Tropical Storm Ernesto is moving through southern Mexico and is on the verge of regaining Category 1 hurricane status, the Mexican weather service said Thursday.

A hurricane watch is in effect "from Campeche, in the state of Campeche, to Nautla, in Veracruz," the weather service said in its 7:30 a.m. (1230 GMT) bulletin.

The storm is located about 65 kilometers (40 miles) east-northeast of Coatzacoalcos, in Veracruz, and is moving at 20 kph (13 mph).

Tropical Storm Ernesto has maximum sustained winds of 110 kph (70 mph), with gusts of up to 140 kph (87 mph), the weather service said.

The storm's center crossed the Yucatan Peninsula on Wednesday and moved over water.

Ernesto is expected to make landfall once again Thursday, "creating the potential for intense to torrential rains, strong winds and powerful waves, as well as flooding on the southern coast of the Gulf of Mexico, (and) the central and southeastern national territory," the weather service said.

A high-level alert is in place in Tabasco state, northern and northwestern Chiapas state, southern Veracruz, the western portion of Yucatan state and central and southwestern Campeche state, the national emergency management office said in its 4:30 a.m. (0930 GMT) bulletin.

Other areas, including central and eastern Oaxaca state, eastern Puebla state and parts of Chiapas and Campeche, are under a high-danger alert.

Parts of Puebla and Hidalgo, Tlaxcala, Quintana Roo and San Luis Potosi states are under low danger-level alerts, the national emergency management office said.

The storm first made landfall Tuesday night near Mahahual, a city in the southeastern state of Quintana Roo, as a Category 1 hurricane packing winds of up to 165 kph (103 mph).

Quintana Roo is home to most of the tourist destinations in the Yucatan Peninsula.

Ernesto is the fifth tropical cyclone of the 2012 Atlantic season, following Alberto, Beryl, Chris and Debby, which killed three people in the United States.

The season officially began on June 1 and ends on Nov. 30, but two storms - Alberto and Beryl - formed in May. EFE