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000 FXUS66 KLOX 141633 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 914 AM PDT SUN SEP 14 2008 .SHORT TERM (TODAY-TUE)...MARINE LYR HAS DECREASED TO ABOUT 1800 FT THIS MORNING AS HIGH PRESSURE BUILDS OVER THE STATE. ONSHORE IS ALSO WEAKER THIS MORNING. THE SIMI VALLEY PROFILER IS SHOWING 5-10 DEGREES OF WARMING ABOVE THE MARINE LYR SO EXPECT FOOTHILLS AND MOUNTAINS ALONG WITH THE SANTA CLARITA VALLEY TO SEE MUCH WARMER TEMPS TODAY. THE AMOUNT OF WARMING TODAY WILL DECREASE TOWARDS THE COAST AND EXPECT LITTLE CHANGE IN TEMPS AT THE BEACHES TODAY WITH SOME CLOUDS AGAIN LINGERING THROUGH THE AFTERNOON. NOT TOO MUCH CHANGE IN THE 12Z MODELS FOR MON AND TUE. BOTH THE GFS AND NAM SHOW GRADIENTS TURNING OFFSHORE MONDAY MORNING, WITH THE OFFSHORE FLOW STRENGTHENING TUESDAY MORNING. WITH 950 TEMPS EXPECTED TO BE CLOSE TO 30C COMBINED WITH THE OFFSHORE FLOW TEMPS AT ALL LOWER ELEVATION LOCATIONS SHOULD SEE IMPRESSIVE GAINS MONDAY AND AGAIN TUESDAY. MOS GUIDANCE VALUES FOR TUESDAY SEEM WAY TOO LOW GIVEN THE OFFSHORE FLOW AND CURRENT FORECAST NUMBERS ARE SEVERAL DEGREES HIGHER. LOCAL TEMPERATURE GUIDANCE EVEN INDICATES HIGHS ON TUE COULD EVEN BE WARMER THAN CURRENTLY INDICATED IF ALL FACTORS COME TOGETHER AS CURRENTLY PROJECTED. 12Z MODELS SHOWED A NARROW BAND OF MOISTURE AROUND 700 MB FOR TUE DUE TO THE INFLUENCE OF THE UPPER LOW OFF NRN CALIFORNIA. HOWEVER, IT`S STILL VERY DRY AT LOWER LEVELS. NAM DID SHOW LI`S DROPPING BELOW ZERO TUESDAY AFTERNOON OVER ERN LA COUNTY. FOR NOW HAVE CONFINED AFTERNOON CLOUDS TO THE INTERIOR PORTION OF THE CWA. IF ANY CONVECTION DOES DEVELOP IT LOOKS LIKE IT WOULD BE OVER ERN LA COUNTY. BUT CHANCES ARE TOO LOW TO PUT IN THE FORECAST FOR NOW. *** LONG TERM FROM PREVIOUS DISCUSSION *** .LONG TERM... EC AND GFS IN GOOD AGREEMENT THROUGH SATURDAY AND THEN DIVERGE. GFS ENSEMBLES POINT TO A LOWER CONFIDENCE FORECAST STARTING FRIDAY BUT MOST OF THE ENERGY IS WELL NORTH OF US AND NOT TOO SURE HOW MUCH THE DEVIATIONS WILL AFFECT THE WEATHER DOWN HERE. IN SHORT THERE IS LIKELY GOING TO BE TROFING THROUGH AT LEAST FRIDAY WITH A PM/AM CLOUD PATTERN AND TEMPS A LITTLE COOLER THAN NORMAL. A SMALL RIDGE WILL BUILD IN LATER FRIDAY AND SATURDAY PROBABLY TOO LATE TO AFFECT THE MARINE LAYER OR COASTAL TEMPS SATURDAY MUCH BUT INLAND TEMPS MAY RISE A FEW DEGREES SATURDAY. && .AVIATION...14/1325Z. IFR CONDITIONS WILL LIKELY REMAIN AT MOST TERMINALS THROUGH AT LEAST 16Z THIS MORNING. CLEARING IS STILL EXPECTED TO BE SLIGHTLY QUICKER WITH VALLEY TERMINALS CLEARING AROUND 16Z AND COASTAL TERMINALS CLEARING BETWEEN 16Z AND 18Z NORTH...TO 17Z TO 21Z SOUTH. AN EARLY RETURN OF THE MARINE LAYER IS LIKELY TONIGHT FOR KLAX...KLGB...KSMX...AND KSBP. OTHERWISE...KPMD AND KWJF WILL REMAIN VFR THROUGHOUT THE PERIOD. KLAX...IFR CONDITIONS WILL PERSIST WITH CEILINGS BELOW 1000 FEET THROUGH AT LEAST 16Z...BUT AS LATE AS 18Z. LOW CONFIDENCE EXISTS IN THE TIMING OF CLEARING...BUT CLEARING SHOULD BE SLIGHTLY EARLIER...BETWEEN 19Z AND 21Z. VFR CONDITIONS SHOULD DEVELOP AFTER 21Z AND PERSIST THROUGH AT LEAST 01Z...OR AS LATE AS 04Z WHEN THE STRATUS LAYER HAS A 70 PERCENT CHANCE OF RETURNING. KBUR...IFR CONDITIONS HAVE DEVELOPED OVER KBUR AND VICINITY THIS MORNING. VFR CONDITIONS SHOULD REDEVELOP BETWEEN 16Z AND 17Z THIS MORNING AND WILL PERSIST THROUGHOUT THE REMAINDER OF THE PERIOD. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXMWWLOX). FIRE WEATHER WATCH (SEE LAXRFWLOX). && $$ PUBLIC...WOFFORD/RORKE AVIATION...HALL WWW.WEATHER.GOV/LOSANGELES