(Updates position, Earl could overpower smaller storm)

By Jane Sutton

MIAMI (Reuters) - Hurricane Earl churned toward the
North Carolina coast of the eastern U.S. seaboard Tuesday
after lashing Puerto Rico and the northeast Caribbean islands
with winds, rain and waves, the U.S. National Hurricane Center
said.

The forecast track of Earl, the second major hurricane of
the 2010 Atlantic season, showed the fringes of the powerful
Category 4 storm clipping the barrier islands of North Carolina's
Outer Banks early Friday and threatening the densely populated
coast northward from there to New England.

A hurricane watch could be posted by Tuesday night for the
mid-Atlantic coast, alerting residents to expect storm
conditions within 72 hours, the forecasters said.

Barry Baxter, a hurricane center meteorologist, said
forecasters had nudged the storm's track slightly to the west
overnight but still had it narrowly missing a direct full-on
hit to the U.S. coast.

"It's still staying off the coast at this point for the
whole eastern U.S.," Baxter said.

He declined to predict how close the hurricane would come
to New York when it churned offshore east of the city during
the weekend.

"It's too early at this point," Baxter said. "We're just
telling everybody to keep their eyes on the track and just keep
checking back."

Forecasters expected Earl to stop just short of becoming a
maximum Category 5 storm on the five-step Saffir-Simpson
intensity scale.

Nevertheless, forecasters say Earl would bring drenching
rain, dangerous seas and surf and gusting wind to the Atlantic
Coast from North Carolina to New England and Atlantic Canada.

Earl, with top sustained winds of 135 miles per hour
, was moving away from Puerto Rico and the Virgin Islands
Tuesday and would cross the open Atlantic east of the Turks
and Caicos Islands, the forecasters said.

At 11 a.m., it was centered about 205 miles
east of Grand Turk Island in the Turks and Caicos, a British
territory at the southern tip of the Bahamas. That was about 1,070
miles south-southeast of Cape Hatteras, North
Carolina.

Tropical storm warnings and watches were in effect for the
Turks and Caicos and the southeastern Bahamas.

Hurricane Earl posed no threat to major U.S. oil and gas
installations in the Gulf of Mexico.

PUERTO RICO MOSTLY SPARED

Earl battered the northeastern Caribbean islands and Puerto
Rico Monday, downing power lines, blowing off roofs, toppling
trees and causing some flooding. There were no immediate reports
of casualties.

"We have been quite fortunate. We did not take a direct hit
... it was not as serious as it could have been," Puerto Rico
Governor Luis Fortuno told CNN.

Tropical Storm Fiona followed in Earl's wake on a similar
path.

At 11 a.m. EST Fiona was 440 miles
east of the Caribbean Leeward Islands on a course that was
expected to take it northeast of those islands Wednesday.
Most forecast models kept Fiona far away from the Gulf of
Mexico.

With sustained winds of 40 mph, Fiona was just
barely a tropical storm and the much more powerful Earl was
hindering Fiona's development. Earl churned up the seas and
brought cold water to the surface, starving Fiona of the warm
water needed for rapid strengthening.

The storms were 900 miles apart but Fiona was
moving much faster on a path that roughly traced Earl's. If Fiona
closes the gap to about 300 miles, high-level winds
spiraling from the top of Earl could shear off and weaken Fiona,
the hurricane center's Baxter said.

"If it gets really close, Earl could actually chew it up
and just kind of kill it," he said.

Elsewhere in the Atlantic, a broad area of low pressure
about 400 miles southwest of the Cape Verde Islands in
the eastern Atlantic had only a 10 percent chance of becoming a
tropical cyclone within 48 hours, the hurricane center said.

Early computer models showed that system moving mostly west
in the Atlantic but toward South America, not the energy-rich
Gulf of Mexico.
(For more information about hurricanes and weather models, see:
http://www.nhc.noaa.gov/ and http://www.skeetobiteweather.com/)
(Reporting by Jane Sutton, Tom Brown and Pascal Fletcher in
Miami, Eileen Moustakis in New York; Editing by Pascal Fletcher
and Bill Trott)