Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 270534 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
935 PM PST WED NOV 26 2014

UPDATED AVIATION SECTION

.SYNOPSIS...
A HIGH PRESSURE SYSTEM WILL CREATE FAIR AND WARM WEATHER FOR
THANKSGIVING DAY. TEMPERATURES WILL COOL ON FRIDAY AND INTO THE
WEEKEND AS THE HIGH EXITS AND ONSHORE FLOW RETURNS. ON SUNDAY...A
LOW WILL APPROACH THE AREA WITH POSSIBLE PRECIPITATION FOR LATE
SUNDAY THEN EXTEND INTO THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM (TONIGHT-SAT)...RATHER WARM ACROSS THE COAST AND VALLEYS
TODAY WITH MANY TEMPERATURES IN THE 80S WITH A COUPLE OF READINGS
INTO THE LOW 90S. THERE WAS ALSO TWO RECORD HIGHS SET WHICH WERE 87
DEGREES AT LONG BEACH AIRPORT (TIED OLD RECORD OF 87 SET IN 1959)
AND 73 AT SANDBERG (OLD RECORD 70 SET IN 1953).

CLEAR SKIES COVERED THE FORECAST AREA THIS EVENING WHICH WILL
CONTINUE OVERNIGHT. DECENT OFFSHORE GRADIENTS PERSIST (-4.8 MB
LAX-DAG AT 03Z) WHICH WILL HELP TO BRING LOCALLY GUSTY NE WINDS
BELOW AND THRU THE FAVORED PASSES AND CANYONS AND ALSO TO FOOTHILL
AREAS OVERNIGHT INTO THU MORNING. TEMPS IN THE BREEZY AREAS AND
FOOTHILLS WILL BE QUITE MILD OVERNIGHT WITH LOWS IN THE 60S. FOR THE
COLDEST WIND SHELTERED COASTAL VALLEYS SUCH AS THE OJAI
VALLEY...LOWS TONIGHT SHOULD DROP INTO THE UPPER 30S.

UPPER LEVEL RIDGING WILL PERSIST OVER SRN CA THRU THANKSGIVING DAY.
THE UPPER RIDGE WILL GRADUALLY WEAKEN AND SHIFT SOUTHWARD FRI THRU
SAT...WITH UPPER LEVEL TROFFINESS MOVING INTO NRN CA BY SAT. THIS
WILL SET UP A BROAD W FLOW ALOFT OVER SRN CA. MOSTLY CLEAR SKIES
WILL CONTINUE OVER THE FORECAST AREA THRU FRI. MARINE LAYER CLOUDS
SHOULD DEVELOP LATER FRI NIGHT INTO SAT MORNING ALONG THE CENTRAL
COAST AND PARTS OF THE COAST S OF POINT CONCEPTION...OTHERWISE
MOSTLY CLEAR SKIES SHOULD CONTINUE THRU SAT...ALTHO SOME HI CLOUDS
WILL LIKELY MOVE INTO THE AREA AT TIMES DURING THE PERIOD. THE
OFFSHORE FLOW SHOULD END BY THU NIGHT WITH INCREASING ONSHORE FLOW
EXPECTED ACROSS THE REGION FRI THRU SAT. SOME GUSTY S TO SW WINDS
CAN BE EXPECTED IN THE L.A. COUNTY MTNS AND ANTELOPE VLY SAT
AFTERNOON. TEMPS ARE FORECAST TO BE WELL ABOVE NORMAL IN ALL AREAS
ON THANKSGIVING DAY. HIGHS WELL INTO THE 80S CAN BE EXPECTED FOR
MUCH OF THE COAST AND VLYS...WITH A FEW LOW 90S IN THE WARMEST VLYS
OF L.A./VTU COUNTY. A FEW MORE RECORD HIGH TEMPS WILL BE POSSIBLE.
TEMPS WILL THEN COOL BACK ON FRI BUT REMAIN SEVERAL DEGREES ABOVE
NORMAL FOR MOST AREAS. FURTHER COOLING IS EXPECTED SAT WITH HIGHS
SLIGHTLY ABOVE NORMAL FOR MOST AREAS.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (SUN-WED)...AND THEN THE FORECAST FUN BEGINS. MODELS IN
DECENT AGREEMENT THROUGH MID DAY SUNDAY SHOWING AN INITIAL IMPULSE
MOVING THROUGH CENTRAL AND NORTHERN CALIFORNIA LATE SAT INTO SUNDAY.
THERE SHOULD BE ENOUGH ENERGY TO SUPPORT SOME LIGHT PRECIP AS FAR
SOUTH AS NRN SBA COUNTY BY SUNDAY AFTERNOON, BUT THE BULK OF THE
PRECIP WITH THIS IMPULSE WILL BE WELL TO THE NORTH.

