2016 Atlantic Hurricane Season Expected to be Most Active Since 2012
By Chris Dolce and Jon Erdman for Weather.com
The 2016 Atlantic hurricane season is expected to be the most active since 2012, according to a forecast released by The Weather Company, an IBM Business.
A total of 14 named storms, eight hurricanes and three major hurricanes are forecast during the coming season.
Numbers of Atlantic Basin named storms, those that attain at least tropical storm strength, hurricanes, and hurricanes of Category 3 intensity forecast by The Weather Company (right column), Colorado State University (middle column) compared to the 30-year average (left column).
This is greater than the 30-year historical average of 12 named storms, six hurricanes and three major hurricanes for the Atlantic basin. A major hurricane is one that is Category 3 or stronger on the Saffir-Simpson Hurricane Wind Scale.
The Weather Company's forecast also calls for a slightly higher number of named storms and hurricanes than an outlook issued earlier in April by Colorado State University (CSU) that is headed by Dr. Phil Klotzbach. That forecast said the Atlantic was expected to see 13 named storms, six hurricanes and two major hurricanes.
An important note about both outlooks is that the seasonal forecast numbers do include Hurricane Alex, a rare January hurricane that struck the Azores a few months back. Though the official hurricane season spans the months from June through November, occasionally we can see storms form outside those months.
Here are three questions about this outlook and what it means for you.
Q: What Does This Forecast Mean For the U.S.?
There is no strong correlation between the number of storms or hurricanes and U.S. landfalls in any given season. One or more of the named storms forecast to develop this season could hit the U.S., or none at all. Therefore, residents of the coastal United States should prepare each year no matter the forecast.
A couple of classic examples of why you need to be prepared each year occurred in 1992 and 1983.
The 1992 season produced only six named storms and one subtropical storm. However, one of those named storms was Hurricane Andrew, which devastated South Florida as a Category 5 hurricane.
In 1983 there were only four named storms, but one of them was Alicia. The Category 3 hurricane hit the Houston-Galveston area and caused almost as many direct fatalities there as Andrew did in South Florida.
In contrast, the 2010 season was active. There were 19 named storms and 12 hurricanes that formed in the Atlantic Basin. Despite the large number of storms that year, not a single hurricane and only one tropical storm made landfall in the United States.
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.
U.S. hurricane landfalls the last 10 years. Note: Sandy in 2012 is not shown since it officially made landfall as a non-tropical cyclone.
Of course, the record-breaking 2005 hurricane season is now outside that current 10-year running total. 2005 was also the last season we saw a Category 3 or stronger hurricane (Wilma) hit the U.S., the longest such streak dating to the mid-19th century.
Bottom line: The U.S. is due for another hurricane strike sooner rather than later, but it's impossible to know if that will occur this season. Keep in mind, however, that even a weak tropical storm hitting the U.S. can cause major impacts, particularly if it moves slowly, resulting in flooding rainfall.
Q: Will El Niño or La Niña play a role?
The strong El Niño we saw this winter continues to fade away and may transition to its counterpart La Niña by this fall. Of course, if this handoff from El Niño to La Niña conditions occurs, it could happen during the middle of the 2016 hurricane season.
Klotzbach said that the transition from El Niño to neutral or La Niña conditions during the 2016 hurricane season makes this particular April hurricane outlook very uncertain.
The transition could cause the early part of the hurricane season to be less active while the second half of the season may more active, according to The Weather Company's outlook.
As you can see, there's quite a spread, ranging from a record low four named storms in 1983 to 14 such storms in 1998. The 1998 season featured seven U.S. landfalling tropical cyclones, three of which - Bonnie, Earl, and Georges - were hurricanes at landfall.
Despite only four named storms in 1983, two of those made U.S. landfall, including Category 3 Hurricane Alicia in southeast Texas. This again illustrates the poor correlation between the number of named storms or hurricanes and landfalls.
In all, there have been a total of six U.S. hurricane landfalls in the five post-strong El Niño seasons dating to 1958, for an average of roughly one a season. Two of those five seasons were without a U.S. hurricane landfall, however.
Klotzbach found that the chance of a U.S. hurricane impact rises dramatically in a La Niña or neutral (neither El Niño or La Niña) season compared to an El Niño season. Without El Niño contributing to stronger wind shear and dry air in the Caribbean Sea like we saw in 2015, it at least loads the dice toward an increased chance of tropical cyclones surviving into the Caribbean Sea, or forming there in 2016, particularly later in the season as El Niño disappears farther in the rear-view mirror.
Q: What Other Factors Are in Play?
The three previous Atlantic hurricane seasons featured either few named storms (2014; 8) or a greater number of storms, but few of which survived long or became hurricanes (2013 and 2015).
2013 and 2014 featured prohibitive dry air and/or wind shear during a significant part of the season, but El Niño was nowhere to be found.
In 2015, El Niño likely played a significant suppressing role in the 2015 Atlantic hurricane season. Klotzbach found that June through October 2015 Caribbean wind shear was the highest on record dating to 1979. Klotzbach also said the magnitude of dry air over the Caribbean Sea in the peak season month of August and September also set a record.
2015 Atlantic Tropical Cyclone Tracks
As you can see, dry air and wind shear can detrimental to tropical storm or hurricane development no matter whether El Niño is present or not. This is one factor to watch for in the 2016 season.
Klotzbach said that wind shear enhanced by El Niño is likely to dissipate the next several months. However, he added that the northern Atlantic Ocean has water temperatures that are colder than average, which can cause atmospheric conditions to be unfavorable for the development and strengthening of Atlantic hurricanes.
The Weather Company forecast said that April water temperatures in the northern Atlantic match previous Aprils where the Atlantic hurricane season was less active. However, the predicted evolution of water temperatures by August, which is when the peak of the hurricane season typically begins, may lead to more favorable conditions for development by that time.