Hurricanes are the most violent storms on Earth. Get the 2018 hurricane forecast—plus facts about hurricanes. Where IS a hurricane? How do hurricanes form? We’ll provide answers to your common hurricane questions.
The Atlantic Hurricane Season lasts from June 1 through November 30. Forecasts cover the Atlantic Basin—the area encompassing the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico.
2018 Hurricane Forecast
As of their August 2 update, Colorado State University predicts that the 2018 Atlantic hurricane season will be one of below-average activity. They currently put the chances of a major hurricane (Category 3 or higher) making landfall along the East Coast (including Florida) at 20%, along the Gulf Coast (including the Florida Panhandle) at 19%, and in the Caribbean at 28%—all at least 10% below the average for the last century. See the full 2018 hurricane forecast here.
This forecast is certainly a welcome change from the above-average 2018 hurricane season.
Keep in mind that although this forecast suggests that there may not be as many storms as last year, that doesn’t necessarily mean that the storms that do occur will be weak ones. If you live in an area regularly affected by hurricanes, always be prepared for the worst case scenario. As CSU states, “it only takes one hurricane making landfall to make it an active hurricane season.”
What does this mean in terms of storm numbers? Well, let’s take a look at CSU’s forecasted totals versus the 1981–2010 median storm counts:
Updated 2018 Forecast
|Named Storm Days||55||53||60.1|
|Major Hurricane Days||4||2||3.9|
|Accumulated Cyclone Energy||90||64||92|
|Net Tropical Cyclone Activity||100%||78%||103%|
Summary of Observed 2017 Season
CSU issues Atlantic hurricane seasonal forecasts in June, July, and early August, just prior to the peak of the hurricane season. For the 2017 season, their forecasts shifted from “average” in June 2017 to “above-average” in July and “above average” again in August, based on the atmospheric and oceanic conditions.
However, the season turned out to be even more active than anticipated with levels of activity that were higher than predicted. As CSU states, “While the overall season was very active, what most stood out about 2017 was the record-breaking levels of hurricane activity that occurred during September. Hurricanes Harvey, Irma and Maria were the most notable storms of 2017, leaving paths of death and destruction in their wake.” The two main reasons for the high levels of activity were well above-average sea surface temperatures and reduced levels of vertical wind shear in the tropical Atlantic.
The 2017 hurricane season set many records. Here’s just a sampling:
- The Atlantic had a record number of 17 named storms, 91.25 named storm days and 10 hurricanes! Each of these were the most that the Atlantic has had in a season since 2012.
- 51.25 hurricane days occurred in 2017—the most in a season since 1995.
- Six major hurricanes formed in 2017—the most in a season since 2005.
- 19.25 major hurricane days occurred in 2017—the most in a season since 2004.
- The continental United States had three hurricane landfalls (Harvey, Irma, and Nate) for the first time since 2008.
- Harvey was the first major hurricane to make continental United States landfall since Wilma in 2005, ending the record-long major hurricane landfall drought at 4323 days.
- Harvey was the first Category 4 hurricane to make landfall in Texas since Carla (1961), bringing epic flooding to the Houston metropolitan area.
- This was the first season on record (since 1851) to have two Category 4 hurricanes make continental United States landfall in the same year (Harvey and Irma).
- Irma and Maria both brought devastation to islands throughout the Caribbean and tropical Atlantic. Irma was the strongest hurricane to impact the Leeward Islands on record, and the first Category 5 hurricane to make landfall in Cuba since 1924.
- Irma was the first Category 4 hurricane to make Florida landfall since Charley in 2004, pummeling the Keys and bringing considerable damage to mainland Florida as well.
- Maria was the first Category 4 hurricane to make landfall in Puerto Rico since 1932 and the strongest hurricane to make landfall in Puerto Rico since 1928.
2017 Hurricane Summary
|Forecast Parameters||2017 Forecast
|Named Storm Days||60||91.25||60.1|
|Major Hurricane Days||5||19.25||3.9|
|Accumulated Cyclone Energy||100||226||92|
|Net Tropical Cyclone Activity||110%||231%||103%|
Facts About Hurricanes
Q. What is a Hurricane?
A. A hurricane is a tropical storm with winds that have reached a constant speed of at least 74 mph in the North Atlantic Ocean, Caribbean Sea, or Gulf of Mexico. A hurricane’s winds blow in a large spiral around a relatively calm center of extremely low pressure known as the eye of the storm. Around the rim of the eye, winds may gust to more than 200 mph. The eye of a storm is usually 20 to 30 miles wide and may extend over 400 miles. The entire storm can be up to 340 miles in diameter, dominating the ocean surface and lower atmosphere for thousands of square miles.
Q. Where Does a Hurricane Form?
A. Hurricanes only form over warm waters in the tropics (usually above 27°C, or about 81°F). Think of a hurricane like a giant engine. It’s fuel is warm, moist air—which rises from from the oceans causing an area of lower pressure below. Then the air from surrounding areas with higher air pressure pushes in to the low pressure area. Then that “new” air becomes warm and moist and rises, too. As the warm air continues to rise, the surrounding air swirls in to take its place. As the warmed, moist air rises and cools off, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface. Around their core, winds grow with great velocity, generating violent seas. Moving ashore, they sweep the ocean inward while spawning tornadoes and producing torrential rain and floods.
Storms that form north of the equator spin counterclockwise. Storms south of the equator spin clockwise. This difference is because of Earth’s rotation on its axis.
