08/31 – Steve’s Midday Tropical Update and Forecast

The reality is that Nine is not very well organized but is starting to show some signs of maturity. One of those signs is better-defined outflow in the northwest and northern sections of the storm. This may indicate a lessening of the shear which has been impacting the storms since the weekend. When you combine that information with the very warm seas surface temperatures in the Gulf of Mexico, you’ve got a recipe for increasing intensity, which is what I believe is going to happen.

As far as storm motion is concerned, it is likely that Nine, rather than bending all the way back into the Big Bend area, will likely end up landfalling east of the Apalachicola area. This is a few hundred miles to the left of the initial predictions that were given the storm earlier in the week. We’ve talked all week about the effect of high pressure building over the southeastern United States and how it could affect the motion of the storm.

With it becoming more likely the storm will be a little closer to coastal Mississippi … and I stress: a LITTLE closer (not coming here, no) … we’ll see some increased effects, but in a dry and hot sort of way, rather than a windy and wet sort of way. Hurricanes are a convective engine, cycling air from below the storm to the periphery of itself. When condensation of water vapor in rising air releases heat energy into storm, a chain reaction occurs. The heat makes the surrounding air more buoyant, causing it to rise further. To compensate for the rising air, surrounding air sinks. The sinking air is compressed by the weight of the air above it, and it warms.

Taking, say, an Apalachicola landfall into account, for example, or proximity to the core low of the storm will enable our air to be compressed nicely, thus warming us up very efficiently on Thursday. High temperatures will top out in the upper-nineties for areas inland and north of the three Coastal counties. Along the I-10, expect mid-nineties, easily. And it will be dry, with rain chances beginning to return on Friday in the twentieth percentile.