User blog:Hurricane Layten/June 17, 2017 Discussion

Well, we are not even 3 weeks into the official hurricane season, and there remains 2 areas to monitor in the coming days, of which both could become tropical cyclones.

The first area I would like to discuss is the tropical wave that is currently designated as Invest 92L, which is situated well to the east-southeast of the Lesser Antilles, well out in the Atlantic Main Development Region. The tropical wave is moving to the west-northwest at 15-20 mph, and the NHC has it tagged with a 40% chance to become a tropical cyclone in 48 hours, and a 70% chance of doing so within 5 days. Personally, I would say this area if low pressure has a 60% chance of becoming a tropical cyclone within the next 48 hours, and a 80% chance of doing so within the next 5 days, before making landfall in either the extreme southern Windward Islands of the Lesser Antilles, or along the northern coast of South America. It's hard to say exactly what 92L will do next, as there is a significant divergence in the modelling solutions for the system. The GFS and GFS Para models both develop the system, along with the NAVGEM and the HWRF, whilst the CMC and European models show a broad low moving into the coast of South America without development. Saying this though, the GFS models, along with the NAVGEM, have a higher latitude system making landfall in the southern region of the Lesser Antilles before moving into the Caribbean and being torn apart by the shear in the region.

The other area of interest is the broad cyclonic gyre that has developed in association with a monsoonal trough and 2 interacting tropical waves in the area. Whilst tagged with a 20% chance of becoming a tropical cyclone within the next 48 hours, and a 70% chance of doing so within the next 5 days, a possible track scenario has finally been suggested by the global modelling, which is another discussion. The GFS has a broad Colin type system heading into the Florida Panhandle as a strong tropical storm, and its ensemble models also show a similar scenario, with varying intensities. The GFS Para model also shows this system, but shows, whilst still relatively broad, classic tropical storm heading for the Florida Panhandle, and takes it inland in around 4 days before rapidly weakening it as it moves inland, being absorbed by a developing extratropical cyclone over the eastern United States. The CMC has a similar scenario tot he GFS, and shows a broad, not fully tropical storm moving into the Florida Panhandle, before again rapidly weakening it once it moves inland. The European model, on the other hand, shows a broad cyclonic gyre moving out into the Bay of Campeche, before making landfall in Mexico without any significant development.

Anyway, an off-topic note to finish this post, and that is that an MJO is forecast to move over the Atlantic basin over the next few weeks, with some of the modelling even suggesting that a convectively coupled Kelvin wave could also move over the basin as well. With the line of impressive tropical waves that has developed over Africa, or have moved off in the last week or so, I seriously would not be surprised to see more than just a Bret, and a possible Cindy before the month is out, but that is something to talk about on another post, when conditions warrant.