My personal prediction for the 2012 Atlantic Hurricane Season is (written May 16, 2012):
15 cyclones attaining tropical depression status
13 cyclones attaining tropical storm status
5 cyclones attaining hurricane status
3 cyclones attaining major hurricane status
These predictions are near normal for an Atlantic Hurricane Season, with the number of predicted tropical storms slightly above average and the numbers of predicted hurricanes and major hurricanes near their respective long-term averages.
Despite being near the average, this prediction is low relative to recent years, in which 7 out of the last 10 seasons have had 15 or more named storms, and have included some of the most active on record. This active period reflects a theoretical phenomenon called the Atlantic Multidecadal Oscillation (AMO), a cycle involving sea surface temperatures that has a period of about 60 years. The whole of the 2000's was in the "active" period of the oscillation, which is expected to persist for at least another five years.
Despite this, an El Nino event is expected to develop in the coming months, characterized by a stronger jet stream, and areas of strong wind shear across the Atlantic basin. El Nino tends to inhibit cyclone development, and this is reflected in the forecast. The exact intensity of the season is dependent on how quickly the El Nino develops and its intensity, but, even in the case of a strong El Nino event, there will be portions of the season where wind shear temporarily abates, possibly allowing strong cyclones to form.
Below, my anticipated risk factors for four major regions of the Atlantic basin are listed. The risk index runs from 1 meaning very low potential to 5 being very high potential.
U.S. East Coast: 2
Despite high sea surface temperatures off of the U.S. coast following a mild winter, the risk is low for an East Coast landfall this year. With a strong jet stream and a weak Bermuda, the steering currents will strongly push cyclones out to sea, which for the most part will miss the East Coast. Bermuda might not be so lucky, however. The greatest risk for East Coast states is from a system on the Gulf side tracking over land and then up parts of the east coast. Though this minimizes the risk of strong winds, flooding may still be the result if such a system combines with an existing front or extratropical system (for example, Tropical Storm Lee of 2011).
U.S. Gulf Coast/Northern Mexico: 3
The Gulf coast has not experienced a hurricane landfall since 2008, but this may change in the 2012 season. The Gulf waters will again be very warm, and the blocking pattern across the Gulf will not be as strong as in previous years. Also, as is characteristic with the El Nino, any troughs across the Gulf are likely to be impermanent, and it is likely that at least a few cyclones will enter the Gulf.
Yucatan Peninsula and Central America: 4
Central America has been hit by a number of cyclones over the past few years, and this shows few signs of abating as we enter the 2012 Atlantic Hurricane Season. With mountainous terrain over much of Nicargua, Honduras, and Belize, flash flooding is a major concern, and the warm and moist southwest Caribbean is a prime location for tropical cyclone formation. I expect at least two landfalls, though they may be by weak storms.
Caribbean Islands: 3
The Caribbean Islands are always at risk for hurricane damage, as they lie in the center of many common tropical cyclone paths. However, the risk for damage is not as high as last year, as any cyclones will probably be more fast moving in areas of the Caribbean, and the scenario of a Cape Verde type hurricane is not as likely as in the previous few years.
Overall, 2012 will be a moderate season in terms of formation, but there is still a fair likelihood for a devastating hurricane, which would most likely effect Mexico and the U.S. Gulf coast.
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