UPDATED: Radioactive Fallout from Japan Reaches Southern California

(Updated on Friday at 5:17 p.m.): Go here for a daily update on Southern California radiation levels.

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(Updated on Friday at 9:04 a.m.): The radioactive fallout has reached Southern California, but the initial indications are that the levels are well below those that could be a health hazard to the public, according to The Associated Press.

A United Nations diplomat who reportedly requested anonymity said the first readings are "about a billion times beneath levels that would be health threatening," AP reports.

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(Updated on Friday at 8:15 a.m.): Elizabeth Ashford, a spokeswoman for Gov. Jerry Brown, said, “At this point, there is no risk to California from radiation,” according to Bloomberg News.

Radiation was reportedly not detected on the West Coast on Thursday, and, “We don’t anticipate any amount of radiation that will cause health effects,” California Department of Public Health interim Director Howard Backer said.

Although radiation levels in California may rise, the increase wouldn't reach a degree that would affect the public health, Los Angeles County Director of Public Health Jonathan Fielding said, according to Bloomberg.

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(Updated on Thursday at 12:41 p.m.): President Obama spoke about the radiation on Thursday afternoon at approximately 12:30 p.m.

"I want to be very clear: We do not expect harmful levels of radiation to reach the United States, whether it's the West Coast, Hawaii, Alaska or U.S. territories in the Pacific," he said. "That is the judgement of our Nuclear Regulatory Commission and many other experts."

"Furthermore, the Centers for Disease Control and Prevention, and public-health experts, do not recommend that people in the United States take precautionary measures beyond staying informed," he added. "Going forward, we will continue to keep the American people fully updated, because I believe that you must know what I know as president."

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A plume stemming from the is projected to reach Southern California in the coming days, although the level of radiation is expected to be low. In a worst-case scenario, the plume could pose minor health risks, according to MSNBC.

Gregory Jaczko, chair of the U.S. Nuclear Regulatory Commission, spoke about the plume during a press conference on Thursday.

"Basic physics and basic science tells us that there really can't be any risk or harm to anyone here in the United States—or Hawaii or any of the other territories," he said.

The plume is believed to consist of low levels of radioactive isotopes from the Fukushima Daiichi Nuclear Power Plant, which was damaged following Japan's recent earthquake and tsunami, according to the Los Angeles Times. MSNBC reports that the plume is on track to reach Southern California by Friday.

The Weather Channel says offshore winds of 5 to 10 mph are forecasted to blow the contaminates across the Pacific Ocean and toward the West Coast of the United States. However, dispersement models reportedly indicate that a major dilution of the plume's radiation will occur as it travels across the Pacific.

A group of radiation experts is monitoring the situation, according to the Times.