A new hurricane season forecast issued by The Weather Channel on Tuesday says we can expect the number of named storms and hurricanes in the 2015 Atlantic season to stay below historical averages.
A total of nine named storms, five hurricanes and one major hurricane are expected this season, according to the forecast prepared by WSI, which, along with The Weather Channel is part of The Weather Company. This is below the 30-year average of 12 named storms, six hurricanes and three major hurricanes. A major hurricane is one that is Category 3 or stronger on the Saffir-Simpson Hurricane Wind Scale.
WSI chief meteorologist Dr. Todd Crawford says, "Both the dynamical models and our proprietary statistical models suggest a relatively quiet tropical season this year."
The WSI forecast for below-average activity during the 2015 Atlantic hurricane season is consistent with what Colorado State University (CSU) said in its forecast issued on April 9. CSU's forecast called for seven named storms, including three hurricanes, one of which is predicted to attain major hurricane status.
The CSU outlook, headed by Dr. Phil Klotzbach in consultation with long-time hurricane expert Dr. William Gray, is based on a combination of 29 years of statistical predictors, combined with analog seasons exhibiting similar features of sea-level pressure and sea-surface temperatures in the Atlantic and eastern Pacific Oceans.
Here are four questions about this outlook and what it means for you.
Q: Does this mean a less destructive season?
There is no strong correlation between the number of storms or hurricanes and U.S. landfalls in any given season.
"It is important to note that our - The Weather Channel - forecasts are for the total number of storms that may occur anywhere within the Atlantic Ocean, and do not attempt to predict the number of storms that will make landfall in the U.S.," said Dr. Peter Neilley, vice president of Global Forecasting Services at WSI.
The 2014 season featured the fewest number of named storms in 17 years (eight storms), but also featured the strongest landfalling hurricane in the mainland U.S. in six years (Hurricane Arthur on the Outer Banks), and featured two back-to-back hurricane hits on the tiny archipelago of Bermuda (Fay, then Gonzalo).
Furthermore, six of those eight storms became hurricanes, and Gonzalo was the strongest Atlantic hurricane since Igor in 2010.
In 1983, there were only four named storms, but one of them was Alicia, a Category 3 hurricane which clobbered the Houston-Galveston area.
The 2010 season featured 12 hurricanes and 19 named storms, which tied 1995 for the third most named storms in any Atlantic season, at the time. But not a single hurricane, and only one tropical storm, made landfall in the U.S during that active season.
In other words, a season can deliver many storms, but have little impact, or deliver few storms and have one or more hitting the U.S. coast with major impact.
Therefore, it's important to be prepared for hurricanes and tropical storms every year, regardless of seasonal forecasts.
Dr. Crawford of WSI says, "A new El Niño event is emerging that will likely be stronger than last year's weaker event. The cooler ocean temperatures and subsidence/shear associated with the El Niño event will likely be a deterrent for widespread tropical cyclone development in the Atlantic."
There is a body of scientific evidence linking the occurrence of El Niño with increased wind shear in the tropical Atlantic Basin, which is one factor, along with dry air, that limits the development and strengthening of tropical cyclones.
However, exactly where the warming of the equatorial Pacific waters takes place and the magnitude of that warming plays at least a partial role in the number of Atlantic named storms.
- Warming in the eastern equatorial Pacific: lower number of Atlantic tropical cyclones
- Warming in the central equatorial Pacific: higher number of Atlantic tropical cyclones
Klotzbach and Gray of CSU found five other hurricane seasons with comparable Atlantic and Pacific sea-surface temperatures both in February-March, as well as what is forecast for August-October: 1957, 1987, 1991, 1993 and 2014. Those years averaged eight named storms, four hurricanes, and 1-2 major hurricanes.
Despite the low numbers in those years, in addition to 2014's Hurricane Arthur, there were two other historic hurricanes during those seasons:
- Hurricane Bob (1991): One of the costliest and most intense New England hurricanes on record ($1.5 billion damage; 17 killed; 5-8 foot storm surge in Rhode Island; waves battered south coasts of Nantucket and Martha's Vineyard)
- Hurricane Audrey (1957): Only Category 4 June Atlantic hurricane on record; Seventh deadliest Atlantic hurricane with at least 416 killed.
In short, the exact role El Niño may play in the 2015 season remains uncertain.
