Rain started to fall along the U.S. Gulf Coast as Hurricane Dolly closed in on towns straddling the Texas-Mexico border, packing 85 mph (137 kph) winds that could strengthen when it hits land later Wednesday. The Category 1 hurricane was expected to dump up to 15 inches (38 centimeters) of rain, threatening flooding that could breach levees in the heavily populated Rio Grande valley, the Associated Press reported. Dolly was upgraded from a tropical storm Tuesday afternoon. At 7 a.m. EDT (1100 GMT) Wednesday, the storm's center was about 55 miles (88 kilometers) east of Brownsville in southern Texas, moving northwest at about 8 mph (13 kph). The National Hurricane Center said Dolly could approach Category 2 strength, meaning wind speeds of at least 96 mph (154 kph), when it reaches the coastline later Wednesday. A hurricane warning was in effect for the coast of Texas from Brownsville to Corpus Christi and in Mexico from Rio San Fernando northward.