Forecasters issued hurricane watches for the U.S. and British Virgin Islands on Tuesday as Tropical Storm Ernesto began dumping heavy rain on Puerto Rico and churning up the surrounding Atlantic Ocean. “Data from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds have increased to near 60 mph (95 km/h) with higher gusts,” the National Hurricane Center said in a 5 p.m. ET update. “Additional strengthening is forecast, and Ernesto is expected to become a hurricane by early Wednesday.” Ernesto was about 135 miles east-southeast of San Juan, Puerto Rico, and movin…