Lancaster, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

171
FXUS66 KLOX 220517
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1017 PM PDT Wed May 21 2025

.SYNOPSIS...21/110 PM.

A cooling trend will begin Thursday with highs falling below
normal Friday and Saturday. A return of night and morning low
clouds and fog is expected for coast and some valleys as well.
Breezy and dry conditions focused across the interior will lead to
heightened fire weather concerns.

&&

.SHORT TERM (WED-SAT)...21/812 PM.

***UPDATE***

Latest satellite and surface observations indicate clear skies for
most areas except for some stratus/dense fog between Catalina
Island and the LA coast. Current sounding data indicates marine
inversion remains very shallow (around 500 feet deep). As for
winds, west to northwest winds, gusting 25-40 MPH, are observed
across the Antelope Valley and the Santa Ynez range.

Forecast-wise for the immediate short term, main "concern" will be
the extent of the marine layer stratus/fog. Overnight, high
resolution models indicate an eddy circulation will develop over
the bight. With a shallow, but strong inversion, in place, stratus
and fog should become more widespread across the coastal plain,
south of Point Conception. Looking at the HREF cloud forecast,
stratus will likely creep northward up to around the Carpinteria
area late tonight. The inversion should not deepen appreciably
overnight, so dense fog will continue to be an issues. Still too
much uncertainty in overnight coverage to issue any advisories
this evening. However, the night shift will need to monitor the
situation.

Other than the marine layer stratus/fog, no significant weather
issues are expected overnight. So, current forecast has a good
handle on the immediate short term and no big changes are
anticipated.

***From Previous Discussion***

The heat advisory in the valleys is limping along as the air mass
ended up not being as warm as models had originally predicted and
light offshore flow didn`t materialize either. Highs in the lower
to mid 90s in the warmer valleys are 8-12 degrees above normal
but not really worthy of heat advisories, especially when
factoring overnight lows in the 50s. Will leave it up for this
afternoon but it will end at 5pm with no heat hazards for
tomorrow.

Dense fog is still lingering this afternoon in the Santa Monica
Bay down to around Catalina Island. Expect that will continue
overnight and possibly spread up the coast towards Ventura and
Santa Barbara early Thursday.

A weak trough moving into the Pac NW Thu and a stronger one Friday
and Saturday will bring significant cooling to the area. Just
minor cooling Thursday (3-6 degrees), then more substantial
cooling Fri/Sat on onshore flow increases as does the marine
layer depth, which should reach the valleys by the weekend if not
before. Highs are expected be below normal in most areas by
Saturday, and as early as Friday along the Central Coast.
Interior areas will notice an increase in afternoon southwest
winds as well.

.LONG TERM (SUN-WED)...21/154 PM.

No significant weather concerns Sunday through the middle of next
week. A quick little ridge pops up Sunday with a corresponding
light offshore trend so temperatures will likely jump a few
degrees most areas with earlier marine layer clearing. But then
quickly returning to a trough pattern Monday through Wednesday
with slightly cooler temperatures. Most days will feature at
least some marine layer clouds across the coast and some valleys
during the the night and morning hours. Highs in most areas will
be within 2-4 degrees of normal.

&&

.AVIATION...22/0214Z.

Around 00Z, the marine layer was around 300 feet deep at KLAX.
The top of the inversion was 1700 feet with a temperature near 25
degrees Celsius.

Low confidence in coastal TAFs with a 30-60 percent chance of LIFR
to IFR conds. Best chances after 11Z with the highest probability
for the LA coast. Timing of flight category changes may be off by
3 hours.

High confidence in VFR conditions elsewhere.

KLAX...Low confidence in cigs, best chances from 10-14Z. Any
easterly wind component will very likely remain less than 7 knots.

KBUR...VFR conditions are expected through the period. No winds
impacts are expected at this time.

&&

.MARINE...21/1016 PM.

Moderate confidence in forecast with a 30-60 percent chance of
Gale conditions focused across the outer waters by Thursday
afternoon through Friday or Saturday with the highest chances
across the outer waters, especially near the western Channel
Islands to near Point Conception.

There is a 20-30 percent chance of localized Gale conditions for
western portions of PZZ645 and PZZ650 Thursday/Friday
afternoons/evenings. Otherwise, Small Craft Level conditions are
expected for PZZ645 and PZZ650, focused over western portions and
near Santa Cruz Island. However, Friday evening has the best
chance for more widespread SCA winds throughout the Santa Barbara
Channel.

Dense fog with reduced visibility is possible at times through
Thursday evening.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 3 PM Thursday to 3 AM PDT Friday
      for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Thursday for
      zone 645. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Friday for zone 670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT Thursday for
      zones 673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM Thursday to 3 AM PDT
      Saturday for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...MW/Thompson
AVIATION...Phillips
MARINE...Phillips
SYNOPSIS...MW

weather.gov/losangeles

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