Brisk offshore winds today will continue to direct any released radioactive matter out to sea from sites along the quake-ravaged northeastern coast of Japan.
The favorable winds will blow mostly from the northwest at 15-30 mph throughout northeastern Honshu into Thursday, local time.
This would follow a bout of onshore winds in the lowermost atmosphere on Tuesday and Tuesday night, local time.
Tuesday's easterly to southeasterly winds wafting along the east-facing coast would imply that any radioactive matter being released at the time by stricken nuclear power plants should have drifted over land normally having a significant population.
Authorities have cleared all residents from a 20-km-radius (or about 12 miles) exclusion area.
Light winds, still off shore, will return Friday with direction becoming southerly at night. South to southwest wind will then dominate through at least Sunday, although brief onshore winds will also be possible.
The ill-fated Fukushima reactors are located along the northern east coast of Honshu, which faces essentially towards the east. The combination of earthquake-triggered power failure and subsequent damage from a massive tsunami paved the way for multiple reactor failures, according to reports.
Broader transport of any hypothetical major radiation release would be subject to the prevailing winds, which for Japan and the Northern Hemisphere mid latitudes are west-to-east on average. Thus, such a release would tend to track away from Japan and, ultimately, follow a path toward North America.
However, details of this transport would be highly complex and subject to many factors, especially related to the weather at the release site at the time of the incident.
Evacuees are screened for radiation contamination at a testing center Tuesday, March 15, 2011, in Koriyama city, Fukushima Prefecture, northern Japan, four days after a massive earthquake and tsunami struck the country's north east coast. (AP Photo/Wally Santana)
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