Gulf Waters Slightly Cooler than a Year Ago

A finding that has surprised me is that compared to the same time last year, the Gulf of Mexico and Caribbean are slightly cooler this month. With a rather warm winter where New Orleans did not see a freeze at all, I figured the Gulf waters would be warmer than normal. Warm waters above 80 F degrees are breeding grounds for tropical cyclones and my logic is that the warmer the water temperature the more chance for a hurricane developing and also the possibility for stronger storms.

I just so happen to have a oceanographer friend that works at the Naval Research Laboratory. He guided me to the Laboratory's website which has several types of remote sensing data available online for most of the oceans in the world. One data set is the Sea Surface Temperatures for the Gulf and Northern Caribbean.

In this image of Sea Surface Temperatures from one year ago, the dark maroon color that dominates the central and Northern Gulf of Mexico is right at the 30 Celsius mark(86 F).

This Sea Surface Temperature map taken 2 days ago clearly shows that the Gulf, Caribbean, and Western Atlantic waters are cooler than 1 year ago.

Although comparison of the two maps make them look much different, I have determined that the Northern Gulf is only 1 shade lighter in the 8-16-2006 image (using Photoshop to test the colors). Since there are 5 different shades of color between each Celsius degree, this means that the Northern Gulf of Mexico is only cooler by 0.2 degrees Celsius (0.36 F).

However, compare and contrast the northern tip of the Yucatan where yellow shades are present this month. Also notice that the Caribbean and especially the Atlantic waters are several shades cooler. This is significant because these are often the breeding grounds for most of the storms that end up in the Gulf.

The cooler Sea Surface Temperatures may only be a partial reason for a quiet tropical season so far. According to Climate Physicist Robert Korty, warm waters are not the determining factor in cyclone development:

One oft-stated misconception about climate change and hurricanes is that the region of tropical cyclone formation will expand with warming temperatures. Many meteorologists note that tropical cyclones rarely form in regions where the sea surface temperature is colder than 26 degrees C (78 degrees F). There is nothing magical about that temperature, however, and it's a threshold that's likely to be a function of climate. In truth, regions prone to tropical cyclone genesis are better characterized as areas in which air in the lowest layer of the atmosphere (the troposphere) is slowly ascending (that is, able to convect) -- this is true in the tropics, but not in higher latitudes.

Whatever the reasoning for the relative tropical quiteness, I can at least begin to understand why this season's storm predictions have been downgraded, even though we head into what has been historically the most active month. It's at least nice to know that water temperatures are not as hot as last year.

TAGS: Katrina, New Orleans, NOLA, Hurricanes, Water Temperature, Gulf of Mexico