UPDATE 6:30 a.m.: Life-threatening freshwater flooding is likely from heavy rainfall, which may extend inland over the Carolinas and Mid Atlantic. Large swells affecting Bermuda and portions of the U.S. East Coast will continue this week, which may cause life-threatening surf and rip currents.
UPDATE 11 p.m.: Hurricane Florence is taking aim at the U.S. East Coast with Category 4 winds, spurring North Carolina’s governor to urge coastal residents to evacuate. At 11 p.m., the storm’s winds remained at 140 mph but some strengthening is expected, according to the National Hurricane Center.
On the current forecast track, the hurricane center predicts, the center of Florence will move over the southwestern Atlantic between Bermuda and the Bahamas on Tuesday and Wednesday, then approach the coast of North Carolina or South Carolina on Thursday.
North Carolina Governor Roy Cooper is urging residents to evacuate the state’s coastal areas as Florence moves closer to landfall.
Cooper’s office said in a statement that the Category 4 hurricane is expected to hit the Wilmington area on Thursday, but impacts of the storm will likely begin Wednesday. Cooper says the state faces three threats from Florence: “ocean surge along our coast, strong winds, and inland flooding from heavy rain.”
Meanwhile, Isaac weakened to a 70-mph tropical storm as it moved westward in the Atlantic toward the Leeward Islands. Isaac is forecast to be at or near hurricane strength as it approaches the Lesser Antilles later this week, forecasters said.
On the hurricane center’s forecast track, Isaac should move across the Lesser Antilles and into the eastern Caribbean on Thursday, according to the 11 p.m. advisory.
Hurricane Helene is on a different track, projected to turn toward the northwest and then north-northwest on Wednesday and Thursday. Packing 110-mph winds, Helene is expected to gradually weaken as it meanders into open waters.
STORM 2018: CHECK THE INTERACTIVE TRACKING MAP
UPDATE 5 p.m.: Hurricane Florence continues to strengthen this afternoon, reaching 140 mph winds that could intensify to 155 mph – a dangerous high-end Category 4 storm.
Category 5 hurricanes begin at 157 mph.
“Unfortunately, the models were right,” National Hurricane Center forecaster Eric Blake wrote in the 5 p.m. advisory. “Florence has rapidly intensified into an extremely dangerous hurricane.”
The official forecast from the hurricane center has Florence nearing the coast between South Carolina and Virginia Thursday.
“The bottom line is that there is high confidence that Florence will be a large and extremely dangerous hurricane, regardless of its exact intensity,” Blake said.
UPDATE 12 p.m.: Hurricane Florence is now a powerful Category 4 storm with 130 mph winds.
The National Hurricane Center increased Florence’s intensity in a special updated statement after getting new information from a NOAA Hurricane Hunter.
The storm is 575 miles south-southeast of Bermuda and heading west at 13 mph.
Florence’s intensification was forecast as it moves over warmer waters and wind shear decreases. Hurricane force-winds extend outward up to 30 miles from the center with tropical storm force winds extending outward up to 140 miles.
Florence’s unusual track – unprecedented for storms that form where it did – is being influenced by two high pressure areas. The Bermuda High is pushing it west, while a second high over the northeast Atlantic is blocking it from heading north.
Michael Bell, an associate professor for atmospheric science at Colorado State University, said he fears Florence will get stuck between the two high pressure areas and stall. That could mean a deluge of rain.
“Certainly we’re not expecting a Harvey, which was almost eight days of rain,” Bell said. “But even a few days of tropical rainfall can cause flooding.”
The Weather Prediction Center is forecasting up to 15 inches of rain over the next seven days for areas of the Carolinas.
UPDATE 11 a.m.: Hurricane Florence has strengthened to a major Category 3 hurricane with 115 mph winds.
Florence is moving west at 13 mph over progressively warmer water with temperatures as high as 85 degrees.
Wind speeds are forecast to reach 150 mph within 36 hours and the storm is expected to approach the coast of the Carolinas and Virginia as a Category 4 hurricane.
