Hey, I could use the jet stream to send balloons across the Pacific Ocean, too. What I can't do, however (and I don't understand how anyone in 1945 could have done it), is: 1) ensure that it follows a precise track that takes it directly over the U.S., and 2) runs out of air over the U.S. (as opposed to landing in the Pacific Ocean, the Atlantic Ocean in Europe, or -- heaven forbid -- floats all the way around the world and lands in Japan).
"From the late fall of 1944 through the early spring of 1945, the Japanese launched more than 9,000 of these "fusen bakudan", or fire balloons, of which 300 were found or observed in the US."
http://www.japan-101.com/history/fire_balloons_or_balloon_bombs.htm
It's like talking to a wall with some people
Again, just because you don't see how it could happen doesn't mean that it didn't happen. You really should at least know a little bit about the ACTUAL history of WWII before making ridiculous statements.
I do understand your point. You confirmed that Japan didn't launch any of these balloons with the express intent of having them land in San Francisco -- they simply launched them in the hope that some or all of them would land anywhere in the United States.