Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 071222

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
422 AM PST Sat Dec 7 2019

.SYNOPSIS...07/306 AM.

A cloudy and showery weather pattern will continue across the
region into Sunday as a moist air mass with a storm system moves
over the area. Dry weather will develop for much of next week
along with some warming for latter half of the week.


.SHORT TERM (TDY-MON)...07/351 AM.

A showery weather pattern continues to develop across the area
this morning as an upper-level trough near 40N and 130W continues
to move toward the North Coast of California. A moist air mass
continues to stream over the area this morning. A look into some
breaks in the cirrus deck on GOES-West shows a large swath of
clouds moving northeast into southern California. NAM-WRF
solutions show 850 mb mixing ratios greater than 8 g/kg across the
area pushing into the southern area this morning. An upslope flow
with weak warm air advection will interact with the moisture and
continue precipitation across the region. Orographic lift should
enhance precipitation totals right along the south facing slopes
of foothills and mountains. PoPs have been nudged high across the
coastal and valley areas today.

Around an additional 0.33 to 0.50 inch of rainfall is forecast
across the coastal and valley areas into Sunday night, with up to
between an additional 0.75 inch to 1.50 inches in the foothills
and mountains. Storm total precipitation should come in around
0.50-1.00 inch across the coastal and valley areas. Mountain
locations could do a tad better with some local amounts between
2.00 and 2.50 inches possible. Much drier conditions are forecast
for the desert with totals ranging around 0.10-0.20 inch.

Some marginal instability moving across the region late tonight
and Sunday could bring isolated thunderstorms to portions of the
area, mainly north and west of Ventura County, which includes the
Cave burn area in Santa Barbara County. Isolated higher rainfall
rates up to around 0.50 inch per hour are possible as this
instability moves, but rainfall should remain less than USGS
estimates for mud and debris flows.

While snow levels will largely remain above 6000 feet with this
storm system, colder air aloft with the trough moves into the
region Sunday night and into early Monday, which could lower the
snow levels as low as 5000 to 5500 feet in some locations. With
the moisture source region of this system, snow to water ratios
should be a little lower and only an inch or two of snow is
expected above 7000 feet.

.LONG TERM (TUE-FRI)...07/340 AM.

Drier weather is the theme for next week. Ridging aloft will
build in across the region between Monday and Tuesday, then a weak
weather system will brush the area. A slight cool down is expected
for Tuesday and Wednesday with a bit more clouds. By late next
week, ridging aloft should grab ahold of the weather pattern for
the latter half of next week and bring warmer temperatures.



At 0945Z, there was no marine inversion at KLAX.

Low to moderate confidence in all 12Z TAFs. MVFR conditions are
likely through the period. During periods of heavier rainfall,
cigs and vis may briefly drop to IFR levels with the best
confidence after 00Z.

KLAX...Low to moderate confidence in TAF. MVFR conditions will
become likely through the period after 15Z. There is a 30 percent
chance of IFR conditions in heavier rainfall through 03Z, then a
better chance afterward. East winds up to 8 knots are likely
to continue through 21Z. There is a 40 percent chance that east
winds up to 6 knots may linger into the evening.

KBUR...Low to moderate confidence in TAF. MVFR conditions are
likely through the period. There is a 30 percent chance of IFR
conditions in heavier rainfall through 02Z, then better
chance afterward.


.MARINE...07/258 AM.

For the Outer Waters, moderate confidence through this afternoon,
than high confidence through at least Monday. A Small Craft
Advisory (SCA) remains in effect for the northern zone PZZ670
through this afternoon and for PZZ673 just to the south through
mid morning. There is a 30% chance that the southern zone PZZ676
will need a SCA through mid morning as well. On Tuesday and
Wednesday, there is a 60% chance of SCA level winds across PZZ673
and PZZ676.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. A SCA remains in effect. There is
an 80% chance of SCA level winds and seas this morning. There is
a 60% chance of SCA winds continuing into Saturday afternoon. For
Sunday through Wednesday, high confidence in winds and seas
remaining below SCA levels.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. There is a 30%-40% chance of SCA
level southeast winds across the northwestern half of the Santa
Barbara Channel tonight through this morning. Otherwise, high
confidence in winds and seas remaining below SCA levels through
Tuesday. On Wednesday, there is a 50% chance of SCA level
northwest winds across the western half of the Santa Barbara


.BEACHES...07/302 AM.

A relatively large, long-period, west to northwest swell will
bring high surf conditions to the Central Coast as well as the
Ventura county coast through Sunday morning.

For the Central Coast, surf heights will peak between 9 and 12
feet with local sets to 14 feet. For west-facing beaches of
Ventura county, surf heights between 4 and 7 feet. Local sets to
9 feet can be expected through tonight. High surf will continue
for these areas as HIGH SURF ADVISORIES will remain in effect
through mid Sunday morning.
For the west-facing beaches of southern Santa Barbara county and
Los Angeles county, elevated surf conditions can be expected
across exposed west facing beaches through Sunday with surf
heights of 3-6 feet for Los Angeles county and 3-5 feet for
southern Santa Barbara county.

For all coastal areas...there will be an increased risk for ocean
drowning. Rip currents can pull swimmers and surfers out to sea.
Large breaking waves can cause injury...wash people off beaches
and rocks...and capsize small boats near shore.


CA...High Surf Advisory in effect until 8 AM PST Sunday for zones
      34-35-40. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 PM PST this afternoon
      for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PST this morning
      for zone 673. (See LAXMWWLOX).



No significant hazards expected.



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