Twin Storm Systems To Threaten U.S. East Coast: See Possible NY Impacts

NEW YORK — Two new tropical threats are brewing in the Atlantic Ocean and could organize in close proximity to each other and the U.S. East Coast over the next week, according to the latest forecasts.

The storms could bring rain, wind and dangerous surf conditions to parts of New York.

On Long Island, indirect impacts could mean increased sea activity on the ocean — which could also result in higher threat of rip currents, said Brian Ciemnecki, meteorologist with the National Weather Service Office in Upton. But, he added, "We have to wait and see how these two systems are going to play out. It's still early. We have to see where these two storm system are going to track."

A tropical rainstorm formed late Tuesday in the central Atlantic and could impact Bermuda as a hurricane by early next week, AccuWeather forecasters said in an outlook released Wednesday.

Meanwhile, a tropical wave near the Lesser Antilles could also become a named tropical system near the Bahamas as early as late this week.

"We predicted this burst of tropical activity in late September, after an unusually quiet stretch in the tropics during the climatological peak of the season," said AccuWeather lead hurricane expert Alex DaSilver, adding that hostile atmospheric conditions across much of the Atlantic basin prevented tropical waves from developing in late August and early September.

He continued: "Disruptive wind shear and dry air have eased, allowing tropical waves to organize into storms. We will likely see Humberto and Imelda form before the end of the weekend."

In the central Atlantic, the National Hurricane Center said a system located several hundred miles east of the Leeward Islands continues to show signs of organization, and conditions are forecast to be favorable for further development.

The system, called Invest 93L, had a 90 percent chance of developing into a tropical depression by Thursday, according to National Hurricane Center forecasters.

Currently, the storm is forecast to pass between Bermuda and the U.S. East Coast, and it is expected to bring some rain and gusty winds to Bermuda starting Sunday evening.

"This storm will likely create rough surf and rip currents that could impact beaches across the Bahamas and the East Coast starting this weekend," DaSilva said. "People in Bermuda and along the East Coast should monitor forecast updates closely. The storm may develop quickly."

Meanwhile, forecasters are also watching a tropical wave over the northeastern Caribbean Sea, which is producing disorganized showers and thunderstorms and has tracked farther west than any other system this season. The storm, called Invest 94L, has an 80 percent chance of developing into a tropical depression over the next seven days, according to the National Hurricane Center.

This wave was expected to move west-northwestward at 15 to 20 mph, spreading heavy rainfall and gusty winds into Puerto Rico and the Virgin Islands on Wednesday, and across the Dominican Republic beginning Wednesday night, according to National Hurricane Center forecasters.

The system is likely to form into a tropical depression near the Bahamas before it's expected to slow down and turn northwestward when it reaches the southwestern Atlantic later this week.

"Most computer forecasts show the depression or storm tracking north off the Florida coast in the general direction of North Carolina," Fox Weather Hurricane Specialist Bryan Norcross wrote on his blog, Hurricane Intel. "But enough forecasts curl it toward the coast into Florida, Georgia, or South Carolina, that everyone is going to have to watch it closely."

While it remains unclear how the forecast will unfold over the coming days, Norcross said the storms could potentially affect the East Coast by late in the weekend or early next week.

Some models suggest that the two systems could interact with each other, resulting in a rare phenomenon called the Fujiwhara Effect.

The Fujiwhara Effect happens “when two hurricanes spinning in the same direction pass close enough to each other, they begin an intense dance around their common center,” according to the National Weather Service. “If one hurricane is a lot stronger than the other, the smaller one will orbit it and eventually come crashing into its vortex to be absorbed."

If the storms are similar in strength, they might merge as they gravitate towards each other or spin around each other before shooting off in different directions, the NWS said. “In rare occasions, the effect is additive when the hurricanes come together, resulting in one larger storm instead of two smaller ones."

Meanwhile, several models show the relatively high-certainty path of 93L in the general direction of Bermuda, and the less-certain development zone of 94L over the Bahamas and along the east coast of Florida and the Southeast, according to Norcross.

"A fundamental rule of forecasting is that forecasts for disorganized, just-organizing, or slow-moving systems are subject to larger-than-normal errors and subject to change," Norcross said. "For now, there's nothing to do but watch for developments."