Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 201021

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
321 AM PDT Mon Aug 20 2018

.SYNOPSIS...19/917 PM.

Continued warm temperatures through the week with overnight and
morning low clouds and fog along the coast. The humidity level
will lessen but remain above normal into next weekend.


.SHORT TERM (TDY-WED)...20/312 AM.

Three very similar days are slated for the short term. There will
be weak onshore flow both to the north and east each day. Aloft a
positive tilted trof will xtnd from Montana to far northern CA
while an upper high slowly moves eastward from AZ to NM.

Dry SW flow aloft will set up between these two systems over

Hgts fall form 592DM today to 590DM Tue and Wed. Max temps will
dip a degree or two Tuesday as the hgts fall. Wednesday will not
see much change at all.

Max temps will be pretty close to normal while overnight lows will
remain 3 to 6 degrees above normal.

The weak onshore push will bring low clouds to most of the coasts
each night through morning and since the marine layer 1100 ft deep
there will be local stratus incursions into the lower vlys right
around or even a little after dawn.

The only winds of note will be across the western portion of the
Antelope Vly and even there the west winds will be well under
advisory criteria.

.LONG TERM (THU-SUN)...20/320 AM.

Weak ridging will build back into the state from the SE Thursday
and this will persist through the weekend. The upper level flow
will remain from the SW so there is no threat of Monsoon
transport. Hgts really do not change much and temperatures will
really not change much from day to day either. Weak onshore flow
will keep the night through morning coastal stratus pattern going
although weak Sundowners may keep the SBA south coast cloud free.

A slightly stronger sundowner might occur Friday and Saturday
nights but it does not look that strong.



At 0545Z at KLAX, the marine layer was around 1100 feet deep. The
top of the inversion was near 4200 feet with a temperature of 27
degrees Celsius.

Moderate confidence in coastal TAFs flight cat transitions could
be off by +/- 90 minutes. There is a 30 percent chc of IFR conds
at sites with MVFR cigs forecast.

Low confidence in KBUR and KVNY with a 40 percent chc of LIFR cigs

Good confidence in desert TAFS.

Low confidence in KPRB TAF with a 40 percent chc of LIFR conds

KLAX...Fairly good confidence in TAF. There is a 20 percent chc
of IFR cigs 10Z-15Z. Good confidence that any east wind component
will be under 5 kt. VFR transition should occur within 30 min of

KBUR...Low confidence in TAF from 12Z-16Z with a 40 percent chc
of no cigs...otherwise high confidence.


.MARINE...20/312 AM.

For the Outer Waters, Overall it will remain fairly quiet with NW
winds between 10 to 20 kt strongest in the afternoon and evening
hours. Strongest western portions. There will be a 20-30% chance
for SCA level gusts each late afternoon and evening for areas
between Point Conception to NW of San Nicolas Island. the next
decent chance 50% for Small Craft Advisories (SCA) should not be
until Wednesday evening between Point Conception to NW of San
Nicolas Island. Higher chance for widespread SCA level winds
beginning Thursday afternoon and continuing through late this

For the Inner Waters, conditions are expected to remain below
Small Craft Advisory levels through Thursday.

Patchy fog, possibly dense at times will continue to form during
the late night and morning hours, especially north of Point
Conception through at least Wednesday.





Gusty Sundowner winds and elevated fire weather conditions are
possible for late this week.



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