MEXICO CITY, June 3 Tropical Storm Boris formed off the southern Pacific coast of Mexico on Tuesday, churning northward toward the largest refinery of national oil company Pemex, Salina Cruz.
The U.S. National Hurricane Centre (NHC) said Boris was heading north at 5 miles per hour (7 km per hour) and was about 125 miles (205 km) southeast of Salina Cruz, where Pemex can refine up to 330,000 barrels of crude per day.
Blowing maximum sustained winds of 40 mph (65 kph) on Tuesday afternoon, the storm was not expected to strengthen significantly before it makes land, the Miami-based NHC said.
Heavy rain hit the southern state of Oaxaca on Tuesday, prompting classes to be canceled in some schools.
A tropical storm warning is in effect from Salina Cruz to Mexico's border with Guatemala to the southwest.
The center of Boris is forecast to be close to the coast of Mexico within the warning area by early Wednesday. (Writing by Dave Graham; Editing by Marguerita Choy)