Upcoming hurricane season
We have just entered the month of June as I write this newsletter, and since June 1st is the nominal start of the Atlantic hurricane season, it seems like a good time to talk a bit about these storms, which can have such a significant impact on marine interests.
Every year, seasonal hurricane forecasts are issued for the Atlantic basin by a research group at Colorado State University, and also by the U.S. National Hurricane Center. These forecasts are not meant to be date and location specific forecasts for hurricanes through the year, but rather are general outlooks for the amount of hurricane activity that will occur in a season, and the forecasts will compare the amount of expected activity to the average activity over a 30-year period.
Over many years of research, meteorologists specializing in seasonal hurricane forecasting have been able to find a relationship between several atmospheric and oceanic parameters during the months leading up to the hurricane season and the amount of hurricane activity during the ensuing season. These parameters include things like sea surface temperatures in certain areas of the Atlantic and the Pacific, upper level winds in the tropical Pacific, and sea level atmospheric pressure in the central Atlantic. By knowing that this relationship exists, the parameters can be measured during the months leading up to the current hurricane season, and a projection can be made about the season. Because this is a statistical method, it will not always yield a correct forecast, but more often than not, the seasonal forecast shows more skill than simply predicting an average amount of activity every year (the climatological normal) would.
For the 2012 season, the scientists at the National Hurricane Center have predicted a “near normal season” and the Colorado State University group has predicted “slightly below average activity.” In both cases, this would mean less activity than there was in the 2011 season.
The 2012 season has already had two named storms, which occurred before the “official” start of the season. The first was tropical storm Alberto which developed off the Carolina coast in the middle of May, meandered southwest for a time, then moved northeast well off the southeastern U.S. coast and lost its tropical characteristics after a few days as it passed north of Bermuda over the open Atlantic. The second was tropical storm Beryl which formed about a week later in the same general area as a subtropical storm, and moved west-southwest, becoming a tropical storm just before making landfall in northeastern Florida just below hurricane strength. The system then meandered slowly for about a day and a half over interior Florida and northern Georgia before moving quickly northeast and passing over Cape Hatteras as it transitioned to a non-tropical low.
A couple of observations regarding these two systems: First, Beryl, while messing up the Memorial Day holiday weekend for parts of the Georgia and Florida coasts, also produced a great deal of rain for portions of northern Florida and southern Georgia, which had been one of the areas of the nation most severely affected by drought conditions, and this is a good example of the beneficial effects that tropical systems can have. Second, there is a temptation to think that the early appearance of tropical cyclones in the Atlantic could portend a difficult season, but in fact, history does not support this. As the Colorado researchers point out, “Pre-1 June activity has very little bearing on the rest of the hurricane season. The only two seasons on record with two named storms prior to 1 June were 1887 and 1908. While 1887 was a very active season, 1908 had average levels of activity. The last season with a U.S. landfall prior to 1 June was 1976, which was a relatively quiet season.”
It is also important to realize that the amount of activity in a season does not necessarily have any bearing on how a particular coastal location will fare during that season. A very appropriate example is the case of Hurricane Andrew, which is noted by the NOAA meteorologists in their seasonal forecast. This year is the twentieth anniversary of Andrew, which caused significant damage as it moved across south Florida, and went on to cause more damage with a second landfall in Louisiana. What is noteworthy about this storm is that it occurred in late August — and it was the first named storm of the 1992 season which would go on to have only six named systems. The bottom line here is that if a tropical storm or hurricane impacts your particular location of interest, or an ocean passage that you are undertaking or planning, then no matter how active (or inactive) the season as a whole ends up being really doesn’t matter from your perspective.
The early days of the 2012 season are a good opportunity for all mariners to refresh their memories about the products and advisories that are available for tropical cyclones. The best way to do this is to visit the National Hurricane Center website (www.nhc.noaa.gov) and do some exploring. It is also a good time to update a plan to protect your family and your property should a threat arise for your location. Because actions usually need to be taken with fairly short notice, it is a good idea to have a plan in place for your property. Examples of things to think about well before a storm threatens are: 1.) Having hurricane shutters available well in advance and to knowing how to deploy them; 2.) Having a place to go away from the coast that will be safe, and having a plan to get there; and 3.) Having a plan in place to move boats to secure locations, either “hurricane holes” or haul-out options, keeping in mind that others will be looking at the same options you are. There are many other things that will be need to be done in a hurry when faced with an imminent threat, and it is best to have a checklist so nothing gets forgotten.
Here are the links to the seasonal forecasts referenced above:
There are some comments in the Colorado State paper about the impact of climate change on hurricane activity, which many will find interesting.