FXUS66 KLOX 261628 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 915 AM PDT TUE MAR 26 2013 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... A DEEPENING MARINE LAYER AND ONSHORE FLOW WILL RESULT IN AN INCREASE IN NIGHT THROUGH MORNING LOW CLOUDS ACROSS THE COASTAL PLAIN AND VALLEYS THIS WEEK. TEMPERATURES WILL LIKELY BE NEAR NORMAL FOR MOST OF THE PERIOD. A LOW PRESSURE SYSTEM WILL DEVELOP WELL OFF THE COAST LATE IN THE WEEK...POSSIBLY BRINGING RAIN AND COOLER WEATHER TO SOUTHERN CALIFORNIA LATE IN THE WEEKEND OR EARLY NEXT WEEK. && .SHORT TERM (TODAY-THU)...DO NOT ANTICIPATE AN UPDATE THIS MORNING. MARINE INVERSION WAS DISORGANIZED AND WEAK WITH TOPS RANGING FROM 2KFT OVER THE LA COUNTY TO 1.5KFT ON THE CENTRAL COAST. AND EXPECT LITTLE CHANGE IN STRENGTH THROUGH WEDNESDAY. LOW LEVEL PROFILER AT LAX INDICATED THE CLOUD THICKNESS APPROXIMATELY 1KFT OR LESS. AND PICTURES FROM SPACE INDICATED A LIMITED CLOUD FIELD NEAR SHORE OVER THE BIGHT AND A LARGER FIELD NORTH OF POINT CONCEPTION. LOW CLOUDS WILL LIKELY MIX OUT THROUGH THE MORNING AND RETURN TONIGHT AS THE CLOUD FIELD OVER THE COASTAL WATERS NORTH OF POINT CONCEPTION SHIFTS SOUTHEAST. THE FOLLOWING IS AN EXCERPT WRITTEN BY THE PREVIOUS SHIFT PRESSURE GRADIENTS...HOWEVER...ARE TRENDING STRONGLY ONSHORE AND SHOULD BE AROUND +6 TO KDAG BY THIS AFTERNOON. THIS STRONG AN ONSHORE GRADIENT WILL KEEP SOME LOW CLOUDS AT THE BEACHES. A STRONGER SEA BREEZE AND SLIGHTLY LOWER HGTS WILL CONTRIBUTE TO TODAYS MAX TEMPS RUNNING A DEGREE OR TWO UNDER MONDAYS VALUES. THE ONSHORE PUSH WILL ALSO MAKE FOR A BREEZY DAY ACROSS THE ANTELOPE VLY WHERE THERE WILL BE SOME 35 MPH GUSTS THIS AFTERNOON. NOT MUCH CHANGE ON WEDNESDAY. SAME MARINE CLOUD LAYER PROBLEM WILL PERSIST. WITH GRADIENTS RUNNING ABOUT 3 MB STRONGER TONIGHT THAN LAST THINK A BETTER MARINE LAYER CLOUD PATTERN IS LIKELY. THERE WILL BE SLOW CLEARING AGAIN AND MAX TEMPS WILL BE WITHIN A DEGREE OR TWO OF TODAYS VALUES. ON THURSDAY AN UPPER LOW SWINGS DOWN TO OUR LATITUDES BUT STAYS SEVERAL HUNDRED MILES OFFSHORE. THIS LOW WILL CHANGE THE FLOW PATTERN FROM W TO SW. THIS FLOW PATTERN WILL ALLOW FOR QUITE A BIT OF CLOUDS TO STREAM OVERHEAD. THE PROXIMITY OF THE LOW WILL ALSO BOOST UP THE MARINE LAYER AND LOW CLOUDS SHOULD BLANKET MUCH OF THE COASTS AND VLYS. OVERALL IT WILL BE A MOSTLY CLOUDY DAY. THERE WILL BE ENOUGH LIFT NORTH OF