Wildfire in California, June 15 to 19, 2020

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
158 PM PDT Mon Jun 15 2020

.SYNOPSIS...15/157 PM.

Other than some low clouds and fog across the coasts and coastal
valleys, mostly clear skies will prevail through Thursday with
temperatures near normal. Gusty winds can be expected in the
mountains and deserts. For Friday through the weekend, warmer
conditions are expected with less low clouds and fog.

&&

.SHORT TERM (TDY-THU)...15/157 PM.

Overall, 12Z models in very good synoptic agreement for the short
term period. At upper levels, broad cyclonic flow will remain over
the area through Thursday. Near the surface, onshore flow will
continue through the period with a bit of northerly offshore push
tonight.

Forecast-wise, just a typical June forecast for the area over the
next few days. Main challenge will be forecasting the extent of
the marine layer stratus each day. South of Point Conception, the
combination of cyclonic flow aloft, onshore flow and forecast eddy
circulations, stratus should become more extensive across the
coastal and valley areas each night. With onshore gradients
forecast to be rather strong in the afternoon hours, some beach
areas may see limited clearing by Wednesday/Thursday. North of
Point Conception, the stratus forecast is a bit more challenging
and confidence in development/extent of stratus/fog in rather low.
High resolution models indicate a little bit of northeasterly flow
each night (especially Tuesday night) which will likely help to
limit the extent/development of stratus. Other than any potential
stratus/fog, skies should remain mostly clear through Thursday.

As for temperatures, coastal and coastal valley areas will cool a
few degrees on Tuesday due to increased marine influence with
temperatures remaining relatively persistent Wednesday and
Thursday. For interior sections, expect several degrees of cooling
on Tuesday, but then some warming Wednesday/Thursday as
thicknesses and H5 heights increase. Overall, just very seasonable
temperatures for mid-June.

As for winds, the continued onshore flow will generate gusty
afternoon and evening winds across the mountains/deserts and
interior sections. Winds may approach advisory levels across the
Antelope Valley (especially the foothills) Tuesday afternoon, but
will let future shifts look at the potential need for any advisories.
Otherwise, there may be some locally gusty north winds tonight
and Tuesday night across the Santa Ynez Range (mainly near Refugio
and Gaviota areas), but do not anticipate any widespread advisory
level winds.

.LONG TERM (FRI-MON)...15/157 PM.

Overall, 12Z models continue to exhibit decent synoptic agreement
through the long term period. At upper levels, ridge will
gradually build over the area through the weekend (noting that the
ECMWF is stronger with the ridge by Sunday/Monday). Near the
surface, weak to moderate onshore flow is forecast to continue.

Forecast-wise, the above pattern should provide rather typical
June weather for the area. With the H5 heights building over the
area, the marine inversion should become more shallow, but
continued onshore flow will keep stratus from being totally
obliterated. So, will indicate less extensive night/morning
stratus and fog for the area each night, with stratus likely
confined to the coastal plain by Sunday/Monday. Other than this
stratus, skies are expected to remain mostly clear through the
period.

As for temperatures, expect a warming trend through the period
with less marine influence and rising thicknesses/H5 heights. If
the ECMWF verifies, temperatures will be warmer than currently
forecast for Sunday/Monday time frame.

&&

.AVIATION...15/1824Z.

At 1703Z, the marine layer depth was around 1600 feet deep at
KLAX. The top of the inversion was near 4000 feet with a
temperature around 19 degrees Celsius.

Moderate confidence for the coastal terminals, otherwise high
confidence in the remaining terminals. Less confidence exists in
timing. More confidence in flight categories.

KLAX...There is a 30 percent chance of the marine clouds arriving
plus or minus two or more hours from the forecasted time. There is
a 30 percent chance of east winds of 8 knots or more.

KBUR...There is a 30 percent chance of the marine clouds arriving
plus or minus two or more hours from the forecasted time.

&&

.MARINE...15/142 PM.

Moderate confidence in the current forecast. Higher confidence in
gales during the afternoon and evening hours farther offshore,
less confidence for the nearshore and inner waters.

For the waters northwest through southwest of the Channel Islands,
gales will likely occur at times, especially during the afternoon
and evening hours. Winds could drop below gale warning levels during
the late night and early morning hours, but will strengthen again
by the afternoon.

The lull will be most pronounced for the nearshore waters along
the Central Coast. Winds will fall below SCA levels between
Wednesday and Friday, but there is a chance of SCA level seas
lingering into Wednesday afternoon.

Inside the southern California bight, winds will be elevated and
gusty to SCA levels in the afternoon and evening hours Monday
through Tuesday, especially across the western portion of the
Santa Barbara Channel. Otherwise, conditions will be below SCA
level.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Gale Warning in effect until 3 AM PDT Wednesday for zones
      645-670-673-676. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 650. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (THU-MON).

No significant hazards expected.

&&

PUBLIC...Thompson
AVIATION...Sweet/Hall
MARINE...Sweet
SYNOPSIS...RAT

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