SINT MAARTEN/CARIBBEAN - Satellite imagery and weather analysis indicates that there are two tropical waves that Crown Weather is watching right now, the weather service said on Saturday.
“The first is located in the eastern Caribbean along the 65 West Longitude line and the second is located just east of the Lesser Antilles along the 57 West Longitude line. Strong westerly wind shear is impacting much of the Caribbean right now and tropical development is highly unlikely with either of these tropical waves.
“The reason why I am keeping an eye on them is because it appears that they will bring an energy kick to help and develop either one broad area of low pressure or multiple little low pressure systems in the central and southwestern Caribbean by about Tuesday and Wednesday. This will lead to coupious amounts of moisture to be drawn from the central and southern Caribbean into the Bahamas leading to heavy rainfall and potential flooding across Jamaica, Hispaniola, Puerto Rico and much of the Bahamas starting around Tuesday and continuing through at least next weekend.
“The question then becomes whether this whole wet weather system will remain an area of disturbed weather or will it try to develop into a tropical depression or a tropical storm. Even though some of the model guidance has hinted at tropical development, it appears that the wind shear conditions across much of the western Atlantic and the Caribbean is too strong to support development into a tropical cyclone.
“Right now only the GFS model guidance forecasts tropical development which ends up occurring in the central Bahamas in about 10 days from now. The GFS model then forecasts this system to rapidly pull northward along the US East Coast into southern New England by May 24th and May 25th. I am very skeptical of this forecast by the GFS model as it is the only model predicting this type of a scenario and also the GFS ensemble guidance doesn't even support its operational counterpart.
“With that said, the analog guidance, which matches the current weather pattern with those from the past, indicates a forecast weather pattern of a large high pressure system over the north-eastern United States by next weekend. This would probably lead to lowering barometric pressures over the western Caribbean.
“This pattern is similar to one that occurred during late May of 2007 and this led to the development of Tropical Storm Barry which tracked north-eastward from the western Caribbean and up the US East Coast. So, perhaps the GFS model may not be so far off with its forecast – although, I'm not buying into it yet.
“It looks like periods of heavy rain with squalls will develop across Jamaica, eastern Cuba and parts of Haiti starting around Tuesday into Wednesday. This rain will gradually spread into the central and south-eastern Bahamas by Friday into next Saturday.
“This feed of moisture will impact the southern and central Caribbean and the Bahamas, including Jamaica, eastern Cuba and Hispaniola through next weekend with total rainfall amounts from Tuesday to Sunday of 10 to 20 inches possible in some areas and widespread rainfall amounts of 4 to 10 inches expected. My thinking is that eastern Jamaica and the mountainous regions of Haiti will see the highest rainfall amounts next week into next weekend.
“At this point, I'm not convinced that we will see tropical development next week as the wind shear is too strong across the Caribbean and there are no indications that it will decrease anytime soon. By next weekend, however, we might have to keep an eye on the outside possibility of tropical development in either the central or western Caribbean.
“The reason why is because if the weather pattern across the eastern United States shifts into one that features a upper level high pressure system over the north-eastern United States, it would cause a lowering of barometric pressures over the Caribbean and a more favorable environment for tropical development. Also, the weather pattern next weekend could be potentially analogous to late May of 2007 in which Tropical Barry formed then.
So, at this point it is something to keep an eye on, but it is definitely nothing to really sit up and take notice.”