. >>> and part of this mass exodus is nbc's chris jansing who talked from tokyo last night. >> reporter: interesting to see what the japanese people think when they hear this news because america is the strongest ally. for them to say some of their key people need to leave the dependents of their embassy personal, recognition there is some danger here. >> bring in meteorologist christina loren, talking earlier about the amount of radiation is very minor but it's going to miss us altogether thanks to the jet stream. can you explain that to me? >> we hope it's going to miss us altogether. the jet stream as weather is not a perfect science. this is what we're forecasting. the jet stream is really clear. i did leave this on this morning. satellite shows a clear picture where the jet is centered right now. you can see it's taking this river of air that carries our low pressure system, just brings our weathermakers onshore. it's carrying those into los angeles area, into the southern california area. so for us, this is going to be the picture for the next couple of days. i've looked at every

. >> moments ago chris jansing, one of the crews remaining in tokyo filed this report along with our chief medical correspondent along with robert boozele. the question, simple, what's the impact of what happened in the last few hours. >> let's talk about what just happened in the last hour or so. 50 workers, the last workers at the nuclear plant pulled out for 45 minutes because of dangerously high levels of radioactivity. we are told they are now being let back into the plant, but the question is, can it be stabilized after all the developments? more fires, more explosions, two workers there now missing. bob has been monitoring through our interpreters what's going on through japanese television. >> you have to understand there is no nuclear chain reactors. some were shut down before the earthquake, all of them shut down during the earthquake. you have a lot of enormously hot radioactive fuel. the battle is to get it cool enough so it doesn't burn through and escape into the environment. so far very little of it has. the amount of radiation that's escaped, the amount of radiation h

among those, nbc's chris jansing who talked with us minutes ago from the airport in tokyo. >> reporter: it's going to be interesting to see what the reaction of the japanese people is when they hear this news because america is the strongest ally. and i think for them to say that their people need to leave the dependence of their embassy personnel said that there's a recognition that there is some danger here. >> nbc's lester holt now with the latest on the frantic effort to stop that nuclear crisis. >> reporter: there are concerns tonight about a possible breach in the containment vessel at reactor 3. a confirmed breach in reactor 2 is already leaking radiation. and there are new fears at the all-important water cooling the still highly radioactive spent fuel rods at reactor 4 is dangerously low. workers were temporarily evacuated during the night. and a water drop by helicopter was aborted after radiation levels briefly surged. but the public no longer knows what to believe. 77-year-old emperor ahito made a rare tv address. "i am deally concerned about the nuclear situation because i