199 
FXUS66 KLOX 211804
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA 
1104 AM PDT Thu Mar 21 2019

Updated Aviation Section

.SYNOPSIS...21/752 AM.

Shower activity will end today through most of the region, with
lingering showers possible in the mountains tonight. Clouds
increase Friday as another storm system brings a chance of rain north
of Point Conception Friday night. Rain and snow are possible in
the mountains Saturday. Below normal temperatures are expected
through the rest of the week.

&&

.SHORT TERM (TDY-SAT)...21/948 AM.

Another low pressure system coming through the negatively tilted
trough over California today. Visible satellite imagery is nicely
capturing the low level circulation drifting south about 60 miles
west of Santa Maria this morning. The rain bands ahead of it were
a little more energetic than expected and generated rain rates up
to .2-.3"/hr as they moved through SB County this morning and now
moving into Ventura County. This activity will continue moving 
southeast and into LA County shortly and into the afternoon. Hi 
res models indicate some additional enhancement over LA County 
this afternoon as the showers pick up some additional lift from 
the mountains and colder air aloft that could lead to slightly 
higher rates there, but still below critical levels and not
expecting thunderstorms locally.

Showers expected to rapidly decrease this evening and be pretty
much done by midnight with clearing skies and northwest flow
developing. Exception being the Grapevine area which likely will
see some low clouds and fog through early Friday as moisture banks
up from the southern San Joaquin Valley.

***From previous discussion***

A little ridge moves into the state on Friday. It is not that warm
a ridge and hgts only rise to 566 DM. Skies will be partly cloudy
as the ridge is not strong enough to prevent some mid and high
level clouds to sneak through. Max temps will jump about 5 degrees
but will still come in blo normal.

The barest of trofs moves over the state on Saturday it does
little more than to knock down the trof. It will bring a chc of
showers to the Central Coast and the mtns. At this time it looks
too weak to bring any showers to the rest of the area. Max temps
will cool 2 or 3 degrees and will end up 4 to 8 degrees blo
normals.

.LONG TERM (SUN-WED)...21/326 AM.

Another weak ridge moves into the state on Sunday. More
importantly some offshore flow develops. Skies will clear out and
max temps will rise about 5 degrees and most cst and vly locations
will have max temps a degree or two either side of 70. Still 2 to
3 degrees blo normal.

An upper low will move into the north of the state on Monday and
will push the ridge off to the east. Clouds will increase esp
over SLO and SBA counties, but it will remain dry over almost of
the area with the only chc of rain over the NW corner of SLO
county. Despite the ridge moving off hgts will continue to rise 
up from the south by a broad ridge that is also responsible for 
the north track of the upper low. These higher hgts will lead to a
few degrees of warming esp over the less cloudy VTA and LA 
counties. 

The upper low pulls more to the north and its associated front
does not make much in the way of eastward progress and the chc of
rain will be confined to SLO and SBA counties. The rest of the
area will see mostly cloudy skies. Max temps will cool north of Pt
Conception but will not change much to the south.

The front finally makes its eastward push Tuesday night and
Wednesday. A chance of rain will develop over all over the 4
county area and persist into Wednesday afternoon. This really
looks like a late March system with minimal rainfall amounts and
rates. Hgts do collapse and along with overcast skies max temps
will roundly fall to 6 to 8 degrees blo normals.

&&

.AVIATION...21/1759Z.

At 17Z, there was no marine layer or inversion at KLAX.

Moderate confidence in VFR SCT-BKN050 common through 02Z, with
MVFR BKN025 common under -SHRA. After 03Z, moderate confidence in
VFR conditions common. There is a small chance of IFR/LIFR post-
rain FG/BR around 12Z Friday in random locations, with the 
highest chance at KPRB. 

KLAX...Moderate confidence in -SHRA at times, and VFR CIGS 
common, except for MVFR CIGS under some showers. Moderate
confidence in timing +/- 2 hours. Moderate confidence in VFR
conditions tonight.

KBUR...Moderate confidence in -SHRA at times, and VFR CIGS 
common, except for MVFR CIGS under some showers. Moderate
confidence in timing +/- 2 hours. Moderate confidence in VFR
conditions tonight, but there is a 10 percent chance if IFR/LIFR
post-rain FG/BR around 12Z Friday.

&&

.MARINE...21/949 AM.

Moderate confidence in NO thunderstorms today, but showers will
persist through the day. Gusty west to northwest winds will
increase this afternoon and evening south of Point Conception,
with a 60 percent chance of reaching Small Craft Advisory (SCA)
strength. These winds will also generate choppy seas on top of the
long period west swell. Similar conditions are likely on Friday.
Northwest winds will increase some on Saturday with SCA likely off
the Central Coast.

&&

.BEACHES...21/414 AM.

A relatively large, long period west-northwest swell will slowly
subside today and surf should decrease below High Surf Advisory
levels by late afternoon. Another long period west-northwest swell
could bring high surf to area beaches again late Sat and Sun.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 3 PM PDT this afternoon
      for zones 40-41-87. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zones 650-655-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (SAT-WED).

High surf and dangerous rip currents are expected over the 
weekend.

&&

$$

PUBLIC...MW/Rorke
AVIATION...Kittell
MARINE...Kittell
BEACHES...DB
SYNOPSIS...Phillips

weather.gov/losangeles