Isaac is disorganized this morning, which is to be expected from interaction with the mountains of Haiti. The storm has taken a significant jog north of where it was “supposed” to be this morning, due to the frictional effects of the mountains which I warned about yesterday being a wildcard for the short-term track. It goes to show how the model cluster can be way off even at the 12-24 hour verification. The significance of this is that Isaac is now only moving over the eastern tip of Cuba instead of the entire eastern half of the island, and thus he will be spending more time over water before hitting the Florida keys or south Florida. With about 36 hours over the very warm Florida straights, Isaac should have enough time to regenerate a core and strengthen into a lower Cat 1 hurricane.
The models, although they have shifted east since yesterday, have not come over to the peninsula, and remain over the eastern Gulf of Mexico and into the Florida panhandle with Isaac’s track. They have at least mostly dropped the improbable northwesterly track into the central gulf coast, and now show a more likely recurve northward into the coast farther east. With the models tightly clustered this close to the end of the forecast, my track has to shift westward to meet closer with the model consensus. There still, however, remains some uncertainty, and as we just saw last night, the models can be off even with a 24-hour forecast. With Isaac now coming west of Florida, further intensification is called for after he scrapes south Florida. However, intensification over the eastern gulf is expected to be slower than intensification over the Florida straights, due to a track close enough to the Florida peninsula that Isaac’s main inflow channel, which is from the east, will be passing over land and bringing some drier air into the storm. Normally storms taking a track like this struggle to strengthen at all and often weaken. However, a very favorable upper pattern will be developing above the storm as a trough-split backs away to the southwest, ventilating the eastern gulf, and this should offset the normal trend and allow slow strengthening through a 2nd landfall in the panhandle. On the current track a low-end Cat 2 hurricane is expected near Apalachicola, Florida in about 3 days, though a track just a little farther west could result in a stronger storm, and a track closer to the Florida peninsula could result in a weaker storm.
We shall see what happens!