Vindauga

Its not actually hurricane season yet but try telling that to the tropical storms.

Let me first apologize for not being on the ball with sub-tropical storm Andrea, I was on vacation. Seriously, I was in Mississippi and didn’t even think about the possibility of a hurricane. But could you blame me? Hurricane season doesn’t start until June 1st.

Okay, fine. You’re right. Hurricane season is really just a compilation of historical averages. There is no natural law that states that hurricanes can’t come out to play until after June, there is just the recognized tendency for storms to not appear until after that date. Also, hurricanes require certain conditions, the most important of which is warm water (though I suspect temperature differential might, in some cases, be just as useful) and before June there really isn’t enough warm water out in the Atlantic to start a storm’s engine.

And yet here we are with one sub-tropical storm under our belt and all models predicting another this weekend. the next storm, if it forms, likely won’t affect the US but still, we will enter the season with 2 (sub) tropical storms already named. Not the most auspicious start. Or is it?

The Earth is really one giant homeostatic system. If we stop thinking about the Earth in terms of our short terms wants and needs (global warming) we see that the Earth often has fluctuations and changes in its climate but these trends inevitably equalize. Only external forces (comets, asteroids, massive sun spots) really ever add energy. Meanwhile, the Earth’s molten core is cooling and its rotation is slowing. On the grand scale the Earth is as it is.

On the human scale (not in terms of importance but in time) weather phenomena transfer energy between the various arenas of the Earth’s being. Focusing only on hurricanes, cyclones transfer “excess” heat from the ocean into the atmosphere. Once in the atmosphere, the energy is expended by moving the winds at high velocity and with rain. As you might remember from your high school chemistry class water is the standard by which we measure heat transfer. And, if you’ve ever been boating in cold waters (Great Lakes, North Atlantic) you may have been warned about how quickly one can die from exposure to cold water. Hypothermia sets in much more quickly when you are wet. Its one of the reasons why a paramount rule of survival is to stay dry; even 60 degree water, if you are exposed long enough, can cause hypothermia. So, water’s role in atmospheric heat transfer is two-fold. First, water vapor condensing into rain robs the atmosphere of energy. Secondly, the rain itself absorbs heat energy as it passes through the air. Remember, it is way colder at 20,000 feet than it is here (not to mention the pressure differential). Cold fronts almost always come with rain but rain by itself will cause a drop in temperature.

Hurricanes (or even tropical storms) then are taking heat from the ocean and releasing it into the air where the energy propels winds. Warm water heats the air, which rises heavy with moisture. The moisture rich air rises, expands, and cools. The rising process creates a low pressure zone which draws in more air at the sea surface. The rising air begins to move away, when it reaches a level in which it can no longer rise, before its cooler temperature causes it to drop. Coriolis sets in and the whole thing begins to rotate.

But, and this is the point that I am getting to, in the wake of this storm the ocean water is cooler; it has delivered its energy to the air. This is one reason why stalled storms invariably weaken and why multiple storms along the same track almost never happen (certainly not at the same intensities). So, two storms this early in the season might do a lot to diffuse much of the potential danger. Because even though warm water is important, atmospheric conditions have to be right too. Without the right atmospheric conditions all that hot water just piles up and next thing you know its a category five storm.

I know what you are thinking, “Hud, this is just more evidence of global warming.” I may sound like a broken record here but these two storms are evidence of anything. For the record, I do believe in global warming, which I take to mean that humans have had an impact on global temperatures, making them warmer than they would be without our interference. I just don’t think that this is evidence of that.

Funny thing is, right before I learned about these two storms, I was thinking about how I needed to right a “Get Ready for Hurricane Season” post in which I was going to predict that we would have a relatively uneventful season. I was going to bet on the statistics. We need a year or two of lower than average seasons to balance out 2004 and 2005. I’m not sure I want to make that claim now but it was going to be “3 storms hit US mainland, none greater than cat 3.”

I should warn you, I suck at predicting storms. I am only any good at describing them. I haven’t looked at any real data about this. Its just a guess based on past seasons. When I have a bit more time, I present some stats on past seasons. This has grown too long already.