As of 4pm, Tropical Storm Isaac is again slightly stronger with winds of 65mph. The storm is better organized, and the central pressure has dropped to 994 mb. Forward motion is now a more certain n’west at 16 mph. The forecast track is now a bit more to the east, but still includes all of our area. It is still expected to become a Category One hurricane in the Gulf next week.
Changes in the long range forecast track are expected. The poorly defined center of Isaac has repeatedly reformed to the south a few times, altering the storms actual position. The elongated system has also wobbled a good bit through the eastern Caribbean. Each wobble and change in position can make a big change in the predicted forecast track. The models shifted again today, this time more to the east. Expect more changes in the forecast. We will have a much clearer idea on the outcome of Isaac by Sunday.
The intensity forecast is also very tricky. This rather broad storm is not expected to rapidly intensify before reaching Cuba Saturday. It will spend a good bit of time over Cuba. The specific track across the mountains of s’east Cuba will have a big impact on the amount of weakening that will occur. The tallest peaks in the island nation are located in the Sierra Maestra and Sierra Cristal ranges, with some peaks above 6,000 ft. We do see a favorable environment for strengthening when Isaac eventually reaches the Florida straits and the Eastern Gulf. The interaction with the higher terrain could really disrupt the inner mechanics of the system , making reorganization over the Gulf more difficult.