Tropical Storm Peter strengthens, Air Force says; Tropical Storm Rose sees little change.

Tropical Storm Peter, the season’s 16th named storm, continued to gain strength Sunday with top winds of 50 mph, up slightly from earlier in the day, according to the National Hurricane Center.

Peter formed early Sunday over the Atlantic Ocean, far east of the Caribbean Sea, and was expected to generally maintain its wind speed Sunday. However, it may weaken to a tropical depression on or before Wednesday, experts said. U.S. Air Force hurricane hunters said Peter gained strength Sunday night over previous observations from the afternoon.

The presence of cooler waters and stronger upper-level winds are forecast in the coming days, according to experts. These factors hinder the storm development.

Rose formed into a tropical storm Sunday afternoon, making 2021 only the third hurricane season since 1966 to have had at least 17 named storms by Sept. 19. The other years are 2020 and 2005, according to Colorado State University hurricane expert Phil Klotzbach.

The storm’s maximum sustained winds were at 40 mph as of 11 p.m., remaining largely unchanged in its 16 mph northwest movement.

Peter’s outer bands to its south could produce 1 to 2 inches of rain across parts of the Virgin Islands, as well as Puerto Rico, from late Sunday through Tuesday.

By midweek, upper-level winds will reach the southwestern Atlantic. These winds will decrease chances of Peter’s development.

An easterly cold front is expected to push Peter away from the U.S., but it rough surf, wind and heavy rain to Bermuda late next week, forecasters said.

As of 11 p.m., Peter was moving west-northwest at about 14 mph with maximum sustained winds of 50 mph.

“Intensification of anything more than a low-end tropical storm is unlikely as the storm moves into the western Atlantic early next week,” AccuWeather senior meteorologist Rob Miller said.

Both systems are forecast to stay well out to sea, according to the hurricane center.

Meanwhile, a tropical wave off the west coast of Africa is forecast to emerge offshore Sunday. It could become a tropical depression by late this week, forecasters said.

Including Rose, the remaining storm names for the season are Sam, Teresa, Victor and Wanda.

The former Tropical Storm Odette, which formed Friday off the U.S. coast to the southeast of New Jersey, had become a remnant low by Sunday.

So far in the Atlantic hurricane season, which runs through Nov. 30, there have been 17 named storms, six hurricanes and three major hurricanes.