The National Hurricane Center issued a hurricane watch and tropical storm warning for Puerto Rico early Tuesday as Tropical Storm Dorian moved through the Windward Islands. The center said that, as of 5 a.m. eastern today, the storm had maximum sustained winds of 50 mph and was forecast to strengthen over the next 48 hours as it moved toward Puerto Rico.

Dorian’s center was some 30 miles southeast of St. Lucia and the storm was moving west-northwest at 13 mph. Tropical-storm-force winds extend outward up to 45 miles from the center.

The storm was expected to dump between 3 to 8 inches of rain on the Windward islands, with isolated amounts up to 10 inches.

In Puerto Rico, people crowded into grocery stores and gas stations to prepare for Dorian, buying food, water and generators.

Many are worried about power outages and heavy rains on an island still struggling to recover from Hurricane Maria, a Category 4 storm that hit in September 2017. Some 30,000 homes still have blue tarps as roofs and the electrical grid remains fragile and prone to outages even during brief rain showers.