Hurricane Irma tightened her grip on South Florida early Friday, becoming overnight what everyone has long dreaded: a monster hurricane bearing down on Miami and a coast with 6 million people.

Reliable forecast models projecting the storm’s path predictably began to agree on a final, fateful track, with a direct hit along the south coast Sunday, although any wobble at this point could still change the storm’s course. At two days, forecasts still have an 80 to 90-mile margin of error, National Hurricane Center forecaster Mike Brennan said.

Irma is heading west and should continue moving in that direction over the next 24 to 36 hours, forecasters said early Friday, with hurricane conditions in the Keys and mainland starting Saturday night. Tropical storm-force winds should start in the morning.

Irma was located just under 450 miles southeast of Miami at 8 a.m., forecasters said.

Overnight, the hurricane weakened slightly, with sustained winds dropping to 150 mph Friday morning. Fluctuations in intensity are expected, but Irma is still projected to hit as a dangerous Cat 4 storm, something not seen in South Florida since Andrew, a far smaller hurricane, slammed south Dade 25 years ago last month as a Cat 5.

Irma’s eyewall began collapsing and rebuilding overnight, a common restructuring in fierce storms that can cause them to weaken slightly. In Irma’s case, the storm has rekindled with each replacement. There’s a possibility Irma weakens more if it passes closer to Cuba Friday, forecasters said, but that remains to be seen.

Once Irma hits land, it should lose intensity quickly, forecasters said. However hurricane-strength winds near the storm’s center are still expected to be widespread, with tropical storm force winds lasting at least 14 hours as it passes.

Overnight, Irma continued rolling through the Caribbean after pounding islands in the French territories. The Turks and Caicos, where communications were knocked out, reported roofs ripped off, widespread blackouts and flooding. Dangerous storm surge and heavy rain will likely continue pounding the islands through Saturday, with heavy rain also forecast for Hispaniola.

The U.S. Virgin Islands lost its 911 call lines. The small island of Barbuda reported damage to 95 percent of the island, including its hospital and airport. At least 11 deaths so far have been blamed on the storm, with dozens more injured. The number of deaths is likely to climb.

Irma should move between Cuba’s north coast and the southeastern Bahamas throughout the day Friday.