"Aggregate Atlantic basin sea surface temperatures are as cool as they've been since 2009, and are at the second coolest levels in 20 years," said Dr. Crawford.
Looking at the Atlantic Basin as a whole as of late March 2015, warmer sea-surface temperatures (hereafter, SSTs) were in place in the western Atlantic Ocean and Caribbean Sea but generally cooler-than-average SSTs dominated in the eastern Atlantic Ocean from the western African coast to about halfway to the Windward Islands.
All other factors – such as the amount of wind shear and dry air aloft – being equal, warmer waters offer more heat to fuel the tropical cyclone.
It is important to note, however, that a large majority of the destructive hurricanes during the record-setting 2005 hurricane season developed in the western Atlantic Basin.
"The big question marks with this season's predictions are how strong El Niño is going to be, as well as if tropical and North Atlantic sea-surface temperature anomalies remain as cool as they are now," said Klotzbach and Gray.
Q: There was no El Niño the past two seasons. Why were they relatively quiet?
We mentioned the somewhat paradoxical 2014 Atlantic hurricane season earlier. Fewest named storms since 1997, but back-to-back strikes on Bermuda, as well as Hurricane Arthur ruining the July 4th holiday on the Outer Banks of North Carolina.
In 2014, Klotzbach and Gray noted July sea-surface temperatures in the main development region between the Lesser Antilles and Africa were the coolest since July 2002. Interestingly, sea-surface temperatures were actually warmer than average in a broad swath of the western Atlantic Ocean, western Caribbean Sea, and Gulf of Mexico.
Vertical wind shear, namely the change in wind direction and/or speed with height, was found to be near the strongest on record in July 2014 over the Caribbean Sea, according to the CSU study. Wind shear disrupts tropical cyclones or inhibits them from developing by displacing thunderstorms from the center of circulation.
Following Arthur, five remaining named storms forming in the Atlantic Ocean all took north, then northeast turns away from the U.S. mainland, thanks to the orientation of winds aloft and the orientation of the Bermuda high. Tropical Storms Dolly and Hanna buried themselves in eastern Mexico and Central America, respectively.
In the 2013 season, for the first time since 1994, no hurricanes stronger than Category 2 developed. Since the satellite era began in 1960, only four other seasons failed to produce a single Category 3 or stronger hurricane (1994, 1986, 1972, 1968).
"By most measures, 2013 was one of the strangest years in the tropical Atlantic in many decades," said Dr. Crawford.
"The 'usual suspects' of pre-season indicators suggested a reasonably active season as relative warm Atlantic SSTs and an expected lack of El Niño resulted in fairly bullish seasonal forecasts."
While the number of storms predicted (14) in 2013 was above the long-term average, the dominance of dry air and wind shear limited the intensity of existing storms or squelched the development of others.
Hurricane Sandy 2 Years Later
The Weather Channel issues the 2015 Atlantic hurricane season forecast
The McDonald's on Broad Channel Drive in Rockaway Beach only days after Sandy ravaged the neighborhood. (Instagram/GormoJourno)
The completely rebuilt McDonald's as it stands today. (AOL News Photo)
Beach 91st Street & Shorefront Parkway as they were in the days after Sandy. (Flickr)
Windows on the street are still taped even today. (AOL News Photo)
The famed Rockaway Skating Park was destroyed by Sandy. (Flickr)
It has been completely rebuilt. (AOL News Photo)
Another view of the destroyed skating park. (Flickr)
It is now better than ever. (AOL News photo)
The boardwalk is still being rebuilt, but it is no longer in the street. (AOL News photo)
The beach still has a long way to go, but it is in better shape with each passing day. (AOL News photo)
Another view of the beach as it is today. (AOL News photo)
In this photo provided by the Port Authority of New York and New Jersey a surveillance camera captures the PATH station in Hoboken, N.J., as it is flooded shortly before 9:30 p.m. EDT on Monday, Oct. 29, 2012. (AP Photo/Port Authority of New York and New Jersey)
The Hoboken PATH station has been completely restored since Sandy's floodwaters ravaged it. (AOL News photo)
