Tropical Storm Colin threatens Florida, southeastern US

A tropical depression threatening Florida and parts of the southeastern United States with severe thunderstorms was upgraded on Sunday to Tropical Storm Colin by the US National Hurricane Center.

The storm is expected to hit Florida's Gulf Coast by Monday, with rain having drenched parts of the southeastern United States on Sunday afternoon. Forecasters warned of severe thunderstorms along the East Coast and issued a tropical storm warning for Florida's Gulf Coast.

Colin is the second named storm in a week at the beginning of what is expected to be a brisk Atlantic Ocean hurricane season running through Nov. 30. Over Memorial Day weekend the Carolinas were lashed by heavy rain and winds from Tropical Storm Bonnie.

The first hurricane of the year, Alex, brought rain and wind but little damage to Portugal's Azores archipelago in January.

By early evening on Sunday, heavy rain from Colin was spreading northward toward Florida, the hurricane center said. At 11 p.m. EDT, it was about 450 miles southwest of Tampa, with maximum sustained winds of 40 mph and moving north at about 9 mph.

A tropical storm warning was in effect from Indian Pass to Englewood, and from Altamaha Sound to Sebastian Inlet.

The storm could dump up to eight inches of rain on parts of the state, with the potential for one to three feet of flooding if storm surge occurs at high tide, the hurricane center said. Sandbags were being made available in the Tampa area.

Florida heightened the response level of its State Emergency Operations Center on Sunday.

"Floridians should remain vigilant and have an emergency plan for their families and businesses in place today," Florida Governor Rick Scott said in a statement.

Other areas on the US eastern seaboard were also drenched on Sunday, as storms moved from the west. Rain fell on and off in New York, Pennsylvania, Virginia and parts of the Carolinas.

As the East Coast braced for storms, the west of the country braved a heat wave that spurred wildfires in California and pushed temperatures to record highs.

Temperatures soared well above 100 degrees Fahrenheit (38 Celsius) in parts of southern California, Arizona and Nevada, with unseasonable heat also afflicting inland areas of the Pacific Northwest, the National Weather Service said.

In Texas, where torrential rains led to flooding last week that killed at least 16 people, waters were expected to recede as the weather dries out, said Mark Null, hydrologist at the National Weather Service.