Hurricane Erin strengthens to a fierce Category 5 storm in the Atlantic

USA Today

18 hours ago

Hurricane Erin rapidly strengthened into a Category 5 storm. It is not expected to make a direct hit on the U.S. but will create dangerous surf.
Hurricane Erin, on Saturday, Aug. 16, strengthened into a fearsome Category 5 hurricane with sustained winds of 160 mph as the storm traveled west over the Atlantic, according to the National Hurricane Center.
The hurricane is not expected to make a direct hit on the United States, but it will still drive dangerous surf conditions along the East Coast.
"We still expect this to eventually make a more northward turn and stay offshore of the East Coast of the United States. So that certainly is good news when dealing with a storm this powerful," AccuWeather senior meteorologist Dan Pydynowski told USA TODAY.
Under the Saffir-Simpson Hurricane Wind Scale, Category 5 hurricanes are the strongest possible, with minimum winds of 157 mph.
On the afternoon of Aug. 16, Erin was passing to the north of the northern Leeward Islands in the Caribbean and was just over 200 miles from San Juan, Puerto Rico. By evening, the hurricane was continuing to pass north of the northern Leeward Islands, prompting the Government of the Bahamas to issue a Tropical Storm Watch for the Turks and Caicos Islands.
According to the National Hurricane Center, tropical storm conditions are possible in the Turks and Caicos Islands during the next 48 hours. Additionally, tropical storm force wind gusts are possible in the southeast Bahamas beginning Sunday, Aug. 17, the center said.
Erin is only the fifth Category 5 hurricane on record to form this early in the hurricane season and the only Category 5 observed outside the Gulf or Caribbean this early in the year, according to WPLG-TV hurricane specialist Michael Lowry.
The Atlantic hurricane season officially began on June 1 and will last through the end of November. Active hurricane weather typically peaks between mid-August and mid-October. The first hurricane of the Atlantic season, on average, forms on about Aug. 11.
Where is Hurricane Erin? Storm path tracker
As of 8 p.m. ET on Aug. 16, Erin was about 160 miles northwest of Anguilla, among the northern Leeward Islands, and 150 miles northeast of Puerto Rico. It was moving west at about 15 mph with wind speeds of 150 mph.
This forecast track shows the most likely path of the center of the storm. It does not illustrate the full width of the storm or its impacts, and the center of the storm is likely to travel outside the cone up to 33% of the time.
Erin strengthened rapidly and is expected to grow
Erin formed as a hurricane on Aug. 15. It was the first hurricane of the Atlantic season, and quickly became the first major hurricane as well. A major hurricane is one that reaches at least Category 3 status.
"(B)y the middle of next week, Erin is forecast to at least double or triple in size, which will result in rough ocean conditions over the western Atlantic," the hurricane center said.
Erin's hurricane-force winds had a mean diameter of 43 miles on Aug. 16 but are expected to increase to 132 miles in diameter by Aug. 19, while its tropical storm force winds are forecast to reach a mean diameter of 385 miles over the same period.
The storm's outer bands of rain were already beginning to impact the northern Leeward Islands, forecasters said on Aug. 16. Heavy rainfall is expected in the northern Leeward Islands, the Virgin Islands and Puerto Rico for the rest of the weekend, bringing 2 to 4 inches of rain with localized amounts of 6 inches and possible flash flooding.
In its 5 p.m. update, the hurricane center said, "Erin is expected to move just north of the northern Leeward Islands, the Virgin Islands and Puerto Rico through Sunday and pass to the east of the Turks and Caicos Islands and the southeastern Bahamas Sunday night and Monday."
Erin's intensity is expected to fluctuate during the next 24 hours, but it should "remain a strong hurricane during this time," according to hurricane center forecaster Jack Beven.
"Although Erin is a somewhat compact hurricane now, the models are in strong agreement that the system will grow in size over the next several days," Beven said in the hurricane center's 5 p.m. update. "In fact, by the middle of next week, Erin is forecast to at least double or triple in size, which will result in rough ocean conditions over the western Atlantic."
What is an eyewall replacement cycle?
According to an 8 p.m. update from the hurricane center, Erin is possibly undergoing an eyewall replacement cycle.
The National Oceanic and Atmospheric Administration (NOAA) says an eyewall replacement cycle is a natural occurrence for intense hurricanes, such as Erin, in which a new eyewall (ring of thunderstorms) forms outside the existing one, eventually replacing it.
"As a hurricane grows older, it is common for the eyewall to eventually weaken and get replaced by a newer, larger eyewall," according to the NOAA.
When a hurricane has a newer, larger eyewall, it can "bring dangerous weather over a larger region than the older, smaller eyewall would have," the government agency says. During the eyewall replacement cycle, hurricanes often undergo temporary changes in strength (both up and down).
The NOAA added that what causes the newer, larger eyewall to form during this process is "not well understood."
Ways communities in Coastal North Carolina can prepare for Hurricane Erin
With Hurricane Erin predicted to move between the Outer Banks and Bermuda, North Carolina Emergency Management has offered guidance for people on the coast to prepare.
