07 July 2013

Early season tropical wave heading toward Caribbean

An unseasonally strong easterly wave exited the African coast on July 3, and has been making its way across the deep tropics.  As of this writing (9am EDT), the almost-Depression is centered near 9N 42W, or about 1400 miles east of the Windward Islands.  The first image below is a zoomed-out satellite image to show the disturbance in relation to landmasses, and the second is cropped in to see the detail.

Conditions are favorable to this to develop further and could easily be upgraded to Tropical Depression 3 today or tomorrow (if it becomes a tropical storm, the next name on the list is Chantal).  On its current trajectory, it should reach the Lesser Antilles sometime on Tuesday... the intensity at that point is anyone's guess at this point, unfortunately.  Intensity forecasts of pre-Depression systems are very difficult, mostly because so much is possible: it could encounter unforeseen hostile shear or dry air and fall apart in two days, or it could rapidly intensify to a hurricane in two days. 

A variety of model forecasts... the green ones are very simple models that are not skillfull, while the others are more skillfull and are much more sophisticated.  The track with the black diamonds (XTRP) is just an extrapolation of the current motion.  None of these are official forecasts, and are just shown to give an idea of where the storm could track. (SFWMD)
As I mentioned, this is quite early in the season to have a strong easterly wave like this, and going back to 1851, I could only find one other storm that formed or passed within 100 miles of this disturbance's location in all of July: Tropical Storm Arthur 1990.  However, if one removes the July restriction, the list opens up to include infamous storms: Flora 1963, Joan 1988, and Ivan 2004.

Stay tuned for updates!

No comments:

Post a Comment