Hurricane Helene continued to gain strength as a major Category 3 storm Monday, posing a potential threat to Bermuda later in the week, while a hurricane warning was issued for the Azores as Hurricane Gordon intensified to Category 2.

It was too soon to tell whether Helene would hit Bermuda, but the storm, with top sustained winds near 115 mph, was expected to be near the British territory Thursday night or Friday, said Hugh Cobb, a forecaster with the National Hurricane Center in Miami.

Cobb said the storm had turned west but should still be considered a possible danger.

“It’s a potential threat,” he said. “The question is how far west it will go before it turns north again.”

Helene strengthened late Sunday into the second major hurricane of the Atlantic season and intensified even more early Monday. Major hurricanes are those Category 3 and higher, with sustained winds of at least 111 mph.

At 11 p.m. EDT, it was centered about 990 miles east-southeast of Bermuda. It was moving west-northwest near 8 mph and was expected to continue on the same path into Tuesday, forecasters said.

Conditions appear favorable for the storm to strengthen within the next day.

Meanwhile, at 2 a.m. EDT Tuesday, Gordon was in the open Atlantic, centered about 710 miles west of Terceira in the Azores and moving east near 28 mph. This motion was expected to continue throughout the next day, with some increase in forward speed.

It was expected to be near the Azores on Tuesday afternoon or evening, forecasters said.

Gordon had maximum sustained winds near 100 mph and was expected to slowly weaken Tuesday. Even if it does become an extratropical storm that gets energy from colliding weather fronts, it could still have tropical storm-force winds.

The National Hurricane Center’s latest forecast for the Atlantic season expects seven to nine hurricanes, a slight reduction from earlier predictions.

Scientists have said that weak El Nino conditions had inhibited hurricane development by bringing higher ocean temperatures that increase crosswinds over the Caribbean. The winds can rip storms apart or stop them from forming.

The National Oceanic and Atmospheric Administration has warned that the El Nino effect on hurricanes has been small so far. The season, which lasts until Nov. 30, is still at its traditional peak.

On the Net:

National Hurricane Center: http://www.nhc.noaa.gov