The hatched areas on the National Hurricane Center's tropical outlook map indicate "areas where a tropical cyclone — which could be a tropical depression, tropical storm or hurricane — could develop," said National Hurricane Center Deputy Director Jamie Rhome.

Tropical Storm Erin is expected to become a hurricane by late on Aug. 14, according to the NHC's advisory. What's the impact to Palm Beach County?

Tropical cyclones become tropical storms when sustained winds reach 39–73 mph, are upgraded to hurricanes at 74 mph, and become “major” hurricanes at 111 mph or higher, corresponding to Category 3–5 on the Saffir-Simpson Hurricane Wind Scale.