Just a quick update on the tropics this morning, and I hope to post more on Katrina later today.
The most significant threat in the tropics is the potential on Sunday or Monday for a tropical depression to develop in the waters between the Bahamas and Bermuda. This is the same location that Katrina developed. This development would occur at the tail end of a cold front that is expected to push off of the East Coast. The latest GFS model run is showing two possible areas of formation, one near Bermuda, and one near the east coast of Florida. If a depression does form near the east coast of Florida, the likely track would be across Florida and into the Gulf of Mexico. If formation occurs closer to Bermuda, the likely track would be northeastward away from land. I think it is unlikey that two systems would form in the this region; the energy for storm formation will probably concentrate in one area and create one storm. Let's hope that if this occurs, the formation region will be closer to Bermuda and the storm will head out to sea. Figure 1. GFS forecast for 2am Monday, showing two possible locations a tropical depression may form.
Tropical Depression Lee is nothing to worry about, it is too far north to have a chance at affecting land, and is suffering from shear that will keep it weak or potentially dissipate it over the next few days. The well-organized wave 1100 miles east of the Lesser Antilles is looking better organized today. The shear over it is relaxing, the dry air on its west side has decreased some, and deep convection is starting to build on the north side. This system will probably become Tropical Depression 14 later today, but its relatively northerly location and northwesterly motion make this system no threat to land. This system will probably recurve out to sea. The most significant threat in the tropicas may be from the tropical wave southwest of the Cape Verdes Islands. This system is far enough south, near latitude 9N, that it will not get recurved out to sea by the mid-Atlantic trough. The tropical wave is currently in a region of strong enough shear that development will not occur, but this shear is expected to relax by Saturday as the wave continues westward over the open Atlantic. As was the case with yesterday's model runs, the GFS forecasts that this wave will become a major hurricane and a potentially threaten the Leeward Islands a week from now.