238 
FXUS66 KLOX 251119
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA 
319 AM PST Mon Nov 25 2019

.SYNOPSIS...25/157 AM.

It will be cooler and windier today. Cloudier and cooler still on
Tuesday. An early season storm will bring periods of rain and 
mountain snow as well as a slight chance of thunderstorms Tuesday
night through Saturday. Temperatures will be well below normal
Wednesday through Friday.

&&

.SHORT TERM (TDY-WED)...25/318 AM.

Sunny skies today (maybe some high clouds over srn LA county).
Yesterday's offshore flow has turned onshore and this along with
some cold air advection in the afternoon will knock off 5 to 10
degrees from yesterday's highs. The bigger news is a trof passage
that will occur around noon today. It will usher in good cold air
advection and upper level wind support (850-700mb wind speeds will 
range from 40-60kt). Strong northerly sfc grads will also develop.
Warning level wind gusts from 60 to 70 mph will develop in the 
mtns with the strongest gusts occuring in the I-5 corridor. 
Advisory level gusts from 35 to 45 mph will develop across the 
Central Coast and the SBA south coast. By early evening advisory 
level wind gusts will filter into the all of the LA and VTA vlys 
xcp for the San Gabriel vly. The winds will diminish towards dawn 
as the gradients shift to the NE and upper support wanes.

Tuesday will start off sunny with Santa Ana winds that will be
mostly below advisory criteria in the vlys but probably slightly
above advisory levels in the LA mtns. All of the cold air
advection will shave another 4 to 8 degrees off of the max temps
and almost all coast and vly locations will see highs in the 60s.
Skies will begin to cloud up across SLO and nrn SBA counties in
the afternoon.

The storm Tuesday night and Wednesday is still on track. The only
problem is that the mdls have not been that consistent with the
exact handling of it. While the 12Z NAM had good south flow and
generous upslope precip totals the 00Z and 06Z runs do not. What
is pretty for certain is that rain will develop across the Central
Coast after midnight early Wednesday morning as the cold front
pushes in. The front and the rain will then move into the VTA and
LA counties in the morning. The NAM is a touch slower and it it
comes true the LA county morning commute would be mostly spared.
Rain will turn to showers in the afternoon in the wake of the
trof. There will be enough instability to generate numerous
showers as well as a slight chc of TSTMs. It looks like the
frontal system will drop about a half inch to an inch of rain with
maybe a little more across the coastal mtn slopes. Rainfall rates
will be moderate at times but the front will be moving fast 
enough that flood risks in and around the recent burn areas will 
be minimal. The greater burn area worry would come from the slim 
chc that a TSTM would move over a burn area in the afternoon.

Snow levels will start out around 6500 ft. Snow levels will fall 
rapidly Wednesday afternoon and overnight and there could be some
accumulating snow over the Grapevine as early 6 PM but more likely
a little later in the evening. A winter storm watch is in effect
for the mtns of SBA/VTA/LA due to the potential for 12 to 24 
inches of snow with lesser but more impactful amounts over the mtn
passes.

Max temps Wednesday will struggle to reach 60 degrees across the
csts and vlys.

.LONG TERM (THU-SUN)...24/210 PM.

Following the frontal passage Wednesday we'll generally be in a
showery period with highly variable rainfall amounts and even sky
conditions. There is a second impulse that is expected to rotate
around the base of the trough on Thanksgiving day though models 
are taking most of this energy south into Orange and San Diego 
Counties. This will generate a secondary increase in precipitation
mainly across LA County, though again the cold air aloft with
500mb temps ranging from -30C to -32C and ample moisture below
700mb will spawn numerous showers elsewhere and possibly some
isolated thunderstorms. Snow levels will be very low, mostly 
around 3000', though as low as 2000' in convection. Rain amounts 
Thursday will vary from as low as a quarter inch to as much as 
1.5", and generally speaking the higher amounts in eastern LA 
County.

Snow totals in the mountains will range from 6-12", though as 
much as 2 feet in the eastern San Gabriels. The Grapevine should 
receive 3-6". Should see up to a few inches in the Antelope 
Valley foothills and possibly a dusting down to the valley floor.

Activity expected to wind down quickly Friday as the trough lifts
out. Can't rule out an isolated shower or two, especially over
higher terrain but minimal amounts.

Right now it's looking dry and slightly warmer most areas next 
Saturday with weak/dirty ridging aloft but models are showing a 
lot of high clouds passing through the ridge. The next system to 
our west gets very close to the Central Coast Saturday night and 
Sunday and some ensemble members are showing some light rain so 
will go with small rain chances there but dry elsewhere.

