The plume is projected to migrate onshore and to the north and northeast throughout the afternoon and evening of Wednesday April 6 Japan Standard Time (JST). This could affect areas where relief efforts are underway, if radiation releases are continuing.
Japanese officials speculate that airborne releases could continue for months. And yesterday the U.S. began deploying the Marines’ Chemical Biological Incident Response Force (CBIRF) of 150+ highly trained personnel to Japan, reportedly due to concerns over the situation at Fukushima.
The Nature blog has timely updates on the evolving situation.
A footnote to yesterday’s forecast post…
The latest forecast shows the plume was anticipated to linger longer over the Boso Peninsula (separating Tokyo Bay from the Pacific) through the late evening of April 4 than was predicted in the prior day’s forecast. (See plots below and compare with post from 4/5). And the more recent forecast shows the plume that was expected to be over Choshi for the evening of April 5 does not actually touch there. Again, illustrating the high sensitivity to initial conditions, among other factors, in the strongly variable coastal zone.
The Naval Research Laboratory’s 5 km resolution skillful data-assimilating mesoscale meteorological model COAMPS produced the fields, using a passive tracer to map the expected plume trajectory. Lighter gray contours show more concentrated material. [Plume images are a research tool; contours are arbitrary units for visualization purposes.]