Afternoon Isaac Update

A hurricane warning is in effect from Morgan City, LA to Destin, FL.

While the hurricane's path is slowly coming into better focus, its intensity is not. While the barometric pressure has fallen 3 millibars since 10am CDT the organization of the core of the storm has not improved the last couple of hours.

Here is what I think is occurring. Below is a satellite image that measures the amount of water vapor in the atmosphere. During the afternoon, some dry air (orangish tint in rectangle) has fed into the storm, inhibiting development on its southeast side (keeping in mind the counter clockwise air movement).

To the north of the storm, the dry air over the Southeast sends a different signal. It tells us the storm is not going to turn north anytime soon. That indicates the high pressure system over the Southeast is strengthening and a tropical system will not move directly toward a strengthening high.

So, the most likely area for landfall of the eye would seem to me to be from Mobile Bay to Morgan City. That would take the center over the very warm water of the central Gulf. It seems logical that would cause intensification. The question is, how much? The models do not show intensification of any consequence until tomorrow afternoon when it gets over the warmer waters.

A category 2 seems like a good bet.  That said, if Isaac could get its central core organized before passing over the warmest water, a cat. 3 or 4 becomes possible.

An important bit of perspective:

When Katrina was over the Gulf waters southwest of Ft. Myers, it was a tropical storm like Isaac.

While Katrina was a 5 over the central Gulf, which helped generate its huge storm surge, it was a 3 at landfall. My point: Any hurricane of category 3 intensity or higher is capable of major damage.

So, Isaac should be treated with a great deal of respect until we know what its ultimate intensity will be.