Hurricane Florence appears to be aiming for North Carolina, according to forecasters Monday night, with much of South Carolina possibly escaping the brunt of this powerful storm.

But National Hurricane Center specialist Eric Blake warned that damaging hurricane-force winds, life-threatening storm surge and freshwater flooding are likely along at least portions of South Carolina.

Mark Malsick, the severe weather liaison for the S.C. Climate Office, said the Charleston area could see winds near tropical storm strength of 40 mph and several inches of rain, with worse conditions farther north.

The hurricane had strengthened to Hurricane Hugo-like 140 mph winds capable of catastrophic damage. Blake said it could reach Category 5 strength of winds 156 mph or more by Tuesday, before weakening somewhat as it nears landfall Thursday.

Computer model runs began to key on a landfall near Wilmington, N.C. The southern edge of the area of potential landfall was moved to the north of Charleston and the northern edge to the Outer Banks of North Carolina.

"While the intensity forecast shows some weakening of the maximum winds near landfall, the wind field is expected to grow with time, which increases the storm surge and inland wind threats," Blake said. "The bottom line is that there is high confidence that Florence will be a large and extremely dangerous hurricane, regardless of its exact intensity."

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florence arrival time 5p  monday

The predicted arrival time for tropical storm force winds for Hurricane Florence as of 5 p.m. Monday, September 10, 2018. National Hurricane Center

The National Weather Service office in Charleston continued to caution that a hurricane landfall near the city is possible.

Weather Service meteorologists predicted 1 to 4 inches of rain from the storm in the Charleston area, with more rain to the north. The rain should begin Thursday afternoon.

The worst of the flooding rain is expected to fall in North Carolina, said Weather Service meteorologist Emily McGraw.

But "any kind of shift in the (Hurricane Center forecast) track could bring those (flood) totals farther south," she said. 

Dangerous rip current and coastal flooding advisories have been issued and will continue for the next few days, McGraw said. Impacts of the storm could well be felt far from the center of the storm, including the possibility of tornadoes.

The overall size of Florence is shaping up to spin hurricane or tropical force winds over a span bigger than Hugo, which covered an area about as large as the state of South Carolina, said Charleston-based meteorologist Shea Gibson, with the private company WeatherFlow.

The forecast shift in the storm path came after Gov. Henry McMaster issued an evacuation order for the South Carolina coast effective noon Tuesday, along with school closings and interstate lane reversals.

At a press conference, Charleston area officials urged residents to heed the evacuation order, noting that law enforcement and emergency workers will not respond to calls for service when winds reach 39 mph or greater.

Charleston County Council Chairman Vic Rawl encouraged residents to consider the devastation caused by Hurricane Hugo.

“If you live on the beach and don’t evacuate, you’re basically inviting suicide,” he said. “The bottom line is it’s up to the citizens to take some responsibility for their own health and well-being.”

Nine shelters will open Tuesday in the tri-county area. Goose Creek High School will be the primary location for Charleston County residents and will also accept others. Cane Bay High School and DuBose Middle School will be pet-friendly shelters, and owners must stay with their animals for the duration of their stay.

As residents wrestled with whether to evacuate, care agencies such as the Medical University of South Carolina prepared to handle storm impacts as well as assisting other hospitals farther north in the state.

"Our facilities have been here for decades," said Matt Wain, chief operations officer for MUSC Health. "They've survived many other hurricanes."

The storm's rapid intensification from a Category 1 to a Category 4 on Monday was historic, Gibson said. Only Hurricane Umberto in 2007 did anything like that at that latitude.

Only three hurricanes in recent history reached South Carolina as a Category 4 storm: Hugo in 1989, Gracie in 1959 and Hazel in 1954, according to the Climate Office. 

Once inland, the storm is expected to stall, dropping flooding rain across a wide region.

Lisa Sharrard, an insurance agent and owner of U.S. Flood Solutions in Columbia, has worked in floodplain management and flood insurance in various capacities for decades. She said if Hurricane Florence slows down once it makes landfall, that's probably going to mean hours and hours of continuous rain.

Even if the storm moves past South Carolina and hits North Carolina, so much rainfall could eventually cause flooding downstream as the excess water makes its way through South Carolina's rivers and streams.

"When that watershed fills up in North Carolina, about four or five days later we’ll get the boomerang effect where water comes back down through South Carolina," she said.

The city of Charleston planned to open its parking garages free of charge at 2 p.m. Tuesday for car storage. No curfew was planned, but that could change as the storm track evolves. The city also lowered water levels in Colonial Lake and Lake Dotterer in West Ashley to provide more stormwater storage in case of flooding.

Most municipalities and counties along the coastal portions of South Carolina were offering free sandbags by Monday. Contact your local government for more information.

"Interests at the coast and inland from South Carolina into the mid-Atlantic region should closely monitor the progress of Florence," said Hurricane Center specialist Daniel Brown.

Get preparations in place and follow the guidance of local officials, Brown said, echoing the advice of emergency managers across South Carolina.

"There is an increasing risk of life-threatening impacts from Florence: storm surge at the coast, freshwater flooding from a prolonged and exceptionally heavy rainfall event inland, and damaging hurricane-force winds. While it is too soon to determine the exact timing, location and magnitude of these impacts," Brown said.

With Florence moving west, eyes elsewhere were on other storms in the Atlantic. Both Isaac and Helen had become hurricanes in the tropical Atlantic, although neither was considered a threat to the Southeast coast as of Monday. Forecasters began watching a storm in the Caribbean Sea expected to strengthen into a tropical storm or worse.

It appeared to be headed toward Texas.

Not so coincidentally, Monday was considered the peak of the hurricane season, the day most likely to have the storms form.

MK Wildeman, Angie Jackson and Abigail Darlington contributed to this report.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.