FXUS66 KLOX 101158 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
400 AM PST WED MAR 10 2010

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...

A COLD AIR MASS WILL REMAIN IN PLACE THROUGH THURSDAY AS A WEAK
TROUGH MOVES THE REGION. A STRONG SURFACE GRADIENT ACROSS THE AREA
WILL CONTINUE WINDY CONDITIONS...PARTICULARLY IN THE MOUNTAINS AND
ANTELOPE VALLEY. A WARMING TREND WILL DEVELOP OVER THE AREA ON
THURSDAY AS HIGH PRESSURE BUILDS OVER THE REGION. A COOLING TREND IS
EXPECTED SATURDAY WITH A CHANCE OF RAIN NORTH OVER THE CENTRAL COAST.

&&

.SHORT TERM (TODAY-FRI)...
A WEAK COLD FRONT OVER MONTEREY COUNTY IS ACTUALLY A LITTLE
STRONGER THAN EXPECTED AND IT WILL PRODUCE SCATTERED SHOWERS OVER
SLO AND SBA COUNTIES THIS MORNING AS WELL AS THE NORTH SLOPES OF
THE L.A. AND VTA COUNTY MOUNTAINS. HEAVY RAIN WAS BRIEFLY REPORTED
AT KMRY AND KSNS SO A BRIEF HEAVY SHOWER IS ALSO POSSIBLE. THIS IS A
FAST MOVING FRONT HOWEVER AND WILL NOT PRODUCE MUCH MORE THAN A
TENTH OF AN INCH OF RAINFALL. SNOW LEVELS REMAIN LOW AND THERE COULD
BE SNOW AS LOW AS 3000 FEET THIS MORNING BUT AGAIN NOTHING TOO HEAVY.

WINDS CONTINUE TO BE VEXING AS THE WRF WHICH WAS SORT OF END OF THE
WORLDISH LAST NIGHT HAS TONED THINGS DOWN SUBSTANTIALLY. CURRENT
ASSORTMENT OF WIND WARNINGS AND ADVISORIES LOOK GOOD. THE BEST WINDS
WILL BE IN THE MOUNTAINS OF LA AND VTA COUNTIES ESP THROUGH THE I-5
CORRIDOR. THE WINDS WILL PEAK LATER THIS MORNING AS THE COLD AIR
BEHIND THE COLD FRONT SWEEPS IN THERE WILL BE A SECONDARY PEAK EARLY
THIS EVENING AS THE UPPER FLOW ALIGNS NICELY WITH THE LOW LEVEL
WINDS WITH ENOUGH COLD AIR TO HELP TRANSPORT THESE WINDS DOWN.

THE SBA MTNS AND SOUTH COASTS WILL LIKELY NEED WIND ADVISORIES AGAIN
LATE THIS AFTERNOON AND EVENING.

THERE WILL BE A QUICK SHIFT IN THE WINDS OVERNIGHT AS THE NORTH FLOW
TURNS NORTHEAST. THIS WILL QUICKLY SHUT OFF THE NORTH WIND FAVORED
AREAS AND LIGHT UP THE NORTHEAST FAVORED LOCATIONS. THE NORTHEAST
PUSH IS NOWHERE NEAR AS STRONG AS TODAYS WINDS AND THERE WILL LIKELY
BE NO NEED FOR ADVISORIES.

MAX TEMPS TODAY WILL BE QUITE COOL WITH 545DM THKNS OVERHEAD. AGAIN
MAX TEMPS WILL BE 5 TO 10 DEGREES BELOW NORMAL.

SPEAKING OF COLD WEDNESDAY NIGHT WILL BE QUITE CHILLY IN SOME
LOCATIONS. WITH A VERY DRY AND COOL AIRMASS IN PLACE OVERNIGHT LOWS
IN NON BREEZY LOCATIONS WILL FALL INTO THE 30S WITH SOME INLAND VLY
AND DESERT LOCATIONS SEEING FREEZING TEMPS. IT WILL BE VERY
DIFFICULT TO FIGURE OUT EXACTLY WHERE THE COLDEST TEMPS WILL BE
BECAUSE ANY AMOUNT OF WINDS WILL KEEP THE TEMPS 10 DEGREES WARMER
THAN CALM LOCATIONS.

THURSDAY WILL SEE A DRAMATIC CHANGE IN THE WEATHER. A 572DM RIDGE
QUICKLY BUILDS IN AND THIS COMBINED WITH THE OFFSHORE FLOW WILL
ALLOW FOR A DRAMATIC LEAP IN TEMPS OF 5 TO 10 DEGREES ACROSS THE
BOARD WITH THE GREATEST GAINS ACROSS THE LA AND VTA VLYS.

