Weakening high pressure ridge could help Frances' turn north

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Weakening high pressure ridge could help Frances' turn north

By Ken Kaye
Sun-Sentinel
Posted August 30 2004, 11:45 AM EDT

While South Florida is hardly off the hook, the projected path of Hurricane Frances, now a slightly weaker Category 3 system, continued moving farther to the north on Monday, reducing the chances that this region will take a direct hit.

The reason: Forecasters now believe that a subtropical ridge of high pressure will start to weaken over the next four to five days and allow the tempest to turn before it reaches the Florida coastline.


However, that prediction remains uncertain because of the large errors in five-day forecasts, and hurricane officials implore residents to continue preparing for a potential landfall as early as Friday night or Saturday morning.

"The track does turn a bit more to the northwest after three or four days, but all of Florida remains in that cone of uncertainly. So it's best to just keep your guard up," said meteorologist Robbie Berg of the National Hurricane Center in Miami-Dade County.

"As we saw with Charley, these things can shift just a little bit," he added, referring to the Category 4 hurricane that was initially forecast to hit Tampa but made an unexpected turn toward Punta Gorda on Aug. 13.

At 11 a.m. on Monday, Frances was about 300 miles east-northeast of the northern Leeward Islands, or about 1,400 miles from Miami, moving west at almost 13 mph with sustained winds of 120 mph.

Because it has entered an area of wind shear, the system has weakened from what was once a Category 4 with 135 mph winds. However, forecasters expect it to build back to Category 4 status with sustained winds of 132 mph or greater, which would make it a monster hurricane capable of vast destruction.

A hurricane watch has been posted for the British and northern U.S. Virgin Islands, including St. Thomas and St. John, as well as several other nearby islands. A tropical storm watch was issued for Puerto Rico.

Under the latest forecast track, the threat of a direct hit is shifting from South Florida to Central and North Florida, Georgia and South Carolina. If it holds to that path, it would skirt the central and northern Bahamas and come within 100 miles of the Florida coastline, near Vero Beach in the wee hours of Saturday morning.

However, officials note that as long as Frances is south of South Florida, it could still aim in this direction.

Further, even if the core of France remains off shore, the region still could see heavy rain, winds and large waves from the storm's outer bands, which extend 140 miles from its center.

"It depends on how close it gets," said meteorologist Jim Lushine of the National Weather Service in Miami. "If it were to stay 200 miles off shore, we probably wouldn't see anything. But if it gets within 100 miles or less, we'd have to deal with the outlying effects."

Lushine said Frances is a bit reminiscent of Hurricane Floyd, which was initially aiming at South Florida as a Category 4 system in September 1999, but made a last minute turn toward North Carolina.

The difference, he said, is that Floyd had distinct steering currents, allowing forecasters to confidently anticipate that turn. He said the forces influencing Frances are iffier.

"I think it's going to be the last minute, the last day before we know for sure it's going to take that turn to the north," he said. "It doesn't take much to push it one way or the other, and I'd say anybody from Key West to Myrtle Beach, S.C., has an equal chance."

As if Frances wasn't enough to worry about, the peak of the hurricane season is still almost two weeks away, and several more systems could develop.

Indeed, the hurricane center expects a new tropical depression to form today in the far eastern Atlantic near the coast of Africa, and it could become Tropical Storm Ivan.

"They're kind of like bowling balls, rolling off hurricane alley," Lushine said. "We just have to hope one of them doesn't strike here."

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