Caribbean Disturbance Little Threat to Develop

A concentrated area of heavy thunderstorms has developed over the Southwest Caribbean near the coast of Nicaragua in association with a tropical wave that is moving slowly west northwest towards Nicaragua and Honduras. Wind shear is a high 20 - 30 knots, which will keep any development slow. The high shear is due to the presence of the subtropical jet stream, which is expected to push northwards over the next few days. This may allow wind shear to fall to the moderate range on Monday, when the wave will be in the Northwest Caribbean, between Honduras and Belize. NHC is giving the disturbance only a 10% chance of developing into a tropical depression or tropical storm by Monday, but these odds may increase on Monday when the wave has crossed into the Northwest Caribbean--if the wind shear drops. The wave will cross over the Yucatan Peninsula on Tuesday and may emerge into the Southern Gulf of Mexico's Bay of Campeche as early as Wednesday. At that point, the models continue to predict a slow west-northwest motion, bringing the wave ashore into Mexico between Veracruz and Tampico late in the week. Wind shear is expected to remain high during the entire period, keeping any development slow. The Bay of Campeche is a region where the topography aids the spin-up of tropical cyclones, so the disturbance's odds of formation are the greatest on Wednesday through Friday, after it crosses the Yucatan. None of the models develop the disturbance, and there is no indication that this system will affect the U.S., as a strong ridge of high pressure over the U.S. during the coming week should keep the tropical wave trapped in the southern Gulf of Mexico.


Figure 1. MODIS satellite image of the tropical disturbance in the Southwest Caribbean on Saturday, June 15, 2013. Image credit: NASA.

Have a great weekend, everyone, and I'll be back Monday with a new post.

Jeff Masters