Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 161601
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
900 AM PDT TUE SEP 16 2014

...MARINE DISCUSSION UPDATED...

.SYNOPSIS...
HIGH PRESSURE ALOFT AND WEAK ONSHORE FLOW WILL RESULT IN VERY HOT
WEATHER TODAY...ESPECIALLY FOR AREAS AWAY FROM THE IMMEDIATE COAST.
THERE WILL BE SOME COOLING ON WEDNESDAY...WITH MORE SIGNIFICANT
COOLING ON THURSDAY AS A TROUGH APPROACHES THE WEST COAST. THERE IS
A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE
EASTERN MOUNTAINS AND THE ANTELOPE VALLEY WEDNESDAY AND POSSIBLY
THURSDAY DUE TO REMNANT MOISTURE FROM HURRICANE ODILE. TEMPERATURES
WILL RETURN TO NEAR NORMAL FOR FRIDAY AND SATURDAY...THEN SLIGHT
WARMING MAY BEGIN BY LATE IN THE WEEKEND.

&&

.SHORT TERM (TODAY-THU)...CLEAR SKIES ACROSS THE REGION THIS
MORNING. W-E PRESSURE GRADIENTS WERE WEAKLY OFFSHORE FROM KLAX TO
KDAG. N-S GRADIENTS WERE MODERATELY OFFSHORE...AND GUSTY WINDS CONTD
THROUGH AND BELOW PASSES AND CANYONS OF SRN SBA COUNTY. HAVE
EXTENDED WIND ADVISORIES THROUGH 9 AM FOR THE SANTA YNEZ RANGE AND
ADJACENT S COAST OF SBA COUNTIES BELOW PASSES AND CANYONS. IT WAS
VERY WARM EARLY THIS MORNING...ESPECIALLY IN THE VLYS AND IN BREEZY
AREAS...WHERE TEMPS WERE STILL IN THE 80S AS OF 3 AM PDT...AND UPPER
80S IN SOME CASES. EXPECT TODAY TO BE A VERY HOT DAY JUST ABOUT
EVERYWHERE AWAY FROM THE IMMEDIATE BEACHES. WHILE HGTS/THICKNESSES
HAVE DROPPED A BIT...950 MB TEMPS REMAINED VERY HIGH...WITH AMDAR
SOUNDINGS SHOWING TEMPS AT 950 MB OF NEAR 90F OR 32C. WITH SUCH A
WARM START TO THE DAY...AND WEAK OFFSHORE FLOW TO BEGIN...EXPECT MAX
TEMPS TO BE AS HIGH AS THEY WERE ON MON IN MANY AREAS...AND WOULD
NOT BE SURPRISED IF A FEW LOCATIONS WERE EVEN A BIT HOTTER.

WHILE THERE WILL BE SOME INCREASE IN MID LEVEL MOISTURE AND
INCREASING PRECIPITABLE WATER VALUES TODAY...FEEL THAT THE
STRONG UPPER RIDGE AXIS OVERHEAD WILL SUPPRESS ANY CONVECTION.
HOWEVER...THERE COULD BE A FEW BUILDUPS IN THE MTNS.

AN UPPER TROUGH WILL APPROACH THE WEST COAST TONIGHT AND WED. LOW
LEVEL N-S GRADIENTS SHOULD PRODUCE GUSTY SUNDOWNER WINDS THROUGH THE
SANTA YNEZ RANGE AND ACROSS THE SOUTH COAST OF SBA COUNTY THIS
EVENING...AND WINDS COULD GET CLOSE TO ADVISORY LEVELS THERE
TONIGHT. SOME STRATUS COULD MOVE INTO THE CENTRAL COAST...BUT
OTHERWISE...EXPECT SKIES TO REMAIN MOSTLY CLEAR TONIGHT. MAX TEMPS
ON WED SHOULD BE DOWN SEVERAL DEGREES IN MOST AREAS...BUT TEMPS WILL
PROBABLY STILL REACH OR SLIGHTLY EXCEED 100 DEGREES IN THE WARMEST
LOCATIONS IN THE VLYS...LOWER ELEVATIONS IN THE MTNS AND IN THE
ANTELOPE VALLEY. WITH A BIT MORE IN THE WAY OF MID LEVEL MOISTURE
OVER ERN SECTIONS OF THE FCST AREA WED AND LESS SUBSIDENCE ALOFT...
THE SLIGHT CHANCE OF THUNDERSTORMS IN THE AFTERNOON AND EVENING IN
THE MTNS OF L.A. AND VTU COUNTIES AND IN THE ANTELOPE VALLEY LOOKS
REASONABLE.