POINT CONCEPTION TO CREATE PATCHY DRIZZLE. A LITTLE IMPULSE MOVES OVER THE CENTRAL COAST IN THE AFTERNOON AND EVENING AND WILL BRING A SLIGHT CHANCE OF LIGHT RAIN TO SLO AND WESTERN SBA COUNTIES. RAINFALL TOTALS IF ANY WILL BE UNIMPRESSIVE LESS THAN .05 OF AN INCH. ALL THE CLOUDS WILL KNOCK A FEW DEGREES OFF OF THE DAYS MAX TEMPS. .LONG TERM (FRI-MON)... ALL MDLS ARE IN PRETTY GOOD AGREEMENT FOR THE XTND PERIOD. ALL INDICATE THAT THE LARGE UPPER LOW (ABOUT THE SIZE OF THE STATE) WILL SIT AND SPIN JUST OFF THE COAST THROUGH SATURDAY. IT WILL SPIN OVER THE STATE SUNDAY (EXACTLY WHERE IS SOMEWHAT UP IN THE AIR) AND THEN EXIT THE STATE EARLY MONDAY. ON FRIDAY THE SW FLOW AHEAD OF THE FRONT SHOULD CREATE ENOUGH LIFT TO BRING ABOUT A DEEP MARINE LAYER AND SOME DRIZZLE. HGTS HOWEVER JUMP UP AS A LITTLE RIDGE DEVELOPS AHEAD OF THE TROF AND THERE IS A BIT OF OFFSHORE FLOW GENERATED BY THE SFC REFLECTION OF THE UPPER LOW OFF TO THE WEST SO MAX TEMPS WILL ACTUALLY BUMP UP A FEW DEGREES ACROSS THE AREA. CLOUDIER AND COOLER SATURDAY AS THE LOW APPROACHES THE STATE. RAIN COULD MOVE INTO THE OUTER WATERS LATE IN THE AFTERNOON OR EARLY EVENING. THE BEST CHANCE OF RAIN LOOKS TO BE SUNDAY AS THE LOW IN SOME FORM MOVES OVER THE STATE. STILL HAVE CHC POPS DUE TO THE FACT THE MDLS HAVE BEEN FLIP FLOPPING LIKE A CARP ON A PIER BUT IF THE MDL CONSENSUS HOLDS IN TODAYS MDL RUNS THINK POPS CAN BE BUMPED UP INTO THE LIKELY CATEGORY. SUNDAY WILL BE THE COOLEST DAY OF THE WEEK. THE SYSTEM SHOULD MOVE OUT EARLY MONDAY WHICH WILL LEAD TO A PARTLY CLOUDY AND DRY (MAYBE A STRAY MORNING SHOWER DEPENDING ON HOW FAST THE SYSTEM EXITS) DAY. MAX TEMPS WILL BE BELOW NORMAL BUT WILL BE A DEGREE OR TWO WARMER THAN SUNDAYS COOL READINGS. && .AVIATION... 26/1130Z S OF POINT CONCEPTION... LOW CONFIDENCE IN 12Z TAFS FOR THIS MORNING. STRATUS HAS BEEN CHAOTIC UNDER HIGH CLOUD SHIELD. CIGS HAVE VARIED FROM IFR OVER LA COUNTY TO VLIFR AT KOXR. NOT CONFIDENT WITH STRATUS BURNOFF TIMES AS WELL. 40 PERCENT CHANCE FOR TAF BURNOFF TIMES TO BE +/- 2HOURS FROM CURRENT TAFS. OR 30 PERCENT CHANCE THAT KOXR WILL STAY CLOUDY THROUGH 23Z. LOW CLOUDS SHOULD HAVE AN EASIER TIME FILLING IN ACROSS COAST AND VALLEYS LATER TONIGHT WITH HIGH IFR/LOW MVFR CIGS. N OF POINT CONCEPTION...MODERATE CONFIDENCE WITH 12Z TAFS. LIFR/IFR CIGS SHOULD BURNOFF +/- 1 HOUR FROM CURRENT TAF. HIGH CONFIDENCE FOR