(Recasts lead and adds details) MEXICO CITY, May 30 (Reuters) - Tropical Storm Barbara, the first Pacific cyclone to form close to the coast this year, swirled erratically off Mexico on Wednesday and may reach hurricane strength within four days. Mexico's Civil Protection Agency said Barbara was veering slightly southwards about 190 miles (305 km) south of the port of Puerto Angel in the state of Oaxaca. "Interests along the Pacific coast of southeastern Mexico and Guatemala should closely monitor the progress of Barbara," the U.S. National Hurricane Center in Miami said. Barbara could convert into a hurricane within four days, the center said, and according to some models may track close to the small Mexican oil port of Salina Cruz. Experts at the center said it was difficult to know what route loosely formed Barbara would take, but most likely the storm would move slightly away from the Mexican coast over the next two days and then turn and head for land. Barbara is packing sustained winds of near 45 mph (75 kph) and should gain strength over the next four days, the hurricane center said. First forecasts were for Barbara to barrel toward Acapulco, Mexico's world-famous vacation resort. But latest predictions have the storm nearing land close to Puerto Escondido, a much smaller resort further to the south. Tropical Depression Alvin, which earlier this week reached tropical storm strength, is also lurking in the Pacific Ocean but is a long way off the coast.
