Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 261008
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
308 AM PDT Wed Jul 26 2017

.SYNOPSIS...
Dry southwest flow aloft and building high pressure will gradually
warm temperatures this week to a few degrees above normal.
Overnight and morning low clouds will continue along the coast.

&&

.SHORT TERM...(TDY-FRI)

The marine layer is near 1300 feet deep and there are weak onshore
gradients both to the north and south. There are...however...
offshore trends both from the north and the east. These offshore
trends and the total lack of an eddy have really slowed the
stratus formation this morning and even by dawn do not think that
all of the coasts will be covered and there will only be a few
clouds in the SAn Gabriel Vly and the Santa Ynez Vly. The large
upper high that is dominating the SW will expand into SRN CA today
and this along with the reduced low cloud coverage and the
offshore trends will bring 2 to 3 degrees of warming to the area.
This warm up will bring max temps to normal across the majority of
the area. There is no monsoon push and there will only be some
cumulus build ups over the Eastern LA mtns.

Thursday will be much like today. The high will expand just a
little more. Hgts will reach 591 DM. Max temps will rise 1 or 2
degrees and max temps will be slightly above normal.

Friday will be the warmest day of the next 7...but not by much.
Look for another degree of warming. There will be a smattering of
triple digit heat in the desert and warmest mtn locations but
since we are in the warmest part of the year max temps will really
only be 2 to 4 degrees above normal and even less than that
across the coastal areas. There will still be morning low clouds
but they will be gone by mid morning.

.LONG TERM...(SAT-TUE)

Both the 00Z and 06Z runs of the GFS swing hurricane Hillary
northward weaken it dramatically and then run the remnants over
SRN CA Monday night or Tuesday. This probably will not happen as
the GFS ensembles greatly favor a westerly track. The EC has
consistently favored the westerly track as well. This westerly
track is the one used for this forecast. But will monitor it
because stranger things have happened.

Not much action for the weekend. A little trof moves into the PAC
NW and this shifts the upper high a little to the east which will
reduce the hgts and increase the marine layer. Both of these
factors will knock 1 to 3 degrees off of the max temps compared to
Fridays readings.

On Sunday hgts rebound slightly and some non coastal areas will
see 1 or 2 degrees of warming. There is a slight chc that some
monsoon moisture or tropical moisture may make it into the area.
There is a 20 percent chc of a mtn or desert TSTM in LA county to
cover this possibility.

Low confidence in the Monday and Tuesday forecast. It all depends
on what happens to Hillary and/of the remnant moisture. For now
just a have pretty standard summer forecast in place with normal
temps...morning clouds along the coast and a slight chc of mtn and
desert TSTMs during the afternoon and early evening.

&&

.AVIATION...

26/1000Z

At 1000Z, the marine inversion at KLAX was based at 1500 feet. The
top of the inversion was 3700 feet with a temperature of 22
degrees Celsius.

Overall, moderate confidence in 12Z TAF package. Stratus slowly
developing this morning, but should impact most coastal TAF sites
by sunrise (although KSBA could remain clear). Once stratus
dissipates by late morning, VFR conditions are anticipated for all
sites this afternoon. For tonight, high confidence in return of
stratus to coastal sites, but low confidence in timing and flight
category.

KLAX...moderate confidence in 12Z TAF. Stratus dissipation could
be anytime between 1630Z and 1900Z. For tonight, high confidence
in return of stratus, but low confidence in timing (could be +/- 4
hours of current 08Z forecast).

KBUR...high confidence in 12Z TAF. There is a 15% chance of IFR
conditions 12Z-16Z.

&&

.MARINE...

26/130 AM

For the Outer Waters, good confidence in current forecast. Winds
and seas will remain below Small Craft Advisory (SCA) levels
through Thursday night. On Friday and Saturday, there is a chance
of SCA level winds across PZZ670/673. Winds should decrease below
SCA levels across all the Outer Waters on Sunday.

For the Inner Waters, good confidence in current forecast. For all
the waters, winds and seas are expected to remain below SCA levels
through Sunday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect from Friday morning through
      Tuesday evening for zones 40-41-87. (See LAXCFWLOX).
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK...(FRI-TUE)
A significant surf event could develop late Thursday as swells
from Hurricane Hilary arrive at the Southern California beaches.
High surf and strong rip currents will occur from Friday through
Sunday.

&&

$$

PUBLIC...Rorke
AVIATION...Thompson
MARINE...Thompson
SYNOPSIS...Smith

weather.gov/losangeles



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