Q. How do we know a hurricane is coming?
A. Now, thanks to satellite technology, no hurricane goes unnoticed. See our article on “Predicting Hurricanes: The Eyes Have It” to learn more.
It also usually takes several days to a week for a tropical storm to grow into a hurricane and there is often plenty of time to take precautionary measures unlike some extreme weather events (such as a tornado).
But if conditions are just right, a powerful major hurricane can develop in just hours. This has been called “rapid intensification” by the National Hurricane Center. When conditions are just perfect, a storm can increase its wind speed 35 mph in 24 hours or less—about two categories on the Saffir-Simpson scale, which grades hurricane strength from 1 to 5. Rapid intensification, however, is rare, with just one or two Atlantic storms per year undergoing such an acceleration.
Q. What is the cause of hurricane damage?
A. Hurricanes actually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. When hurricanes move over large landmasses, they can die out quickly because they lose the power of the heat and condensation. However, they often move far inland, dumping many inches of rain and causing lots of wind damage before they die out completely. So it’s not just high winds that cause danger; it’s the torrential rains and storm surges. A hurricane can last for 2 weeks or more over open water and can follow a path across the entire length of the eastern seaboard, coastal areas, and barrier islands.
Q. Which areas are most susceptible to hurricanes?
A. All Atlantic and Gulf coastal areas are subject to hurricanes or tropical storms. Although rarely struck by hurricanes, parts of the Southwest and Pacific Coast suffer heavy rains and floods each year from the remnants of hurricanes spawned off Mexico. Islands such as Hawaii, Guam, American Samoa, and Puerto Rico also are subject to hurricanes.
Hurricane Felix (2007)
Q. Is a hurricane the same as a cyclone? How is tropical weather classified?
A. A hurricane is actually one of three kinds of tropical storms, or cyclones, that circulate over tropical waters. The circulation is counterclockwise in the Northern Hemisphere. Tropical cyclones are classified as follows:
Tropical depression: An organized system of clouds and thunderstorms with a defined circulation and maximum sustained winds of 38 mph (33 knots) or less.
Tropical storm: An organized system of strong thunderstorms with a defined circulation and maximum sustained winds of 39 to 73 mph (34 to 63 knots).
Hurricane: An intense tropical weather system with a well-defined circulation and maximum sustained winds of 74 mph (64 knots) or higher. In the western Pacific, hurricanes are called typhoons. Similar storms in the Indian Ocean are called cyclones. Hurricanes are further classified by rank according to how strong their winds are.
Q. How are hurricanes classified and what are hurricane categories?
A. The Saffir-Simpson Hurricane Scale is a 1-5 rating based on the hurricane’s present intensity. This is used to give an estimate of the potential property damage and flooding expected along the coast from a hurricane landfall. Wind speed is the determining factor in the scale, as storm surge values are highly dependent on the slope of the continental shelf in the landfall region. Wind speeds are measured using a 1-minute average. See more about the Saffir-Simpson Hurricane Scale.
|Saffir-Simpson||Wind (mph)||Hurricane Examples|
|Category One||74 - 95||Allison (1995), Danny (1997)|
|Category Two||96 - 110||Bonnie (1998), George (1998), Gustav (2002)|
|Category Three||111 - 130||Roxane (1995), Fran (1996), Rita (2005)|
|Category Four||131 - 155||Opal (1995), Iniki (1992), Charley (2004), Katrina (2005)|
|Category Five||156 +||Andrew (1992), Matthew (2016), Irma (2017), Maria (2017)|
Q. What do the hurricane warnings mean?
A. A hurricane watch means that hurricane-force winds are possible within 48 hours. A hurricane warning means that hurricane-force winds are likely within 36 hours.
Q. What caused Hurricane Katrina?
A. We are often asked about Hurricane Katrina (2005), one of the five deadliest hurricanes to ever strike the U.S. and tied with Hurricane Andrew (2017) as one the most costly hurricanes in the Atlantic (both storms did an estimated $125 billion of damage each). The damage and loss of life inflicted by this powerful hurricane in Louisiana and Mississippi were devastating, with effects stretching into Florida panhandle, Georgia, and Alabama.
Katrina was a complex storm, but to put it simply: Katrina started with the interaction of a tropical wave and the remnants of a weakening storm known as Tropical Depression Ten; the pressure disturbance become organized over the central Bahamas on August 23. It rapidly strengthened into a tropical storm and then a hurricane by the next day. Katrina was lifted towards Florida by upper-level steering winds and became a category 1 hurricane a few hours before landfall in southern Florida on the 25th. Katrina was on shore for about 7 hours and then moved into the Gulf of Mexico, reaching category 5 intensity on August 28. Katrina weakened to a strong category 3 or category 4 hurricane before making landfall on the northern Gulf coast.
Q. How are hurricane names chosen? Can the same name be used twice?
A. Most storm names are taken from a permanent list that rotates every 6 years. Here are this year’s tropical storm and hurricane names for both the Atlantic Basin and Eastern North-Pacific. Is your name listed?
Names can be used more than once, but if a storm is significant enough, its name is usually retired. More than 60 names have been retired since 1950 because they resulted in significant property damage or deaths. A name can be retired at the request of a country affected by the storm. See the most recent list of retired hurricane names.
Have you ever experienced a hurricane first hand? Tell us about it in the comments below.