Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 311640
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
940 AM PDT TUE MAY 31 2016

.SYNOPSIS...

Onshore flow at the coast and valleys will continue the marine layer
into midweek...and should cause clouds to linger at the beaches into
next week. A high system will build in this week for a decrease in
clouds and a warming trend with Friday and Saturday the hottest. A
low will arrive on Sunday to drop temperatures...going below normal
by Monday with increase in cloud coverage.
&&

.SHORT TERM...(TDY-THU)

Strengthening high pressure aloft will shrink the marine lyr and
warm temperatures signficantly across inland areas through the
week. Coastal areas will continue to see night and morning low
clouds/fog each day, however the inland extent will lessen each
day as the high builds and the air mass aloft warms. Forecast
soundings overnight show the marine lyr shrinking anywhere from
500-800 ft tonight. While that still likely brings clouds into the
valleys tonight the ceilings will be much lower and there likely
will be some dense fog as well. Not seeing too much decrease in
onshore flow through the week so the temperature contrast from
coast to valleys will be increasing through the week as well. And
some beaches will have a tough time clearing out the next couple
days at least. Forecast highs look on track through Thu, warming
up the low to mid 90s for the coastal valleys and 100+ for the
Antelope Valley and interior SLO. Coastal areas expected to remain
in the 60s and 70s.

***From previous discussion***

.LONG TERM...(FRI-MON)

For the extended, 00Z models continue to exhibit good synoptic
agreement. At upper levels, ridge will peak in strength on Friday
then will weaken and move eastward as an upper low moves
toward/inland over the area Saturday through Monday. Near the
surface, onshore flow will gradually strengthen through the
weekend.

Forecast-wise, Friday is expected to be the warmest day with ridge
peaking in strength (with most coastal valleys in the 90s). For
Saturday through Monday, a noticeable cooling trend is anticipated
as well as an increase in marine layer stratus coverage as the
upper low swings through the area. Looking at all moisture progs
this upper low looks to be very moisture starved. However, given
the time of year, this low`s potential cannot be discounted as it
will bring some increase in instability. So, there is a non-zero
chance of showers/thunderstorms over the mountains Saturday/Sunday
but not high enough to warrant any mention in the official
forecast. This feature will need to be watched as we get closer to
the weekend.

&&

.AVIATION...31/12Z...

AT 08Z AT KLAX... THE INVERSION WAS ABOUT 3450 FEET DEEP. THE TOP
OF THE MARINE INVERSION WAS NEAR 4800 FEET WITH A TEMPERATURE OF
22 DEGREES CELSIUS.

OVERALL... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAFS. THE
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. CIGS MOSTLY LIFR/IFR
OVERNIGHT NORTH OF POINT CONCEPTION AND MOSTLY MVFR TO THE SOUTH.
ONSHORE GRADIENTS ARE TRENDING WEAKER OVER THE NEXT 24 HOURS SO
THERE IS A 40 PERCENT CHANCE THAT CIGS COULD SCOUR OUT EARLY WITH
SCATTERED STRATUS LINGERING ACROSS SOME COASTAL AREAS. OTHERWISE
AND ELSEWHERE VFR CONDITIONS ARE EXPECTED.

KLAX... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THE 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. CIGS MOSTLY MVFR WITH PERIODS DIPPING DOWN
TO IFR. ONSHORE GRADIENTS ARE TRENDING WEAKER OVER THE NEXT 24
HOURS SO THERE IS A 30 PERCENT CHANCE THAT CIGS COULD SCOUR OUT
EARLY TO SCATTERED STRATUS.

KBUR... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THE REDUCED
CONFIDENCE IS DUE TO THE GENERAL UNCERTAINTY IN MARINE INCURSION
BEHAVIOR. ONSHORE GRADIENTS ARE TRENDING WEAKER OVER THE NEXT 24
HOURS SO THERE IS A 40 PERCENT CHANCE THAT CIGS COULD SCOUR OUT
EARLY TO SCATTERED STRATUS.

&&

.MARINE...31/900 AM...

Small Craft Advisories have been allowed to expire this morning
and, although there is a 40 percent chance of advisory winds
returning late this afternoon into this evening, the winds have
been forecasted just below Small Craft Advisory criteria for now.
The winds should continue below SCA criteria for the rest of
the week. Swell will also remain below SCA criteria. There will be
some patchy fog at times across the coastal waters, especially
Wednesday and Thursday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect from Wednesday morning
      through Thursday evening For zones 40-41-87. (See LAXCFWLOX).
PZ...NONE.

&&

$$

PUBLIC...MW/RAT
AVIATION...KJ
MARINE...Sweet
SYNOPSIS...Seto

weather.gov/losangeles


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