In places like Tampa and Port Charlotte, as the storm approaches from the south, strong winds blowing from the northeast have pushed water out of shallow parts of bays and harbors, according to CNN meteorologist Judson Jones.
"As soon as the wind shifts direction, the water will come back quickly and continue to move inland," Jones said.
"Urgent warning about the rapid rise of water on the SW FL coast with the passage of #Irma's eye. MOVE AWAY FROM THE WATER!"
The tweet was accompanied with this note of caution:
"With the passage of the eye of Irma during the next couple of hours, the wind direction will shift to onshore, causing water levels along the southwest coast of Florida to rapidly rise in a matter of minutes. MOVE AWAY FROM THE WATER! Life-threatening storm surge inundation of 10 to 15 feet above ground level is expected in this area."