The following simulation shows Hawaii to be the point of maximum fallout concentration of Cesium 137 on March 21-22. Note that the simulation is based on an initial release of C-137 from Fukushima. The level of contamination indicated in the simulation is not an absolute value, it is relative to some assumed value. The authorities are censoring the actual levels of contamination released at the Fukushima disaster.
I suspect the actual data is being censored because the release of that information would result in a storm of nuclear regulator compliance issues in the private sector. It is interesting to note that differences between this simulation based on a specific isotope and the "jet stream" based fallout maps played up in the media. The key take aways are the 7-9 day cycle from peak at Fukushima to peak at Hawaii. Note that the peak fallout levels always seem to stay inside the ring of fire. Remember, this is a simulation and should be consider one data point in a probabilistic continuum.
A simulation of the event with on going releases would be helpful, but I also expect that such simulation would cause public discord. Barring some intervention by the Government with the insurance agencies, it would be wise to expect a shut down of commercial air traffic over the Pacific ocean in the coming days and weeks.