Wildfire in California, November 1 to 2, 2019

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
836 PM PDT Thu Oct 31 2019

.SYNOPSIS...31/212 PM.

Santa Ana winds will gradually decrease in strength tonight, with
the fire danger persisting for Los Angeles and Ventura Counties
as dry conditions remain over the region. Cold temperatures
overnight are expected tonight into the weekend, especially over
the interior regions.

&&

.SHORT TERM (THU-SUN)...31/831 PM.

The strong Santa Ana wind event that we saw yesterday into this
morning is gradually diminishing tonight, however breezy offshore
wind conditions and extremely dry air will remain in place through
Friday. The LAX-Daggett gradient is currently at -5.3 mb as of
8 pm, with little change expected through Friday morning.
Northeast winds gusting between 25 and 35 mph will be common
through Friday morning across the mountains of LA/Ventura
counties, Ventura county valleys, and Santa Clarita Valley,
where Red Flag Warnings were extended until 6 pm Friday. A new
brush fire developed this evening on South Mountain in Ventura
county where gusty Santa Ana winds and single digit humidities
will persist tonight. Warming trend still underway for Friday,
with warmest coastal/valley areas expected to climb into the
lower 80s.

*** From previous discussion ***

Very cold overnight temps expected again for inland SLO County,
the Antelope Valley and wind protected areas south of Pt
Conception. Lows in the teens shattered records in the Antelope
Valley this morning and while it likely won't be quite as cold
Friday morning more records will likely be broken. Very cold as
well in the Ojai Valley, parts of the Central Coast and srn SB
County. Morning temps will warm a few degrees as onshore flow
returns over the weekend.

.LONG TERM (MON-THU)...31/210 PM.

A much quieter week next week with a couple little troughs coming
through but no precipitation. Gradients will vary from light to
moderate onshore and we likely will see some marine layer clouds
returning to most coastal areas at some point. Otherwise, daytime
temps will be within a few degrees of normal. High pressure
building in aloft later next week should lead to some warming by
Thursday. Overnight lows will be seasonably cool but not as cold
as it's been this week.

&&

.AVIATION...01/0033Z.

At 0010Z at KLAX, there was no marine inversion.

High confidence in 00Z TAFs with CAVU conds thru the period.
Offshore winds will continue to diminish tonight into Friday
morning with a more established sea breeze expected across coastal
areas Friday afternoon.Winds will be strongest thru and below
passes and canyons in the mountains and valleys, with LLWS and mdt
UDDF at times.

KLAX...High confidence in the 00Z TAF with CAVU conds thru the
pd.

KBUR...High confidence in the 00Z TAF with CAVU conds thru the
pd.

&&

.MARINE...31/826 PM.

High confidence in the current forecast. There is a 20% chance of
localized Small Craft Advisory (SCA) level northeast wind gusts
for the nearshore waters north of Morro Bay at times late tonight
into Friday morning. Otherwise, winds and seas will likely remain
below SCA levels for all coastal waters tonight through Tue.

&&

.FIRE WEATHER...31/834 PM.

Santa Ana winds continue will continue to diminish gradually
tonight into Friday, with wind gusts generally ranging between 25
and 35 mph across the mountains of Los Angeles and Ventura
counties, as well as the Santa Clarita Valley and Ventura
County Valleys. Very dry air will persist through the rest of
the week, with single digit minimums common (as low as 2 to 5 percent)
and poor overnight recoveries. As a result, the Red Flag Warnings are
in effect through 6 pm Friday for the above mentioned  areas, while
the other Red Flag Warnings were allowed to expire. Use extra
caution with any potential ignition sources, and residents in high
fire risk areas should be ready and set to evacuate if emergency
officials say so.

Elsewhere, the combination of gusty north winds with relative
humidities just above critical levels will bring elevated fire danger
to the western portion of the Santa Barbara south coast for at least
several hours this evening. The northern sections of the San Luis
Obispo County coast will also experience elevated fire danger Friday
morning due to gusty northeast winds and near or just above critical
relative humidity values.

Very dry conditions with long durations of single digit humidities will
persist across much of the area beyond Friday and into Saturday,
with continued dry conditions across interior areas Sunday into
Monday. Interior areas will see little to no humidity recoveries both
Friday night and in some areas Saturday night as well. Breezy
offshore conditions will remain during the late night and early
morning hours with gusts generally in the 20 to 30 mph range across
the mountains and wind prone valleys. Areas of elevated to brief
critical fire danger are thus still possible Saturday into Sunday,
and possibly Monday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory in effect from 2 AM to 9 AM PDT Friday for
      zones 34>36. (See LAXNPWLOX).
     Hard Freeze Warning in effect until 9 AM PDT Friday for zones
      37-59. (See LAXNPWLOX).
     Freeze Warning in effect until 9 AM PDT Friday for zone 38. (See LAXNPWLOX).
     Freeze Warning in effect from 2 AM to 9 AM PDT Friday for
      zone 44. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PDT Friday for zones
      244-245-253-254-288. (See LAXRFWLOX).
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK (SUN-THU).

No significant hazards expected.

&&

PUBLIC...Gomberg/MW
AVIATION...Gomberg
MARINE...Sirard/Stewart
FIRE...Gomberg/Jackson
SYNOPSIS...Phillips/Stewart

weather.gov/losangeles