THE TROUGH WILL EVOLVE INTO AN UPPER LOW WED NIGHT AND MOVE INTO
THE NRN CA COAST BY THU AFTERNOON. AT THE SURFACE...N-S GRADIENTS
ACTUALLY INCREASE A BIT ACROSS SBA COUNTY WED EVENING...SO EXPECT
ANOTHER ROUND OF GUSTY NW-N WINDS...POSSIBLY TO ADVISORY LEVELS
ACROSS SRN SBA COUNTY. THE WRF INDICATES STRATUS BECOMING WIDESPREAD
IN COASTAL AREAS WED NIGHT/THU MORNING...WITH THE EXCEPTION OF THE S
COAST OF SBA COUNTIES...WHERE N-S GRADIENTS SHOULD KEEP STRATUS AT
BAY. GOOD HEIGHT FALLS...COOLING AT 850 MB AND 950 MB AND
STRENGTHENING ONSHORE FLOW SHOULD LEAD TO SIGNIFICANT WIDESPREAD
COOLING ACROSS THE REGION THU...WITH MAX TEMPS DOWN 8 TO 15 DEGREES
IN MANY VALLEY LOCATIONS AND ACROSS INTERIOR SECTIONS OF THE L.A.
COUNTY COASTAL PLAIN. THERE MAY STILL BE A SLIGHT CHANCE OF
CONVECTION OVER THE MTNS OF L.A. AND ERN VTU COUNTIES AND THE
ANTELOPE VALLEY THU...BUT THE LATEST MODELS SHOW THE BULK OF ANY
MOISTURE ASSOCIATED WITH THE REMNANTS OF ODILE PUSHING WELL EAST
OF THE REGION AS THE UPPER FLOW TURNS SWLY AHEAD OF THE TROUGH.
LATER SHIFTS MAY BE ABLE TO REMOVE THOSE SLIGHT CHANCES FROM THE
FORECAST.

.LONG TERM (FRI-MON)...THE UPPER LOW WILL DROP SWD THROUGH CA
THU NIGHT AND FRI...AND BE LOCATED NEAR POINT CONCEPTION FRI
AFTERNOON. THERE SHOULD BE A RATHER DEEP MARINE LAYER THU NIGHT/FRI
MORNING. A FEW SHOWERS ARE NOT OUT OF THE QUESTION N OF PT
CONCEPTION WITH THE WEAKENING SFC FRONT THU NIGHT AND EARLY
FRI...AND THERE COULD BE SOME DRIZZLE OR LIGHT RAIN ACROSS THE
FOOTHILLS OF L.A. COUNTY AS SOME LOW LEVEL LIFT DEVELOPS IN THE
INCREASINGLY CYCLONIC FLOW. THE LATEST RUN OF THE GFS IS A BIT
FARTHER W WITH THE UPPER LOW...KEEPING IT WEST OF THE REGION THROUGH
THE DAY...SO CLEARING MAY BE SLOWER AND LESS COMPLETE THAN CURRENTLY
FORECAST. MAX TEMPS WILL BE DOWN A FEW MORE DEGREES IN MOST AREAS
FRI...DOWN TO NEAR OR BELOW NORMAL LEVELS. THE WEAKENING UPPER LOW
WILL DRIFT ACROSS THE REGION SAT AND THEN MOVE EWD...SO MAX TEMPS
COULD BEGIN TO RISE IN MANY AREAS BY SUNDAY AND MONDAY.

&&

.AVIATION...16/1145Z

OVERALL...HIGH CONFIDENCE IN 12Z TAF PACKAGE. LOCALLY GUSTY WINDS
THROUGH AND BELOW PASSES AND CANYONS OF SRN SBA COUNTY THROUGH LATE
TONIGHT...AND AGAIN TUE EVENING WITH LOCAL LLWS AND MDT UDDF NEAR
KSBA FOR THE AREA THROUGH TUESDAY.

KLAX...HIGH CONFIDENCE IN CAVU TAF.

KBUR...VERY HIGH CONFIDENCE CAVU TAF.

&&

.MARINE...16/900 AM
HIGH CONFIDENCE IN CURRENT MARINE FORECAST. ADVISORY LEVEL WINDS
ACROSS THE OUTER WATERS THROUGH LATE IN THE WEEK.  THE STRONGEST
WINDS WILL BE NEAR POINT CONCEPTION IN MID-LATE AFTERNOONS AND
EARLY EVENINGS.

THE WESTERN HALF OF THE SANTA BARBARA CHANNEL WILL HAVE NORTHWEST
GUSTS TO 25 TO 30 KT DURING THE NEXT FEW LATE AFTERNOONS AND
EVENINGS.

&&

.BEACHES...16/900 AM
A LONG PERIOD (19-20+ SECOND) SOUTHERN HEMISPHERE SWELL WILL MOVE
THROUGH THE WATERS THROUGH TODAY. IT WILL BRING ELEVATED SURF ALONG
SOUTH FACING BEACHES AND A SIGNIFICANT AMOUNT OF RIP CURRENT
ACTIVITY.

THERE IS NO LONGER A THREAT OF SWELLS FROM HURRICANE ODILE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING (SEE LAXNPWLOX).
RED FLAG WARNING (SEE LAXRFWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...DB
AVIATION...ASR
MARINE...ASR/KJ
SYNOPSIS...DB

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