VLIFR/LIFR CIGS TO BUILD IN ONCE AGAIN THIS EVENING AND PERSIST THROUGH THE OVERNIGHT HOURS. HIGHER CONFIDENCE FOR IFR CIGS AT KPRB AFTER 10Z WED MORNING. KLAX...MODERATE CONFIDENCE IN TAF. 30 PERCENT CHANCE THAT IFR CIGS COULD BECOME LIFR FROM 13Z-16Z. A 30 PERCENT CHANCE OF SCT CONDS 22Z-03Z. KBUR...MODERATE CONFIDENCE IN TAF. CIGS SHOULD ARRIVE A 13-14Z. STRATUS SHOULD BE IFR BUT 30 PERCENT CHANCE FOR LIFR CIGS OR A 20 PERCENT CHANCE OF NO CIGS AT ALL. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXMWWLOX). && $$ PUBLIC...RORKE/ AVIATION...KAPLAN SYNOPSIS...SUKUP WWW.WEATHER.GOV/LOSANGELES  FXUS66 KLOX 290951 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 255 AM PDT MON JUL 29 2013 .SYNOPSIS... A WEAK UPPER LOW WILL MOVE ACROSS THE AREA TODAY...BRINGING LOW CLOUDS AND FOG INTO THE VALLEYS...ALONG WITH PATCHY DRIZZLE. STRONG ONSHORE FLOW WILL CONTINUE TO PRODUCE GUSTY WINDS DURING THE AFTERNOON AND EVENING HOURS FOR THE INTERIOR SECTIONS AS WELL. A DECREASE IN MARINE LAYER CLOUDS AND SLIGHTLY WARMER WEATHER CAN BE EXPECTED STARTING MID WEEK...FOLLOWING THE PASSAGE OF THE UPPER LOW. && .SHORT TERM (TODAY-WED)...EXPECT A SIMILAR WEATHER PATTERN AS YESTERDAY IN RESPECT TO THE DEEP AND PESKY MARINE LAYER AND ASSOCIATED LOW CLOUDS. LATEST AMDAR SOUNDING NEAR LAX INDICATED THE MARINE LAYER AT 2400 FT. ALTHOUGH THE ONSHORE SURFACE GRADIENT BETWEEN LAX-DAG WILL BE A COUPLE MILLIBARS WEAKER THIS AFTERNOON... THE INVERSION WILL REMAIN RELATIVELY STRONG WHICH WILL MAKE IT TOUGH FOR LOW CLOUDS TO MIX OUT NEAR THE BEACHES. LOW CLOUD DEPTH IS MUCH DEEPER ACROSS THE CENTRAL COAST AS WELL THIS MORNING COMPARED TO YESTERDAY. ON TOP OF THIS DEEP MARINE LAYER...THE CUTOFF LOW THAT WAS HANGING OFF THE COAST THE LAST FEW DAYS WILL BEGIN TO FILL IN AS IT MOVES ACROSS THE REGION THIS MORNING. THIS WILL CAUSE SOME ADDITIONAL LIFTING WHICH SHOULD SQUEEZE OUT LIGHT MOISTURE IN THE FORM OF DRIZZLE ACROSS THE ENTIRE CENTRAL COAST AS WELL AS COAST AND VALLEYS ACROSS LOS ANGELES...VENTURA AND SOUTHERN SANTA BARBARA COUNTIES THIS MORNING. EXPECT A SIMILAR OR SLIGHTLY QUICKER BURNOFF ACROSS THE COASTAL VALLEYS THIS MORNING. THERE WILL CONTINUE TO BE GUSTY SW WINDS INTO THE ANTELOPE VALLEY...ESPECIALLY AROUND LAKE PALMDALE THIS AFTERNOON. WITH THE MID LEVELS MUCH DRIER AND A PREDOMINANT SW FLOW EXPECTED MOST OF THIS WEEK...ALL MONSOONAL MOISTURE WILL REMAIN WELL EAST AND SOUTH OF THE FORECAST AREA. MODELS ARE ADVERTISING A THIN POCKET OF MID LEVEL MOISTURE BETWEEN 650-500 MB OVER THE VENTURA COUNTY MOUNTAINS THIS AFTERNOON...SO A FEW CU BUILDUPS COULD OCCUR OVER THE HIGHEST MOUNTAIN PEAKS NEAR LOCKWOOD VALLEY LATER THIS AFTERNOON. FOR TONIGHT AND TUESDAY...EXPECT LOW CLOUDS TO PUSH INLAND ONCE AGAIN AFFECTING COASTAL VALLEYS...BUT SHOULD NOT BE AS DEEP. THIS SHOULD ALLOW FOR A QUICKER BURNOFF TO THE COAST ON TUESDAY. HIGH TEMPS MIGHT A BE A DEGREE OR TWO WARMER ALONG THE COAST WITH INLAND TEMPS ABOUT THE SAME AS TODAY. THERE COULD BE ADDITIONAL WARMING ALONG THE SANTA BARBARA CENTRAL COAST IF THE NAM-WRF IS CORRECT AS SE FLOW OVER THE SANTA YNEZ RANGE SHOULD CAUSE SOME COMPRESSIONAL HEATING ON THE NORTHERN SLOPES INTO THE CENTRAL COAST TUE AFTERNOON. BY WEDNESDAY...HIGH PRESSURE ACROSS THE SOUTHWESTERN STATES WILL BEGIN TO EXPAND WESTWARD WHILE ANOTHER UPPER LOW OFF THE PAC NW COAST DEVELOPS. AS IS TYPICAL FOR OUR REGION THIS TIME OF YEAR...THERE WILL BE A BATTLE BETWEEN THE UPPER HIGH TO OUR SE AND A LINGERING TROUGH TO OUR NW. IT LOOKS LIKE THE RIDGE WILL EXPAND ENOUGH TO SHRINK THE MARINE LAYER DOWN ALLOWING NIGHT THROUGH MORNING CLOUDS LIMITED TO THE COAST AND SAN GABRIEL VALLEY...WHILE THE SAN FERNANDO VALLEY REMAINS MOSTLY CLEAR. HIGH TEMPS WILL INCREASE AS WELL AS HEIGHTS AND THICKNESS LVLS INCREASE. THE ANTELOPE VALLEY WILL REACH THE UPPER 90S ON WED...WHILE MOST VALLEYS WILL BE IN THE MID 80S TO AROUND 90...EXCEPT SAN LUIS OBISPO INTERIOR VALLEY SHOULD REACH THE LOWER TO MID 90S. .LONG TERM (THU-SUN)... THE UPPER RIDGE WILL CONTINUE TO EXPAND THROUGH THE WEEKEND OVER THE SOUTHERN PORTION OF CALIFORNIA...WHILE A WEAK TROUGH LINGERS ACROSS THE NORTHERN PORTION OF THE STATE. THE MARINE LAYER SHOULD CONTINUE TO SHRINK LIMITING LOW CLOUDS ACROSS THE COASTAL AREAS...WITH SOME PATCHY LOW CLOUDS LIKELY REACHING THE SAN GABRIEL VALLEY EACH NIGHT AFTER MIDNIGHT. HIGH TEMPS ACROSS THE INLAND AREAS WILL BEGIN TO TREND WARMER...BUT REMAIN NEAR NORMAL THROUGH FRI...BUT INCREASE A FEW MORE DEGREES THIS WEEKEND WITH THE ANTELOPE VALLEY REACHING 100 DEGREES BY SATURDAY AND WARMEST VALLEY LOCATIONS IN THE MID 90S. && .AVIATION...WILL BE UPDATED WITH 12Z TAF PACKAGE. && .LOX WATCHES/WARNINGS/ADVISORIES... NONE && $$ PUBLIC...KAPLAN AVIATION...BRUNO SYNOPSIS...SUKUP WWW.WEATHER.GOV/LOSANGELES