In an Aug. 16 Facebook post, the state agency said people in Coastal North Carolina should:
The NWS Morehead City, North Carolina, said on the afternoon of Saturday, Aug. 16, that a strong long-period swell from Erin will begin to arrive late on the night of Sunday, Aug. 17. Those in the area should expect heightened rip current threats through the upcoming week with swell and seas peaking Wednesday, Aug. 20, into Thursday, Aug. 21.
The Dare County Sheriff's Office, located within the Outer Banks, said in a Facebook post on Saturday, Aug. 16, that people along the coast who "routinely see ocean overwash due to no dune between them and the ocean" should "be ready to protect (their) property and to move away from the oceanfront."
What happens to a hurricane that doesn't make landfall?
If a hurricane does not make landfall, it will eventually dissipate over the ocean, according to the Hurricanes: Science and Society (HSS).
Once a storm moves northward – in the Northern Hemisphere – out of the tropical ocean and into mid-latitudes, "It begins to move over colder water, again losing the warm water source necessary to drive the hurricane," according to the HSS.
"As less moisture is evaporated into the atmosphere to supply cloud formation, the storm weakens," the educational resource says. "Sometimes, even in the tropical oceans, colder water churned up from beneath the sea surface by the hurricane can cause the hurricane to weaken."
According to the center's 5 p.m. update, the slow weakening of Erin is expected to begin on Monday, Aug. 18.
If a hurricane does make landfall, it usually decays quickly because the storm requires evaporation from the warm ocean surface to survive, according to the HSS.
What impacts will Hurricane Erin have on the US?
Erin is expected to make a turn to the north and avoid making landfall altogether. It will pass somewhere between North Carolina's Outer Banks and Bermuda, National Hurricane Center Director Mike Brennan said.
Despite staying well off the coast, Erin will cause dangerous surf conditions up and down practically the entire East Coast, from Florida all the way up to New England beaches, Pydynowski said. The conditions will include high waves and dangerous rip currents. The Outer Banks could see some beach erosion and coastal flooding from high waves, he said.
Erin is expected to bring dangerous conditions to offshore waters and beaches along the Northeast Florida coast from Aug. 18 - 21, including rip currents and rough, high surf with breakers greater than 7 feet on the 19th and 20th, said the weather service office in Jacksonville, Florida.
Weather conditions may seem ideal for a beach trip, but these types of conditions are when rip current fatalities tend to occur, Brennan said. Rip currents may not be visible from shore, so beachgoers should swim near lifeguards and pay attention to posted warnings.
'Catastrophic' Erin underwent unusually rapid intensification
Rapid intensification occurs when a tropical cyclone (whether a tropical storm or hurricane) strengthens by at least 35 mph in a 24-hour period.
In Erin's case, winds strengthened to roughly 80 mph in about a day. Erin was declared a hurricane (winds of at least 74 mph) shortly before 11 a.m. on Aug. 15. A day later, it had strengthened into a Category 5 cyclone (winds of at least 157 mph).
Warm water ahead of Erin as it moved west, a lack of wind shear and its position far enough away from any land to interfere contributed to the strengthening, Pydynowski said.
"These kind of rapid intensification events do occur, but that much that quickly is certainly more toward the uncommon end of things," he said.
Data shows Hurricane Erin's remarkable power
Since 1979, only Hurricane Allen in 1980 had a lower minimum central pressure by August 16, said Phil Klotzbach, a senior research scientist at Colorado State University. Lower pressure in a hurricane means a stronger storm.
Since 1970, only 5 storms in the Atlantic hurricane basin have had 145 mph maximum winds or more by Aug. 16: Allen in 1980, Charley in 2004, Dennis in 2005, Emily in 2005 and Beryl in 2004, Klotzbach noted.
Another disturbance off the East Coast
Another tropical disturbance off the East Coast of the United States had little chance of forming as of Aug. 16, forecasters said.
Disturbance 1 is an area of low pressure off the coast of North Carolina that has about a 10% chance of development into a cyclone, but will likely lose steam by early next week, the hurricane center said. It was producing showers to the east of its center over the Atlantic.
Hurricane Erin spaghetti models
Illustrations include an array of forecast tools and models, and not all are created equal. The hurricane center uses only the top four or five highest-performing models to help make its forecasts.
How do hurricanes form?
Hurricanes are born in the tropics, above warm water. Clusters of thunderstorms can develop over the ocean when water temperatures exceed 80 degrees Fahrenheit. If conditions are right, the clusters swirl into a storm known as a tropical wave or tropical depression.
A tropical depression becomes a named tropical storm once its sustained wind speeds reach 39 miles per hour. When its winds reach 74 mph, the storm officially becomes a hurricane.
Prepare now for hurricanes
Delaying potentially life-saving preparations could mean waiting until it's too late. "Get your disaster supplies while the shelves are still stocked, and get that insurance checkup early, as flood insurance requires a 30-day waiting period," NOAA recommends.
Prepare now for hurricanes: Here's what you should do to stay safe before a hurricane arrives