Big Trouble Brewing in Caribbean

After shedding nearly every environmental obstacle in its path, Gustav was finally named yesterday. After traversing some very warm, deep water, Gustav has strengthened appreciably in the last 24 hours and is now a Category 1 hurricane with 90 mph winds, despite a rather high central pressure of 981 mb. Additional strengthening is likely until Gustav moves over Southern Haiti later today.

A trough in the Western Atlantic was responsible for pulling Gustav more to the north and northwest, but a strong ridge is forecast to build over Gustav tomorrow and should push it more to the west. I will actually give major props to the GFDL for its handling of Gustav so far. Usually, it and the GFS are too far to the right because they break down the ridge too quickly. The GFS has been quite poor thus far in its handling of Gustav, but the GFDL has been very impressive with its track and intensity. It's not very often I get to brag on the American models, but the GFDL is performing extremely well. However, let's hope the GFDL's excellent performance comes to a screetching halt. More on that in a moment.

Most of the model guidance has shifted much further to the left and all are in decent agreement that Gustav generally stays south of Cuba. This will have major implications on the future intensity. The models move Gustav south of Cuba and then there is some slight disagreement about whether Gustav clips the western tip of Cuba or stays over the open water between Cuba and the Yucatan. Given that Gustav will probably be a very significant hurricane by Friday, I feel that a tremendous amount of extra heat will be pumped into the ridge and Gustav will probably go even more left than what the models are currently predicting. At this point, I think it will split the Yucatan and Cuba, but it's certainly possible that it could even clip the Yucatan. After the encounter with Yucatan or Cuba, Gustav will emerge in the Gulf of Mexico.

This is a more ominous scenario than when I was worried that Fay would impact the northern Gulf Coast. I expected Fay to stay over more of the eastern half of the Gulf of Mexico, but it appears that Gustav will unfortunately stay over more of the power keg of the central and western half of the Gulf.

By Saturday, the models are in agreement that Gustav will turn more to the northwest as a trough in the Central U.S. breaks down the subtropical ridge. I still feel that the ridge will be a bit stronger as depicted by the Canadian and will push Gustav more to the left than what is currently being forecast. However, I'm not leaning as far left as the European or UKMET. The ultimate destination to me looks like a northwest Gulf of Mexico landfall next week. The 06Z GFDL is particularly ominous as it has Gustav threatening Louisana by late Sunday as a strong Category 4 hurricane. Let's hope that is wrong!

The short-term intensity of Gustav depends on a couple of things. Any interaction with the mountainous terrain of Haiti could disrupt the core and will prevent significant strengthening for a few days. Also, any interaction with the rugged terrain of Eastern Cuba could also have a negative impact on the strength. At this point I feel that Haiti may temporarily disrupt the circulation, but I still feel that Gustav will only weaken slightly. Given the oceanic heat content in the path of Gustav, a building upper-level anticyclone, and moist ambient air surrounding the hurricane, all the conditions appear pristine for rapid intensification and support for a Category 5 hurricane in the northwest Caribbean and southern Gulf of Mexico by the end of the weekend. It's never a good thing when there is a Western Pacific environment in the Caribbean and Gulf of Mexico. It's a recipe for a catastrophic hurricane.

Expected conditions in the Gulf of Mexico will also favor the maintenance of a Category 4 or 5 hurricane with moist ambient air, low shear, and high heat content. It appears that trochoidal oscillations and eye wall replacement cycles will dictate the fluctuations in strength when Gustav reaches that intensity. Due to that, it's impossible to forecast the exact landfall intensity this far out, but environmental conditions are expected to support at least a Category 4 hurricane up to landfall.

To summarize, I think Gustav will be a Category 5 hurricane at some point by the end of the weekend as it moves into the southern Gulf of Mexico. At that point, I feel that the ridge will break down by Monday and begin to turn Gustav toward the Texas coast. Gustav should maintain Category 4-5 intensity for quite some time and could be a Category 4 hurricane at landfall in Texas next week.

This doesn't even begin to touch on the potential for several more tropical cyclones in the next few days. More on that later!