They call them "fish storms," tropical cyclones that stay out to sea. Tropical Storm Bertha is expected to do just that after raking Puerto Rico and possibly the Dominican Republic this weekend.

National Hurricane Center specialists on Friday forecast the storm to remain shy of hurricane winds for at least the next five days, but some model runs suggested it would reach hurricane strength as it passes well offshore South Carolina on Monday night and early Tuesday.

"The storm is expected to clip the southeastern Bahamas and Turks and Caicos Islands on Sunday, then turn north in response to a strong trough of low pressure over the Eastern United States. This trough should be strong enough to recurve Bertha to the northeast without the storm hitting the mainland U.S. coast," said Jeff Masters, of Weather Underground, on Friday afternoon.

The storm moved into the Caribbean Sea on Friday afternoon, passing between the islands of Martinique and Dominica, buffeted by shear winds, with marginal tropical storm force winds and moderate rain. Hurricane specialist Jack Beven with the National Hurricane Center said it's possible the storm will weaken to a tropical wave, losing its tropical cyclone characteristics, before regenerating.

On Friday afternoon, the storm had 50 mph winds but a ragged symmetry. The Southeast remains for now potentially in the path of the storm. But none of the various computer modelling runs Friday afternoon suggested the storm could make landfall here.

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