FRIDAY IS NO LONGER LOOKING QUITE AS WARM AS FORECAST YDY. THE FRONT
THAT WAS FORECAST FOR SATURDAY IS NOW ON TRACK FOR A FRIDAY NIGHT
ARRIVAL. THIS MEAN THAT THE RIDGE WILL BREAK DOWN FASTER ON FRIDAY
AND THE OFFSHORE FLOW WILL BE WEAKER. THERE WILL ALSO BE MORE HIGH
LEVEL CLOUDS OVERHEAD. IT WILL STILL BE A NICE DAY BUT JUST NOT AS
NICE AS WE HOPED AND PROBABLY A DEGREE OR TWO COOLER THAN THURSDAY.

.LONG TERM (SAT-TUE)...
LIKE ALL FRONTS LATELY THE FRIDAY NIGHT SATURDAY MORNING ONE LOOKS
TO FALL APART AS IT ROUNDS POINT CONCEPTION. RIGHT NOW WILL GO WITH
A CHANCE OF RAIN NORTH OF POINT CONCEPTION AND SOME NORTH SLOPE
RAIN FOR THE LA. VTA MTNS. DID NOT BUMP POPS UP HIGHER THAN CHC TO
ACCOUNT FOR THE TIMING ISSUES WHETHER THE RAIN WILL ARRIVE FRIDAY
NIGHT OR SAT MORNING. THE FRONT IS FAST ENOUGH MOVING THAT RAIN WILL
LIKELY NOT AFFECT BOTH PERIODS. ELSEWHERE IT WILL MAKE FOR COOLER
SATURDAY WITH HGTS FALLING TO 565 DM AND PLENTY OF CLOUDS. TEMPS
WILL FALL ABOUT 5 DEGREES ACROSS THE BOARD.

BOTH GFS AND EC FORECAST ANOTHER LONGER LASTING RIDGE TO BUILD INTO
THE AREA SUNDAY AND LAST INTO TUESDAY. LOOK FOR MOSTLY CLEAR SKIES
AND TEMPS WARMING TO ABOVE NORMAL BY MONDAY AND MAYBE A FEW MORE
DEGREES ABOVE NORMAL TUESDAY.

&&

.AVIATION...10/1200Z.

A GUSTY NORTHWEST TO NORTH FLOW PATTERN WILL PERSIST ACROSS THE AREA
THROUGH THE TAF PERIOD. THE NORTHERLY FLOW MAY PRODUCE SOME
SCATTERED SHOWERS NORTH OF POINT CONCEPTION THIS MORNING BUT EXPECT
ANY CIGS TO REMAIN AT VFR LEVELS. WITH THE NORTHERLY FLOW...SOME
GUSTY WINDS ALONG WITH TURBULENCE AND LLWS CAN BE EXPECTED
ESPECIALLY THROUGH/BELOW PASSES AND CANYONS.

KLAX...MODERATE TO HIGH CONFIDENCE IN 12Z TAF. WITH THE NORTH
FLOW...THERE COULD BE SOME LLWS AND LIGHT TURBULENCE THIS MORNING
AROUND THE AIRFIELD.

KBUR...MODERATE TO HIGH CONFIDENCE IN 12Z TAF. NORTHERLY FLOW WILL
PRODUCE SOME GUSTY WINDS AT THE AIRFIELD ALONG WITH LLWS AND SOME
TURBULENCE.

***NOTE***
THE ASOS EQUIPMENT AT KBUR...KVNY...KHHR...KCMA...AND KOXR HAS A
SOFTWARE ERROR THAT MAY LEAD TO INCORRECT CLOUD HEIGHTS WHEN THERE
ARE TWO OR MORE CLOUD LAYERS PRESENT. OBSERVATIONS AT KBUR WILL BE
QUALITY CONTROLLED 24 HOURS A DAY...OBSERVATIONS AT KVNY WILL BE
QUALITY CONTROLLED FROM 13Z-07Z...OBSERVATIONS AT KOXR WILL BE
QUALITY CONTROLLED FROM 15Z-05Z. TAFS FOR KVNY AND KOXR WILL NOT BE
AMENDED FOR CIGS DURING THE TIME THE OBSERVATIONS ARE NOT MONITORED
AND THERE ARE TWO OR MORE CLOUD LAYERS PRESENT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...RORKE
AVIATION...THOMPSON
SYNOPSIS...ASR

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