May 26 - Florida Governor Rick Scott on Saturday declared a state of emergency as subtropical storm Alberto moves north towards the US Gulf Coast, threatening to bring heavy rainfall and flooding by Monday, according to officials.All 67 Florida counties were issued the notice to give state and local governments enough time and resources to prepare, Scott said in a statement."As we continue to monitor Subtropical Storm Alberto's northward path toward Florida, it is critically important that all Florida counties have every available resource to keep families safe and prepare for the torrential rain and severe flooding this storm will bring," Scott said.The storm is expected to approach the US northern Gulf Coast on the Memorial Day holiday on Monday, according to the latest National Weather Service (NWS) advisory. A tropical storm watch is in place from the New Orleans area to the Aucilla River in the Florida panhandle.Alberto, the first named storm of the 2018 Hurricane season, was moving north near 10 miles per hour with maximum sustained winds near 40 miles per hour (65 km/h) with higher gusts on Saturday, the NWS said. Gradual strengthening is forecast until the system reaches the northern Gulf Coast by Monday night.Heavy rains from the slow-moving storm were expected between 5 to 10 inches (13-25 cm), with up to 15 inches possible along from eastern Louisiana, across much of Mississippi, Alabama, western Tennessee and the western Florida panhandle, the NWS said.Alberto's projected storm track has shifted eastward since Friday, lessening its threat to the active oil production areas in the Gulf of Mexico. Royal Dutch Shell plc and Exxon Mobil had evacuated some personnel from offshore Gulf oil facilities on Friday.The storm on Saturday morning was last located about 20 miles (35 km) south of the western tip of Cuba and 250 miles (400 km) south-south west of the Dry Tortugas, which is almost 70 miles (113 km) west of Key West, Florida, according to the US National Hurricane Center (NHC).