AFTER THAT, MODELS CONTINUE TO EXHIBIT LARGE RUN TO RUN AND MODEL TO
MODEL VARIATIONS, MAINLY WITH RESPECT TO TIMING. THE STRENGTH AND
RESULTING RAIN AMOUNTS HAVEN`T REALLY CHANGED MUCH IN THE LAST FEW
DAYS BUT THE TIMING HAS CHANGED SIGNIFICANTLY. STILL NEAR 100%
CERTAINTY FOR RAIN IN THE AREA NEXT WEEK, BUT NAILING DOWN THE MAIN
12 HOUR OR SO PERIOD THAT THE BULK OF THE PRECIP WILL FALL HAS BEEN
(AND LIKELY WILL CONTINUE TO BE) A HUGE CHALLENGE. CERTAINLY THE
SOLUTIONS TODAY FAVOR A MUCH SLOWER ARRIVAL, POSSIBLY AS LATE AS
WEDNESDAY, BUT THERE ARE STILL ENOUGH ENSEMBLE MEMBERS SUPPORTING AT
LEAST A LITTLE RAIN AS EARLY AS SUNDAY NIGHT SO IT`S STILL TOO EARLY
TO PULL THE PLUG ON THE EARLY ARRIVAL SOLUTION. THOUGH CERTAINLY THE
MOMENTUM TODAY FAVORS LATER.

SINCE THE SLOWER SOLUTIONS ARE CUTTING OFF WELL TO THE WEST THEY DO
TEND TO ENTRAIN SOME DEEPER TROPICAL AIR THAN PREVIOUSLY AND PWATS
ARE NOW CLOSE TO 1.5 INCHES FOR OUR SOUTHERN AREAS ON TUE. SO THERE
IS THE POTENTIAL FOR EVEN HIGHER AMOUNTS THAN CURRENTLY FORECAST FOR
AREAS SOUTH OF PT CONCEPTION. BUT WE`RE STILL ONLY TALKING ABOUT A
ROUGHLY 12 HOUR PERIOD WHEN THE BULK OF THE PRECIP WILL FALL SO
DURATION WILL BE A LIMITING FACTOR IN RESULTING RAIN TOTALS, THOUGH
HOURLY RATES COULD STILL BE ENOUGH TO CAUSE SOME PROBLEMS IN OUR
BURN AREAS.

WITH THE TROPICAL TAP OF MOISTURE WITH THIS SYSTEM SNOW LEVELS WILL
BE WELL ABOVE 8000` FOR THE VAST MAJORITY OF THE STORM. THERE IS A
BRIEF PERIOD OF COOLER AIR BEHIND THE TROF WHERE SNOW LEVELS WILL
FALL TO 6000 OR 7000 FT BUT NOT MUCH MOISTURE LEFT BY THAT TIME.

IN SUMMARY, HAVE OPTED TO LEAVE 20-30 POPS IN FOR LATE SUNDAY NIGHT
AND MONDAY WITH HIGHER POPS TUESDAY AND TUESDAY NIGHT. STAY TUNED AS
THIS STORY WILL ALMOST CERTAINLY CHANGE.

&&

.AVIATION...26/2330Z...

AT 0425Z...THERE WAS A SURFACE BASED INVERSION AT KLAX AT WITH AN
INVERSION TOP OF 1100 FEET AND A TEMPERATURE OF 26 DEGREE CELSIUS.

HIGH CONFIDENCE IN VFR CONDITIONS EXPECTED AT ALL AIRFIELDS THROUGH
THE PERIOD.

KLAX...VERY HIGH CONFIDENCE IN THE 06Z TAF WITH VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.


KBUR...VERY HIGH CONFIDENCE IN THE 06Z TAF WITH VFR CONDITIONS
EXPECTED THROUGH THE PERIOD.


&&

.MARINE...26/730 PM...

A LOW PRESSURE SYSTEM IN THE CENTRAL PACIFIC THIS EVENING IS
EXPECTED TO MOVE EAST AND SETTLE OVER THE EASTERN PACIFIC THROUGH
SATURDAY. THE REMNANTS OF A COLD FRONT IS EXPECTED TO MOVE OVER THE
COASTAL WATERS AND SOUTH WINDS MAY CREATE SMALL CRAFT ADVISORY
CONDITIONS SUNDAY FROM THE NORTHERN CHANNEL ISLAND TO POINT PIEDRAS
BLANCAS. OTHERWISE...A LOW PRESSURE SYSTEM IS EXPECTED TO DEEPEN
OVER THE EASTERN PACIFIC SUNDAY AND WILL GRADUALLY SHIFT EAST MONDAY
THROUGH TUESDAY. GALE FORCE NORTH WINDS WITHIN A N-S ORIENTED FETCH
AREA APPROXIMATELY 900 NM FROM THE CENTRAL COAST ARE EXPECTED TO
DEVELOP UPSTREAM FROM THE LOW CENTER WHILE LIGHTER WINDS ARE
EXPECTED SOUTH OF THE LOW CENTER. SEAS GENERATED IN THE N-S ORIENTED
FETCH WILL PROPAGATE SOUTH AND REMAIN WEST OF THE AREA. BUT AS THE
LOW SHIFTS EAST...SEAS GENERATED SOUTH OF THE LOW CENTER WITHIN A
MORE LIMITED FETCH AREA AND ORIENTED BETWEEN 240-270 DEGREES
RELATIVE TO THE AREA ARE EXPECTED TO BEGIN TO ARRIVE LATE TUESDAY
AND BUILD THROUGH WEDNESDAY AND SMALL CRAFT FOR HAZARDOUS SEA
CONDITIONS AREA POSSIBLE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...SIRARD/MW
AVIATION...SIRARD
MARINE...30/SIRARD
SYNOPSIS...SETO

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