Irene's forecast path shifted away from South Florida today and it appeared to aim instead at the Bahamas and South Carolina - as it continues to intensify tonight.
Irene is now a Category 2 hurricane with maximum sustained winds of 100 mph, the National Hurricane Center said in a 7:50 p.m. update.
More details will follow in a special advisory, the hurricane center said.
The 5 p.m. advisory moved the forecast cone for Irene - which became the season's first hurricane this morning - even further east, and off nearly all of Florida. All, except coastal southeast Florida.
Irene was growing not just in punch but in breadth, with tropical storm force winds extending more than 180 miles.
That means that, even if it stays offshore, Palm Beach County and the Treasure Coast could come under tropical storm winds later this week, forecasters said.
And with the system still as far away today as is Arkansas, and South Florida still well inside its forecast cone, there was plenty of time for its track to shift back toward Florida - perhaps with little time to react.
"In the middle of the ocean, who cares?" National Hurricane Center spokesman Dennis Feltgen said. "But if you've got something that's close to the coastline, a shift of even 100 miles to the left would have a dramatic impact."
If a tropical storm or hurricane watch were to be posted for Palm Beach County and the Treasure Coast, that would happen some time on Tuesday, the National Weather Service's Pablo Santos said.
"South Florida is definitely not out of the woods on this yet," Santos, meteorologist-in-charge at the weather service's Miami office, said this morning. "Not until it gets past our latitude."
Just in case, on Monday, leaders of towns, agencies and hospitals were pulling out their "emergency plan" binders.
Irene had moved off Puerto Rico, where it downed trees, flooded streets and cut power to more than a million people. There were no reports of deaths or major injuries.
Irene's top sustained winds at 5 p.m. still were 80 mph. Forecasters had looked to the mountains of Hispaniola to tear up the storm's circulation, but it skirted to the north.
By the time it passes through the central and northern Bahamas on Thursday, top winds were predicted to be around 115 mph. That would make Irene a minimal Category 3 on the Saffir-Simpson scale.
"All of the ingredients are conducive for Irene to intensify over the next few days," hurricane center specialist Lixion Avila wrote in a 5 p.m. forecast discussion.
Forecasters expressed concern for the impact on Nassau and surrounding islands.
And by Saturday morning, the hurricane center's "skinny line" - and forecasters warn it is only an average of odds - would bring Irene around the South Carolina-North Carolina line.
"Although it is still too early to be certain, the guidance trend continues to lessen the threat to South Florida but increases the threat to the Carolinas," the 5 p.m. forecast discussion said.
While more of Florida was sliding out of the forecast path, meteorologists stressed that storms can carry hidden dangers.
In October 1999, another Irene - a tropical storm - moved up the spine of the Florida peninsula but dropped as much as a foot and a half of rain over parts of coastal Palm Beach County.
And in 2008, Tropical Storm Fay, even as its downpours brought historic flooding to Port St. Lucie, spun off a tornado in Wellington that all but flattened a horse center.
Across Palm Beach County Monday, governments were starting to gear up.
They topped off emergency fuel supplies, checked generators, cleaned out storm drains, trimmed trees and policed streets for loose debris.
Several hospitals said they'd cancel elective surgery if the storm became a direct threat.
The 211 telephone referral system moved into hurricane informational mode and already was getting inquiries about special needs shelters.
Palm Beach County Assistant County Administrator Vince Bonvento, who leads emergency management efforts, met Monday afternoon with officials from local governments and fire-rescue departments.
"It's really premature to make any decisions," Bonvento said. "We will wait until Wednesday."
He said two meetings are scheduled for Tuesday - in the morning and the afternoon - for officials to discuss storm projections and preparedness efforts.