A new storm lashed already devastated parts of the Bahamas with heavy rain and strong winds before crawling northwest on Saturday, and forecasters said it was likely to become a hurricane before the end of the weekend.

Tropical storm Humberto, packing maximum sustained winds of 50 miles per hour (85 kilometers per hour), is expected to move well offshore of the east coast of Florida and into the Atlantic Ocean through early next week, according to Miami-based U.S. National Hurricane Center.

Forecasters said the storm could drop up to six inches (15.24 centimeters) of rain in some areas of the Bahamas through Monday, but it would not produce a dangerous storm surge in the northwestern islands, which were hammered earlier this month by Hurricane Dorian.

However, Humberto could complicate relief efforts in the area where thousands of structures were flattened and 70,000 people were left needing shelter, food and water and medical aid.

Category-5 Hurricane Dorian, one of the strongest Atlantic hurricanes ever to hit land, slammed into the Bahamas on September 1, packing top sustained winds of 185 miles per hour.

Bahamian Prime Minister Hubert Minnis has said the official death toll from Dorian stands at 50 but that hundreds of people are missing and it is expected to rise.

United Nations Secretary-General Antonio Guterres arrived in Nassau on Friday in a show of international support. He looked visibly shaken on Saturday after taking an aerial tour of Abaco, which bore the brunt of Dorian's impact.

"I was horrified. I've never seen such a level of systematic devastation," said Guterres. "Hurricane Dorian has been classified as Category 5, I think it is Category Hell, but it was not powered by the devil."

Guterres said Dorian should be a wake-up call for the world about the dangers of climate change.

He said the international community must rally to support countries like the Bahamas, which did not contribute to climate change "but are the first line of the devastating impact."