Tropical Storm Watches have been posted from the South Santee River in South Carolina to Duck North Carolina, including the Albemarle and Pamlico Sounds.
Florida has been experiencing heavy rains for the past several days at this system spun in the area. Some areas have seen several inches of rain over the past few days as this system slowly meandered up the peninsula. This system has been watched for a while as it slowly moved up, but interactions with land and conditions that were neutral or negative for tropical development continued to prevent this system from developing further. Now that the system is heading over the warm water of the gulf stream, convection is beginning to increase and the storm is organizing despite its sheared environment, which Hurricane Harvey has been helping to maintain. These storms are starting to get some separation and we expect to see Tropical Storm Irma form in the next couple of days.
Steering currents across the South of the US have been weak as of late. This is why both this system and Harvey are moving so slowly, as you can see in the early movement of this system. This will begin to change as a trough moves into the Central United States and begins to make this system move.
This system moves slowly north towards the border of South and North Carolina. It will come very close to making a landfall here but much of the circulation will remain over water, which will slow any weakening. This system will flow along the coast up towards the North Carolina Virginia border. This system has the potential to hit the coastline hard with storm surge and high waves ahead of the storm as it strengthens.
As seen in the track above, as on this model image, the system is expected to make landfall along the North Carolina coast and impact the Outer Banks. Beyond that, the forecast gets more difficult. Some models have brought the system further out to sea, but the GFS is bringing the system closer to the coast of New England on some runs and this possibility will need to be monitored in future articles.