Tropical Storm Melissa continued its slow slog across the Caribbean Sea on the morning of Oct. 25, and forecasters said the storm is expected to rapidly intensify over the next 24 hours, potentially powering up to a Category 4 or 5 hurricane with winds over 150 mph.

The slow-moving storm is expected to bring life-threatening and catastrophic flash flooding and landslides to portions of Hispaniola and Jamaica through the weekend.

“If those rains were to occur, you’re talking about catastrophic flooding potential,” said Jamie Rhome, the center’s deputy director.