Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 111143
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
445 AM PDT FRI JUL 11 2014

...UPDATED AVIATION AND MARINE DISCUSSIONS...

.SYNOPSIS...

WEAK LOW PRESSURE OFF THE COAST WILL KEEP A DEEP MARINE LAYER IN
PLACE TODAY...WITH SLIGHTLY BELOW NORMAL TEMPERATURES. HIGH PRESSURE
WILL EXPAND WEST AGAIN OVER THE WEEKEND...RESULTING IN A SIGNIFICANT
WARMING TREND FOR THE AREA...ESPECIALLY INLAND. MONSOONAL FLOW WILL
RETURN BY SUNDAY...BRINGING A SLIGHT CHANCE OF THUNDERSTORMS FOR THE
MOUNTAINS AND DESERTS THROUGH THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM (TODAY-SUN)...OVERALL...00Z MODELS IN GOOD SYNOPTIC
AGREEMENT THROUGH THE PERIOD. AT UPPER LEVELS...RIDGE...CURRENTLY
OVER THE PANHANDLES OF TEXAS/OKLAHOMA...WILL GRADUALLY BUILD TO THE
WEST...BECOMING CENTERED OVER NEVADA BY SUNDAY. NEAR THE SURFACE...A
WEAK TO LOCALLY MODERATE ONSHORE FLOW WILL CONTINUE.

FORECAST-WISE...NO MAJOR CHANGES TO PREVIOUS THINKING. WITH THE
UPPER RIDGE BUILDING OVERHEAD...THE MARINE INVERSION SHOULD BECOME
MORE SHALLOW THROUGH THE WEEKEND. STRATUS COVERAGE WILL PEAK THIS
MORNING (WIDESPREAD IN THE COASTAL VALLEYS)...THEN WILL DIMINISH IN
AREAL COVERAGE SATURDAY/SUNDAY...REMAINING CONFINED TO THE COASTAL
PLAIN BY SUNDAY MORNING. AS FOR STRATUS DISSIPATION...WILL EXPECT
GOOD CLEARING EACH AFTERNOON...WITH THE USUAL RANDOM BEACH LOCATIONS
WHERE STRATUS WILL LINGER THROUGH THE AFTERNOON.

OTHER THAN THE ABOVE MENTIONED STRATUS...SKIES SHOULD REMAIN CLEAR
THROUGH SATURDAY NIGHT. ON SUNDAY...WITH THE UPPER HIGH SETTLING
OVER NEVADA...AN EASTERLY FLOW ALOFT WILL DEVELOP WHICH SHOULD ALLOW
FOR SOME INITIAL INTRUSION OF MID LEVEL CLOUDS/MOISTURE. WILL
CONTINUE WITH A PARTLY CLOUDY/MOSTLY CLEAR SKY WORDING FOR SUNDAY.
ALSO...WILL KEEP CURRENT SLIGHT CHANCE POPS OVER THE SAN GABRIEL
MOUNTAINS SUNDAY AFTERNOON.

AS FOR TEMPERATURES...TODAY WILL BE PRETTY SIMILAR TO THURSDAY...
WITH INLAND AREAS A DEGREE OR TWO WARMER AND COASTAL AREAS POSSIBLY
A DEGREE OR TWO COOLER. FOR SATURDAY/SUNDAY...ALL AREAS WILL EXHIBIT
A WARMING TREND. BY SUNDAY AFTERNOON...COASTAL VALLEYS WILL BE IN
THE 90S TO NEAR 100 WHILE THE DESERTS/INTERIOR VALLEYS ARE OVER 100
DEGREES.

.LONG TERM (MON-THU)...OVERALL...00Z MODELS CONTINUE TO EXHIBIT GOOD
SYNOPTIC AGREEMENT THROUGH THE WEEK. AT UPPER LEVELS...STRONG RIDGE
WILL REMAIN CENTERED OVER THE WEST COAST...BUT WILL GRADUALLY WEAKEN
THROUGH THE WEEK. NEAR THE SURFACE...WEAK ONSHORE FLOW WILL CONTINUE.

FORECAST-WISE...MAIN CONCERN WILL BE THE POTENTIAL FOR MONSOONAL
MOISTURE INTRUSION. GIVEN THE UPPER LEVEL PATTERN...THE AREA WILL BE
UNDER AN EXTENDED PERIOD OF EAST TO SOUTHEAST FLOW...WHICH WILL
LEAVE THE DOOR WIDE OPEN FOR MONSOONAL MOISTURE. 850 MB DEWPOINT
PROGS INDICATE GOOD SURGE OF MOISTURE...ESPECIALLY ON TUESDAY...WITH
THE MOISTURE CONTINUING THROUGH THURSDAY. WILL KEEP MENTION OF
THUNDERSTORMS OVER THE LA/VENTURA MOUNTAINS AND ANTELOPE VALLEY
MONDAY THROUGH THURSDAY. ONLY CHANGE WAS TO INCREASE THIS MENTION TO
CHANCE LEVELS FOR TUESDAY AFTERNOON. ALSO...AS MENTIONED BY PREVIOUS
SHIFTS...WILL HAVE TO WATCH THE POTENTIAL FOR SOME NOCTURNAL/COASTAL
CONVECTION MONDAY NIGHT/TUESDAY AS POTENTIAL EXISTS FOR AN EASTERLY
WAVE. MODELS APPEAR A BIT WEAKER WITH THIS POSSIBILITY...BUT IT IS
SOMETHING THAT FUTURE SHIFTS WILL NEED TO CONTINUE TO MONITOR.
ALSO...WOULD NOT BE SURPRISED TO SEE THUNDERSTORM THREAT EXTEND A
BIT FURTHER NORTH INTO INTERIOR SLO/SBA COUNTIES...BUT FUTURE SHIFTS
CAN ENTERTAIN THAT POSSIBILITY.

