Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 251632
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
932 AM PDT Mon Sep 25 2017

.SYNOPSIS...
Gradually strengthening offshore flow will bring a warming and
drying trend with mostly clear skies to the area through this week
and into the weekend. There will be some gusty north to northeast
winds at times over the region, especially below and through
passes and canyons. Temperatures will be a few degrees above
normal for many areas early this week, then increase to much
above normal for late this week and into the weekend.

&&

.SHORT TERM...(TDY-WED)

It`s going to be a warm week but not record breaking and with the
possible exception of Tuesday winds should be below advisory
levels. Still on the fence for tomorrow`s winds and may hold off
issuing advisories since it does appear to be a marginal and
fairly localized case. Temperatures definitely on the rise today
and forecast highs look on track based on the current parameters
and our local guidance based on historical data. Likely a degree
or two of additional warming Tuesday but then a few degrees of
cooling for coast/valleys Wed/Thu as gradients weaken and lower
level temps decrease slightly. Still well above normal but not as
much as the next couple days. So this is a good little preview of
things to come as we move into our Santa Ana season but not a
major event by any means.

***From previous discussion***

Tonight the gradients will be a little more offshore and there
will be better upper support. This will be enough to generate wind
advisory level gusts 5 to 10 miles either side of the VTA/LA
county line. Aside from the slightly stronger winds Tuesday will
be very similar to today the only other change will be a few more
degrees of warming across the interior.

The offshore flow weakens Wednesday. There will not be enough push
to generate advisory level winds. Instead there will only be gusts
between 20 and 30 mph. There will be an earlier sea breeze and
coastal temps will cool a few degrees esp near the beaches but the
rest of the area will have temps similar to Tuesday.

.LONG TERM...(THU-SUN)

Offshore flow weakens (but still remains offshore) on Thursday.
The upper support vanishes as well as the state will be under a
large cull area. Winds will not be a problem. There will be little
change in temperatures across interior areas but the coasts
will see a few degrees of cooling. The GFS and ECMWF now show
fairly flat 585 DM flow over the area on Fri and Sat...no longer a
ridge. Offshore flow continues and Temps will really not change
to much. The ridge is now forecast to arrive on Sunday and if this
comes true there will be a few degrees of warming.

&&

.AVIATION...25/1600Z.

At 16Z, there was no marine layer at KLAX.

High confidence in VFR conditions throughout the period.
Moderate-to-high confidence in offshore winds. Periods of moderate
to strong wind shear are possible tonight at mainly terminals
south of Point Conception.

KLAX...VFR conditions are expected throughout the period. There is
a 40 percent chance of moderate wind shear between 00Z and 04Z. There
is 10 percent chance of east winds greater than 7 knots after
07Z.

KBUR...VFR conditions are expected throughout the period. There is
a 50 percent chance of moderate wind shear between 10Z and 18Z.

&&

.MARINE...25/900 AM.

Moderate-to-high confidence in the current forecast. Main concern
is winds for the Outer Waters today and across the Inner Waters
tonight and into Tuesday morning.

Low-end Small Craft Advisory winds will likely develop across the
Northern Outer Waters this afternoon and this evening, otherwise
winds and seas will remain below Small Craft Advisory levels
through at least Friday. Winds will likely increase over the
weekend.

For the Inner Waters, winds and seas are expected to remain below
SCA levels through Friday. There is a 30 percent chance of Small
Craft Advisory north to northeast winds each night and morning
through Thursday across the nearshore waters from Ventura south to
Santa Monica.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zones 670-673. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK...(WED-SUN)
A prolonged period of elevated fire danger is expected Wednesday
through Sunday due to the combination of gusty offshore winds,
very warm temperatures, low humidities, and very dry fuels. Brief
critical fire weather conditions will be possible at times on
Wednesday and again next weekend. There will be potential heat
impacts next weekend as triple digit temperatures are possible
for warmest valley locations.

&&

$$

PUBLIC...MW/Rorke
AVIATION...Hall
MARINE...Hall
SYNOPSIS...Sweet

weather.gov/losangeles



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