Sunday, August 11, 2013

Model Guidance Suddenly Threatens Gulf Coast with Tropical Cyclone

The Canadian model's wind speed and sea level pressure forecast for the evening of August 17.

The American model's wind speed and sea level pressure forecast for the evening of August 17.
Model guidance is suddenly projecting a tropical cyclone to develop in the Gulf of Mexico and hit a space anywhere from eastern Louisiana to the Florida Panhandle on August 17th.

As the two images above show, there is remarkable consistency among these two models, with both forecasts having a tropical cyclone making landfall on the United States mainland at the same time (evening hours of August 17). Now, the Canadian (CMC) model is much stronger with this system, which is to be expected- the CMC model is always exaggerating storm forecasts, whether tropical or extratropical. However, with the GFS model now jumping on board with this idea of a landfalling tropical cyclone, it is time we examine just how possible this is.

Global models are indicating we will see an area of enhanced convection in the Atlantic basin, possibly into the Gulf of Mexico over the next 5-10 days. This enhanced convection pulse is timed well with the idea of tropical cyclone formation in the Gulf of Mexico. Adding to this potential is what recently happened in the Pacific waters. We saw a typhoon fail to recurve in the Pacific before hitting East Asia, meaning any tropical cyclone that forms in the Atlantic is unlikely to curve out to sea. As a result, any tropical waves or disturbances coming off Africa are more likely to shift west and thus find themselves entering the Gulf of Mexico.

Current Probabilities

Risk of Tropical Cyclone Formation: 40%
Risk of Hurricane Formation: < 5%
Risk of a Landfalling Tropical Cyclone (in the event a tropical cyclone does form): 80%