Hacienda Heights, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

000
FXUS66 KLOX 290327
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
727 PM PST Sat Dec 28 2024

.SYNOPSIS...28/726 PM.

An extended period of gusty northerly winds is expected through
early next week, then switching to moderate Santa Ana winds on
New Years Day through the end of the week. Slightly cooler
temperatures Sunday with some light rain possible along the
Central Coast in the afternoon. Then turning warmer Monday through
the rest of the next week especially mid week when the Santa Ana
winds arrive and high pressure builds over the area.

&&

.SHORT TERM (SAT-TUE)...28/718 PM.

Etensive low clouds and fog developing this evening across
the Central Coast. Already seeing some visibilities down to
1/4 mile, which prompted the issuance of the Dense Fog
Advisory until 9 am Sunday for the Central Coast and Santa
Ynez Valley. Also seeing some patchy low clouds and desne
fog starting to form for areas south of Point Conception
which may prompt additional Dense Fog Advisory headlines
overnight. Otherwise, look for low clouds and fog to
fill in across the LA Basin tonight into early Sunday morning.

The tail end of the system over northern California brushes the
Central Coast and the Grapevine region tomorrow afternoon and
evening with chances of light rain mainly confined to San Luis
Obispo County and the north facing mountain slopes. Highs will
remain near to slightly below normal for most coastal areas Sunday
but 10-15 degrees above normal for the mountains and Antelope
Valley.

However, things look to be changing next week as systems passing
north and east of the area create a strong gradient from the north
forcing gusty north to northwest winds through the passes and
canyons. Models have been pretty consistent showing a 6-8mb
gradient from the north starting Sunday night into Monday and then
peaking Tuesday. Areas like the I5 corridor region, the Antelope
Valley and southern Santa Barbara County will be seeing the
strongest winds with some gusts to near 60 mph possible. Cooler
air will be moving in as well across the interior, dropping
temperatures by several degrees. However, due to downslope warming
processes, coastal and valleys will warm up 3-6 degrees. The north
flow should also wipe out most of the low clouds. Gusty north
to northeast winds will bring a drying trend to the region,
resulting in the potential for critical fire weather conditions
across portions of LA/Ventura counites. Please see fire discussion
for more details.

.LONG TERM (WED-SAT)...28/212 PM.

North winds Tuesday will transition to Santa Ana winds from the
northeast Tuesday night into Wednesday. Gusty winds will shift to
more of a northeast direction, though perhaps still with a bit of
a northerly bias as models are still hanging onto a 5-7 mb north
gradient along with the 4-5mb gradient to the east. These patterns
would favor strong winds over the Santa Monica mountains and
eastern Ventura County and less so across southwestern Ventura
County. And not expecting any significant winds in the Pasadena
area. Additional downslope warming along with building heights
aloft should warm temperatures several degrees for coast and
valley areas with highs well into the 70s and possibly lower 80s
by Thursday. And very low humidities as well.

The northeast gradients are expected to relax towards the end of
the week but models hang on to a strong northerly gradient through
the week. Temperatures will be warming in all areas with highs
10-15 degrees above normal. No rain in sight through at least the
middle of January so fire weather concerns will remain, especially
during periods of dry offshore flow.

&&

.AVIATION...29/0000Z.

At 2350Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was at 1900 ft with a temperature of 19 degrees
Celsius.

Overall for 00Z TAF package, high confidence in desert TAFs, but
only moderate confidence in coastal/valley TAFs. Lower confidence
for coastal/valley sites due to uncertainties with the marine
layer stratus/fog. Timing of flight category changes through
period could be +/- 3 hours of current forecasts with only
moderate confidence in flight categories. Based on latest
guidance, trending coastal/valley vsbys down tonight, with
increased risk of LIFR/VLIFR vsbys.

KLAX...High confidence that cigs will remain through Sunday
morning, however only moderate confidence in flight categories,
with timing of flight category changes being +/- 3 hours of
current forecast. There is a 30% chance of LIFR cigs/vsbys
08Z-15Z, with a 10% chance of VLIFR conditions. No significant
easterly wind component is expected.

KBUR...Moderate confidence in 00Z TAF. Timing of flight category
changes could be +/- 3 hours of current forecast. There is a
30% chance of VLIFR conditions 08Z-15Z.

&&

.MARINE...28/1219 PM.

For the Outer Waters, moderate to high confidence in current
forecast. Tonight through Monday night, high confidence in
combination of Small Craft Advisory (SCA) level winds and seas
with a 20% chance of Gale force winds Sunday night. For Tuesday,
there is a 50-60% chance that SCA level winds and seas will
continue. For Wednesday through Thursday, high confidence in winds
and seas dropping below SCA levels.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. Tonight through Monday, high
confidence in SCA level seas with a 30-40% chance of SCA level
winds in the afternoon and evening hours. For Monday night through
Thursday, 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. Tonight through Monday, there is a
60-70% chance of SCA level winds across the western half of the
Santa Barbara Channel with high confidence in winds and seas
remaining below SCA levels elsewhere. For Tuesday through
Thursday, there is a 30-50% chance of SCA level northeast winds
from Ventura south to Santa Monica in the late night and morning
hours with high confidence in winds and seas remaining below SCA
levels elsewhere through this period.

