Wind Advisory 72, NWS Los Angeles, CA

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1114 AM PDT Sun Jul 30 2023

.SYNOPSIS...30/209 AM.

Well above normal temperatures will continue today with some
added humidity as well. A cooling trend will start Monday and
continue into Wednesday. Increasing monsoon moisture along with a
weak upper level disturbance will increase the chances for
showers and thunderstorms in eastern and southern Los Angeles
County early next week.

&&

.SHORT TERM (TDY-TUE)...30/1011 AM.

***UPDATE***

The current forecast seems on track in terms of the expected
cooling trend over the next 24 hours and beyond. The Heat Advisory
remains in effect until 8 pm this evening for highs to around 102
in the lower mountains and about 105 in the valleys.

The SBA-SMX pressure gradient goes to -3.6 mb this evening which
should be good enough to support wind gusts to 45 mph below passes
and canyons in western portions of the Santa Barbara County south
coast. A Wind advisory will be issued later today.

South to southwest flow aloft continues across southwest
California with some mid and upper level moisture and instability.
The best moisture and instability is restricted to points south
and east of the forecast area, other than a sliver of elevated
moisture and instability supporting the silent pops over the
eastern San Gabriel Mountains.

***From Previous Discussion***

The marine layer is only 800 ft deep. There is weak onshore flow
to the east and actual offshore flow (~2 MB) from the north.
Marine layer stratus has been slow to develop and currently is
confined to portions of the Central Coast and Srn L.A. county.
Mdls fcst that the low clouds will gather steam and make their way
to VTA county by daybreak but this is not a slam dunk by any
means. The offshore flow from the north and weaker onshore flow to
the east will combine with 593 dam hgts to make for another very
warm day. In fact many areas will see 2 to 5 degrees of warming.
Max temps will end up 5 to 10 degrees above normal and heat
advisories were wisely xtnd to cover today.

There will be an increase in monsoon moisture tonight from the
south. There is some instability as well. But it looks like the
real instability and lift will be further south over SAN county so
for now will not put them in the fcst but there is a non zero
threat. Otherwise look for enough mid level clouds to call skies
partly cloudy and another evening of slow to form and sparse
coverage from the marine layer.

PWATs increase to about 1.6 inches on Monday. The vorticity and
instability creep further north and a 20 percent chc of TSTMs
will develop over srn and eastern LA county. Otherwise the
increased cloud cover, lower hgts and slightly increased onshore
flow will all conspire to lower max temps by 3 to 6 degrees which
will eliminate the need for heat products (there is a slight chc
(20 percent) that the Cuyama Vly will need one more day of heat
advisories.

Look for more cooling (esp inland) on Tuesday as the high pulls
away and onshore flow increases. Most max temps will actually come
in a few degrees under normals. There will be less moisture
available along with less lift and instability but just enough
remains to warrant a 15 percent chc of TSTMs over the eastern San
Gabriels in the afternoon.

.LONG TERM (WED-SAT)...30/317 AM.

Deterministic and ensemble means have not changed much and there
is good confidence that Wed and Thu will be fairly dull days. The
upper high will shift to over TX and hgts will fall over Srn CA.
More importantly onshore flow will increase to moderate levels.
Night through morning low clouds will be more extensive and may
make it into some of the lower vlys. Max temps will cool another 2
to 3 degrees Wed and then change little on

Not the best agreement between the deterministic mdls and the
ensembles are showing more spread than usual for the late week and
weekend forecast. Good confidence that there will be a warming
trend but less so on how much. The EC is much warmer with higher
hgts and offshore flow while the GFS has slightly lower hgts and
much stronger onshore flow. Ensembles mostly follow their parent
mdl. Have to watch this because the some of the EC solutions are
very warm.

&&

.AVIATION...30/1813Z.

At 1731 at KLAX, the marine layer was 1500 feet deep. The top of
the inversion was 3000 feet with a temp of 29 C.

High confidence in valley and desert TAFs.

Low confidence in coastal TAFs. There is a 30% chance of no cigs
at sites with cigs forecasted tonight. Timing of cat changes
could be off by +/- 3 hours. There is a 20% chance of a few hours
of BKN008 cigs from 12-16Z at KSBP, and a 30% chance of BKN015
cigs at KCMA from 12-16Z.

KLAX...Low confidence in TAF. Timing of clearing is likely
between 19-21Z Sun. High confidence that winds will shift to to
the west by 20-21Z Sun. There is a 40% chance of similar
southeast winds tomorrow starting as early as 12Z Mon, and
lasting through 20Z Mon, with a 10% chance of southeast gusts up
to 20 kts. There is a 30% chance of no CIGS tonight.

KBUR...High confidence in CAVU TAF.

&&

.MARINE...30/1018 AM.

For the outer waters, Small Craft Advisory (SCA) winds will
continue, with a 50-60% chance of gale force wind gusts this
afternoon and evening. Then, SCA conds will likely continue
through at least mid-week. Another chance for Gale Force winds
comes around Thursday and Friday. Steep, choppy seas with short
periods are likely through the period.

For the inner waters North of Point Sal, SCA conditions are
likely (60-80% chance) each afternoon/evening through the period.
There is a 20-30% chance for Gale Force wind gusts across the
western portion this afternoon and evening, and again Thursday and
Friday.

For the inner waters South of Point Conception, there is a 40-50%
chance of SCA level winds across the extreme western portion of
the Santa Barbara Channel this afternoon into evening. There is a
30% chance SCA level winds across the western Santa Barbara
Channel Wednesday afternoon and evening, and possibly again
Thursday and Friday. Elsewhere, good confidence in winds
remaining below SCA levels.

Patchy dense fog will affect portions of the coastal waters at
times through the weekend due to a shallow marine layer. The fog
will be most extensive during the late night through morning hours
and will reduce visibilities to less than one mile at times.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory in effect until 8 PM PDT this evening for zones
      38-88-345-348-351>353-369>374-376-378>380. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zones 670-673-676. (See LAXMWWLOX).
     Gale Warning in effect from 3 PM this afternoon to 3 AM PDT
      Monday for zones 670-673-676. (See LAXMWWLOX).

&&

PUBLIC...Sweet/Rorke
AVIATION...Schoenfeld
MARINE...Lund/Schoenfeld
SYNOPSIS...30

weather.gov/losangeles

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