Arroyo Grande, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

563
FXUS66 KLOX 220005
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
405 PM PST Sat Dec 21 2024

.SYNOPSIS...21/112 PM.

A significant high-surf event with coastal flooding is expected
this weekend into the upcoming week, with the most dangerous
conditions expected from Monday into Tuesday. Areas of dense fog
near the coast will create low visibilities at times through
Monday. Aside from a small chance for light rain near the San
Luis Obispo County coast this weekend, it will be dry through
Monday. A stronger weather system could bring light rainfall to
more areas Tuesday and Tuesday night. Temperatures will range
from near normal near the coast, to well above normal for interior
areas.

&&

.SHORT TERM (TDY-TUE)...21/133 PM.

...Significant high-surf event with coastal flooding this weekend
into the upcoming week...

Another day of cooling temperatures across the valleys as a return
to onshore flow has pushed more cool ocean air inland. Meanwhile,
an earlier burn off of the low clouds and dense fog allowed
coastal areas to bounce back from the the mid to high 50s that
were prevalent there yesterday.

High cloud coverage will be increasing through the night and into
Sunday as lots of high level moisture pours in from a low
pressure system moving into the eastern Pacific. Sky coverage
will vary from mostly to partly cloudy and this will likely wreck
havoc on the stratus and fog coverage. Still, given the time of
year and the still fairly light gradients, areas of dense fog are
possible, more so south of Pt Conception than north. With the
moisture moving east of the area Monday night and still light
onshore flow, dense fog may be more prevalent than tonight.

Otherwise, pretty low impact weather through early next week. The
tail end of a weak system will may bring some very light rain to
northwest SLO County tonight into Sunday morning. Coast and
valley temperatures will warm slightly through Monday before
crashing again with the next system on Tuesday. Models have
consistently been showing this one having a slightly farther south
trajectory to it, giving it a better chance for dropping some
light rain even through Ventura and LA Counties Tuesday afternoon
and evening. Rain amounts are expected to be a half to one inch
across coastal SLO county, then dropping off quickly to a quarter
inch or less in Santa Barbara County and a tenth of an inch or
less elsewhere.

Please reference the High Surf Warning and High Surf Advisory, as
well as the Coastal Flood Advisory, regarding the significant
high-surf event.

.LONG TERM (WED-SAT)...21/151 PM.

Following the Tuesday system moderate to locally strong northerly
flow will settle in across the area with gusty winds particularly
in the mountains. Deterministic runs are showing gradients from
the north between 5 and 7mb consistently through the rest of next
week. Christmas day will be sunny but on the cooler side after
the trough passage with some gusty winds through the mountains and
canyons, including the Santa Ynez Range. Periods of gusty winds
will continue all week with a slow warming trend going into next
weekend. Longer range ensembles show very little in terms of
precipitation chances through the first week in 2025. Possibly a
couple weak systems for the Central Coast next weekend and early
the following week but these show little hope of bringing any
meaningful rain.

&&

.AVIATION...22/0003Z.

At 23Z at KLAX, the marine layer was 400 ft deep. The top of the
inversion was at 2200 ft with a temperature of 18 C.

Overall, moderate confidence in 00Z TAF Package. High confidence
for desert sites and KSBA, KBUR, KVNY. Moderate to Low confidence
for remaining sites.

After 06Z, there is a 20 to 30% chance of LIFR conds at cig/vsby
restricted sites. There is a 10 to 20% chance for VLIFR conds
after 10z.

Timing of Cigs/vsby restrictions may be off +/- 2 hours. Flight
cats could be off one or two, especially during worst conditions.

KLAX...Low confidence in 00Z TAF. VLIFR to IFR conds should
persist through 18Z-19Z then improve to MVFR. There is a 30%
chance for vsbys less than 1/2SM and cigs VV001-VV002 after 07Z.
Low confidence in the minimum flight cats after 00Z Monday till
the end of the fcst pd. No significant east wind component
expected.

KBUR...High confidence in 00Z TAF.

&&

.MARINE...21/128 PM.

High confidence in large, long period west to northwest swells
arriving this evening, lasting through next week. Seas will peak
around 20 feet across the Outer Waters and northern Inner Waters,
highest off the Central Coast, and around 12 feet in the Santa
Barbara Channel Monday and Tuesday. Small Craft Advisory (SCA)
seas will likely (60-80% chance) continue most of the time
through at least the end of next week, with best chances in the
northern Outer Waters. These conditions pose a risk for damaging
breaking waves at Morro Bay and Ventura Harbor entrances.

There is a 60-70% chance of SCA level winds for the waters around
the Channel Islands beginning tomorrow morning and persisting
through at least late Monday. SCA winds will then become more
widespread across most of the waters by Christmas Eve (Tuesday)
and last through Friday morning (80-90% chance). There is a 20-30%
chance of Gale Force wind gusts for the Outer Waters from around
Point Conception south to San Nicolas Island from Wednesday
morning through Thursday, possibly extending into the western
portions of the Inner Waters south of Point Concpetion.

&&

.BEACHES...21/133 PM.

A large and long period west to northwest swell will bring
dangerously high surf, especially to west and northwest facing
beaches, of 18 to 25 feet to the Central Coast and 12 to 18 feet
to Ventura County during peak periods Monday through Tuesday. LA
and Santa Barbara Counties will see 8 to 12 foot surf Monday and
Tuesday. Otherwise, from this afternoon through most of next week,
advisory level surf can be expected and minor to moderate coastal
flooding is possible. Please reference our SRF and CFW products
for more details.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect from 10 PM this evening to 4 AM
      PST Wednesday for zones 87-349-350-362-366. (See LAXCFWLOX).
     High Surf Advisory in effect until 1 AM PST Sunday for zones
      340-346-354. (See LAXCFWLOX).
     High Surf Warning in effect from 1 AM Sunday to noon PST
      Tuesday for zones 340-346-354. (See LAXCFWLOX).
     Coastal Flood Advisory in effect from 2 AM Sunday to 9 AM PST
      Tuesday for zones 340-346-354. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 2 AM PST Thursday for
      zones 645-670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect from 10 PM this evening to 4
      AM PST Monday for zone 650. (See LAXMWWLOX).

&&

$$

PUBLIC...MW
AVIATION...Black
MARINE...Lewis
BEACHES...Lewis
SYNOPSIS...MW/Cohen

weather.gov/losangeles

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