Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 280332 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
830 PM PDT FRI MAR 27 2015

.SYNOPSIS...
THE UPPER LEVEL TROUGH WILL COOL TEMPERATURES SEVERAL DEGREES
THROUGH SUNDAY...YET STILL REMAIN ABOVE SEASONAL NORMALS. ANOTHER
HIGH PRESSURE SYSTEM IS EXPECTED TO BUMP TEMPERATURES A COUPLE DEGREES ON
MONDAY...AND THEN LITTLE CHANGE FOR THE REST OF NEXT WEEK.

&&

.SHORT TERM (TONIGHT-MON)...
ANOTHER VERY WARM DAY ACROSS INTERIOR SECTIONS WITH SEVERAL RECORDS
BROKEN. DOWNTOWN LOS ANGELES AND BURBANK TIED RECORDS WITH A HIGH
OF 91 DEGREES. OTHER LOCATIONS THAT BROKE RECORDS TODAY INCLUDED
LONG BEACH AIRPORT...SANDBERG...LANCASTER...PALMDALE...AND PASO
ROBLES. FOR MORE DETAILS ON THESE RECORDS...PLEASE SEE RECORD
REPORTS AT LAXRERLOX. AREAS NEAR THE COAST DID FEEL SOME COOLING
TODAY...ESPECIALLY ACROSS THE CENTRAL COAST WHERE THERE WAS STRONGER
ONSHORE FLOW AND STRATUS HUGGING ALONG THE BEACHES.

LATEST SATELLITE IMAGERY SHOWING LOW CLOUDS AND FOG BEGINNING TO
ADVANCE INLAND ACROSS THE CENTRAL COAST. AN AREA OF LOW CLOUDS AND
FOG OFF THE SAN DIEGO COUNTY IS EXPECTED TO LUNGE NORTHWARD OVERNIGHT
AND IMPACT PORTIONS OF THE LA COUNTY COAST. ACARS SOUNDING OVER THE
LA BASIN STILL SHOWING A VERY SHALLOW AND STRONG MARINE INVERSION...WITH
CURRENT MARINE LAYER DEPTH AROUND 500 FEET. THIS STRONG INVERSION
COMBINED WITH NEARLY NEUTRAL PRESSURE GRADIENTS WILL BRING THE POTENTIAL
FOR PATCHY DENSE FOG ACROSS THE LA COUNTY COAST AS WELL AS THE CENTRAL
COAST.

THE UPPER LEVEL HIGH PRESSURE SYSTEM THAT BROUGHT RECORD HEAT TO THE
SOUTHLAND THE PAST COUPLE OF DAYS IS FORECASTED TO SHIFT EASTWARD
AND WEAKEN AS AN UPSTREAM LOW PRESSURE SYSTEM APPROACHES CALIFORNIA
THIS WEEKEND. ONSHORE FLOW NEAR THE SURFACE IS EXPECTED TO INCREASE
OVER THE WEEKEND BRINGING A COOLING TREND TO THE REGION. AREAS CLOSER
TO THE COAST WILL FEEL THE MOST NOTICEABLE COOLING. IN EVENING
UPDATE...HAVE TEMPERED COOLING TREND A BIT FOR SOME OF THE INTERIOR
SECTIONS ON SATURDAY BY NUDGING UP TEMPERATURES A FEW DEGREES. ALSO...HAVE
BUMPED UP MINIMUM TEMPERATURES ACROSS SOME OF THE FOOTHILLS AND
MOUNTAIN LOCATIONS TONIGHT DUE TO THE STRONG INVERSION.

***FROM PREVIOUS DISCUSSION***

 STRATUS SHOULD STAY AWAY FROM THE CENTRAL COAST SATURDAY NIGHT DUE
TO ENOUGH OF AN OFFSHORE GRADIENT. TEMPS COOL FURTHER ON SUNDAY WITH
THE WEAK TROUGH MOVING BY EARLY. THE TROUGH MAY ALSO BRING AN
INCREASE IN HIGH CLOUDS ON SUNDAY.

ANOTHER RIDGE MOVES IN ON MONDAY FOR ANOTHER WARM UP BUT NOT AS
DRAMATIC AS WHAT WE`VE EXPERIENCED THE PAST COUPLE OF DAYS. HIGHS
PLENTY ABOVE NORMAL BUT RELATIVELY TAME.

