128
FXUS66 KLOX 080253
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
753 PM PDT Fri Aug 7 2026
.SYNOPSIS...07/1247 PM.
Night through morning low clouds and patchy dense fog will be
common over coastal areas and the coastal valleys through the
weekend. Over the interior areas, hazardous heat will continue
through this weekend and expand into the coastal valleys, with
near to above normal temperatures around the beaches. Other than
a small chance for mountain showers during the afternoon and
evening hours through Sunday, dry conditions will prevail.
&&
.SHORT TERM (FRI-MON)...07/752 PM.
***UPDATE***
Generally fair weather covered the forecast area early this
evening. However, the Ridge Fire, which broke out near the
Grapevine area of Interstate 5 around mid afternoon has caused a
large amount of smoke in that area and and Air Quality Alert was
issued by the South Coast AQMD.
Low clouds were starting to move back into the immediate Central
Coast and edging toward the L.A. County coast early this evening.
Overnight, low clouds and fog will spread to many coastal areas
and move inland some as well. The marine inversion was near
surface-based at VBG and only around 700 ft deep at LAX, with a
warm layer around 80 deg at 4000 to 5000 ft. The rather strong
inversion is expected to help contribute to the formation of at
least patchy dense fog especially along the coast overnight.
Otherwise and elsewhere, mostly clear skies will prevail thru the
night. Warm overnight lows in the 70s will contribute to heat
stress across many interior areas as well.
Current forecast is on-track and no evening updates are
anticipated.
***From Previous Discussion***
As has been the case for the last several weeks, a large and wide
ridge of high pressure continues to remain centered over the Four
Corners region through the short term period. 500 mb heights will
increase from 593 dam to 596 dam through Sunday, bringing gradual
warming, with the heat likely peaking on Saturday. High
temperatures will be in 95 to 108 range for the interior areas
(including the lower mountains/foothills), 90 to 100 across the
coastal valleys, and 75 to 90 across the coasts/inland coasts.
Somewhat less confidence in the coastal area temperatures due to
slight variations in the onshore flow and marine layer clouds. If
the night through morning clouds become more expansive, then
temperatures across the coastal area may be on the cooler end of
the range (and vice versa). Heat Advisories and Extreme Heat
Warnings remain in effect for the interior mountains (including
the foothills) and interior valleys (such as the Antelope Valley
and Cuyama Valley). Additionally for this weekend, Heat Advisories
have been expanded toward (but generally not reaching) the
coasts, to include coastal valleys -- as pressure gradients trend
offshore (onshore gradients weakening). Even through most
immediate coastal locations are not included in these advisories,
residents will need to be mindful of the afternoon heat and take
appropriate precautions.
Monsoonal moisture will continue to move over the area through
this weekend, due to the position of the upper high over the
Desert Southwest region. This flow pattern aloft will draw
subtropical moisture across the area, mainly at levels above
around 600 mb, and precipitable water values (PWs) of 1.0 inch to
near 1.25 inches. There will be a 10-15% chance of afternoon/evening
convective showers or thunderstorms through the weekend, mainly
across the mountains of Los Angeles and Ventura Counties, and
expanding into the Santa Barbara County Mountains this weekend.
If thunderstorms do occur, there is the possibility that dry
lightning may result, and may cause fire starts, adding to the
fire weather concern.
The increase in monsoonal moisture will also increase humidities
closer to the surface, at least for the coast and near-coastal
areas. Along with the warmer sea surface temperatures, this will
tend to increase heat impacts during the daytimes and keep
overnight lows warmer than normal.
Onshore winds are expected to be gusty and persistent through the
short term, increasing during the afternoon and evening hours
across interior sections including the Antelope Valley. The
strongest onshore winds are expected to be on Sunday, based on
projected surface pressure gradients. The gusty winds across the
interior in combination with the hot and dry conditions will
produce elevated to brief critical fire weather conditions.
Low clouds and fog will continue to affect coastal areas and some
of the coastal valleys during the night to morning hours through
the short term. This pattern could be disrupted depending on the
amount of monsoonal moisture aloft, which could slow or prevent
marine layer formation. Also, some of the fog could be locally
dense as the marine layer becomes increasingly shallow through the
weekend.
