Small Craft Advisory 33, NWS Los Angeles, CA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
421 PM PST Sat Mar 4 2017

...update for new aviation discussion...

.SYNOPSIS...
A weak cold front will bring light showers to the area Sunday
with much cooler temperatures. The high temperatures will warm
slightly on Monday, and then high pressure and increasing
offshore winds will bring a more significant warming trend, with
the peak heat on Wednesday and Thursday.

&&

.SHORT TERM...(TDY-TUE)

Yesterdays moderate offshore flow has turned weakly onshore.
Skies are mostly cloudy as a cirrus shield streams out ahead of a
weak storm system approaching from the northwest. The marine
layer, lower heights, and onshore flow will all combine to knock
10 to 20 degrees off of yesterdays max temps.

A weak cold front will move through the area on Sunday. This
system is much weaker than our recent storms have been, with
rainfall totals of less than a quarter inch expected. Rain will
start across NW SLO county before dawn. Rain will spread to at
least SBA county during the morning and there is a chance it will
reach VTA county late in the morning, Rain will reach VTA and LA
counties in the afternoon just as a weak post frontal trof brings
some shower activity to the Central Coast. Rain will turn to
showers in the afternoon and then decrease from the NW later in
the afternoon. The showers will end during the evening as the
system exits LA county. A few north slope showers may continue
past midnight as north flow sets up behind the front. Rainfall
amounts will likely range from a tenth to a quarter inch. NW SLO
county may see a little more. Snow levels will start out at 6000
feet and fall to 5000 feet. 1 to 3 inches of snow will fall above
5500 feet during the day. Max temps will be about 10 degrees below
normal.

Cool dry NW flow sets up for Monday. Skies will be partly cloudy.
Max temps will recover 5 degrees or so, but will still be a few
degrees below normal. As surface high pressure builds in to the
north of us on Monday night and Tuesday morning the winds will
pick up and there will be some sub advisory gusts through the
north/south oriented passes especially the I-5 corridor.

Tuesday will continue the warmer and mostly clear trend.

.LONG TERM...(WED-SAT)

The long term outlook is for warm and dry weather. Both the GFS
and the EC agree that weak ridging extending up from the SW will
hold sway over the weather. Afternoon max temps will be above
normal through the period. It looks like Wed and Thu will be the
warmest days with plenty of 80 degree readings across the Ventura
and LA coasts and vlys, with mid to high 70s in Santa Barbara and
SLO Co.

The heat, as is so often the case, will be accompanied by an
extended period of offshore winds from the north. These winds may
be strong enough to warrant low-end advisories and will be
strongest through the I-5 corridor and in the Montecito area.

Extended outlook shows a chance of more rain next weekend. Nothing
really big showing up in our toolkit, but GFS is hinting at rain
beginning on Sunday.

&&

.AVIATION...05/0015Z

At 2307Z, there was a weak inversion at KLAX at around 800 ft deep.
The top of the inversion was at around 1300 ft with a temperature of
13 deg c.

Moderate confidence overall in the 00Z TAFs due to uncertainties in
the timing and extent of low clouds and MVFR cigs at the coastal and
vly airfields from early this evening to later tonight, then persist
thru early to late Sun afternoon. There is generally hi confidence
in the low clouds but the timing of the onset of the low clouds may
be off +/- 1 to 2 hours. For KWJF and KPMD, there is hi confidence
in VFR conditions thru Sun, altho there is a 20 percent chance of
MVFR cigs at times Sun afternoon. Gusty w to nw winds will affect
KPRB, KSBP, KSMX, KLAX, KWJF and KPMD on Sun afternoon as well.

KLAX...Moderate confidence overall in the 00Z TAF due to
uncertainties in the timing and extent of low clouds and MVFR cigs
from 06Z this evening to 03Z Sun evening. There is generally hi
confidence in the low clouds but the timing of the onset of the low
clouds may be off +/- 1 to 2 hours. Gusty w winds can be expected at
the airfield Sun afternoon and evening as well.

KBUR...Moderate confidence overall in the 00Z TAF due to
uncertainties in the timing and extent of low clouds and MVFR cigs
from 08Z this evening thru Sun afternoon. There is generally hi
confidence in the low clouds but the timing of the onset of the low
clouds may be off +/- 1 to 2 hours. There is also a 30 percent
chance of cigs improving to VFR aft 22Z Sun.

&&

.MARINE...04/100 PM...

For the Outer Waters, high confidence in current forecast. Winds
and seas will remain below Small Craft Advisory (SCA) levels
through Sunday morning. By Sunday afternoon, winds will shift to
the northwest behind a cold front and increase to SCA levels. The
SCA level northwest winds are expected to continue across the
Outer Waters through Thursday (with some brief lulls from time to
time).

For the Inner Waters, moderate confidence in current forecast. For
the waters north of Point Sal, winds and seas are expected to
remain below SCA levels through Thursday although there is a 40%
chance of SCA level gusts developing each afternoon/evening from
Sunday through Tuesday. For the waters south of Point Conception,
westerly winds will increase behind the cold front on Sunday with
a 50% chance of SCA level winds developing across western
sections. The chance of SCA level winds will continue through
Monday night.

&&

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

&&

.HAZARD POTENTIAL OUTLOOK...(TUE-SAT)
No significant hazards expected.

&&

PUBLIC...jld
AVIATION...Sirard
MARINE...RAT
SYNOPSIS...B

weather.gov/losangeles