Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 052120
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
150 PM PDT TUE MAY 5 2015

.SYNOPSIS...

STRONG ONSHORE FLOW WILL BRING A DEEPER MARINE LAYER... FOG... AND
DRIZZLE ALONG WITH BREEZY WINDS THROUGH WEDNESDAY. A LOW PRESSURE
SYSTEM WILL ARRIVE WEDNESDAY NIGHT BRINGING A SLIGHT CHANCE OF
THUNDERSTORMS AND SHOWERS THROUGH FRIDAY. TEMPERATURES WILL REMAIN
BELOW NORMAL THIS WEEK THEN WARM TO ABOVE NORMAL BY NEXT WEEK AS
HIGH PRESSURE BUILDS IN.

&&

.SHORT TERM (TODAY-SAT)...
AS EXPECTED THE MARINE STRATUS HAS BEEN SLOW TO DIMINISH TODAY AND
SOME COASTAL AND ADJACENT INTERIOR VALLEYS WILL NOT CLEAR AT ALL.
THE ONSHORE GRADIENT WILL BE A BIT WEAKER TOMORROW BUT NOT BY MUCH
SO THIS SCENARIO WILL REPEAT AGAIN TOMORROW.  MEANWHILE THE GRADIENT
HAS ALSO RESULTED IN GUSTY WINDS ACROSS THE ANTELOPE VALLEY AND
THESE SHOULD CONTINUE INTO TOMORROW AS WELL THOUGH PERHAPS A BIT
LIGHTER DUE TO THE WEAKER GRADIENT.  THE WINDS WILL LESSEN IN THE
OVERNIGHT AND EARLY MORNING HOURS BUT KICK UP AS THE GROUND HEATS
UP.

THE LOW PRESSURE MOVING DOWN FROM THE GULF OF ALASKA REMAINS ON
TRACK TO APPROACH THE SERVICE AREA LATE ON WEDNESDAY AND MAKE ITS
PRIMARY IMPACT ON THURSDAY AND FRIDAY.  THE COLD POOL OF AIR COMING
SOUTH BEHIND THE FRONT IS SIGNIFICANTLY COLD FOR THIS TIME OF YEAR.
THOUGH THE REGION WILL HAVE COOLED CONSIDERABLY TODAY AND
TOMORROW... THE TEMPERATURE GRADIENT WILL BE STEEP AS THE FRONT
PASSES THROUGH AND STRONG INSTABILITY IS INDICATED ACROSS THE ENTIRE
SERVICE AREA AT SOMETIME DURING THE THURSDAY AND FRIDAY PERIOD.

MOISTURE REMAINS LIMITED AS THE PACIFIC FIREHOSE IS NOT EVEN CLOSE
TO THE REGION AS THE COLD AIR MOVES THROUGH.  BEING LOCATED NEXT TO
THE OCEAN WILL ENSURE THAT THE AIRMASS IS NOT BONE DRY... BUT THIS
IS NOT SETTING UP TO BE A VERY WET SYSTEM EVEN WITH A BROAD SWATH OF
THUNDERSTORM CHANCES.  A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
HAS BEEN EXTENDED TO MUCH OF THE SERVICE AREA AND TO THE COASTAL
WATERS... FOCUSED UPON NORTH OF POINT CONCEPTION AT FIRST.  AND
MARINERS SHOULD KEEP WATERSPOUTS IN MIND PRIMARILY ON THURSDAY BUT
ALSO SOUTH OF THE POINT AND IN THE BIGHT ON FRIDAY.

THE AIRMASS WILL BE COLD ENOUGH TO BRING A DUSTING OF SNOW IN THE
VENTURA AND LOS ANGELES COUNTY MOUNTAINS DOWN TO NEAR 6000 FEET ON
FRIDAY MORNING

SATURDAY WILL BRING CLEARING SKIES BUT THERE IS A POSSIBILITY OF
LINGERING SHOWERS IN THE LOS ANGELES MOUNTAINS ESPECIALLY IN THE SAN
GABRIEL MOUNTAINS.

.LONG TERM (SUN-TUE)...
WARMING TEMPERATURES ON SUNDAY AND MONDAY THEN NEAR SEASONAL
TEMPERATURES ON TUESDAY BUT PARTLY CLOUDY AS A WEAK BOUNDARY MOVES
THROUGH THE REGION.

&&

.AVIATION...05/1800Z.

AT 1707Z...THE MARINE INVERSION AT KLAX WAS BASED AROUND 4100 FEET.
THE TOP OF THE INVERSION WAS AROUND 5000 FEET WITH A TEMPERATURE OF
11 DEGREES CELSIUS.

MVFR TO VFR CONDITIONS WILL CONTINUE OVER MOST COASTAL AND VALLEY
TERMINALS THROUGH MUCH OF THE DAY. CLOUDS WILL STRUGGLE TO CLEAR BY
THE AFTERNOON AREAS WITH SOME LOCATIONS REMAINING BKN TO OVC ALL
DAY. THE MARINE LAYER IS GETTING DEEP ENOUGH TO SUGGEST A REVERSE
CLEARING TREND SO THE 18Z TAFS WILL SUGGEST SUCH A SCENARIO WITH
COASTAL TAFS CLEARING BEFORE THE VALLEYS. GUSTY ONSHORE WINDS ARE
EXPECTED FOR THE ANTELOPE VALLEY TERMINALS THIS AFTERNOON. THERE IS
A CHANCE OF LOWERING VISIBILITIES IN BLOWING DUST AND SAND BETWEEN
18Z AND 02Z.

KLAX AND KBUR...MVFR CONDITIONS WILL CONTINUE THROUGH AT LEAST 16Z.
MVFR CEILINGS WILL LIKELY LIFT INTO THE VFR CATEGORY BETWEEN 16Z AND
22Z...WITH CEILINGS BELOW 5000 FEET LINGERING UNTIL AS LATE AS 23Z
OR BEYOND.

&&

.MARINE...05/200 PM.

KEPT THE SMALL CRAFT ADVISORY FOR PZ645 PZ670 AND PZ673. FOR THE
INNER WATERS SOUTH OF POINT CONCEPTION...STRONG ONSHORE FLOW WILL
LEAD TO A PRETTY STRONG SEA BREEZE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
BEACH HAZARD STATEMENT (SEE LAXCFWLOX).

&&
$$

PUBLIC...KJ
AVIATION...SWEET
MARINE...SWEET
SYNOPSIS...DSS

WWW.WEATHER.GOV/LOSANGELES





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