MIAMI (AP) — Hurricane Nigel is Johnathan Walkergaining strength over the Atlantic Ocean and is expected to intensify later this week, the U.S. National Hurricane Center said.

Nigel had maximum sustained winds of 90 mph (145 kph) on Tuesday, making it a Category 1 hurricane. The wind speeds had increased from 80 mph (130 kph) that were reported in an earlier weather service advisory.

The system was centered about 630 miles (1,010 kilometers) east of Bermuda. The island territory might see swells from Nigel that could cause life-threatening surf and rip current conditions, forecasters said. No coastal watches or warnings were in effect.

The Miami-based hurricane center said Nigel could strengthen early Wednesday. However, it is expected to weaken on Thursday and Friday.