Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 301145
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
445 AM PDT MON MAY 30 2016

.SYNOPSIS...

The cut-off low pressure system over southern California will
support the slight chance of thunderstorms this afternoon and
early evening across the mountains and Antelope Valley. High
pressure aloft will build into the area by the middle of next
week, supporting much warmer conditions that may persist into next
weekend.

&&

.SHORT TERM...(TDY-WED)

Marine layer at KLAX is near 3000 feet and capped by a strong
inversion that will only become stronger today as hgts increase.
At the sfc there is moderate onshore flow both to the east and
north. What this means that the coasts and vlys will be covered
with stratus at dawn (LA oddly is slow to fill in this morning)
and that it will be another day of slow clearing to the beaches.
The marine layer will keep the coasts and to a lesser degree the
vlys cool again but there will be nice bump up in max temps across
the interior.

The ridge will continue to build on Tuesday. The 582 dm hgts
moving into the area will squash the marine layer down and there
will less vly penetration. The squashing of the marine layer hgt
and the warming aloft will really put a strong inversion cap on
the marine layer and this will allow the low clouds to stay over
the beaches. Not much change in the coastal temps but the vlys
will have a big warm up and the there will be further warming in
the interior as well.

Wed and Thu will be dominated by ridging with the 585 DM ridge
axis sitting over the state. There will only be a few clouds in
the lower vlys as the marine layer will be smooshed below 1000
feet. There will still be low clouds during the night through
morning hours across the coasts. There will only be a slight
warming trend across the coastal sections and maybe no warming at
the beaches. It will be a different story in the vlys where max
temps will jump into the mid 80s Wed and then the lower to mid 90s
on Thu. Thursdays max temps will be 8 to 12 degrees above normal.
There will be upper 90 degree readings in the interior of SLO
county and perhaps a few triple digit max temps in the Antelope
Vly.

.LONG TERM...(THU-SUN)

Thursday looks to be the warmest day of the week for many areas as
thickness values peak. Warmest valleys expected to climb to around
90 degrees, with Antelope Valley climbing to around 100 degrees.
A shallow marine layer will continue to keep coastal low clouds
and fog. Friday through Sunday, 12z GFS and ECMWF models showing
another cutoff low developing off the Southern California coast,
with cross sections showing a good surge of mid and upper level
clouds. With this type of pattern, not out of the question that
we could see some showers or mountain tstms develop across the
forecast area sometime during this period, but probability at this
time is still around 10 percent.

&&

.AVIATION...30/12Z...

At 08Z at KLAX... the inversion was about 1850 feet deep. The top
was near 4800 feet with a temperature of eighteen degrees Celsius.

OVERALL... Moderate to high confidence in the 12Z TAFS. The
slightly reduced confidence is due to the general uncertainty in
marine incursion behavior and because the category changes and
clearing times may be off by +/- 2 hours. Some locales may not
fully clear prior to the marine incursion returning this evening.
Otherwise and elsewhere VFR conditions are expected.

KLAX... Moderate to high confidence in the 12Z TAF. The slightly
reduced confidence is due to the general uncertainty in marine
incursion behavior and because the category changes and clearing
times may be off by +/- 2 hours. There is a fifteen percent chance
that MVFR conditions will not clear today.

KBUR... moderate to high confidence in the 12Z TAF. The slightly
reduced confidence is due to the general uncertainty in marine
incursion behavior and because the category changes and clearing
times may be off by +/- 2 hours. There is a ten percent chance
that MVFR conditions will not clear today.

&&

.MARINE...30/230 AM...

Conditions will likely remain below advisory levels through at
least Friday. The northwest swell across the coastal waters will
diminish through the middle of the week. A long period south swell
is expected to reach the coastal waters by Tuesday then peak on
Wednesday and Thursday before gradually diminishing. The swells
will likely remain below advisory criteria but there will be
extra surging and currents along exposed south facing shores.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&
$$

PUBLIC...Rorke
AVIATION...KJ
MARINE...KJ
SYNOPSIS...CK

weather.gov/losangeles



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