B737-300 FLT CREW DIVERTS TO ANOTHER ARPT DUE TO WX AND FUEL CONSTRAINTS.

Narrative

PREFLT PLANNING TAF FOR SAN CALLED FOR 6 SM HAZE F008 -- NO ALT REQUIRED. DUE TO POSSIBLE SINGLE RWY OPS AT DEP STATION AND CHANGING COASTAL WX WE ADDED 600 LBS FUEL. WE BLOCKED OUT AT XA48Z. AFTER AIRBORNE; ATIS FOR SAN WAS 1/2 SM FOG VV001. THIS CANE OUT AT XA25 ALONG WITH A NEW TAF -- 3/4 SM BROKEN 004; TEMPO XBXC 4 SM BROKEN SCATTERED 500 FT. THESE CAME OUT 23 MINS PRIOR TO BLOCKOUT. LEGALLY; WE THINK WE REVIEWED THE ORIGINAL TAF IN THE REQUIRED TIME FRAME PRIOR TO FLT. I THINK IF DISPATCH WAS AWARE OF THE WX CHANGE PRIOR TO THE PUSH THEY SHOULD HAVE ALERTED US. AIRBORNE WE FOUND ACFT ALREADY HOLDING FOR ARR TO SAN. OUR FUEL DID NOT LEAVE US AN OPTION TO SHOOT AN APCH; GO MISSED AND THEN DIVERT TO LAX IF NEEDED; NOR DID WE HAVE ANY EXTRA FUEL FOR HOLDING. DISPATCH SAID THE APCH WAS 'DOABLE' BECAUSE WE HAD VISIBILITY REQUIREMENTS. WHAT DISPATCH FAILED TO REALIZE IS THAT PLANES WERE GOING MISSED APCH DUE TO CEILING CONSTRAINTS. OUR MINIMUMS TAKE US DOWN TO 336 FT AND THE ATIS WAS CALLING VV001 (100 FT). VISIBILITY DOES NOTHING IF YOU CAN'T GET BELOW THE CLOUD DECK. KNOWING THIS WE TOOK THE CONSERVATIVE AND ONLY OPTION OF DIVERTING TO LAX PRIOR TO STARTING THE APCH TO SAN. WE LEFT OURSELVES SOME OPTIONS. AFTER REFUELING IN LAX AND RETURNING TO SAN; OUR ASSESSMENT OF THE CLOUD DECK WAS ACCURATE -- WITH NO SUCCESS AFTER 3 ATTEMPTS; RETURN TO LAX. IMPORTANCE OF KEEPING FLTS UPDATED CANNOT BE OVEREMPHASIZED WHICH ALL OF US ARE RESPONSIBLE FOR. IT'S ALSO IMPORTANT FOR DISPATCH TO REALIZE THE VISIBILITY ALONE WON'T GUARANTEE YOU WILL BREAK OUT OF THE CLOUD DECK.