Wildfire in California, June 4 to 13, 2018

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1202 PM PDT Mon Jun 4 2018

.SYNOPSIS...04/802 AM.

There will be night through morning low clouds and fog across
coasts and coastal valleys through this week. Today will be above
normal heat for inland areas. A cooling trend is expected through
mid week as an upper level trough approaches the region. As high
pressure aloft expands over the region later in the week, warming
is expected into the weekend.

&&

.SHORT TERM (TDY-WED)...04/1143 AM.

Overall, 12Z models in good synoptic agreement through the period.
At upper levels, trough will continue to develop along the West
Coast. Near the surface, moderate to strong onshore flow will
prevail.

Forecast-wise, nothing too exciting in the short term. Main
challenge will be the marine layer stratus. With lowering H5
heights and eddy circulations indicated by latest models, expect
marine inversion to deepen over the next three days. So, stratus
and fog will push well inland each night/morning. Stratus should
clear decently each afternoon although some clouds could linger
near the beaches. Otherwise, skies should remain mostly clear
through the period with the occasional scattered high clouds
drifting overhead (due to southwesterly flow aloft).

As for temperatures, expect increasing marine influence and
lowering thicknesses/H5 heights will result in cooler
temperatures for all areas Tuesday and Wednesday. On Thursday,
thicknesses/H5 heights rebound a bit while onshore flow weakens.
So, will anticipate some slight warming most areas on Thursday.

As for winds, the onshore flow will generate typical gusty
southwesterly winds across the mountains and deserts each
afternoon and evening. Additionally, there will likely be some
locally gusty northwesterly winds across southern Santa Barbara
county.

.LONG TERM (THU-SUN)...04/1143 AM.

Overall, 12Z models continue to exhibit decent synoptic agreement
through the period. At upper levels, trough will continue along
the West Coast, varying in strength from day-to-day. Near the
surface, onshore flow will continue although it will be a bit
weaker.

Forecast-wise, Friday and Saturday will be warmer with less
extensive marine layer due to weaker onshore gradients and some
increase in H5 heights. However on Sunday and Monday, things will
reverse a bit with slightly more extensive marine influence,
resulting in slightly cooler temperatures. Essentially, just minor
day-to-day changes.

One thing will be to watch is the potential for some gusty
Sundowner winds Friday night and Saturday night. Models are
indicating some decent northerly offshore gradients (both SBA-SMX
and SBA-BFL). So, there is a decent chance of advisory-level
Sundowner winds both evenings.

&&

.AVIATION...04/1902Z.

At 1702Z, the marine layer was around 1400 feet deep at KLAX. The
top of the marine inversion was around 3300 feet with a
temperature of 25C.

The marine clouds rapidly evacuated most coastal locations yet
continues to affect a couple of coastal TAFs like KOXR and KSBA.
The marine clouds will return late this evening wth IFR/MVFR
conditions.

KLAX...Moderate confidence in the 18Z TAF. There is a 30 percent
chance of marine clouds arriving plus or minus two or more hours
from the forecasted time.

KBUR...Moderate confidence in the 18Z TAF. There is a 30 percent
chance of marine clouds arriving plus or minus two or more hours
from the forecasted time.

&&

.MARINE...04/857 AM.

Northern Outer Waters...Low to moderate confidence in current
forecast. SCA level winds are expected to increase to Gale Force
across the northern two outer waters zones (PZZ670/PZZ673) this
afternoon, and continue thru tonight. The current forecast
continues the Gale warning through Tuesday night, but the models
show weaker winds for Tuesday afternoon and Tuesday night. There
is a 40 percent chance that Gale force winds will not be needed
for Tuesday afternoon and night. Gale winds are then expected to
return for Wednesday and Wednesday night.
Across the southern outer waters zone (PZZ676), there is a 20-30%
chance that SCA level winds will reach Gale force at times tonight
through Tue night.

For the Inner Waters north of Pt Conception, moderate to high
confidence that winds will reach SCA levels this afternoon thru
late tonight, and a good chance of SCA level winds each afternoon
through late evening Tue thru Fri.

For the waters south of Pt Conception, winds and seas are expected
to remain below SCA levels thru Fri...except across far western
portions of the SBA Channel where there is a 20-30% chance of SCA
level gusts during the late afternoon/evening hours thru Thu. SCA
conds are more likely across the SBA Channel Fri afternoon.

A relatively shallow marine inversion may result in some patchy
dense fog across the coastal waters through tonight. Visibilities
less than one nautical mile are possible.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 PM PDT this afternoon
      for zones 670-673. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Wednesday for zones
      670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (WED-SUN).

Advisory level northwest winds are possible for the Central Coast
and western portions of the SBA South Coast for the middle of next
week.

&&

PUBLIC...Thompson
AVIATION...Sweet
MARINE...Sweet
SYNOPSIS...Kaplan/B

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