MIAMI (AP) – Officials organized shelters and urged vacationers to leave the Florida Keys as Tropical Storm Isaac approached on Saturday, though preparations farther north focused on getting ready for the Republican National Convention.

A hurricane warning had been issued for the Keys, though it was still a sunny day in Tampa. Forecast models show Isaac won’t hit Tampa head-on, but the storm will still likely lash the city with rain and strong winds just as the convention ramps up. Protests were to start in full force on Sunday afternoon, and demonstrators have vowed that they will make their presence known rain or shine.

Isaac was blamed for at least three deaths after dousing flood-prone Haiti and was expected to scrape eastern Cuba on Saturday. It was forecast to hit the Keys late Sunday or early Monday, and it then could bring stormy conditions to Florida’s west coast before moving to the Panhandle.

In the Keys, officials said they would open storm shelters and urged vacationers to leave. State officials warned Isaac was a massive storm – even though the eye may not pass over Tampa, tropical storm-force winds extended 230 miles from the center. Key West International Airport was also halting all flights at 7 p.m. Saturday until the storm had passed.

Officials were handing out sandbags to residents in the Tampa area, which often floods when heavy rainstorms hit. Otherwise, however, convention preparations were moving ahead as usual.

Groups including Code Pink, People for the Ethical Treatment of Animals, the AFL-CIO union and Planned Parenthood have already started arriving, regardless of the forecast.

Police said even heavy rain could reduce the protesters’ ranks, and could also bring relief from another worry: extreme heat.

Flooding and beach erosion is also a concern for southwest Florida. The hurricane warning included the west coast of Florida from Bonita Beach southward.