(Updates to show storm makes landfall, updates storms' locations)
MEXICO CITY, Sept 2 (Reuters) - Tropical storm Dolly lashed Mexico's northeast coast on Tuesday night, the U.S. National Hurricane Center (NHC) said, bringing torrential rain and life threatening flash floods.
Dolly was blowing maximum sustained winds of 45 miles per hour (72 km per hour), but having made landfall the storm was expected to lose strength by Wednesday evening, NHC said.
Dolly, which formed in the southern Gulf of Mexico early on Tuesday, has already forced the closure of two of Mexico's three major crude oil export terminals.
According to national water authority Conagua it was whipping up waves of up to 4 meters (13 feet) along the coast.
State oil giant Pemex said in a statement that it was watching Dolly's progress and if needed it would suspend its operations in the eastern states of Veracruz and Tamaulipas, including the Francisco Madero refinery, the country's smallest.
Cayo Arcas port had been shut since Sunday afternoon while the Dos Bocas hub was closed early on Monday, the Communications and Transport Ministry said. Mexico's third major oil export terminal at Coatzacoalcos remained open.
Dolly, the fourth named storm of the 2014 Atlantic hurricane season, was about 25 miles (40 km) south-southeast of Tampico in northeastern Tamaulipas state, the NHC said.
Dolly was moving west at 9 mph, the NHC said. The storm is expected to bring up to 15 inches (38 cm) of rain across areas of Tamaulipas and Nuevo Leon states.
"This rainfall is expected to cause life-threatening flash floods and mud slides in areas of mountainous terrain," the NHC said.
Meanwhile, Tropical Storm Norbert formed on Tuesday off southwestern Mexico, and was about 320 miles (515 km) southeast of the southern tip of the Baja California peninsula, the NHC said.
Norbert was headed further out to sea, churning north-northwest at 8 mph (13 kph), the NHC said, blowing maximum sustained winds of 45 mph. The NHC expected it to reach hurricane strength on Thursday.
Mexico suffered its worst floods on record last September when tropical storms Manuel and Ingrid converged from the Pacific and the Gulf of Mexico, killing more than 150 people and causing damage estimated at around $6 billion. (Reporting by David Alire Garcia and Gabriel Stargardter in Mexico City and Debasis Mohapatra in Bangalore; Editing by Lisa Shumaker and Simon Cameron-Moore)