Katia's future? Look to Japan

Hurricane Katia will make this a very nerve-wracking and interesting weekend for amateur and professional meteorologists -- and for authorities along the East Coast of the United States.

For days, the computer models insisted that Katia would become a major hurricane and curve northward, never coming close to the United States. If any land mass would be threatened, it would be Bermuda.

That has changed considerably over the past 24 or 36 hours.

And Jeff Masters, a really outstanding meteorologist with plenty of tropical forecasting experience, says Katia's future might depend a lot on a tropical storm predicted to hit Japan this weekend.

Here's the set-up:

Many of the computer models show a slow-moving but strong Hurricane Katia moving northwest for a few days, but then veering westward toward the Carolinas coast. That westward turn depends on the strength of a trough (low pressure) along the U.S. East Coast.

A deep trough would recurve Katia away from the United States. A not-so-weak trough would allow high pressure in the Atlantic to strengthen. And the clockwise flow around the high would push Katia into the East Coast.

So what about the Japanese storm?

Tropical Storm Talas is expected to move into Japan on Saturday morning, then convert to a non-tropical storm -- and a very strong one -- in the Gulf of Alaska.

That Gulf of Alaska storm is predicted to have a ripple effect on smaller storm systems downstream -- across Canada and into the United States, including the trough in the East. If Talas becomes a very strong storm, the thinking is that it will deepen the trough in the East and push Katia away from the United States.

A weaker Alaskan low, and Katia could push toward the United States.

You can read Masters' blog at http://bit.ly/qyN9qh.

Katia wouldn't threaten land until the end of next week. But its waves and rip currents could be felt along the Outer Banks and possibly the Grand Strand by Labor Day.

As we said, this will be an interesting weekend. The last thing that anyone on the Outer Banks wants is another visit from a hurricane.