Hurricane Jimena formed in the eastern Pacific near the Mexican resort of Acapulco on Saturday, but in the Atlantic Tropical Storm Danny weakened to a tropical depression and storm alerts were discontinued for the North Carolina coast.
Jimena was located about 285 miles southwest of Acapulco, packing winds of around 80 mph (130 kmh), and was moving west-northwest, roughly in parallel with Mexico's Pacific coastline, the U.S. National Hurricane Center said.
It was the second hurricane of the 2009 eastern Pacific season to brush close to Mexico after Andres pounded the same area in June, flooding Acapulco and sweeping a fisherman to his death. Acapulco, one of many resorts dotted along Mexico's Pacific coast, is popular with Mexican and foreign tourists.
In the Atlantic, Danny's maximum sustained winds fell to 35 miles per hour, the hurricane center said in its 5 a.m. (0900 GMT) advisory.
The remnants of what had been the fourth tropical storm of the 2009 Atlantic season were about 80 miles southeast of Cape Hatteras, North Carolina, and 540 miles south-southwest of Nantucket, Massachusetts.
The system was expected to move rapidly north-northeast and then northeast at 30 to 35 mph.
Forecasters said large swells from the system were expected to generate a second weekend of dangerous surf conditions and rip currents along the U.S. East Coast.
In Mexico's Pacific, hurricane force winds extended outward up to 25 miles from Jimena's center as of Saturday morning and the NHC said further strengthening was likely.
No storm warning had been issued for the area around Acapulco, however, and a beach hotel owner there said the weather was overcast but calm.
Mexico has no oil installations in the Pacific and for the time being the oil exporting port of Salina Cruz and other ports in the area remained open.
Last weekend, Hurricane Bill brought rain and heavy winds to eastern Canada after pounding the U.S. Atlantic coast with heavy seas that killed two people.
Tropical storms and hurricanes are tracked closely by energy traders concerned about disruptions to oil and gas production in the Gulf of Mexico and Canada's Atlantic region, and by commodities traders for damage to citrus, cotton and other crops.
Pricing of insurance-linked securities, which transfer insurance risks associated with natural disasters to capital markets investors, and can be used to hedge other weather risk exposures, can also be affected by the future path of a storm.