Concerns continue to grow this evening as Tropical Depression 9 spins westward towards the Leeward Islands. Right now this system doesn’t look like much at all, largely exposed with little deep convection to speak of. This has a lot to do with dry air it along with all other systems which have crossed the tropical Atlantic this summer so far but the problem is that this circulation is well organised and so if and when the dry air eases and water temperatures increase, then there is a real potential for this thing sparking big time.

TD 9 unlikely to be storm before tomorrow

There is big questions right now as to the track of this system. It appears more likely that the system won’t become a storm until tomorrow and we will likely see another big burst of convection through the overnight hours tonight as we often see and this may bring it to storm status by dawn in the morning.

Track is everything

Ultimately, the weaker this remains, the more it will track west rather than commence a turn northwards. There is a trough over the Eastern US right now which could feel this system if it were to blow up over the next 48 hours. The stronger a system, the taller it becomes and the more it can feel upper level steering winds. These upper winds would have it turn more towards the East Coast. Right now the general consenses has this system track towards the Dom Rep/Haiti.

Now, if the system was to cross this very mountainous island, then this could dent or destroy it. Ultimately many hurricanes which have crossed Hispaniola or Cuba never quite came out the other side quite the same. So for the worst case, this sytem remains weak which keeps a more west than northwest track which keeps the bulk and core offshore which allows the hurricane to draw off the near 90F waters sjust south of these big island nations. This of course would cause big problems for Haiti, Jamaica and Cuba before a turn north into the cauldron that is, the Gulf of Mexico which has the potential this year to turn a Cat 3 into a monster!

A hit straight from the south, over top of Cuba and into the Everglades or even Miami only becomes more likely if this system intensifies fast, forcing the sharper turn but this would also likely be less of a blow as Cuba would take the brunt of the storm, make a dent and then with such short distance across the Straits to South Florida, despite those very warm waters, there’s too little time to reintensify.

As for the more southerly track south of the islands and a push towards western Cuba, then Issac to be would likely become the first category 3 hurricane of the season. It would also mean that unless the system dissipated completely over Cuba, then it’s ontrack to hit the US and more likely the Gulf.

Extremely warm, deep central Gulf waters is concerning

I’m swaying towards the european model which takes this as a hurricane into the eastern Gulf with impact on west coast Florida. What we don’t want to see is the system pushing into Katrina and Rita territory given those skin temperatures in the central Gulf which are at or above 90F with the loop current keeping very warm water way down into the darkest depths. It’s this type of high octane ocean heat content which can drive a tropical cyclone to their maximum potential with these above normal SST’s and a strong loop current. This setup fuelled Camille, Katrina and Rita to their fullest potential.

 

Tags: hurricane isaac, isaac 2012, TD 9, tropical depression 9, tropical storm isaac