The aforementioned ridge of high pressure will start to finally
weaken over the area on Monday as a series of upper level troughs
move into the Pacific Northwest down into NorCal. This will
correspond to a cooling trend for the beginning of next week.
.LONG TERM (TUE-FRI)...07/1117 AM.
500 mb heights will continue to drop to at least 592 dam through
Thursday, and maybe even lower. At the same time, onshore flow
will increase both to the north and the east becoming strongly
onshore in both directions in the afternoons. The marine layer
will respond to this and low clouds will likely begin to extend
into the valleys. Look for slower than normal clearing and some
west facing beaches may see only limited clearing each afternoon
and evening.
The combination of a deeper marine layer, stronger onshore flow,
and falling heights will bring 2 to 3 degrees of cooling each day
through Thursday. Maximum temps will approach normals on Tuesday
and then most areas will see below normal maximum temps on Wednesday
and Thursday, with valley temps in the mid 80s to lower 90s.
PWs will remain elevated through the period, however. In
combination with warmer than normal ocean temperatures off the
immediate coast, conditions will continue to feel a little
more humid than normal. It will also keep overnight lows a little
warmer than normal. The region will remain on the fringe of the
monsoonal moisture through at least Wednesday, with the elevated
moisture and increased instability keeping the low chance (10 to
15 percent) of afternoon mountain convection going. By the end of
next week, medium-range model guidance indicates the potential for
an upper low to develop off the Central California Coast, east of
which large-scale ascent and convective chances could modestly
increase next Thursday and Friday.
Additionally, the strong onshore flow to the east will produce
near advisory level wind gusts across the western Antelope Valley
and the western foothills each afternoon and evening. Gusty
sundowner winds will also be possible early next week in southern
Santa Barbara County.
&&
.AVIATION...08/0001Z.
At 2209Z at KLAX, the marine layer was 900 feet deep. The top of
the inversion was at 1800 feet with a temperature of 27 C.
High confidence in VFR TAFs for KPRB, KBUR, KVNY, KPMD & KWJF.
Low to moderate confidence in remaining TAFs after 05Z Sat.
Mid-level moisture and warm SSTs will disrupt the formation
of Marine layer. This will likely result in intermittent CIGs
especially for KLAX, KSMO, & KLGB. CIG heights accurate within
+/- 200 ft of current forecast.
KLAX...Fair confidence in TAF. Intermittent CIGs (007-010)
possible 07Z-15Z Fri. No significant east wind component expected.
KBUR...High confidence in VFR TAF. No wind issues expected.
&&
.MARINE...07/748 PM.
Winds and seas are expected to remain largely below Small Craft
Advisory (SCA) criteria across the coastal waters thru Wednesday
night. However, northwest winds could locally gust 20-25 kt around
and to the south of Point Conception each afternoon/evening thru
Saturday. Local gusts may reach or exceed 21 kt nearshore Point
Dume (Saturday evening) and across NW portions of PZZ670 (Sunday
evening).
Dense fog may affect portions of the coastal waters each night
through morning this weekend and possibly into early next week.
&&
.BEACHES...07/110 PM.
High astronomical tides are expected to affect low-lying beaches
south of Point Conception with the possibility of minor coastal
flooding starting with the evening high tide Monday and continuing
through at least Wednesday.
Predicted tide heights of up to 7.5 feet are expected between
about 8 and 10 PM each evening. These tides, combined with an
increase in a long-period southerly swell, could result in
flooding of sea water around the time of high tide over low-lying
coastal areas such as parking lots, beaches, and walkways.
Beaches most susceptible to potential minor coastal flooding
issues include those around Point Dume and near Long Beach.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning in effect until 8 PM PDT Sunday for
zones 38-377-381>383. (See LAXNPWLOX).
Heat Advisory in effect from 10 AM Saturday to 8 PM PDT
Sunday for zones
88-342-343-348-349-351-352-356>358-367>374-548. (See LAXNPWLOX).
Heat Advisory in effect until 8 PM PDT Sunday for zones
344-345-353-375-376-378>380. (See LAXNPWLOX).
PZ...NONE.
&&
$$
PUBLIC...Lund/Cohen/Sirard
AVIATION...Black
MARINE...Black
BEACHES...Sirard
SYNOPSIS...KL/Cohen
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
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