By midday, rain bands from Ernesto were lashing the Florida Keys, and Miami-Dade County Mayor Carlos Alvarez was asking for a voluntary evacuation of residents of homes previously damaged in other storms.
Many houses with tell-tale bright blue tarpaulins still have not had roofs repaired from Hurricane Wilma last October, WPLG-TV, Miami, reported.
"If your home currently has a blue tarp, it is not safe," Alvarez said.
The Miami Herald said many filling stations had no gas left to sell after a rush on Monday, although the Port of Miami-Dade had a 10-day supply of fuel and can reopen as soon as the storm passes.
Even politics were affected by Ernesto's approach from the south. The Tallahassee Democrat reported Democratic candidate for governor Jim Davis announced he was suspending campaign commercials in South Florida to "stand together as citizens of Florida until the storm passes."
State political primaries are scheduled next Tuesday.