Tropical storm Danielle formed in the eastern Atlantic Sunday with sustained winds increasing to nearly 40 miles per hour (65 kilometers per hour), the US National Hurricane Center said.

Danielle was the fourth tropical storm of the 2010 hurricane season in the Atlantic.

The center said the storm, 725 miles (1,165 kilometers) west of the southernmost Cape Verde islands, posed no immediate threat to land but could reach hurricane intensity by late Tuesday.

"A turn toward the west-northwest with an increase in forward speed is expected later tonight," the center said at 2100 GMT.

Danielle was moving in a northwesterly direction at a speed of 12 miles per hour (19 kilometers per hour), the center said.

earlier related report
Tropical Storm Frank develops off Mexico coast
Mexico City (AFP) Aug 22, 2010 - Tropical Storm Frank advanced Sunday toward Mexico's southwestern coast as authorities warned that the Pacific storm could reach hurricane status by late Monday.

Packing winds of up to 60 miles an hour (95 kilometers) and higher gusts, Frank moved westward off the southern coast of Mexico, about 130 miles (205 kilometers) from the coastal town of Puerto Angel in Oaxaca at 2100 GMT.

It was not expected to reach the United States.

"The government of Mexico has extended the tropical storm warning westward from Punta Maldonado to Acapulco," the Miami-based US National Hurricane Center said.

The warning means tropical storm conditions were expected in the area within 36 hours.

The NHC said the Mexican government also has issued a tropical storm watch -- advising of possible tropical storm conditions within 48 hours -- for the coast from Acapulco westward to Tecpan de Galeana.

Some additional strengthening was expected in the next 48 hours, with hurricane punch anticipated by late Monday, the NHC said.

Frank was expected to move parallel to the coast of southern Mexico through Tuesday, dumping total rain accumulation of three to six inches (seven to 15 centimeters), the NHC added.

"These rainfall amounts may produce life-threatening flash floods and mudslides," it said.