Likely Tropical Development in the Gulf
A low that is over South Carolina and Georgia on Monday morning is likely to become a tropical depression later this week as it moves south into the northern Gulf of Mexico.
There is a high probability (80%) that a tropical depression is likely to form by the end of the week over the northern Gulf of Mexico. This system also has the potential to produce heavy rainfall along portions of the northern and eastern U.S. Gulf Coast later this week. pic.twitter.com/fm8BnAh26O— National Hurricane Center (@NHC_Atlantic) July 8, 2019
The National Hurricane Center says there is an 80% of tropical development over the next 5 days. Nearly all of the global models forecast the low to enter the Gulf waters adjacent the Florida Big Bend late Tuesday or Tuesday night. The trend of these models over the past 24 hours has been to drift the developing tropical system westward. Should this occur, the direct effects to South Carolina would be minimal, but there are still uncertainties in the eventual path of this system.
Tropical cyclones, especially early in the season can form as low pressure or cold fronts move over warm waters of the Gulf of Mexico, Caribbean or the Gulf Stream. @NHC_Atlantic will be watching this area of low pressure as it drifts south over the Gulf of Mexico this week pic.twitter.com/XSA8X5UOme— NWS Eastern Region (@NWSEastern) July 7, 2019
The manner in which this storm is likely to form is unusual, but not unheard of. A cluster of thunderstorms over Missouri this past weekend separated from the westerly winds that normally steer weather systems across the northern third of the United States in the summer. A weak low pressure has formed from this storm cluster and has meandered southeastward into Georgia and South Carolina. It will be steered into the Gulf around a strong high pressure over Texas and Louisiana.
Most of the recent computer simulations forecast this high to be strong enough to capture the developing tropical system and push it toward the central or western Gulf coast. Such a track would minimize the direct effects of the tropical system to South Carolina. There are still a few models, however, that predict a weaker high because of a trough of low pressure moving through the Great Lakes and Tennessee Valley. If that occurs, the system will move slower and could turn north back toward the Gulf coast farther east. This scenario would increase the likelihood of widespread heavy rainfall over the weekend.
Regardless of the eventual tropical system’s track, the National Weather Service offices in Columbia, Charleston, and Greenville-Spartanburg are all anticipating abundant tropical moisture over the state. An approaching front from the west and existing moisture will be the catalyst for scattered to numerous storms that they say could produce localized downpours and flooding in areas that receive slow-moving thunderstorms. At this time; however, the forecast from the National Weather Service has fewer direct impacts from the system that’s likely to develop in the Gulf.