.LONG TERM (TUE-FRI)...
MODELS STILL SHOWING FAIRLY FLAT WESTERLY ZONAL FLOW FOR THIS
PERIOD. GFS AND EC SHOW A WEAK TROUGH SLIDING THROUGH TO OUR NORTH
WHICH COULD BRING SOME WINDS TO SOME MOUNTAIN AREAS...BUT OTHERWISE
TEMPS REMAINING ABOVE NORMAL THROUGHOUT. COULD SEE A SLIGHT BUMP UP
IN TEMPERATURES ON FRIDAY SINCE THE MODELS ARE FORECASTING A WEAK
RIDGE BY THEN. AN EDDY CIRCULATION WILL BRING CHANCES OF OVERNIGHT
STRATUS TO COASTAL L.A. COUNTY EACH NIGHT AND EARLY MORNING.

&&

.AVIATION...27/2350Z.

MARINE LAYER AT LAX AT 2255Z IS 450 FEET DEEP AND THE INVERSION TOP IS
AT 1700 FEET WITH A TEMP OF 25 DEGREES C.

UPPER LEVEL RIDGE OF HIGH PRESSURE WILL GRADUALLY WEAKEN AND SHIFT
EASTWARD DURING THE NEXT 24 HOURS. PRESSURE GRADIENTS BEGINNING TO
TREND SLOWLY ONSHORE LATE THIS AFTERNOON...AND THIS TREND WILL CONTINUE
THROUGH SATURDAY. LOW CLOUDS AND FOG ALREADY SOLID ALONG THE CENTRAL
COAST...WITH A HIGH PROBABILITY OF MOVING INTO KSMX AND KSBP
TONIGHT. ALSO EXPECTED TO SEE SOME LOW CLOUDS AND FOG SPIN UP ALONG THE
LA COUNTY COAST...POTENTIALLY IMPACTING KLGB AND KLAX. DUE TO THE SHALLOW
INVERSION IN PLACE...ANY LOW CLOUDS AND FOG THAT FORM WILL LIKELY BE
IN THE LIFR CATEGORY...WITH A CHANCE OF VLIFR CONDITIONS.

KLAX...GOOD CHANCE OF LIFR CIGS/VSBYS AT KLAX LATE TONIGHT...WITH A SLIGHT
CHANCE OF BRIEF VLIFR CONDITIONS. CURRENT TAF HAS TIMING OF CIGS BETWEEN
11Z-16Z BUT COULD BE +/- 2 HOUR TIME DIFFERENCE.

KBUR...VFR CONDITIONS LIKELY THROUGH MOST OF THE PERIOD. A CHANCE OF
VSBY 6SM HZ BETWEEN 28/13Z AND 28/21Z AS INCREASED ONSHORE FLOW COULD
BRING SOME MARINE INFLUENCE.

&&

.MARINE...27/800 PM

THERE IS A GOOD CHANCE SMALL CRAFT ADVISORY CONDITIONS WILL EXIST
FROM POINT PIEDRAS BLANCAS TO POINT SAL 10-60 NM AND FROM POINT SAL
TO SAN CLEMENTE ISLAND TONIGHT THROUGH SUNDAY. THE STRONGEST
NORTHWEST WINDS WILL LIKELY OCCUR SATURDAY AFTERNOON THROUGH EARLY
SUNDAY MORNING WITH LOCAL GUSTS TO 35 KT. THERE IS A CHANCE
NORTHWEST WINDS WILL INCREASE TO GALE FORCE NEXT WEEK TUESDAY FROM
POINT PIEDRAS TO SAN NICOLAS ISLAND INCLUDING THE WEST HALF OF SANTA
BARBARA CHANNEL. A MIXED SWELL IS LIKELY THROUGH THE WEEKEND...
WEST-NORTHWEST AT 14 SECONDS...SOUTH SWELL AT 19 SECONDS AND LOCALLY
GENERATED NORTHWEST SWELL AT 8 SECONDS. THE COMBINED SEAS FROM POINT
PIEDRAS BLANCAS TO SAN CLEMENTE ISLAND WILL PEAK 10 TO 12 FEET
SATURDAY NIGHT. THE SHORTER PERIOD SEAS WILL SUBSIDE SUNDAY THROUGH
MONDAY MORNING AND IS EXPECTED TO REBUILD TUESDAY WHILE A FRESH
WEST-NORTHWEST SWELL MIXES INTO THE COASTAL WATERS TUESDAY. PATCHY
DENSE FOG...WITH VSBYS BELOW 1 NM WILL AFFECT MUCH OF THE COASTAL
WATERS THROUGH SAT MORNING.

&&

.BEACHES...A LONG PERIOD SWELL FROM THEN SOUTHERN HEMISPHERE WILL
CONTINUE THROUGH THE WEEKEND. EXPECT ELEVATED SURF AND STRONG RIP
CURRENTS AND LONGSHORE CURRENTS ON BEACHES ALONG EXPOSED SOUTH
FACING SHORES.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...GOMBERG/JACKSON
AVIATION/MARINE...GOMBERG/SIRARD
SYNOPSIS...B

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