Chatsworth, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

520
FXUS66 KLOX 281539
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
839 AM PDT Wed May 28 2025

.SYNOPSIS...28/144 AM.

Dramatic warming is expected late this week, with above normal
temperatures Thursday through Saturday. Heat will peak on Friday,
with highs near or above 100 degrees for the deserts and warmest
valleys. Expect low clouds and fog across the coast and some
valleys each night and morning, becoming confined to the coastal
plains Friday and Saturday.

&&

.SHORT TERM (TDY-FRI)...28/826 AM.

***UPDATE***

Extensive low cloud cover along the coasts this morning with
marine layer height about 3,000 ft. The clouds and lowering
heights with an upper-level trough have temperatures a couple of
degrees lower than yesterday in most locations, with the main
exception of mountain areas which are a couple of degrees warmer
out of the marine layer and with slightly weaker winds. No
impactful changes from the previous discussion.

***From Previous Discussion***

Today a weak low pressure system will approach the area and bring
scattered high clouds. Low clouds may also cling to the beaches
into the afternoon, especially along the Central Coast and LA
County. Little change in temperatures is expected today, with
highs a few degrees above normal across far interior locations,
and a near normal to slightly below elsewhere.

Thursday into the weekend, the low pressure system will separate
from the the steering flow and stall off the coast of Baja
California, well south of the region. Concurrently, a broad ridge
of high pressure will set up over the western United States. The
precise location of this cutoff low will have significant impacts
on high temperatures. Regardless, substantial warming is expected
Thursday and Friday. Peak 500 mb heights and light offshore winds
will make Friday the warmest day, with temperatures around 10 to
18 degrees above normal. Highs are likely to be in the mid 70s to
mid 80s at the beaches, upper 80s to mid 90s for inland coastal
plains/valleys and lower mountains, and up to around 104 for the
deserts and inland San Luis Obispo County.

Heat Advisories are very likely to be issued for Friday across
interior San Luis Obispo and Santa Barbara Counties. Some calender
day records will be in play Friday, most notably for Paso Robles
where the current daily record is 102 and the forecasted high is
right around there. South of Point Conception, there is around a
40 percent chance for Heat Advisories on Friday for some valley
locations. The magnitude of the heat south of Point Conception
will depend greatly on the location and strength of the nearby
cutoff low, which tend to be difficult to forecast. Overall
however, the entire region is expected to see a very warm spell
Thursday into the weekend.

The high pressure aloft will compress the marine layer, thus
clouds will be mostly confided to the coastal plains by Friday.
Dense fog will be possible in the shallow marine layer, including
for the coastal waters, most likely Friday night into Saturday
morning. Areas of gusty north to northwesterly winds will occur
tonight through Thursday night as the low passes by the region,
most notably for southwest Santa Barbara County and the Interstate
5 Corridor.

.LONG TERM (SAT-TUE)...28/339 AM.

Saturday 500 mb heights are expected to drop slightly and onshore
flow will increase, thus widespread cooling of around 2 to 6
degrees is likely. There is a significant spread between ensemble
members for Friday, thus a greater drop in temperatures is
possible, as well as no cooling at all for areas south of Point
Conception.

Late Saturday through Monday, the cutoff low is favored to move
in a northeast direction, crossing over land just south of the
region. This will cause 500 mb heights to fall rapidly and bring
southerly flow, moisture, and instability to the area. Currently
there is around a 10 to 20 percent chance of showers or
thunderstorms Saturday afternoon through Sunday night, focused
south of Point Conception, where PWATs may exceed 1 inch. The
greatest chance of convection will be over the mountains of LA and
Ventura Counties. Temperature will also cool each day, becoming
widespread below normal on Monday, when strong onshore flow is
expected.

By Tuesday, overall low pressure will continue as an unseasonably
strong trough is favored to drop into the region. The cooling
trend will continue, becoming 5 to 10 degrees below normal on
Tuesday, when most areas will see highs between 63 and 73 degrees.
Gusty winds are likely with this pattern, and there is a slight
chance of showers and thunderstorms for the mountains and north-
facing foothills.

&&

.AVIATION...28/1100Z.

Around 0708Z, the marine layer was 2200 feet deep at KLAX. The
top of the inversion was around 4500 feet with a temperature of
17 C.

**No major changes from previous TAF package**

Overall, moderate to high confidence in 12Z TAF Package. Most
confident in fcsts for desert terminals, and lowest for coastal
and valley sites.

Moderate chances of LIFR conditions at times for terminals north
of Point Conception through 15Z Wed. There is a moderate chance
for high-end IFR conditions for LA County terminals through 15Z
Wed. Highest uncertainty for clearing times of cigs - may prevail
through fcst pd.

KLAX...Moderate confidence in TAF. Clearing time of MVFR cigs in
afternoon may be off +/- 2 hours - with a 25% chance they persist
through end of fcst pd. There is a 10% chance of IFR cigs 008-009
through 15Z Wed. No significant east wind component expected.
***No changes from previous TAF Package.***

KBUR...Moderate confidence in TAF. There is a 10% Chance of IFR
cigs 008-009 through 15Z Wed. Arrival and departure times of cigs
may be off +/- 2 hours.

&&

.MARINE...28/1230 AM.

For the outer waters moderate to high confidence that Small Craft
Advisory (SCA) level winds will continue through late tonight,
with a lull of several hours early Wednesday morning. There is a
60-80 percent chance of SCA conditions Wednesday afternoon through
Friday. Thus, small craft advisories will need to be extended.
There is a 40% chance of GALE force winds across northern portions
of PZZ670 Wednesday evening through the overnight hours. Then,
potential (50-60% chance) for GALE force wind gusts will become
widespread across PZZ670/673 and western portions of PZZ676 on
Thursday. Conditions should be below SCA levels Friday afternoon
through Saturday, with increasing chances for SCA winds and seas
into early next week. Higher confidence in seas reaching SCA
levels.

For the nearshore waters along the Central Coast, there is a
60-80% chance of SCA level winds Wednesday afternoon/eve into the
late night hours. There may be a lull in winds Thursday morning,
before increasing to SCA levels by Thursday afternoon. Conditions
are generally expected to remain below SCA criteria through the
weekend. Potential for SCA winds and seas early next week.

For the Santa Barbara Channel, there is a 60-80% chance of SCA
level winds again Wednesday afternoon and evening. There is a
10-20% chance of SCA level wind gusts for western portions of the
channel Thu afternoon/eve. Moderate-to-high confidence in conds
remaining below SCA levels for the weekend.

For the Inner Waters off the Los Angeles and Orange County coasts,
moderate-to-high confidence in conditions remaining below SCA
levels through Sunday - except for a 30% chance of SCA level wind
gusts during the afternoon/evening hours on Wednesday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from noon today to 3 AM PDT
      Thursday for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to
      midnight PDT tonight for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Thursday for
      zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Schoenfeld/jld
AVIATION...Black
MARINE...Black
SYNOPSIS...Schoenfeld

weather.gov/losangeles

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