083 FXUS66 KLOX 012115 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 215 PM PDT SUN JUL 1 2012 .SYNOPSIS... AN UPPER TROUGH OFF THE WEST COAST WILL CAUSE DEEPENING OF THE MARINE LAYER THROUGH MID WEEK...WITH NIGHT THROUGH MORNING LOW CLOUDS AND FOG EXTENDING FARTHER INTO THE VALLEYS EACH DAY. THERE WILL BE A COOLING TREND WEST OF THE MOUNTAINS...WITH BELOW NORMAL TEMPERATURES THROUGH THURSDAY. AN UPPER HIGH OVER THE CENTRAL U.S. WILL BEGIN TO EXPAND INTO THE REGION LATE IN THE WEEK INTO NEXT WEEKEND...BRINGING A REDUCTION IN LOW CLOUDS AND A WARMING TREND. && .SHORT TERM (TONIGHT-WED)... A BAGGY TROUGH OVER THE WEST COAST WILL WEAKEN AND SHIFT INLAND TONIGHT AS AN UPPER LOW IN THE GULF OF ALASKA SWINGS TOWARD THE PACIFIC NW. THIS LOW WILL REMAIN IN PLACE THROUGH MIDWEEK AS SEVERAL WAVES ROTATE AROUND IT. THIS PATTERN WILL MAINTAIN WEAK TROUGHING OVER THE SW CALIFORNIA COAST...DEEPENING SLIGHTLY TONIGHT THROUGH MONDAY NIGHT. THE END RESULT WILL BE A CONTINUED DEEPENING OF THE MARINE LAYER...WITH LOW CLOUDS MOVING FURTHER INLAND THROUGH THE VALLEYS EACH NIGHT AS HEIGHTS ALOFT GRADUALLY DIMINISH. THE STRATUS MAY BE ABLE TO ADVANCE AS FAR INLAND AS THE SANTA CLARITA VALLEY TONIGHT AND MONDAY NIGHT...DUE TO THE COMBINATION OF LOWERING HEIGHTS AND ONSHORE FLOW. EXPECT TO SEE THE MARINE LAYER DEPTH BETWEEN 2000 TO 2500 FEET TONIGHT FOR SOUTHERN SECTIONS AND AROUND 1500 FEET N OF PT CONCEPTION. SBA-SMX GRADIENTS ARE SLIGHTLY WEAKER THIS AFTERNOON...AND NAM12 LOW LEVEL WINDS INDICATE THAT THE NORTHWEST-NORTH WINDS NEAR/WEST OF GAVIOTA WILL BE SOMEWHAT REDUCED COMPARED TO PREVIOUS NIGHTS. EXPECT TO SEE LOCAL GUSTS OF 35 TO 40 MPH BELOW PASSES AND CANYONS...BUT NOT WIDESPREAD ENOUGH TO WARRANT ANY HIGHLIGHTS. STRONG ONSHORE GRADIENTS WILL CONTINUE THROUGH THE SHORT TERM AS THE POSITION OF THE UPPER TROUGH REMAINS ESSENTIALLY UNCHANGED...BRINGING GUSTY WINDS TO THE MOUNTAINS AND DESERTS EACH AFTERNOON/EVENING PERIOD. THIS WILL PRODUCE SLOWER CLEARING OF THE STRATUS EACH DAY...ESPECIALLY NEAR THE COAST...AND THE CENTRAL COAST MAY CONTINUE TO SEE LOW CLOUDS NEAR THE COAST THROUGH EACH AFTERNOON. DAYTIME HIGH TEMPERATURES SHOULD BE DOWN A DEGREE OR TWO EACH DAY FOR THE COAST AND VALLEYS...WITH LITTLE CHANGE IN THE MOUNTAINS AND DESERTS. .LONG TERM (THU-SUN)... MODELS CONTINUE TO DEPICT THE UPPER TROUGH JUST OFF THE COAST THURSDAY...AND BEGIN TO SHIFT IT FURTHER OFFSHORE AS THE CENTRAL U.S. RIDGE BUILDS WESTWARD. SLOWLY RISING HEIGHTS WILL COMPRESS THE MARINE LAYER THURSDAY INTO FRIDAY...WITH CLOUDS LIMITED TO COASTAL AREAS BY FRIDAY MORNING. THE RISING HEIGHTS AND REDUCED ONSHORE FLOW WILL PRODUCE A WARMING TREND ACROSS THE AREA...TO CONTINUE THROUGH THE EXTENDED WITH INLAND HIGHS IN THE UPPER 80S TO NEAR 100 DEGREES BY THE WEEKEND. AS THE RIDGE CONTINUES TO EXPAND WESTWARD INTO SE CALIFORNIA...MODELS HINT AT MONSOONAL MOISTURE CREEPING INTO THE SE INTERIOR OF THE CWA LATE IN THE EXTENDED. && .AVIATION...01/1745Z... LATEST SATELLITE IMAGERY SHOWS STRATUS BURNING OFF QUITE LATE THIS MORNING. VFR CONDS SHOULD PREVAIL AT ALL AIRFIELDS THROUGH THIS AFTERNOON. FOR TONIGHT...EXPECT A RATHER PERSISTENT STRATUS BEHAVIOR AS INVERSION DEPTH SHOULD VARY LITTLE. SO...STRATUS SHOULD RETURN TO COASTAL TAFS THIS EVENING...AND INTO THE VALLEY TAF OVERNIGHT. CIGS/VSBYS SHOULD GENERALLY BE AT IFR/LIFR LEVELS OVERNIGHT. KLAX...MODERATE CONFIDENCE IN 18Z TAF. STRATUS COULD RETURN AN HOUR OR TWO EARLIER THAN CURRENT 06Z FORECAST. KBUR...MODERATE CONFIDENCE IN 18Z TAF. STRATUS COULD RETURN AN HOUR OR TWO EARLIER THAN CURRENT 11Z FORECAST. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXMWWLOX). && $$ PUBLIC...SMITH AVIATION...RAT SYNOPSIS...SWEET WWW.WEATHER.GOV/LOSANGELES