The station has never looked better. (AOL News photo)
The shopping arcade at One New York Plaza, in Lower Manhattan, was completely submerged from Sandy's storm surge. (Alamy)
It is no longer underwater, but has yet to reopen. (AOL News photo)
This Oct. 30, 2012, photo provided by New York's Metropolitan Transportation Authority (MTA) shows a flooded escalator in the South Ferry station of the No. 1 subway line, in lower Manhattan, after Superstorm Sandy passed through New York. (AP Photo/Metropolitan Transportation Authority)
South Ferry Station has since been completely rebuilt and opened. (AOL News photo)
Sandy's storm surge rushed into this parking garage during the night of October 29, 2012. (AOL News photo)
Cars piled on top of each other at the entrance to the garage, on South Willliam Street, in Lower Manhattan on October 31, 2012. (STAN HONDA/AFP/Getty Images)
The parking garage looks today as if no flooding ever happened. (AOL News photo)
FILE - This Oct. 29, 2012 file photo shows flooded streets around a Con Edison substation in the Brooklyn borough of New York as Superstorm Sandy moved through the area. (AP Photo/Bebeto Matthews, File)
This Oct. 17, 2013 photo shows a pedestrian walking along Jay Street near a Con Edison substation in the Brooklyn borough of New York nearly a year after the area was flooded during Superstorm Sandy. (AP Photo/Bebeto Matthews)
FILE - This Oct. 30, 2012 file photo shows downed power lines and a battered road smashed by Superstorm Sandy in Seaside Heights, N.J. Sandy, the storm that made landfall a day earlier, caused multiple fatalities, halted mass transit and cut power to more than 6 million homes and businesses. (AP Photo/Julio Cortez, File)
This Tuesday, Oct. 22, 2013 photo shows traffic flowing on a road connecting the barrier island at Seaside Heights, N.J., with the mainland of Toms River, N.J. A year ago, during Superstorm Sandy, the road was covered in sand and downed power lines caused by the storm which hit Oct. 29, 2012. (AP Photo/Julio Cortez)
FILE - This Nov. 14, 2012 file photo shows a piece of construction equipment working on the pile of debris, collected during the cleanup from Superstorm Sandy, in the parking lot of Jacob Riis Park in the Rockaway section of the Queens borough of New York.(AP Photo/Mark Lennihan, File)
This Oct. 17, 2013 photo shows the parking lot at Jacob Riis State Park empty of all the debris that had been stored there following Superstorm Sandy, in the Rockaway section of the Queens borough of New York. (AP Photo/Mark Lennihan)
FILE - This Oct. 29, 2012 file photo shows sea water flooding the entrance to the Brooklyn Battery Tunnel in New York as Superstorm Sandy struck the city. (AP Photo/ John Minchillo, File)
This Oct. 20, 2013 photo shows a taxi entering New York's Brooklyn Battery Tunnel in lower Manhattan nearly a year after Superstorm Sandy flooded the tunnel and other low-lying areas of the city, including the nearby World Trade Center construction site. (AP Photo/John Minchillo)
FILE - This Nov. 22, 2012 file photo show debris left by Superstorm Sandy where the boardwalk had been in front of Lucky Leo's arcade in Seaside Heights, N.J. (AP Photo/Mel Evans, File)
This Oct. 13, 2013 photo shows people walking along the rebuilt boardwalk in Seaside Heights, N.J., where a year ago Superstorm Sandy left the resort area in ruins. (AP Photo/Mel Evans)
FILE - In this Nov. 1, 2012 file photo, commuters wait in a line to board buses into Manhattan in front of the Barclays Center in the Brooklyn borough of New York. The line stretched twice around the arena and commuters reported wait times of one to three hours to get on a bus. (AP Photo/Seth Wenig, File)
This Oct. 17, 2013 photo shows the scene in front of the Barclays Center in the Brooklyn borough of New York. Nearly a year ago, after Superstorm Sandy knocked out many subway lines, the line stretched twice around the arena and commuters reported wait times of one to three hours to get on a bus. (AP Photo/Seth Wenig)
FILE - This April 25, 2013 file photo shows a flag waving in front of the burned remains of more than 60 small bungalows which were destroyed at Camp Osborn in Brick, N.J., during Superstorm Sandy. (AP Photo/Mel Evans, File)
This Oct. 13, 2013 photo shows a tattered flag flaping in the wind in Brick, N.J., where 60 small bungalows that once made up Camp Osborn were destroyed in a fire a year ago during Superstorm Sandy. (AP Photo/Mel Evans)