&&

.BEACHES...28/1219 PM.

A series of large and long period west to northwest swells will
bring high surf to the west-facing beaches of the Central Coast
(10 to 15 ft, local to 18 ft) and the Ventura County (6 to 10 ft)
and Los Angeles County (5 to 8 ft) beaches for much of the
weekend, then dropping to low end high surf on Monday. Above
normal surf is also expected on west-facing beaches of the south
Santa Barbara County coast through Sun evening.

Nuisance coastal flooding may continue to affect beaches on the
Central Coast and the Ventura and L.A. County Coast around the
time of the early morning high tides thru the weekend. Please
reference our SRF and CFW products for details.

&&

.FIRE WEATHER...28/131 PM.

***FIRE WEATHER WATCH REMAINS IN EFFECT FROM TUESDAY MORNING
 THROUGH THURSDAY EVENING FOR GUSTY SANTA ANA WINDS AND LOW
 RELATIVE HUMIDITY FOR MUCH OF CENTRAL/WEST-CENTRAL/SOUTHWEST LOS
 ANGELES COUNTY AND CENTRAL/EAST-CENTRAL/SOUTHERN VENTURA
 COUNTY***

For this weekend, north-wind-prone locations could experience elevated
to brief critical fire-weather conditions from the Santa Barbara County
mountains to the high terrain of northwest Los Angeles County
surrounding the Interstate-5 corridor. Locally enhanced sundowner
winds will focus such potential over the Santa Ynez Range. However,
humidities will remain elevated in most areas while the strong-
wind risk remains localized, precluding fire-weather headlines
through this weekend.

The weather pattern next week is expected to become favorable for
elevated to critical fire-weather conditions across Santa Ana wind-prone
areas of Los Angeles and Ventura Counties, as well as portions of Santa
Barbara County prone to north-wind enhancements. Next week, an upper-
level ridge is forecast to gradually build along the Pacific coast to
the west of a large upper trough encompassing much of the central and
eastern states. Correspondingly, surface high pressure strengthening
over the Great Basin will facilitate increasing offshore flow amid
slight to moderate upper support, which will combine with unseasonably
warm temperatures assisted by the building upper ridge to produce the
increased fire-weather risk. LAX-Bakersfield offshore gradients are
currently forecast to reach 5-7 mb starting Monday, with LAX-Daggett
offshore gradients reaching 4-5 mb starting Tuesday. Given the enhanced
northerly pressure gradients, wind directions could be 10-20 degrees
more northerly than easterly for this event compared to other November
and December 2024 events, especially early on for this next event.

The greatest potential for critical fire-weather conditions will
include areas prone to a moderate Santa Ana wind event, for Tuesday
through next Thursday. This includes much of Central/West-
Central/Southwest Los Angeles County and Central/East-Central/Southern
Ventura County. Strengthening consensus among weather-model solutions
regarding the pattern favoring critical fire-weather conditions has
warranted the issuance of the Fire Weather Watch.

Regarding alternate scenarios, there is a 60% chance for fire-weather
headlines to be expanded to include the eastern San Gabriels, northwest
Los Angeles County Interstate-5 corridor, and northern Ventura County
mountains. In addition, the enhanced northerly gradients may tend to
expand the fire-weather risk to the east of areas more typically prone
to a moderate Santa Ana wind event, to also include areas from Hollywood
to Beverly Hills and Santa Monica -- Confidence: lower chance at 40%
for fire-weather headlines. Elevated to brief critical fire-weather
conditions will also be a concern farther west across the San
Luis Obispo County and Santa Barbara County mountains especially
including the Santa Ynez range when northerly pressure gradients
are strongest on Monday and Tuesday, though humidities will likely
remain elevated -- Confidence: even smaller but non-zero chance
at 20% for fire-weather headlines.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Dense Fog Advisory in effect until 9 AM PST Sunday for zones
      340-341-346>348. (See LAXNPWLOX).
     High Surf Advisory in effect until 3 AM PST Tuesday for zones
      340-346. (See LAXCFWLOX).
     Wind Advisory remains in effect until 3 AM PST Sunday for
      zones 349-351-378. (See LAXNPWLOX).
     Beach Hazards Statement in effect through Sunday evening for
      zones 349-350. (See LAXCFWLOX).
     High Surf Advisory in effect until 9 PM PST Monday for zone
      354. (See LAXCFWLOX).
     High Surf Advisory in effect until 3 AM PST Monday for zones
      362-366. (See LAXCFWLOX).
     Fire Weather Watch in effect from Tuesday morning through
      Thursday evening for zones
      288-354-355-358-362-369>372-374>376-379. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 3 PM PST Monday for
      zones 645-650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Tuesday for
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/MW
AVIATION...Gomberg
MARINE...RAT
BEACHES...RAT
FIRE...Cohen
SYNOPSIS...MW

weather.gov/losangeles

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