Wildfire in California, August 1 to 9, 2020

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
347 PM PDT Sat Aug 1 2020

Updated Fire Weather section

.SYNOPSIS...01/212 PM.

Temperatures will remain above normal through Monday with minimal
marine layer clouds and fog before a cooling trend begins
Tuesday. Locally gusty Sundowner winds expected in Santa Barbara
County through Tuesday night. Weakening high pressure will drop
temperatures below normal for the latter half of the week and low
clouds and fog will push well into the valleys each night.

&&

.SHORT TERM (TDY-TUE)...01/158 PM.

Overall a very similar day today as yesterday with the primary
exception being the Central Coast where temps were up 4-8 degrees
on average and as much as 15 degrees in the hills above the marine
inversion. Farther south coastal areas were slightly warmer as
well due to a little southeast eddy flow which creates a little
downsloping effect while that same eddy resulted in 3-6 degrees of
cooling on average for the LA/Ventura valleys.

High pressure remains locked in across the area and won't likely
weaken much until Tuesday. However, the westerly onshore flow
will be increasing which will bring some cooling to LA/Ventura
Counties Sunday. Not quite as much northerly flow expected tonight
so Sundowners will be weaker than last night. Minimal marine layer
again tonight but what there is will likely be dense, possibly
impacting some coastal airports like LAX/LGB.

Monday will be interesting because the northerly flow increases
again and models show a slight increase in 950mb temps along with
a drop in humidities. So we're likely to see a decent bump in
temperatures along the Central Coast and srn SB County as well as
stronger Sundowners that may reach low end advisory levels.
Meanwhile for the Antelope Valley the westerly onshore flow will
continue to increase and will see increasing westerly winds while
temps remain above 100 and humidities drop to as low as 2-3%. So
there will be some fire weather concerns again for several areas
Monday, possibly some brief critical conditions for a few hours in
srn SB County and the AV. Marine layer clouds will remain minimal
again Monday night, mostly northwest SB County and srn LA County.

With the high aloft weakening Tuesday and a trough approaching
from the west the cooling trend should begin in earnest with highs
dropping 5-10 degrees from Monday's levels which would bring them
very close to normal levels. Another round of Sundowners expected
for srn SB County Tuesday evening, likely stronger than Monday
night as models now showing northerly gradients in excess of 4mb.

.LONG TERM (WED-SAT)...01/204 PM.

Cooling trend to continue right on through the end of the week,
though leveling off Thu/Fri at around 4-8 degrees below normal
and with marine layer clouds pushing well into the valleys each
night, especially Thu/Fri. Wednesday morning the Sundowners in SB
County may limit low cloud coverage but northerly gradients will
weaken the rest of the week and allow clouds to spread to all
coast/valleys. May not be the best beach week as clouds will
likely be very slow to clear, especially the latter half of the
week. Gusty winds expected in the AV each afternoon.

&&

.AVIATION...01/1800Z.

At 1750Z, the marine inversion at KLAX was based at 500 feet. The
top of the inversion was 2100 feet with a temperature of 32
degrees Celsius.

Overall, moderate to high confidence in 18Z TAF package. For the
Central Coast, high confidence in LIFR/VLIFR conditions for
KSMX/KSBP overnight into Sunday morning. High confidence in VFR
conditions through TAF period for most of the TAF sites south of
Point Conception as well as KPRB, however moderate confidence
for KLAX and KLGB where there is a 40 percent chance of SCT-
BKN004-006 conditions between 12Z-16Z Sunday.

KLAX...Moderate confidence in 12Z TAF. Mostly VFR conditions
through forecast period, however there is a 40 percent chance
of sct-bkn004-006 conditions between 12z-16z Sunday. A weak
eddy circulation is expected to bring southeast winds of 4 to 7
knots on Sunday morning.

KBUR...High confidence in 18Z TAF as CAVu conditions are expected
through TAF period.

&&

.MARINE...01/214 PM.

For the Outer Waters, high confidence in current forecast. Small
Craft Advisory (SCA) level winds will likely continue through at
least Wednesday with the strongest winds during the afternoon and
evening hours. Local Gale force wind gusts to 35 knots will be
likely across zones 670/673 at times through Tuesday evening.
Additionally, seas will approach SCA levels through Wednesday.

For the Inner Waters north of Point Sal, moderate confidence in
current forecast. Today through Sunday, there is a 40% chance of
SCA level winds during the afternoon and evening hours. For Monday
through Wednesday, there is a 60-70% chance of SCA level winds
during the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate to high
confidence in current forecast. For the western half of the Santa
Barbara Channel, there is a 60% chance of SCA level winds Monday
through Wednesday during the late afternoon through overnight
hours. Elsewhere across the southern Inner Waters, high confidence
in winds and seas remaining below SCA levels today through
Tuesday with a 40% chance of SCA level winds Wednesday afternoon
(across western sections).

&&

.FIRE WEATHER...01/346 PM.

Widespread elevated fire weather conditions will continue through
Monday away from the coast. The areas of most concern include the
windiest mountain areas of all four counties, as well as the
Santa Clarita and Antelope Valleys, where brief and localized
critical conditions are expected. While conditions are NOT extreme
enough to need a Red Flag Warning, they are still elevated enough
that the public needs to use extreme caution with anything that
could start a fire.

These concerning fire weather conditions are due to a strong
upper level high pressure system which will continue to bring hot
temperatures, very low humidity, and locally gusty winds over
interior sections through Monday. Interior areas will continue to
see high temperatures of 95 to 105 degrees, similar to Saturday,
with an increased risk for deep vertical plume growth with any new
fire starts. Minimum humidity values will vary between 5 and 15.
Foothill areas will see poor overnight humidity recoveries well
below 30 percent with low temperatures as high as 80. West to
north wind gusts between 20 and 40 mph are also expected,
strongest over the interior areas each afternoon, and over the I-5
Corridor and southern Santa Barbara County each night. Coastal
valleys will remain warm, but see improved humidities with cooler
conditions compared to Saturday. Cooling and a slight increase in
humidity is expected for Tuesday through Thursday, including
improved overnight recovery. Gusty northwest winds will increase
in some areas Monday night through Wednesday however, including
southern Santa Barbara County.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory in effect until 9 PM PDT this evening for zones
      37-38-44>46-51>54-88-547. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Monday for
      zones 650-670-673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (TUE-SAT).

Gusty Sundowner winds will bring driving hazards to southern
Santa Barbara County Tuesday night.

&&

PUBLIC...MW
AVIATION...Gomberg
MARINE...Gomberg/RAT
FIRE...Kittell
SYNOPSIS...MW

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