Florida braced for new Tropical Storm Debby rain
Heavy rain from Tropical Storm Debby, which has made landfall in north-western Florida, is drenching the state's Gulf coast.
Up to 8in (20cm) of rain and flooding is forecast for the next two days, the National Hurricane Center says.
Florida officials have ordered an evacuation for thousands in anticipation of flooding.
President Barack Obama said his administration was ready to offer federal assistance to Florida.
In a phone call, the president asked Florida Governor Rick Scott "to continue to identify any additional support his administration could provide, and told the governor that his thoughts and prayers are with the citizens of Florida", a statement from the White House said.
Mr Scott declared a statewide emergency on Monday, allowing the state to suspend certain laws as it responds to the storm, and access federal funds.
As much as 26in (66cm) of rain is thought to have fallen on coastal Wakulla County, the Associated Press reports.
Parts of the cross-state Interstate 10 have been closed because of flooding.
By landfall, the storm had maximum sustained wind speeds of 40mph (65 km/h), the NHC said.
It was expected to be downgraded to a tropical depression by Tuesday evening.
Debby is crawling east at a speed of about 6mph and is not expected to cross the state until Wednesday afternoon.
Flooding remains a primary concern, with emergency managers ordering the evacuation of 14,000 to 20,000 people living between the Anclote and Pithlachascotee rivers in the central Gulf Coast area.
The Anclote has risen from nine feet to 27ft since Debby's approach, far above major flood level, Pasco County spokesman Eric Keaton told the AP.
Meanwhile, crews in neighbouring Alabama are continuing their search for a South Carolina man missing off the coast.
The man, who was on holiday with his family, disappeared on Sunday afternoon in rough surf off Orange Beach.
A woman killed in a tornado whipped up by the storm on Sunday is reported to have been a young mother who died when her house was lifted off its foundations.
Heather Town was found holding her baby in her arms - but the infant survived.
"She was a great mother, and held her baby through all of this and held her so tight," Elmer Town, the child's father, told local news station WFLA-TV.
"She was holding her during the tornado. And when they found her, she was still holding her."
Residents in low-lying neighbourhoods near the Florida coast have been advised to leave their homes, while the bridge to St George Island - a popular holiday spot - has been closed off.