Potential Tropical Cyclone (PTC) #9 has not been upgraded to Tropical Storm Isaias this afternoon. The hurricane hunters have still not been able to find a closed center of circulation with this system. Although winds have been in excess of tropical storm force the last several hours, the storm is lacking a true closed center which is needed in order for it to be upgraded and classified as a tropical storm.
The road ahead appears to be a rough one for PTC #9 as it will have to survive land interaction with the islands in the Caribbean as well as encounter dry air and wind shear that lie ahead. Despite these obstacles, very warm waters in the Caribbean Sea and Florida Straights will give the storm a fighting chance to hang on as it nears the continental U.S. by the weekend.
It is important to remember that the intensity forecast remains the most difficult to nail down.
The track forecast is the most advanced out of the two, but even this forecast remains a bit tricky. So let's dive into the details.
The Bermuda high sitting out in the Atlantic will generally steer the system to the west/northwest in the coming days. The forecast will then depend on a deepening trough that will swing in from the plains.
This is where the strength of the storm will play a role. A stronger system will have a tendency to 'feel' that weakness aloft and make a turn to the north sooner than a weaker system. This is why it will be critical to see how the storm interacts with the islands and at what strength does it emerge. However, in any scenario, we remain fairly confident that the storm will make that turn to the north and pose no threat to Acadiana as high pressure looks to build into the Gulf and sort of act as a block from this system as well.
Of course, you'll want to stay with the KATC storm team for the very latest with everything regarding the tropics.