577
FXUS66 KLOX 172108
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
208 PM PDT Sat Aug 17 2024

.SYNOPSIS...17/206 PM.

Aside from night and morning low clouds and fog near the coast at
times, quiet weather is expected through next week. A warm-up is
expected for Tuesday and Wednesday particularly for the interior.

&&

.SHORT TERM (TDY-TUE)...17/206 PM.

Through the remainder of this weekend, dry southwesterly flow
will prevail over the local area -- between persistent upper
troughing off the Pacific Northwest coast and a midlevel ridge
building over the south-central states. Onshore flow will maintain
significant coverage of low clouds and perhaps patchy fog over
coasts and coastal valleys during the night and morning -- given
marine-layer depths over 2000 feet observed at KLAX this
afternoon with, initially, little change in midlevel heights.
Night and morning low clouds and fog will dissipate by mid-day
each day. The onshore flow will keep high temperatures near the
coast a few to several degrees below normal near through Monday,
with highs over interior areas of a few to several degrees above
normal. Modest offshore pressure gradients for SBA-SMX will
facilitate sub- advisory Sundowner winds across southern Santa
Barbara County each day. Tuesday high temperatures will increase
2-4 degrees areawide in response to the mid-level ridge expanding
westward over the local area, which will also correspond to a
shallower marine layer and lower-coverage marine stratus and fog
especially as synoptic-scale subsidence yields drying trend.
Probabilities for heat headlines over interior areas are less than
20%.

.LONG TERM (WED-SAT)...17/206 PM.

Wednesday high temperatures will still be quite warm away from the
coast -- running a few to several degrees above normal over
interior areas -- as the strengthened midlevel ridge persists
over the region. Light onshore flow will keep temperatures cooler
near the coast. Later in the week, the latest medium-range model
consensus indicates the aforementioned trough becoming reinforced
with heights aloft falling across the local area. Correspondingly,
a cooling trend is expected for Thursday and Friday and into next
weekend. Despite the lower heights aloft, significant synoptic-
scale drying will slow the return of marine stratus and fog over
coastal areas -- though low clouds and fog should return to the LA
County coast and Central Coast by late next week and then
overspread other coastal areas thereafter. The upper-level pattern
will be unfavorable for convective development through next week.

&&

.AVIATION...17/1752Z.

At 16Z over KLAX, the marine layer was 2300 ft deep. The top of
the inversion was 3300 ft with a temperature of 22 Celsius.

High confidence in VFR conditions through at least Sunday at KPMD
and KWJF with slightly stronger and more persistent than usual
onshore flow.

Slow clearing chance at KSBA KOXR, with a 30% chance of staying
MVFR through 20-22Z.

Moderate confidence in lower ceilings tonight compared to last
night. Chances for LIFR/IFR ceilings at KPRB (40%) KSBP (50%) KSMX
(70%). Chances for IFR/MVFR ceilings at KSBA (30%) KCMA (30%) KOXR
(50%) KSMO (70%) KLAX (80%) KLGB (80%) KBUR (60%) KVNY (50%). Low
confidence on timing.

KLAX...Moderate confidence in VFR conditions by 19Z lasting
through at least 00Z. There is a 30% chance of 1-4 hours of
BKN008 from 00-05Z. 80% chance of OVC008-015 forming for good as
early as 06Z and as late as 12Z. High confidence that any east
wind component will stay under 6 knots.

KBUR...High confidence in VFR conditions through at least 04Z. 60%
chance of BKN006-10 forming as early as 08Z and as late as 14Z.

&&

.MARINE...17/147 PM.

For the outer waters from the Central Coast to San Nicolas
Island, moderate confidence in Small Craft Advisory (SCA) level
winds for the waters south of Point Sal (Zones PZZ673/676) through
Tuesday night, with lulls possible in the morning hours each day.
For the furthest northern zone (PZZ670), high confidence winds
will be below advisory levels through Sunday morning. Moderate
confidence in winds picking up to SCA level Sunday afternoon thru
Tuesday night.

For the nearshore waters off the Central Coast, high confidence
in conditions remaining below SCA levels through Sunday morning.
Moderate confidence in SCA level winds occuring during the
afternoon thru evening hours tomorrow through early next week.

For the Santa Barbara Channel, moderate high in winds remaining
below SCA level thru Sunday morning, and moderate confidence thru
Monday morning. There is a better chance of SCA level winds in
the Western Portion of the Channel Monday and Tuesday afternoon
thru evening hours. In the eastern portion, high confidence in
conditions remaining below SCA level through early next week.

For the southern inner waters, high confidence in conditions
staying under SCA levels through the period.

With a shallowing marine layer, moderate confidence in patchy
dense fog with visibilities under 1 nautical mile effecting the
Central Coast waters tonight thru at least Monday morning,
especially in the overnight to morning hours.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Monday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Cohen
AVIATION...Kittell
MARINE...Lewis/Lund
SYNOPSIS...Cohen

weather.gov/losangeles

Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox