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000 FXUS66 KLOX 171208 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 440 AM PDT WED SEP 17 2008 .SHORT TERM... UPDATE...MARINE LAYER INTRUSION IS MUCH STRONGER THAN EARLIER THOUGHT AND ISSUED AN UPDATE TO COOL THINGS OFF. MARINE LAYER HAS RISEN TO 1200 TO 1300 FEET AND GRADIENTS ARE ABOUT 3 MB ONSHORE BOTH TO THE NORTH AND TO THE EAST WHICH IS CLOSE TO A 4 MB ONSHORE TREND. THIS WILL NOT COOL THE VLYS MUCH...WHICH IS UNUSUAL...SINCE THERE WILL BE MUCH MORE SUNSHINE THAN YDY. THE CENTRAL COAST WILL BE VERY SIMILAR TO YDY WITH SUNNY SKIES AFTER MORNING LOW CLOUDS. TEMPS ON THE COAST WILL BE SIMILAR TO YDY WHILE THE SALINAS VLY WILL DROP A FEW DEGREES WITH A DEEPER MARINE LAYER. STILL ENOUGH MID LEVEL MOISTURE AND INSTABILITY OVER THE MTNS TO WARRANT A SLGT CHC OF AFTERNOON AND EVENING TSTMS BUT IF THEY DO FORM THEY SHOULD BE MORE ISOLATED THAN YDY DUE TO THE DECREASE IN MOISTURE. THE MARINE LAYER SHOULD REMAIN ABOUT THE SAME WEDNESDAY NIGHT AND THURSDAY MORNING. ALSO WITH LITTLE CHANGE IN THE HGTS THE GRADIENTS AND THE MARINE LAYER THURSDAY SHOULD BE VERY SIMILAR TO TODAY EXCEPT THAT THE MID LEVELS WILL BE VERY DRY AND THERE WILL BE NO CHC OF TSTM FORMATION. A NEGATIVE TILT UPPER LOW MOVES INTO NRN CA FRIDAY. THIS SHOULD LIFT THE MARINE LAYER INTO ALL COASTS AND VLYS AND COOL THINGS DOWN. THE NAM HOWEVER THROWS A LITTLE CURVE INTO THE MIX AND FORECASTS ZERO MARINE LAYER FOR AREAS SOUTH OF POINT CONCEPTION. THERE IS LITTLE TO INDICATE WHY SUCH A CLEARING SHOULD TAKE PLACE OTHER THAN A WEAKER EDDY. WENT AGAINST GUIDANCE AND DID BRING A GOOD MARINE LAYER WITH COOLER TEMPS. .LONG TERM... THE IMPULSE ON FRIDAY CONTINUES TO FLUMMOX THE MEDIUM RANGE MODELS. SATURDAYS FORECAST LOOKS ON TRACK WITH THE LOW MOVING OUT AND HGTS RISING THE MARINE LAYER SHOULD SHRINK A LITTLE AND TEMPS SHOULD WARM A FEW DEGREES. AFTER SATURDAY THE MDLS GO THEIR OWN WAYS AND THE GFS ENSEMBLES BOMB-BURST INTO A SQUIGGLY MESS. WITH LITTLE OR NO CONFIDENCE IN THE LONG RANGE FORECAST MADE A FEW ADJUSTMENT TOWARD CLIMATOLOGY BUT IN GENERAL LEFT THINGS UNCHANGED FROM SUNDAY ON. HOPEFULLY THE MODELS WILL GET A HANDLE ON FRIDAYS IMPULSE AND THE MEDIUM RANGE MDLS WILL GET A HANDLE ON THINGS. && .AVIATION... 17/1100Z MARINE LAYER IS NEAR 1300 FEET AND PUSHED IN NICELY BY A 3 MB GRADIENT. CIGS ARE HIGH ENOUGH TO MAKE IT INTO THE VLYS BUT WILL ALSO BE HIGH ENOUGH TO NOT PRESENT MUCH OF VISIBILITY PROBLEM. THE CENTRAL COAST WILL BE SLOW TO CLEAR. THE MARINE CLOUD PATTERN THIS EVENING AND OVERNIGHT SHOULD BE VERY SIMILAR TO YDY NIGHT. KLAX...VERY GOOD CONFIDENCE IN 12Z TAF. CIG CLEARING WILL VERY LIKELY BE WITHIN AN HOUR OF FORECAST. KBUR...GOOD CONFIDENCE IN TH 12Z TAF. CIG BURN OFF COULD BE ONE OR TWO HOURS LATER THAN FORECAST. CIG ARRIVAL TONIGHT WILL BE AFTER MIDNIGHT AND MORE LIKELY TOWARD DAWN. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXMWWLOX). && $$ PUBLIC...RORKE AVIATION...BRUNO WWW.WEATHER.GOV/LOSANGELES