Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 011617 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
915 AM PDT TUE SEP 1 2015

.SYNOPSIS...A WEAK TROUGH OF LOW PRESSURE WILL PASS OVERHEAD TONIGHT
INTO WEDNESDAY MORNING...BRINGING SCATTERED HIGH CLOUDS TO THE SOUTH
OF POINT CONCEPTION. MODERATE ONSHORE FLOW WILL SUPPORT MORNING
CLOUD COVER AND MAYBE SOME DRIZZLE TO THE WEST OF THE MOUNTAINS WITH
BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. TEMPERATURES ARE
EXPECTED TO REBOUND TO NEAR NORMAL BY EARLY NEXT WEEK.

&&

.SHORT TERM (TODAY-THU)... THE MARINE LAYER IS CURRENTLY BETWEEN
2600 AND 3200 FEET THIS MORNING...WITH AMPLE STRATUS COVERING THE
COASTAL SIDE OF THE MOUNTAIN RANGES. THANKS FOR THIS INCREASE IN
CLOUDS GOES TO A WEAK TROUGH JUST OFF THE COAST...ONSHORE PRESSURE
GRADIENTS UP 1-2 MB FROM YESTERDAY...AND A HEALTHY COASTAL EDDY
SOUTH OF SBA THAT BROUGHT SOUTHEAST WINDS UP TO 15 MPH. ALL THIS
WILL ADD UP TO WIDESPREAD COOLING FROM YESTERDAY...WITH COASTAL
AREAS SETTLING IN TO AROUND NORMAL AND EVERYWHERE ELSE ABOUT 5
DEGREES BELOW NORMAL. STRATUS SHOULD CLEAR BY THE AFTERNOON ALMOST
EVERYWHERE...BUT SOME COASTAL AREAS FROM PISMO TO OXNARD COULD SEE
GLOOMY CONDITIONS WELL INTO THE AFTERNOON.

***FROM PREVIOUS DISCUSSION***

AN UPPER LOW SLOWLY MOVES INTO WASHINGTON STATE AND AN ASSOCIATED
TROF XTNDS INTO NRN CA AND SHARPENS UP A BIT. THE LOWER HGTS WILL
LIKELY KNOCK ANOTHER 1 OR 2 DEGREES OFF OF MAX TEMPS BUT OTHERWISE
BOTH WED AND THU WILL LOOK VERY SIMILAR TO TODAY.

.LONG TERM (FRI-MON)... EC AND GFS AGREE THAT THE UPPER LOW WILL
MOVE INTO OREGON ON FRIDAY AND THEN INTO FAR NRN CA ON SATURDAY.
PERSISTENT TROFFING WILL CONTINUE OVER SRN CA. THE NIGHT THROUGH
MORNING LOW CLOUD PATTERN WILL CONTINUE. FRIDAY WILL BE THE COOLEST
DAY OF THE NEXT 7. SATURDAY MAY BE A DEGREE WARMER AS THE TROF MOVES
OUT IN THE MORNING WITH SOME HGT RISES FOLLOWING IN ITS WAKE DURING
THE EVENING.

THE EC AND GFS DISAGREE ON THE SUN MON. THE EC ADVERTISING SHALLOW
TROFFING OVER THE AREA WHILE THE GFS THINKS AN UPPER LOW WILL FORM
NEAR EUREKA AND THEN RETROGRADE SW TO A LOCATION ABOUT 150 MILES
WEST OF MONTEREY. DESPITE THE DIFFERING SOLUTIONS HGTS ARE ABOUT THE
SAME. BOTH MDLS SHOW DECENT WARMING FOR THIS PERIOD WHICH DOES NOT
MAKE TOO MUCH SENSE GIVEN THE TROFFING AND ONSHORE FLOW AND KEPT
FORECAST COOLER THAN MDLS WOULD INDICATE.

&&

.AVIATION...

01/1200Z

AT 12Z...THE MARINE LAYER AT KLAX WAS AROUND 3000 FEET
DEEP. THE TOP OF THE INVERSION WAS AROUND 3500 FEET WITH A
TEMPERATURE OF 22 DEGREES CELSIUS.

WIDESPREAD MVFR CONDS IN ALL COASTAL AND VALLEY AREAS EARLY THIS
MORNING...WITH LOCAL IFR CONDS ON THE CENTRAL COAST AND IN THE
FOOTHILLS. EXPECT CLEARING IN MOST AREAS BY LATE MORNING...
ALTHOUGH CLOUDS WILL LIKELY LINGER INTO THE EARLY AFTERNOON
AT THE BEACHES S OF PT CONCEPTION. THERE IS A CHANCE THAT CLOUDS
COULD LINGER ALL DAY AT SOME COASTAL LOCATIONS FROM SRN SBA
COUNTY THRU L.A. COUNTY.

KLAX...MODERATE CONFIDENCE IN THE 12Z TAF. THERE IS A 30
PERCENT CHC THAT MVFR CIGS WILL LINGER ALL DAY.

KBUR...GOOD CONFIDENCE IN THE 12Z TAF. THERE IS A 10 TO 20 PERCENT
CHANCE THAT CIGS WILL LINGER THROUGH 20Z.

&&

.MARINE...01/900 AM.

OUTER WATERS... MODERATE NORTHWEST TO NORTHERLY WINDS AND AN
INCREASED SWELL WILL KEEP A SMALL CRAFT ADVISORY IN EFFECT ACROSS
THE OUTER WATERS THROUGH AT LEAST LATE TONIGHT.  THE WINDS WILL
DIMINISH TO BELOW CRITERIA TODAY IN SOME LOCATIONS BUT WILL INCREASE
AGAIN IN THE AFTERNOON AND EVENING HOURS... AND THE SWELLS WILL
LIKELY INCREASE THROUGH THE DAY.  THERE IS A POTENTIAL FOR MODERATE
WINDS ACROSS THE OUTER WATERS THROUGH SATURDAY AND MARINERS SHOULD
PLAN FOR AT LEAST LOCALLY MODERATE WINDS ACROSS WESTERN PORTIONS OF
THE ZONES.

INNER WATERS... SWELLS IN THE INNER WATERS WILL ALSO INCREASE
THROUGH THE DAY AND THERE IS A THIRTY PERCENT CHANCE THAT A SMALL
CRAFT ADVISORY FOR HAZARDOUS SEAS MAY BE NEEDED.  AT THIS TIME
CONDITIONS ARE EXPECTED TO REMAIN BELOW CRITERIA BUT MARINERS SHOULD
BE PREPARED FOR CHOPPY CONDITIONS.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...RK/RORKE
AVIATION/MARINE...KH/DB
SYNOPSIS...RM

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