain across the region during that time. Lowering
heights and thicknesses and increased cloudiness should knock
several degrees off max temps Wed, with temps down to normal or
slightly below normal levels.

&&

.AVIATION...16/1140Z.

At 0831Z, there was a surface based inversion at KLAX. The top of
the inversion was around 800 feet with a temperature of 20C.

N of Point Conception...Expect VFR conditions for most areas over
the next 24-hours. Except for VLIFR/LIFR cigs at KSMX after 08z.
There will be a 40% chance that similar cigs could develop at KSBP
after 10z. Not expecting CIGs to develop at KPRB.

S of Point Conception...Moderate confidence with 12z TAFs with
LIFR/IFR cigs possible for coastal TAFs for L.A. County. There
will be a 40% chance for LIFR/IFR cigs to develop at KOXR after
10z. 10% chance for CIGS to develop across valley TAF sites
tonight into Saturday morning.

KLAX...High confidence in the 12Z TAF with VFR conds thru 08z then
moderate confidence for LIFR/IFR CIGs through 15z. There is a 30%
chance that cigs could develop and scour out +/- 2 hours from
current TAF. There is a 10% percent chance of VLIFR to LIFR
conditions between 11Z and 15Z. Any east winds will likely remain
less than 7 knots.

KBUR...High confidence in the 12Z TAF with VFR conds thru the pd.

&&

.MARINE...16/132 AM.

High confidence in winds staying below Small Craft Advisory (SCA)
through at least this weekend and probably through Monday. Patchy
dense fog will be possible off the Central Coast early this
morning. There is over a 50% chance for more widespread dense fog
occurring tonight into Saturday morning across the inner waters
from the Central Coast into the SoCal bight.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK (SUN-THU).

No significant hazards expected.

&&

$$

PUBLIC...DB
AVIATION...Kaplan
MARINE...Kaplan
SYNOPSIS...DB

weather.gov/losangeles

NWS LOX Office Area Forecast Discussion