Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 220528 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1028 PM PDT TUE OCT 21 2014

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...

HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION WITH WEAK OFFSHORE
FLOW EXPECT THROUGH FRIDAY. THIS WILL START A MODEST WARMING TREND
BEGINNING TOMORROW THROUGH FRIDAY. AN UPPER LEVEL TROUGH THEN SLIDES
THROUGH THE AREA OVER THE WEEKEND WITH COOLER TEMPERATURES EXPECTED
AND POSSIBLY SOME LIGHT PRECIPITATION NORTH OF POINT
CONCEPTION...MAINLY ON SATURDAY.

&&

.SHORT TERM (WED-FRI)...HIGH TEMPS WERE A FEW DEGREES WARMER ACROSS
IN A FEW LOCATIONS...ESPECIALLY AROUND THE CENTRAL COAST WHERE THE
SAN LUCIA MTN OFFSHORE WINDS HELPED TO CAUSE TEMPS TO RISE TODAY.
MOST VALLEYS WERE A FEW DEGREES WARMER WHILE COASTAL AREAS SOUTH OF
POINT CONCEPTION WERE JUST ABOUT THE SAME AS YESTERDAY. LATEST
SATELLITE IMAGERY INDICATED CLEAR SKIES WITH A FEW PASSING CIRRUS
MOVING NW TO SE WITH THE BROAD UPPER NW FLOW.

FOR TONIGHT...SKIES SHOULD REMAIN MOSTLY CLEAR. FOR NOW THERE IS
SOME STRATUS IN THE FORECAST TO AFFECT THE SOUTHERN LA COUNTY COAST
AS A VERY WEAK EDDY DEVELOPS TO THE SOUTH OF OUR FORECAST AREA...BUT
WITH THIS DOMINANT NORTHERLY GRADIENT BETWEEN LAX-BFL AND SBA-SMX
WOULD THINK LOW CLOUDS WILL HAVE A TOUGH TIME DEVELOPING OVERNIGHT.

THERE WILL BE GUSTY NORTHERLY WINDS ACROSS THE LA/VTU COUNTY
MOUNTAINS TONIGHT AROUND 15 TO 30 MPH WITH GUSTS TO 40 MPH...WHILE
SOME OF THE ENERGY WILL PUSH SOUTH INTO THE SANTA CLARITA VALLEY AND
NORTHERN SAN FERNANDO VALLEY OVERNIGHT. SANTA CLARITA VALLEY SHOULD
RECEIVE GUSTS TO 30 WITH LOCAL GUSTS TO 35 MPH AT TIMES...WHILE THE
SAN FERNANDO VALLEY WILL BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
405 CORRIDOR INTO VAN NUYS. NOT ANTICIPATING ANY WIND ADVISORIES FOR
THESE LOCATIONS. A WIND ADVISORY IS IN PLACE FOR THE SANTA BARBARA
SOUTH COAST AND ALTHOUGH NW WINDS AROUND GAVIOTA HAVE NOT BEEN TOO
IMPRESSIVE...THE LATEST SBA-BFL GRADIENT WAS CLIMBING TO -5.2 MB.
THIS IS A FAVORABLE NORTH TO NORTHEAST WIND ZONE AFFECTING THE HILLS
ABOVE AND AROUND MONTECITO. SO WILL BE ADDING THE SANTA YNEZ RANGE
TO GO ALONG WITH THE SANTA BARBARA SOUTH COAST THROUGH LATE TONIGHT
WITH GUSTS BETWEEN 35 AND 45 MPH LIKELY THROUGH AT LEAST MIDNIGHT.

ONLY CHANGES NEEDED TONIGHT WAS FOR THE TEMPERATURES FOR THE CENTRAL
COAST AND COASTAL VALLEYS FOR SLO/SBA COUNTIES. A DECENT OFFSHORE
FLOW WILL FOCUS OUT OF THE SAN LUCIA MOUNTAINS AND BRING SOME
ADDITIONAL WARMING TO THE CENTRAL COAST TOMORROW AS WELL AS
THURSDAY. HIGH TEMPS SHOULD REACH THE LOWER TO MID 80S IN SOME
LOCATIONS.

AS FAR AS OFFSHORE WINDS FOR LA/VTU COUNTIES...NOT LOOKING
IMPRESSIVE AT ALL. LAX-DAG WILL LIMP TO JUST UNDER -2 MB BY WED
MORNING. HOWEVER...AN UPPER RIDGE WILL START TO BUILD IN FROM THE
WEST TOMORROW AND WITH RISING HEIGHTS AND THICKNESS LVLS...BOUNDARY
LAYER TEMPS WILL BE ON THE RISE...AND WITH WITH THE WEAK OFFSHORE
FLOW...EXPECT A MODEST INCREASE WITH TEMPS...WITH MORE WARMING FOR
THE COAST AND COASTAL VALLEYS ON THU WHERE HIGHS SHOULD REACH THE
UPPER 80S IN THE WARMEST VALLEY LOCATIONS TO THE LOWER TO MID 80S
FOR THE LA/VTU COAST. WITH THE OFFSHORE FLOW RELATIVELY WEAK...TEMPS
COULD BE TRICKY ALONG THE LA/VTU COAST ALLOWING A VERY SHALLOW
INVERSION TO DEVELOP WHICH COULD CAUSE SOME PATHCY DENSE FOG RIGHT
ALONG THE COAST EARLY THU MORNING.