FILE - This Tuesday, Oct. 30, 2012 file photo shows Robert Connolly, left, embracing his wife Laura as they survey the remains of the home owned by her parents that burned to the ground during Superstorm Sandy in the Breezy Point section of New York. (AP Photo/Mark Lennihan, File)
This Oct. 21, 2013 photo show foundations, which are all that remain of a house that burned to the ground during Superstorm Sandy a year ago in the Breezy Point neighborhood of the Queens borough of New York. The view is similar to the one that Robert and Laura Connolly had of her parents' burned house on Oct. 30, 2012. New homes, top center and top right, are under construction in the seaside community that lost more than 100 homes to a firestorm during Sandy. (AP Photo/Mark Lennihan)
FILE - In this Nov. 5, 2012 file photo, Rockaway resident Christine Walker walks along the beach under what is left of the Rockaway boardwalk days after Superstorm Sandy in the Queens borough of New York. (AP Photo/Craig Ruttle, File)
This Oct. 21, 2013 photo shows a view along the beach with reinforced dunes and the buried remains of the former boardwalk in a Rockaway neighborhood in the Queens borough of New York. Nealry a year ago, the boardwalk stood above the beach, used by the neighborhood and many other New Yorkers, but was wiped away by the storm surge of Superstorm Sandy. (AP Photo/Craig Ruttle)
FILE - This Dec. 4, 2012 file photo shows the ruins of Breezy Point in the Queens borough of New York where fire burned 130 houses and flooding destroyed another 220 during Superstorm Sandy. (AP Photo/Mark Lennihan, File)
This Oct. 13, 2013 photo shows a sign in a section of Ortley Beach in Toms River, N.J., on an empty lot in an area where the debris from numerous homes was removed after being destroyed last October during Superstorm Sandy. (AP Photo/Mel Evans)
FILE - This Oct. 29, 2012 file photo shows lower Manhattan in the dark during Superstorm Sandy, as seen from the Brooklyn Heights promenade in the Brooklyn borough of New York. One World Trade Center, background center, remains brightly lit. (AP Photo/Bebeto Matthews, File)
This Oct. 17, 2013 photo, taken nearly a year after Superstorm Sandy, shows the illuminated skyscrapers of lower Manhattan as a backdrop to ongoing construction in the Brooklyn Heights neighborhood, in the Brooklyn borough of New York. Almost a years ago, the skyline was forced in to darkness during the floods from Sandy. (AP Photo/Bebeto Matthews)
FILE - This Oct. 30, 2012 file photo show Brian Hajeski of Brick, N.J., reacting while looking at the destruction left behind when the Atlantic Ocean breached over land in Mantaloking, N.J., the morning after Superstorm Sandy rolled through. (AP Photo/Julio Cortez, File)
This Oct. 22, 2013 photo shows Brian Hajeski of Brick, N.J., standing at the same spot where a year earlier he witnessed the destruction left behind when the Atlantic Ocean breached over Mantaloking, N.J., during Superstorm Sandy. (AP Photo/Julio Cortez)
FILE - This Oct. 30, 2012 file photo shows a statue of the Virgin Mary that survived an overnight fire in the Breezy Point section of the Queens borough of New York the morning afer Superstorm Sandy tore through. In the beachfront enclave fire burned 130 houses and flooding destroyed another 220. (AP Photo/Frank Franklin II, File)
This Oct. 15, 2013 photo shows a view of Gotham Way in the Breezy Point section of the Queens borough of New York where a statue of the Virgin Mary that survived a massive fire once stood. The statue became an iconic image of Superstorm Sandy's wrath, which caused a fire that burned 130 houses and flooding that destroyed another 220. (AP Photo/Kathy Willens)
FILE -This Feb. 25, 2013 file photo shows the sun rising in Seaside Heights, N.J., behind the Jet Star Roller Coaster which had been sitting in the ocean after part of the Casino Pier was destroyed during Superstorm Sandy. (AP Photo/Mel Evans, File)
This Oct. 13, 2013 photo shows an empty section of the Atlantic ocean off Seaside Heights, N.J., where, for months after Superstorm Sandy, the Jet Star Roller Coaster rose out of the water after the Casino Pier was destroyed by the storm. The pier was the former site of the roller coaster that was swept into the ocean, creating one of the storm's enduring images. The roller coaster was removed in May. (AP Photo/Mel Evans)