000
FXUS66 KLOX 202006
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
100 PM PDT SAT SEP 20 2008

NEW AVIATION DISCUSSION

.SHORT TERM...
A TATTERED MARINE INVERSION IS ALL THAT IS LEFT AFTER SOME COLD AIR
MOVED OVER THE AREA FROM THE NORTH LAST NIGHT. OTHER THAN A FEW
STRANDS OF LOW CLOUDS NEAR THE IMMEDIATE LA AND VTU CO COAST...THE
LACK OF A HEALTHY INVERSION HAS KEPT MOST OF THE AREA SOUTH OF POINT
CONCEPTION CLEAR. THIS ALL HAS HELPED COOL THINGS OFF THIS
MORNING...WITH A SLIGHT CHILL TO THE AIR. TO THE NORTH...THE
NORTHERLY FLOW HAS HELPED STRATUS MOVE DOWN THE COAST FROM MONTEREY
AND COVER A LARGE PORTION OF INTERIOR SLO CO AND THE CENTRAL COAST.
WITH THE WEAK INVERSION...THINGS SHOULD CLEAR OUT FAIRLY QUICKLY.
ALTHOUGH THE CLOUD COVERAGE AND WEAK NORTHERLY FLOW HAS HELPED KEEP
MORNING MONS UP...THE COOLER AIR ALOFT WILL KEEP TEMPS THE SAME OR
COOLER FROM YESTERDAY ACROSS THE ENTIRE REGION. FORECAST TEMPS
REFLECT THIS CHANGE AND LOOK GOOD. WIND-WISE...BREEZY CONDITIONS
EXPECTED THIS AFTERNOON OVER THE CENTRAL COAST...LA MTNS...AND THE
ANTELOPE VALLEY. ALTHOUGH A FEW VERY LOCALIZED SPOTS MAY CLIP
ADVISORY THRESHOLDS...THE MAJORITY OF THESE AREAS WILL REMAIN BELOW.

...FROM PREVIOUS DISCUSSION...

THE UPPER LOW OVER NRN CA WILL OPEN UP AND LIFT NEWD TODAY...BUT A
BROAD UPPER TROUGH WILL LINGER ACROSS THE AREA THROUGH MONDAY
WITH WKLY CYCLONIC FLOW ALF. AT THE SFC DECENT LOW LVL N-S GRADS
SHOULD CAUSE SOME GUSTY WINDS ACROSS THE CENTRAL COAST AGAIN
THIS AFTERNOON...AND WITH GOOD W-E GRADS...STRONG WESTERLY WINDS
SHOULD AFFECT THE ANTELOPE VALLEY. THERE WILL BE ANOTHER ROUND
OF GUSTY WINDS THRU AND BELOW PASSES AND CANYONS OF SRN SBA COUNTY
TONIGHT. IT LOOKS AS THOUGH NWLY FLOW WILL BECOME MORE WDSPRD ACROSS
THE MTNS OF L.A./VTU COUNTIES TONIGHT...SO EXPECT LOCALLY STRONG
WINDS NEAR THE INTERSTATE 5 CORRIDOR TONIGHT/SUN MORNING. IT LOOKS
AS THOUGH WINDS WILL REMAIN BELOW ADVISORY LEVELS IN MOST AREAS.

UPSLOPE NLY FLOW SHOULD BRING SOME LOW CLOUDS TO THE NRN SLOPES OF
THE L.A/VTU COUNTY MTNS TONIGHT/SUN MORNING. THE WRF SHOWS A
STRONGER EDDY CRCLN TONIGHT/SUN MORNING...WITH MORE IN THE WAY OF
LOW CLDS/FOG IN CSTL SXNS OF L.A. AND PROBABLY VTU COUNTIES. CLOUDS
SHOULD AGAIN BE FAIRLY WDSPRD ON THE CENTRAL COAST AND IN THE SANTA
YNEZ/SALINAS VALLEYS. WITH THE EDDY CRCLN...SOME CLOUDS MAY PUSH
INTO THE SAN GABRIEL AND POSSIBLY SAN FERNANDO VALLEYS LATE TONIGHT
INTO SUN MORNING. WITH LITTLE CHANGE IN HGTS/THICKNESSES ACROSS THE
AREA ON SUN...EXPECT LITTLE CHANGE IN MAX TEMPS IN THE MTNS AND
DESERTS. ADDITIONAL SLIGHT COOLING AT 950 MB SHOULD BRING SLIGHT
COOLING TO COASTAL AND VALLEY AREAS ON SUNDAY.

