Hurricane Franklin roared toward Mexico's central Gulf coast early Thursday, threatening to pound a mountainous region prone to flash floods and mudslides with torrential rains and heavy winds.

Franklin strengthened into the first hurricane of the Atlantic season on Wednesday and its expected landfall on the coastline of Veracruz state early Thursday will be its second on Mexican territory in three days. As a tropical storm, Franklin made a relatively mild run across the Yucatan Peninsula earlier in the week.

Authorities in Veracruz ordered classes cancelled at public schools as a precautionary measure. Schools are frequently used as storm shelters in Mexico.

The U.S. National Hurricane Center said Franklin had maximum sustained winds of 85 mph (140 kph) late Wednesday night. The storm was expected to gain power as it moved across the southern Gulf of Mexico.

Franklin's center was 70 miles (110 kilometers) north of the city of Veracruz, and it was heading west at 13 mph (20 kph).

A hurricane warning was in effect for the coast from Veracruz city north to Cabo Rojo. A hurricane watch extended north from Cabo Rojo to Rio Panuco.

Mexico Civil Defense director Ricardo de la Cruz said Tuesday that the storm's impact on Yucatan was not as bad as initially feared, with some trees down and power out in some areas.

But, he warned, "the second impact could even be stronger than the first."

Forecasters said Franklin could drop four to eight inches (10 to 20 centimeters) of rain, with localized amounts of up to 15 inches (38 centimeters).