Saturday, September 18, 2010

West Caribbean/Gulf Heating up over the next few weeks

The tropics over the past week have certainly lived up to the statistical expectations as we head past the peak of the 2010 hurricane season. So far this part of the state has seen just the outer most affects from several tropical storms and hurricanes that have entered the western Gulf the past few months, giving the region some much needed rainfall and break from what has been a very hot summer.

The upper level steering flow thus far in the season has thankfully kept such storms as hurricane Alex, tropical storm Hermine, and Hurricane Karl, south of the border, all making landfall in northern Mexico. However, long range computer models have been hinting that things might really start to ramp up across the western Caribbean sea later in the week...an area that has seen very little tropical activity so far and is therefore a prime region for rapid development should a system develop locally or move into that area.

An indice that hurricane forecasters monitor closely throughout the season is called the MJO or Madden-Julian Oscillation. It tracks the 30-60 day fluctuation of rising and sinking air, most notable across the Indian and Western Pacific oceans. The two scientists found that there was a pulse of increased thunderstorm development and tropical cyclone development that begins in the Indian Ocean and then moves east across Indonesia, into the western Pacific, central Pacific, and then into the eastern Pacific ocean. What was also found out is that about 8-10 days after the MJO reaches the eastern Pacific, there was a significant increase in tropical development across the Gulf of Mexico and Caribbean sea.

The latest projections indicate that we will be seeing a MJO pulse moving into the eastern Pacific which will likely be a positive factor, helping to increase the potential for development across the western Caribbean over the next week or so. This pattern looks to be getting picked up by the global models as well as they are now forecasting the development of a tropical system in the western Caribbean sea late next weekend and early next week (9/26 through 9/28) depending on which model you are looking at. Right now, since it is so far out in the future, it would be pointless to try and determine where such a system might go but the consistency among the models is a good indication that we will likely see activity start to ramp up as we head into the latter part of September and first week of October.

12z GFS Model









12z ECMWF