Hurricane Irma has strengthened to a Category 5 storm and catastrophic damage is possible in the Florida Keys and southern Florida this weekend.
Irma is packing 180 mph winds and gusts up to 220 mph as of 11 a.m. ET Tuesday and is expected to continue churning with deadly hurricane-force winds and a dangerous storm surge across a wide swath of the Caribbean this week before moving toward southern Florida.
The National Hurricane Center (NHC) on Tuesday called Irma the strongest hurricane in the Atlantic basin outside of the Caribbean Sea and Gulf of Mexico in NHC records.
Hurricane warnings are in effects for islands including the U.S. territory of Puerto Rico, where the governor Tuesday called the storm unprecedented as the island braces for Irma to hit this week.
By Sunday around 8 a.m., the hurricane is expected to be near the Florida Keys with winds of 145 mph as a Category 4 hurricane.
As of Tuesday morning, the NHC predicts that the storm will follow a more western track, heading up the west coast of Florida; however, that still could change.
Florida Gov. Rick Scott on Monday declared a state of emergency for every county to ensure that local governments have enough "time, resources and flexibility to get prepared for this dangerous storm," according to a statement from his office.
Scott said in the statement that Irma is a "life-threatening" storm and Florida "must be prepared."
"In Florida, we always prepare for the worst and hope for the best," Scott said, "and while the exact path of Irma is not absolutely known at this time, we cannot afford to not be prepared."
Category 5 is the strongest hurricane category on the Saffir-Simpson hurricane strength scale. In a Category 5 storm, winds reach more than 157 mph and damage is expected to be catastrophic, with buildings and roofs destroyed.
What awaits Hurricane Harvey evacuees after they leave shelters Texas deputy in this touching Harvey rescue photo calls it 'just me doing my job' A bird's-eye view of Harvey's devastation
The current NHC storm track puts Irma near the Leeward Islands, including Antigua and Barbuda, on Tuesday.
The Virgin Islands and Puerto Rico are forecast to see deteriorating conditions throughout the day on Wednesday with the worst of the rain and wind arriving Wednesday night.
The storm is expected to pass north of Puerto Rico Wednesday night into early Thursday morning.
In Puerto Rico, a state of emergency has been declared, activating the National Guard as the U.S. territory prepares for a storm Gov. Ricard Rossello called unprecedented.
"This is the time to take action," the governor said Tuesday.
Héctor Pesquera, the superintendent of the Puerto Rico police, said at least 14 hours of wind and rain is expected, calling the storm more dangerous than Hurricane Harvey, which made landfall in Texas Aug. 25 as a Category 4 storm.
Rossello warned that emergency services will stop when winds reach 50 mph.
Shelters are being opened in preparation for the storm, and the governor said all those who have vulnerable homes or flood prone areas need to start evacuation plans and head to shelters.
The governor has canceled classes for Tuesday and declared a half-day of work.
Meanwhile, Tropical Storm Jose has formed over the open Atlantic, following closely behind Irma, the NHC said Tuesday. Jose could become a Category 2 hurricane as it brushes the most northeastern Caribbean islands at the end of the week. However, there is no threat to the U.S. or Puerto Rico at this time. The NHC warned that residents in the Leeward Islands, already expected to face Irma, "should monitor the track."
ABC News' Ginger Zee, Max Golembo, Dan Peck, Armando Garcia and Josh Hoyos contributed to this report.