The New York Times has a detailed, animated forecast for the plume from Fukushima, Japan.
The prediction is from the Nuclear Test Ban Treaty Organization, and based on weather patterns this week. It shows how a continuous cloud from the atomic power plant might disperse across the Pacific.
Like the ZAMG version I wrote about yesterday, this doesn’t show levels of radioactivity. According to the NYT article, nuclear experts emphasize these are expected to be extremely low – if detectable at all.