What happened to the hurricane season?
The predictions back in the spring were quite ominous, with all of them calling for an above-average number of hurricanes: The forecasting team from Colorado State University predicted nine hurricanes would develop, while the National Oceanic and Atmospheric Administration (NOAA) said there would be seven to 11 hurricanes.
Both the Weather Channel and AccuWeather also predicted unusually active seasons.
Yet, as of late October, with only a few more weeks left in a season that ends Nov. 30, just two hurricanes have formed in the Atlantic Ocean, the fewest since 1982, according to data from the National Hurricane Center. And for the first time since 1994, there have been no "major" hurricanes (Category 3 or above) anywhere in the Atlantic Ocean.
"It's the biggest seasonal forecast bust we've ever had," said Colorado State meteorologist Phil Klotzbach, part of the team of forecasters that first started issuing seasonal hurricane predictions in the early 1980s. "It's a huge surprise, since all of the forecasts were calling for an active season."
And while the number of named tropical storms and hurricanes - 12 - is about average, the number of hurricanes and major hurricanes is well below average. A typical season sees about six hurricanes, of which three are major.
So what happened? The top reasons include an increased amount of dry, dusty air from the Sahara Desert as well as "sinking" air over the Atlantic, both of which worked to suppress hurricane activity, said Klotzbach.
Sinking air - caused by high atmospheric pressure areas that force air down - prevents storms from forming by making the air drier and thus more "stable," which stops thunderstorms (which like more humid air) from developing.
Wind shear - a difference in wind speed and direction at various levels of the atmosphere - also worked to tear apart storms before they could strengthen, said hurricane center spokesman Dennis Feltgen.
"These conditions have acted to offset the more conducive climate patterns," said Feltgen, such as above-average sea-surface temperatures, the lack of typical hurricane killer El Niño, and stronger West African monsoons that fuel hurricanes.
"There were plenty of positive factors for above-average activity," added Feltgen. "What was not anticipated was all the sinking motion and resulting dryness - factors that occasionally disrupt what would otherwise be an active season - but which are impossible to predict."
Feltgen said that two areas that were somewhat favorable for development this year were the Bay of Campeche and southwest Gulf of Mexico. "These areas produced Tropical Storm Andrea, which made landfall onto the U.S in early June, along with Tropical Storm Barry, Tropical Storm Fernand and Hurricane Ingrid - all of which impacted Mexico.""Nobody saw this coming," agreed Klotzbach. "No one understands why there was so much sinking motion this year." He admitted that it's a huge forecast problem that he and his colleagues will be working to solve.
Indeed, Mexico has been hard hit by hurricanes this year, as the country has been pelted by storms from the Atlantic and the eastern Pacific.
Additionally, Tropical Storm Karen formed over the Gulf of Mexico in early October, Feltgen said, but was torn apart by wind shear and dry air, and dissipated.
The long-term drought of major hurricanes hitting the U.S. also continues: It's been eight years since a Category 3 or stronger hurricane has made landfall on U.S. shores, according to the hurricane center. The last was Hurricane Wilma, which battered Florida in October 2005.
However, this is one example of why a fixation on hurricane categories may not be practical, as powerhouse storms like Superstorm Sandy last year or Hurricane Ike in 2008 still caused catastrophic destruction, despite their lack of "major" status.
"It's too soon to know what the season's final levels of activity will be," noted Feltgen. "However, the odds that the season will produce the expected numbers of hurricanes and especially major hurricanes are rapidly decreasing.
"While the below-normal activity thus far is welcomed, we hope everyone will continue to be vigilant and remain prepared during the final six weeks of the season," he said. "It only takes one storm hitting your area to make it a bad year. And storms do occur in November."
Though the worst of the season is likely over, "it is possible we see a couple of weak systems come and go over the next couple of weeks over the southwestern Gulf of Mexico and the western Caribbean," said AccuWeather meteorologist Dan Kottlowski.