The 'Official' Start of the Hurricane Season: June 1

Hey!... why didn't anyone tell me that today was the first official day of the Hurricane Season? ;) Really, unless you've been living in a tree or under a rock, there's very little chance that you wouldn't know this by now.

What's out there:
There is low pressure system which has associated with it a mass of water vapor, clouds, thunderstorms etc covering the western Caribbean-eastern Gulf of Mexico region right now. I agree with all the official forecasts, it's unlikely to develop into anything much. Cuba is getting a lot of rain at the moment, and Florida is overcast and will be getting rain today and tomorrow, and possibly even some on Sunday. Good thing too... it might put out some of the fires we have going on in this state.

A quick overview of storm systems:
So, as nothing much is going on out there, I'm going to take this opportunity to answer a question (as best I can) that quite a few of you asked me when Subtropical Storm Andrea was out there in May - What is the difference between an extratropical storm, a tropical storm, and a subtropical storm?

An Extratropical Storm: These usually form in the extratropics (quelle suprise!)  and have cold air at their core. A cold air mass meets a warm air mass, and as the warm air rises (because it is lighter than the cold air), it releases potential energy that results in these systems. Because warm air rises, a low pressure is formed which is why these are also called low pressure systems.They are usually associated with fronts which are depicted on weather maps as lines of blue triangles (for a cold front) or red semi-circles (for a warm front). Because it's the collision of air masses, these systems can occur over land or water, and occur frequently in the winter in the US as snowstorms/blizzards or Nor'easters.

A Tropical Storm: These usually form in the tropics (aren't we good at naming things?) and have warm air at their core. The energy source for these differ from extratropical storms. These storms form over water only and the energy source is latent heat. Warm water evaporates into the air. As the rising warm moisture-laden air in the center reaches colder altitudes in the atmosphere, the water vapor condenses to form clouds and latent heat is released. The heaviest rains and winds are in a band close to the center. No fronts are associated with these storms (although 'waves' in the atmosphere are) - which makes it difficult to determine too far ahead of time when a storm will develop. A tropical storm is when the winds are greater than 34 knots (39 miles per hour). If the winds are less than that, it is a tropical depression.

A Subtropical Storm: These usually contain some characteristics of both extratropical and tropical systems.  For example, imagine an extratropical storm moving over warmer water.  Now the storm begins to get some energy from latent heat as well, and the cold air in the center (near the surface) is replaced by warm air, so the storm core can change from cold to warm. The heaviest rains and winds are not near the center. Like a tropical system, a subtropical storm is when the winds are greater than 34 knots (39 miles per hour). If the winds are less than that, it is a subtropical depression. Subtropical Storm Andrea was formed from an extratropical low pressure system/front that moved eastward off the coast of the US over warmer waters.

It's only since 2002 that subtropical storms were given names from the hurricane name list - which would partly account for why we have had more named storms in the past few years.

That's all for now. Enjoy the rain if you live in Florida. Enjoy whatever weather you have if you live in a different state :)
J.
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DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast.
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