The Florida Keys, Miami and Fort Lauderdale areas have a 61 to 80 percent chance of being impacted by oil from the BP spill in the Gulf of Mexico, according to a report from the National Oceanic and Atmospheric Administration.
However, any oil reaching these areas would have spent considerable time degrading and dispersing and would be in the form of tar balls, not a large surface slick, NOAA added.
Much of Florida's west coast has a low probability - 20 percent or less - of oiling.
NOAA used modeling of historical wind and ocean currents to project the likelihood that surface oil will impact additional U.S. coastline.
"This NOAA model shows where oil may be likely to travel, thereby giving coastal states and communities information about potential threats of shoreline impacts. This kind of information should assist in the preparation of adequate preparedness measures," said Jane Lubchenco, undersecretary of commerce for oceans and atmosphere and NOAA administrator, in a statement.
The coastlines with the highest probability for impact - 81 to 100 percent - extend from the Mississippi River Delta to the western Florida Panhandle, where there has been and will likely continue to be oil impacts.
The oil is more likely to move east than west, with much of the Texas coast showing a relatively low probability of oiling, NOAA said.
There is a low probability - 20 percent or less - of shoreline impacts from eastern central Florida up the Eastern Seaboard. Potential impacts become increasingly unlikely north of North Carolina as the Gulf Stream moves away from the continental United States at Cape Hatteras. If oil does reach these areas, it will be in the form of tar balls or highly weathered oil.
To date, no "significant amount" of oil has entered the Loop Current, NOAA said.