Good evening! Showers and thunderstorms are covering a good chunk of real estate this evening in the eastern half of the Caribbean Sea as the tropical wave we've tracked for the last week -- INVEST 92L -- makes its way toward Hispanolia and Cuba. There is also some additional energy coming out of the central Atlantic behind 92L; in fact, the amount of convection in the central and eastern Atlantic is much more like something you'd see in mid summer rather than the first day of summer (top image, wide-view of the Atlantic satellite).
That said, upper level wind remains unfavorable for any sort of organized tropical activity in the Caribbean, for now. This moisture will continue to work westward to the south of a ridge of high pressure that is located over much of the Gulf and Atlantic. The National Hurricane Center is giving the areas in the eastern Caribbean a low (<10%) chance of development and I generally agree with these thoughts (second image).
Later this week, the large high that's been controlling our weather over the southeast will likely begin to break down and this will allow some of the tropical moisture to start to work toward the north. A couple of our forecast models even indicate the possibility of some slow development in the Florida Straits or northern Caribbean as upper level wind becomes more favorable for organization (remember, the water is unusually warm to an unusally deep depth for this time of year!). Whether something develops or not, we should see more showers and storms move into the picture late week after a period of slightly drier days at mid week.
This scenario all fits with the evolution that's been on our long range forecast models for a couple of weeks now -- an uptick in activity in the Caribbean and Gulf (but not necessarily development). This is all coincident with something known as the Madden-Julian Oscillation: periods of enhanced and suppressed upward motion that move eastward through the tropics. Right now, there is an enhanced phase of the MJO in the eastern Pacific (not coincidentally, where there is a hurricane and tropical storm as I write this) -- this phase will be moving into the Atlantic basin over the next week which favors increased thunderstorm activity.
Stay tuned, it could be an interesting next couple of weeks!
Brian