The National Hurricane Center said a hurricane watch will likely be issued by Tuesday morning for coastal areas of South Carolina and North Carolina. A hurricane watch means tropical storm-force winds are anticipated within 48 hours. Emergency preparations should be completed before tropical storm-force winds arrive.
Hurricane Florence is rapidly intensifying this morning with a beady 10 nautical mile-eye and chilling cloud tops.
The storm, a Category 2, is expected to gain major hurricane status today, then ramp up to a raging Cat 4 by tomorrow with 140 mph winds. Within two days, it could be a 150 mph storm.
With a track showing Florence making landfall Thursday or early Friday morning from South Carolina through Virginia, NHC forecasters are warning of “an increasing risk of life-threatening impacts from Florence.”
Storm surge, wind and freshwater inland flooding are all concerns. Most weather models are in agreement with the hurricane’s track, but storms typically stay within the cone 60 percent of the time, meaning they veer outside the forecast 30 percent of the time.
“The odds have increased that Florence will stall on Friday and meander near or over the coast for several days, making the hurricane a huge rainfall and coastal flooding threat,” said Weather Underground co-founder Jeff Masters in his Cat 6 blog.
North Carolina Gov. Roy Cooper declared a state of emergency Friday. In a Sunday press release, he warned people to “take steps now” for Florence’s arrival.
“Everyone in North Carolina needs to keep a close eye on Florence and take steps now to get ready for impacts later this week,” Cooper said. “State emergency management, transportation, health experts and others are making sure North Carolina is prepared for the storm, and I urge the public to review your emergency plans and gather your supplies now.”
The Weather Prediction Center is forecasting 10 to 15 inches of rain from Florence over the next seven days in North Carolina and Virginia. About 27 percent of direct storm-related deaths are drowning sin freshwater flooding from rain.
For South Florida, Hurricane Florence is going to mean a high risk of rip currents beginning Wednesday.
The National Weather Service in Miami expects the surf to be highest off Palm Beach County with tides running 1 to 1.4 feet above normal over the next few days, with swell heights reaching 5 to 7 feet.
“The time frame is beginning late Wednesday propagating north to south, peaking late Thursday into Friday, and subsiding through Saturday,” Miami meteorologists wrote.
Isaac was upgraded to a hurricane at the Sunday 11 p.m. advisory from the National Hurricane Center.
It is about 1,300 miles east of the Windward Islands moving west at 14 mph.
The 5-day forecast for Isaac shows it reaching only Category 1 strength before dropping back to tropical storm strength Thursday as it moves into the Caribbean.
But because Isaac is a small storm, it is more subject to the environment and at least one weather model has it reaching Category 3 strength by late today.
“After that, however, an increase in shear first from a trough over the central Atlantic and later from the outflow form Florence should result in weakening when the system moves across the Lesser Antilles and into the Caribbean Sea,” NHC forecasters wrote.
In other areas of the tropical Atlantic, the National Hurricane Center is watching two zones that have been given medium chances of development over the next five days.
The first disorganized area of showers and thunderstorms over the northwestern Caribbean Sea and western Cuba is forecast to move near the Yucatan Peninsula before reaching the warm waters of the Gulf of Mexico where winds are expected to be conducive for development.
The second spot is an area of non-tropical low pressure that could form in the northeastern Atlantic several hundred miles west of the Azores in about two days. Some tropical development is possible by the end of the week while the low moves southwestward.
Satellite imagery indicates that Florence’s maximum sustained winds have increased to 105 miles per hour as it moves west across the Atlantic.
It is expected to make landfall Thursday along the southeast coast as a Category 4 hurricane, according to the National Hurricane Center.
At 5 a.m., Florence was 625 miles southeast of Bermuda and 535 miles north-northeast of the Leeward Islands.
Hurricane Isaac is following right behind Florence with maximum sustained winds at 75 miles per hour. It is expected to strengthen within the next few days, but then weaken by the middle of the week.
And just behind Isaac, is Hurricane Helene.
Helene is about 300 miles west of the Cabo Verde Islands with 85 miles per hour maximum sustained winds.
The storm is expected to veer northwest on Wednesday and as of now, is not forecast to make landfall.