Lets stay put

Guys

Actually,
a) If the bulk of the US fleet is still in San Diego then would the Japanese still attack Pearl Harbour? It was a risky operation and consumed a lot of resources which they could definitely use elsewhere. The only likely reason I can think form this is that they might attack what was there, i.e. things like the oil storage tanks and repairs facilities. If they did this AND it was successful that could seriously handicap USN operations in the Pacific until the damage was made good.

b) If they don't attack then there is one nasty complication. The USN still has its battleships and hasn't seen how devastating carrier a/c can be, although land based air while probably still have shown their effectiveness against Force Z. Hence they could continue with their existing doctrine, centred around the battle-fleet with the carriers being used singly and primarily as scouts, instead of being forced to concentrate on their carriers. This would limit their operations as the battle-fleet is a lot slower and also it would consume a lot of supplies and escorts for those ships. Furthermore if this force clashes with the Japanese main force then it could get a nasty shock from the Japanese CVs, with much heavier losses than at Pearl as ships sunk would go down in deep water rather than largely be refloatable and repairable.

It's very unlikely to greatly change the outcome of the war as the Japanese are hopelessly outclassed by their combined opponents but could change a lot of the early stages.

Steve

PS  There are two possible serious butterflies but their probably fairly unlikely options.
1)  That the lack of a clear threat from the US means that the Japanese don't attack the US but only the British and Dutch.  This could be seriously disastrous for the allied powers.

2)  That the US, with a complete battle-fleet is forced by political pressure to attempt a relief of the Philippines.  This would be likely to be a major disaster and IF also the Japanese haven't attacked Pearl with the resulting upsurge in war feeling in the states there is the outside chance that the US might see a move for peace with Japan.

  Lordroel

  Short of ASB intervention or multiple years of planning and logistical build-up that it would be very difficult to hide the answer is no.  In terms of range alone Pearl was pretty much at the limits of their operations and I think some of their escorting destroyers had to be towed back to base as they ran out of fuel.  San Diego would be even further and even if they could get the range somehow they would probably have even greater difficulty approaching to within attack range without being detected.  Not to mention the risk, once the attack takes place of retreating all the way across the Pacific without being attacked, by air and subs if nothing else.

  Steve

The Japanese would still attack Pearl Harbor ITTL. They have to do their best to destroy American power in the Pacific.

Philippines the primary target on their flank to the East Indies,with fleet in San Diego,I think they pass on Pearl Harbor.

  The USN will still work from Pearl, once the war starts.  There is the chance that the Japanese might get the chance to try their decisive battle doctrine if political pressure and the existence of a US battle-fleet means that the USN is driven into being more aggressive.  As I say the naval experts already agreed that the Philippines were indefensible but the politicians might not agree or they may be lured into a big battle somewhere else.  The Japanese carrier force used as a concentrated strike force could be a very nasty shock for the US and their older ships would be a lot slower to escape if they were forced to retreat.  Not going to decide the war in the longer run but could make for a much nastier defeat for the USN than Pearl was OTL.

Why would that happen, the carriers most likely will operate as they did in OTL.