OTHERWISE...HIGH PRESSURE WILL CONTINUE TO PERSIST INTO FRIDAY OVER
THE SOUTHERN AND CENTRAL CALIFORNIA. THIS WILL KEEP TEMPS ABOVE
AVERAGE FOR THIS TIME OF YEAR. THE SEABREEZE SHOULD KICK IN A BIT
EARLIER ACROSS THE CENTRAL COAST AND POSSIBLY IMMEDIATE COASTAL
AREAS SOUTH OF POINT CONCEPTION...WHICH SHOULD BRING A FEW DEGREES
OF COOLING FOR THAT AREA. OTHERWISE HIGH TEMPS SHOULD BE SIMILAR TO
THURSDAY FOR THE MOST PART. EXPECT HIGHS TO BE 5 TO 10 DEGREES ABOVE
NORMAL THU/FRI.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (SAT-TUE)...
BY SATURDAY MODELS ARE NOW ALL IN PRETTY GOOD AGREEMENT WITH PLACING
A DIGGING TROUGH JUST OFF THE WEST COAST...AND AT THIS POINT
SWINGING ITS MAIN AXIS THROUGH THE AREA LATE ON SATURDAY. 12Z
GUIDANCE PUSHES A WEAK FRONT THROUGH DURING THE DAY ON
SATURDAY...AND ALTHOUGH MODELS DO PRODUCE SOME LOW POPS OVER AREAS
NORTH OF POINT CONCEPTION ON SATURDAY...FRONT APPEARS PRETTY WEAK
THIS FAR SOUTH WITH BEST QPF WELL NORTH OF OUR AREA INTO NORTHERN
CALIFORNIA. LEFT CURRENT FORECAST OF SLIGHT CHANCE POPS NORTH OF
POINT CONCEPTION AS IS FOR SATURDAY. AT THIS TIME DON`T EXPECT ANY
MEASURABLE PRECIP SOUTH OF THE POINT WITH THIS SYSTEM...ESPECIALLY
GIVEN THE LATEST 12Z ECMWF HAS BACKED OFF ON THE TROF`S INTENSITY
FROM ITS PREVIOUS RUN.

THE PASSING TROUGH WILL HELP DROP TEMPERATURES ACROSS THE AREA ON
SATURDAY AND SUNDAY...WITH HIGHS 10 TO IN SOME PLACES 15 OR SO
DEGREES COOLER THAN HIGHS ON FRIDAY AND PLENTY BELOW
NORMAL...HELPING IT FEEL VERY FALL LIKE. TROUGH AND ASSOCIATED FRONT
WILL ALSO BRING SOME GUSTY NORTHERLY WINDS THROUGH PASSES AND
CANYONS.

SOME VERY MINOR DIFFERENCES BETWEEN GFS AND EC PAST SUNDAY AS FAR AS
THE BRINGING HIGH PRESSURE IN BEHIND SATURDAY`S TROUGH. BUT IN
GENERAL RISING HEIGHTS WILL WARM AFTERNOON TEMPERATURES A FEW
DEGREES EACH DAY ON MONDAY AND TUESDAY. OFFSHORE FLOW WILL BE
STRONGEST ON MONDAY ALTHOUGH NOT MUCH TO SPEAK OF.

&&

.AVIATION...22/0525Z...

THE MARINE LAYER AT KLAX AT 0325Z WAS 1100 FEET DEEP AND THE
INVERSION TOP IS AT 1900 FEET WITH A TEMPERATURE OF 20 DEGREES C.

OVERALL...HIGH CONFIDENCE IN THE 06Z TAF PACKAGE. THERE IS A SLIGHT
CHANCE OF SOME LIFR CONDS DEVELOPING AT KSMX...AND IFR CONDS AT KLGB
OVERNIGHT. OTHERWISE...SKIES ARE ANTICIPATED TO REMAIN CLEAR.

KLAX...HIGH CONFIDENCE IN 06Z TAF. THERE IS A 10% CHANCE OF IFR
CIGS/VSBYS 10Z-16Z WEDNESDAY MORNING.

KBUR...HIGH CONFIDENCE IN 06Z TAF.

&&

.MARINE...21/900 PM...

NORTHWEST GALES EXPECTED TO CONTINUE OVER THE OUTER WATERS THROUGH
LATE TONIGHT...STRONGEST BETWEEN POINT CONCEPTION AND SAN NICOLAS
ISLAND WITH GUSTS AROUND 35 MPH. THE SOMEWHAT LONG PERIOD OF
SUSTAINED STRONG WINDS HAS PRODUCED LARGE COMBINED SEAS...AS SHORT
PERIOD WAVES COMBINE WITH A LARGER LONG PERIOD NORTHWEST SWELL. PEAK
WAVE HEIGHTS ARE 10-14 FEET AND WILL LIKELY CONTINUE INTO THE EARLY
MORNING HOURS...AND WILL BEGIN TO DIMINISH AS WINDS START TO SUBSIDE
AROUND 3 AM. FOR THE INNER WATERS...WINDS HAVE SUBSIDED BELOW SMALL
CRAFT LEVEL HOWEVER SEAS CONTINUE TO BE A LARGER MIX OF LONG AND
SHORTER PERIODS...PEAKING AROUND 5 TO 6 FEET AT 7-8 SECONDS.

WINDS AND SEAS WILL DIMINISH LATE TONIGHT ACROSS THE OUTER
WATERS...HOWEVER IT IS LIKELY THAT SMALL CRAFT NORTHWEST WINDS WILL
PERSIST THROUGH WEDNESDAY AFTERNOON AND POSSIBLY INTO THE EVENING
HOURS. SEAS WILL GRADUALLY SUBSIDE...FALLING BELOW 10 FEET BY THE
AFTERNOON.


&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&
$$

PUBLIC...KAPLAN/JACKSON
AVIATION...RAT
MARINE...SMITH
SYNOPSIS...SETO

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