Daily Archives: Thursday, May 26th, 2011

Tropical trouble to start the season?

There are some indications this evening that the tropics may heat up around the turn of the month. Numerous of the computer models that show different solutions to the atmosphere each with different beginning conditions are showing that the sea level pressure may begin to fall in the southern Caribbean. During the month of June, we must begin to watch the Caribbean Sea for tropical development because climatology suggests that most cyclones that form during the first month of the hurricane season begin here. Below, I have highlighted the area I am gaining interest in from one of the computer models: the GFS.

At this time the chances of any development at all are extremely low to nil being many days out, but it does give us the chance to discuss some of the requirements that are necessary for tropical development:

 1. Warm waters is the fuel that drives storms in the tropics. The common rule of thumb is 80°F (26.5°C) down to at least 160 feet below the surface. The warm water allows tropical cyclone such as hurricanes and tropical storms to do many things. One of which is to create lift in the atmosphere. We all know warm air rises, and with warm sea surface temperatures below the air rises. As it rises further, it gets cooler, condenses, and forms clouds When clouds form something you cannot see or feel called latent heat is released. This heat allows the air to rise even further. This process continues as long as there is a fuel source…the warm ocean. Tiny pieces of air and all of the water it contains has a certain weight. As the air above the surface rises, more air comes in to replace it at the surface.

2. The warmer the air is aloft, the faster the air rises, and the faster the air moves in below. This effect is called instability, and in cyclones is the wind we all feel as when a hurricane gets too close to us. Also, as the air goes up, the amount of weight on the surface falls, which is the pressure reading that is sometimes reported in the news and is measured by hurricane hunters and buoys in the path of a tropical cyclone.

 In this update we looked at the first possible tropical disturbance of the 2011 Atlantic Hurricane Season, and the fuel source it may use if the other five conditions are met for tropical cyclogenesis, the process of tropical development. In coming updates, we will discuss the remaining requirements and the possibility that the Caribbean may harvest the seasons first tropical storm. Until then follow me on twitter by clicking the twitter box at the top right of this screen.

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