Tag Archives: the Yucatan Peninsula

2011 Atlantic Hurricane Season: a New Level of Activity Ahead?

In my recent post 2011 Atlantic Hurricane Season: an Empirical Assessment I shared some thoughts on the relative inactivity during the first seven weeks of the 2011 season, based on my observations thus far.

Now, here I am just one week later observing signs of new levels of activity in the various components of the larger Atlantic basin. Does this mean Mother Nature is shifting into a higher gear as various triggers and factors, all potential contributors to cyclogenesis, appear to have become better coordinated in recent days?

This potential recent change in the level of activity of the 2011 Atlantic Hurricane Season illustrates the need for a continuum of predictive efforts rather than relying on seasonal forecasts, such as those issued by folks in Colorado early in the calendar year to be subsequently reviewed prior to or early during the season, which are truly of little value for preparedness and mitigation purposes despite their anecdotal flavor.

In my opinion, the possibility for a new and higher level of cyclonic activity just ahead reinforces my thinking along the following lines: (a) one of the constants in nature is continuous change; (b) cyclogenesis is driven by the conjunction of numerous factors and external triggers, some of which act over long distances, influencing the coupled ocean-atmosphere at a specific point in time, that constant monitoring is required for effective forecasting and prediction; (c) to be effectively useful hurricane prediction must be relevant at the local level.

Among the changes I’ve noticed since my previous posting regarding the 2011 Atlantic Hurricane Season the following merit mentioning:

* A more continuous and regular, almost sinusoidal, pattern of pulses has begun to appear along the ‘Tropical-wave assembly line” over equatorial Africa, leading to a train of tropical waves moving westward toward the eastern Atlantic;

* Recent weather pulses and tropical waves over equatorial Africa appear to be better organized  and capable of generating stronger rainfall and thunderstorms;

* Hurricane Alley is now populated by a more continuous chain of tropical waves, while also following a track that has shifted ever so sightly northward, which takes them toward the Lesser Antilles and the Caribbean rather than through the northern portion of South America. This increases the potential for cyclogenesis to occur in sub-basins of the Atlantic with a higher probability of affecting interests in the Caribbean, Gulf and USA Atlantic regions.

* Surface waters have become quite warmer along Hurricane alley, the Caribbean and especially in the Gulf, raising the potential for cyclogenesis in any of those sub-basins.

Evidence of the increased activity mentioned above is seen on the satellite images that follow:

Color-enhanced infrared GOES satellite image showing a tropical wave near Cancun, Mexico in the channel between the Yucatan and Cuba in the early morning hours on 27 July 2011
Close-up on a GOES satellite image for the aviation industry on 27 July 2011 showing a strengthening tropical wave some 180 kilometers to the east of Cancun, moving west by northwest at 25 kph
Color-enhanced infrared METEOSAT satellite image on 27 July 2011 showing a chain of tropical waves along western equatorial Africa and the eastern Atlantic
Map of sea surface temperature based on satellite data on 26 July 2011 confirming a continuing warming trend along 'Hurricane alley', the Caribbean and the eastern Gulf of Mexico and Florida Straits