OTHERWISE...EXPECT COASTAL STRATUS TO BE RATHER LIMITED AND CHAOTIC
IN ITS FORMATION NEXT WEEK...DUE TO SHALLOW INVERSION AND POTENTIAL
FOR MID/HIGH LEVEL CLOUDS. AS FOR TEMPERATURES...WILL EXPECT THINGS
TO REMAIN ON THE WARM SIDE...BUT A VERY SLIGHT COOLING TREND IS
EXPECTED.

&&

.AVIATION...11/1140Z...

N OF POINT CONCEPTION...MODERATE CONFIDENCE IN 12Z TAF PACKAGE.
LATEST AMDAR SOUNDINGS INDICATE INVERSION AROUND 1600 FEET. LOOK FOR
A SIMILAR IFR STRATUS PATTERN AS YESTERDAY WITH CLEARING TO THE
COAST WITHIN AN HOUR OF YESTERDAY MORNING/EARLY AFTERNOON. MARINE
LAYER SHOULD BE A TAD SHALLOWER TONIGHT WHEN STRATUS REDEVELOPS
LATER THIS EVENING INCLUDING KPRB.

S OF POINT CONCEPTION...MODERATE CONFIDENCE WITH MOSTLY MVFR CIGS TO
BURNOFF AT SIMILAR TIMES AS YESTERDAY. HOWEVER...STRATUS DECK IS
SLIGHTLY LESS ORGANIZED WHICH COULD CAUSE STRATUS TO BURNOFF AN HOUR
QUICKER THAN YESTERDAY. LESS CONFIDENCE WITH TIMING FOR STRATUS TO
REDEVELOP TONIGHT. COULD SEE A FEW MORE LOCATIONS WITH IFR CIGS
INITIALLY...BUT BECOME MVFR BY 10Z FOR MOST COASTAL TAF SITES.

KLAX...MODERATE CONFIDENCE IN 12Z TAF. BURNOFF OF MVFR CIGS COULD BE
AN HOUR OR TWO LATER THAN CURRENT 17Z FORECAST.

KBUR...MODERATE CONFIDENCE IN 12Z TAF. THERE IS A 30% CHANCE THAT
CIGS COULD LINGER AN HOUR LONGER THAN TAF SUGGESTS.

&&

.MARINE...11/440 AM...

OUTER WATERS...INCREASING NORTHWEST WINDS FOR ZONES 673/676 LATER
THIS AFTERNOON. SMALL CRAFT ADVISORY LEVEL WIND GUSTS TO 25 KNOTS
WILL BECOME MORE WIDESPREAD LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HOURS. STRONGEST WINDS WILL OCCUR FROM POINT CONCEPTION TO
THE CHANNEL ISLANDS AS WELL AS NORTHWEST OF SAN NICOLAS ISLAND.
THERE WILL BE A BRIEF PERIOD SATURDAY MORNING WHEN WINDS WILL
DIMINISH SOME...BUT EXPECT MORE WIDESPREAD NORTHWEST WINDS WITH
GUSTS TO 30 KNOTS AFFECTING THE ENTIRE OUTER WATERS THROUGH THIS
WEEKEND...AND POSSIBLY INTO EARLY NEXT WEEK.

INNER WATERS...THERE WILL BE LOCAL GUSTY WEST TO NORTHWEST WINDS
ACROSS THE WESTERN PORTION OF ZONE 650 LATE THIS AFTERNOON. 30
PERCENT CHANCE FOR GUSTS TO 25 KNOTS. THERE WILL BE A HIGHER CHANCE
OF SMALL CRAFT ADVISORY LEVEL WIND GUSTS TO 25 KNOTS FOR SATURDAY
AFTERNOON AND EVENING. THERE WILL BE LOCAL GUSTY NW WINDS AROUND
ANACAPA ISLAND AND ACROSS THE NORTHWESTERN PORTION OF ZONE 655
SATURDAY EVENING...BUT NOT WIDESPREAD ENOUGH TO ADD A SMALL CRAFT
ADVISORY TO THAT ZONE. EXPECT WEST TO NORTHWEST WINDS TO INCREASE
SLIGHTLY FOR THE WESTERN PORTION OF ZONE 655 SAT/SUN AFTERNOON AND
EVENING. 30 PERCENT CHANCE FOR SMALL CRAFT FOR THIS ZONE FOR THOSE
TIME PERIODS. (INNER WATERS BETWEEN POINT PIEDRAS BLANCAS AND POINT
SAL)...NOT ANTICIPATING ANY WIND ISSUES TODAY...BUT NORTHWEST WINDS
WITH LOCAL GUSTS TO 25 KNOTS WILL BE LIKELY. 40 PERCENT CHANCE THAT
SMALL CRAFT ADVISORY WILL BE NEEDED BY SATURDAY AFTERNOON.

&&

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

&&

$$

PUBLIC...RAT
AVIATION/MARINE...KAPLAN
SYNOPSIS...SUKUP

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