THE WRF SHOWS SOMEWHAT WEAKER N-S GRADS AND NWLY LOW LVL FLOW SUN
NIGHT/MON...SO EXPECT LESS IN THE WAY OF WINDS IN THE MTNS AND
ACROSS THE SANTA YNEZ RANGE AND THE SBA COUNTY S CST. THERE MAY BE
SLIGHTLY DEEPER INLAND PENETRATION OF THE STRATUS SUN NIGHT/MON.
WITH HEIGHTS/THICKNESSES BEGINNING TO EDGE UPWARD ON MON...THERE MAY
BE A FEW DEGREES OF WARMING IN THE MTNS AND DESERTS...BUT WITH 950
MB TEMPS CHANGING LITTLE...EXPECT LITTLE CHANGE IN BELOW NORMAL MAX
TEMPS W OF THE MTNS FOR MON.

.LONG TERM...HEIGHTS WILL RISE ACROSS THE AREA TUE AS A FLAT RIDGE
BUILDS ALONG THE W CST. AT THE SAME TIME...LOW LVL ONSHORE GRADS
WILL WEAKEN. EXPECT THE MARINE LAYER TO BECOME MORE SHALLOW MON
NIGHT/TUE...WITH CLOUDS PROBABLY CONFINED TO THE CSTL PLAIN. MAX
TEMPS SHOULD BE UP A FEW DEGREES IN MOST AREAS ON TUE...MOST
NOTICEABLY IN THE VLYS. MODELS ARE A BIT DIFFERENT WITH THE UPPER
PATTERN LATER IN THE WEEK...SPECIFICALLY WITH THE PLACEMENT OF THE
UPPER HIGH WHICH IS NOW FCST TO BE SE OF THE FCST AREA AS OPPOSED TO
RIGHT OVER THE AREA. HEIGHTS ARE STILL RATHER HIGH...AND MODELS
STILL SHOW WEAK OFFSHORE TO NEUTRAL LOW LVL FLOW...AT LEAST WED AND
THU MORNINGS. THEREFORE...STILL EXPECT SIGNIFICANT WARMING ON WED...
ESPECIALLY IN THE VALLEYS...WHERE TEMPS SHOULD RISE WELL INTO THE
90S IN WARMER LOCATIONS...THEN IT WILL CONT TO BE RATHER WARM THU
AND FRI. MARINE LAYER SHOULD BE RATHER MINIMAL IN COVERAGE WED THRU
MORNING...CONFINED MAINLY TO AREAS WITHIN A FEW MILES OF THE CST.


&&

.AVIATION...20/2000Z.
AN EDDY WILL SPIN UP A MARINE LAYER TONIGHT...BRINGING LOW CLOUDS
AND PATCHY FOG WITH MVFR CONDITIONS TO AT LEAST LA AND VENTURA
COUNTY COASTAL SECTIONS. OF GREATER UNCERTAINTY IS WHETHER THE LOW
CLOUDS AND FOG WILL ALSO SPREAD TO THE SANTA BARBARA SOUTH COAST AND
THE LA COUNTY VALLEY TAF SITES. THE CENTRAL COAST AND KPRB ARE
LIKELY TO HAVE LOW CLOUDS AND FOG WITH MVFR CONDITIONS OVERNIGHT.

KLAX...FAIR TO GOOD CONFIDENCE IN THE CURRENT TAF. CLEAR SKIES UNTIL
07Z WHEN LOW CLOUDS AND PATCHY FOG WILL ARRIVE WITH MVFR CONDITIONS.
A 40 PERCENT CHANCE OF LOW CLOUDS AND FOG ARRIVING AS SOON AS 05Z OR
AS LATE AS 09Z. THEN LOW CLOUDS AND FOG UNTIL LATE MORNING SUNDAY.

KBUR...LITTLE OR NO CONFIDENCE IN THE TAF FORECAST FOR KBUR. A 50
PERCENT CHANCE OF LOW CLOUDS AND FOG ARRIVING AFTER MIDNIGHT...AND A
50 PERCENT CHANCE OF CLEAR SKIES.

&&

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

&&

$$

PUBLIC...BRUNO
AVIATION...SWEET

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