Atlantic Tropical Outlook

Quiet weather continues in the tropical Atlantic basin as a strong TUTT dominates the Caribbean and Central Atlantic. That hasn't stopped the African wave train from rolling impressive waves off the coast of Africa, but they have been beaten by dry air and cool waters once they emerge into the Atlantic. Easterly winds remain strong across the Eastern Atlantic, but recent migration of subtropical ridge to the north and west has allowed for a relaxation of the easterlies. Normally, this would allow water temperatures to warm slightly, but an expansive area of Saharan dust will likely prevent full sunshine from warming temperatures in the main development region. If this dust continues, it will have a substantial impact on long-track Cape Verde systems in August and September.


The weather should be great today for most of the Caribbean islands, but a few showers and thunderstorms may affect the Lesser Antilles this evening as an easterly wave approaches. This tropical wave is centered near 14N and 54W and is quickly encountering a very hostile upper level environment. This wave should rapidly dissipate in the next 24-36 hours due to wind shear in excess of 30 knots and significant amounts of dry air and Saharan dust.

A second and healthier looking tropical wave is centered near 12N and 35W. A small area of thunderstorms is associated with the wave, but a QuikSCAT pass this morning did not indicate a closed circulation. Despite this, wind shear remains light and water temperatures are sufficient for some development as this wave moves to the west. However, dry air and Saharan dust remain to the west and north of this tropical wave so it's very possible it could be entrained into this wave. A few computer models indicate a lowering of pressure in the vicinity of the wave, but no model forecasts any development through this weekend. This seems reasonable given the dry air, marginal water temperatures, and a downward motion pulse. Still, this will need to be watched as it moves west and west northwest over the next several days. The subtropical high is forecast to shift westward early next week at the same time a trough split occurs in the Eastern U.S. With warmer water temperatures in place across the Western Atlantic, a more favorable environment for development will exist at that time.

Showers and thunderstorms are located in the tropical waters off the Gulf Coast and Carolinas, but development of these areas will become highly unlikely through this weekend as a trough deepens into the Southeast.