&&

.AVIATION...25/0640Z.

At 0545Z at KLAX, there was no marine layer. There was a weak sfc
based inversion with a top of 700 ft and a temp of 18 C.

High confidence in TAFs.

KLAX...High confidence in CAVU TAF. There is a 20 percent chc of
an east wind component greater than 8 kt 12Z-17Z.

KBUR...High confidence in CAVU TAF.

&&

.MARINE...25/233 AM.

Outer Waters...Small Craft Advisory (SCA) level gusts are expected
across the southern portion of the outer waters through mid
morning. A GALE WARNING is in effect from 3 AM this morning for 
the northern zone (PZZ670)through 3 AM Tuesday. The remaining 
outer water zones will be under a GALE WARNING by mid morning 
through the same time period. After that, there is good confidence
that SCA level winds and seas will continue for the remainder of 
the outer waters through at least midweek. 

Inner Waters N of Point Sal...Should remain below SCA levels through
this morning. There is a 80% chance of SCA conditions developing 
this afternoon through tonight and again at times Tuesday night 
through Wednesday night.

Inner Waters S of Point Conception...There is a 60% chance for Gale
force winds across the western portion of the Santa Barbara 
Channel from this afternoon through late tonight, with SCA 
conditions by mid morning leading up to the GALE WARNING valid 
from 3 PM this afternoon through late tonight. Also, there is a 
50% chance for a SCA for gusty North- Northeast winds tonight 
across the Santa Monica Basin to Point Mugu. There will then be a 
50% chance of SCA winds Wednesday and Wednesday night.

There will be an increasing NW swell approaching 12-18 feet 
from late today through Tuesday night affecting the outer waters.

&&

.BEACHES...25/1223 AM.

A High Surf Advisory remains in effect as a seconday, larger northwest
swell moves in across the Central Coast this morning. High surf is
expected to continue through Wednesday at 10-15 feet. 

Furthermore, the area affected by high surf is expected to expand into
areas south of Point Conception, specifically west facing beaches of
Ventura County with surf 4 to 7 feet this afternoon through Tuesday.
Los Angeles County beaches will experience elevated surf between 
3 to 6 feet which will bring a high risk for strong rip currents, 
but remain below High Surf Advisory thresholds.

Finally, astronomical high tides will peak near 7 feet early this
week during the morning hours between 7-8AM, and combined with 
high surf will result in the issuance of a Coastal Flood Advisory 
for minor tidal overflow during the time of peak tide, mainly for 
Los Angeles and Ventura counties. Minor flooding will be confined 
to the lowest areas of coastline, including possibly some exposed 
beach parking lots.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 3 PM PST Wednesday for
      zones 34-35. (See LAXCFWLOX).
     Wind Advisory in effect from noon today to 9 PM PST this
      evening for zones 34-35. (See LAXNPWLOX).
     Wind Advisory in effect from noon today to 3 AM PST Tuesday
      for zones 39-59. (See LAXNPWLOX).
     Coastal Flood Advisory in effect until 10 AM PST Tuesday for
      zones 40-41. (See LAXCFWLOX).
     High Surf Advisory in effect from 1 PM this afternoon to 7 AM
      PST Tuesday for zone 40. (See LAXCFWLOX).
     Wind Advisory in effect from 6 PM this evening to 3 AM PST
      Tuesday for zones 44>46-88-547. (See LAXNPWLOX).
     High Wind Warning in effect from noon today to 3 AM PST
      Tuesday for zones 52>54. (See LAXNPWLOX).
     Winter Storm Watch in effect from late Tuesday night through
      late Thursday night for zones 52>54. (See LAXWSWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PST Tuesday for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 9 AM this morning to 3 PM
      PST this afternoon for zone 650. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PST
      Tuesday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 9 PM this evening to 6 AM
      PST Tuesday for zone 655. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PST Tuesday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PST this morning
      for zones 673-676. (See LAXMWWLOX).
     Gale Warning in effect from 9 AM this morning to 3 AM PST
      Tuesday for zones 673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (WED-SUN).

Wednesday and Thursday with periods of heavy rain, thunderstorms,
and low elevation snow causing major travel disruptions along 
with possible mud and debris flows near burn areas. Cold 
temperatures are forecast for latter half of next week with 
widespread frost or freeze conditions likely across the interior, 
possibly extending into some coastal valley locations.

&&

$$

PUBLIC...Rorke/MW
AVIATION...Rorke
MARINE...Kaplan
BEACHES...Kaplan/Sweet
SYNOPSIS...30

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