Florida’s northern Gulf Coast faces its most serious hurricane threat in more than a decade as Michael edges ever closer. The intensifying storm is likely to make landfall Wednesday as a Category 3 hurricane, and conditions will begin to deteriorate Tuesday night.

(National Weather Service image)

The hurricane has strengthened to Category 2, with the storm’s winds near 100 mph as of 8 a.m. Tuesday, according to the National Hurricane Center.

Florida’s Panhandle, from Pensacola to Apalachicola, and its Big Bend area are the zones of greatest concern. Michael is poised to push ashore a “life-threatening” surge of ocean water that will inundate those coastal areas. The storm also will unleash flooding rain and destructive winds starting Tuesday night and continuing through Wednesday.

“There are warnings for more than 300 miles of coastline,” the National Weather Service tweeted, predicting that Michael will become a “large and dangerous hurricane.”

Some of the population centers that could witness some of the most severe hurricane effects include Fort Walton Beach, Destin, Panama City Beach and Apalachicola.

The surge, or the rise in ocean water above normally dry land along the coast, could reach at least eight to 12 feet in the hardest-hit areas, inundating roads, homes and businesses. Mandatory evacuations have been ordered in several Florida counties.

Devastating hurricane effects are expected to expand inland far beyond the coast.

(National Weather Service image)

“A potentially catastrophic event is developing,” the National Weather Service forecast office serving Tallahassee and surrounding areas wrote. The office warned of “widespread power outages, downed trees blocking access to roads and endangering individuals, structural damage to homes and businesses, isolated flash flooding and the potential for a few tornadoes.”

Damaging winds and flooding rain were also predicted to reach southern Georgia and southeast Alabama on Wednesday.

“This will not be just a coastal event, with dangerous winds and flooding rains spreading far inland over the southeastern U.S,” said Rick Knabb, the Weather Channel’s hurricane expert. “Shelter from hurricane-force winds like you would for a tornado, and don’t stay in mobile homes, even for a tropical storm.”

By Wednesday night and Thursday, heavy rains from Michael are likely to streak into the Carolinas and the Mid-Atlantic, perhaps bringing more flooding to some of the same areas still recovering from Hurricane Florence.

As of 8 a.m. EDT Tuesday, Michael’s peak winds were close to 100 mph as it moved north-northwest at 12 mph. The storm was centered about 390 miles south of Apalachicola.

Environmental conditions are favorable “for at least steady intensification” through Tuesday night, the Hurricane Center said. Warm ocean temperatures, which fuel storm development, are two to four degrees above normal, and wind shear, which tends to slow hurricane development, was forecast to ease.

The Hurricane Center predicts that the hurricane’s peak winds will reach 120 mph at landfall, which would make Michael a Category 3 storm.

At its current rate of speed, tropical-storm-force winds should reach the northern Gulf Coast as early as Tuesday evening, after which conditions will deteriorate. Landfall is projected Wednesday – although models differ on whether it will occur early or late in the day.

Hurricane warnings have been posted from the Alabama-Florida border to the Suwannee River, just northwest of Cedar Key on Florida’s west coast. Tropical storm warnings extend farther south, to Chassahowitzka, Fla., and to the west, along the Alabama coast. Tropical storm watches are in effect for the Mississippi coast and around the Tampa Bay area.

Storm-surge warnings are in effect from the Okaloosa/Walton County line in Florida to the Anclote River around Tarpon Springs. The Tampa Bay area is under a storm-surge watch.

Storm surge

Michael is projected to strike an area that is exceptionally prone to storm surge because of the adjacent shallow shelf water and the concave shape of the coast. Like a bulldozer, the storm will push a vast amount of ocean water inland, potentially inundating homes, roads and businesses.

Areas to the east of where the storm center tracks will experience the greatest storm surge, and flooding will be worst around the high tides.

Storm surges just east of where the center makes landfall could reach eight to 12 feet if the storm comes ashore around high tide. Here are specific initial storm-surge projections from the Hurricane Center:

• Indian Pass to Crystal River: 8-12 feet.
• Cedar Key to Crystal River: 6-8 feet.
• Okaloosa/Walton County line to Indian Pass: 6-9 feet.
• Crystal River to Anclote River: 4-6 feet.
• Anclote River to Anna Maria Island, including Tampa Bay: 2-4 feet.
• Alabama/Florida border to Okaloosa/Walton County line: 2-4 feet.

Rainfall

The National Hurricane Center projects widespread rainfall amounts of four to eight inches, from the Florida Panhandle and Big Bend areas north into Georgia and South Carolina, and isolated amounts of up to a foot. “This rainfall could lead to life-threatening flash floods,” it said.

Over the Florida Peninsula and Florida Keys, one to three inches are predicted, with isolated amounts up to six inches.

Heavy rain could arrive in Florida on Tuesday night and in south Alabama and south Georgia early Wednesday. By Wednesday night and into Thursday, heavy rain will rapidly streak through Georgia and into the Carolinas.

Flooding rainfall is likely to affect some of the areas recovering from Hurricane Florence.

The rain is expected to reach the Mid-Atlantic, including North Carolina, Virginia, Maryland and Washington, late Wednesday night into Thursday before rapidly exiting by Friday. Depending on the track of Michael’s remnants, southern New England could also see a period of heavy rain late Thursday.

The potential rainfall in the Mid-Atlantic and New England ranges from two to four inches, with higher amounts locally. Because these areas have seen heavy rain in recent weeks, flooding may become a concern here, as well.

Wind

Michael’s maximum sustained winds are forecast to be around 120 mph when it strikes the coast. Winds this strong will be confined to the ring around its calm eye, known as the eyewall, and “devastating” wind damage could occur in this narrow zone.

“Well-built framed homes may incur major damage or removal of roof decking and gable ends,” the National Hurricane Center said of areas experiencing Category 3 winds. “Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.”

After the storm strikes land, this eyewall will quickly collapse, and winds will weaken.

While hurricane-force winds of over 74 mph will be confined to a relatively small area, tropical-storm winds of 39 to 73 mph will occur over a much larger zone and could result in minor structural damage and many downed trees and power outages.

The Washington Post’s Brian McNoldy contributed to this article.