User blog:Hurricane Layten/Eyes on the Tropics: July 7, 2017

Several areas to talk about again today, from the stubborn tropical depression in the Atlantic, to an invest area with a high chance of tropical cyclone formation, to a possible development in the medium range in the Atlantic basin.

So, first off, let's start on the depression in the Atlantic basin. Tropical Depression Four developed yesterday, and has since then struggled against the usual shear and Saharan air that usually prevents tropical cyclone development in the Atlantic during July. Yet Invest 94L, a tropical wave that moved off Africa on June 30, managed to beat the odds, mainly due to being embedded in the monsoon trough and its unusual slow movement, to become a tropical cyclone. The depression continues to be a 30 mph depression officially, yet since the last satellite classifications at 0600 UTC, the system has continued to improve, and so I'm going to say its a 35 mph depression at this time as a result. The depression isn't expected to intensify any further, and could well open up into a tropical wave later today or early tomorrow as it speeds towards the west-northwest, no threat to land. However, it is interesting to not that the depression could regenerate near the Bahamas according to some of the modelling, which again, would be unusual for a July tropical cyclone in the Atlantic basin.

Now, onto Invest 95E, which now has a 90% chance of tropical cyclone formation, and could become a tropical depression later today before moving out into the colder waters of the Pacific, which will inhibit development. Models seem to have backed off on this system as of late, so I doubt if it does become a tropical cyclone it will be anything more than a short lived, large depression, well away from any land areas.

Now, onto the western Pacific, where both Invest 91W and 92W seem to have dissolved, and are no longer being monitored for tropical cyclone formation over the next few days. However, modelling on Invest 92W does suggest a tropical cyclone could develop as the system continues to move southwestwards towards the Malaysian Peninsula and Thailand, and so I will continue to track this system until it is no longer an area of interest.

In the longer range, whilst this is the most uncertain point in the forecast, there is a consensus of some sort that suggests a tropical cyclone could develop in the central tropical Atlantic in the 7-10 day period. The GFS appearsto show a tropical depression developing in 6 days, before bringing it through the Lesser Antilles in 8 days as a strong tropical storm, then bringing it to hurricane intensity as it moves into the Caribbean Sea. The European model shows a similar result on its latest run as well, developing a tropical depression in 6 days, before bringing it through the Lesser Antilles as a hurricane in 9 days, and hitting Puerto Rico in 10 days.

Anyway, I will continue to monitor the situation, and do another blog post tomorrow if conditions warrant.