A westward-moving tropical wave accompanied by a broad low pressure area is located over the eastern Caribbean Sea just west of the Windward Islands. Associated shower and thunderstorm activity continues to show signs of organization, and environmental conditions are expected to gradually become more conducive for development. A tropical depression is likely to form during the next day or two while the system moves moves westward at about 15 mph across the central Caribbean Sea. Interests in Jamaica, Honduras, Belize, Guatemala and Yucatan should monitor the progress of this disturbance.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...80 percent.
Crown Weather: Invest 99-L Now Entering The Eastern Caribbean Is Likely To Develop This Coming Week
Satellite imagery at midday today indicated that the thunderstorm activity with Invest 99-L has increased significantly in just the last 12 hours and it is showing signs of organization. In addition, satellite estimated wind data indicates that the very least there is a broad area of low pressure that seems to be forming as well.
The environmental conditions are favorable for additional organization and it looks quite possible, if not likely that this disturbance will become a tropical depression and then a tropical storm as it heads westward reaching the central Caribbean on about Tuesday and then the western Caribbean on Wednesday and Thursday.
Given the way the global model guidance such as the GFS and European model have been with forecasting tropical development, it is not surprising that they arenít really showing anything in the way of development. The Canadian model shows some hints at development especially once it reaches the longitude of Jamaica on Tuesday night into Wednesday morning.
The track model guidance shows a general westward track taking Invest 99-L to the south of Jamaica by Tuesday night and then into Central America by about Thursday. In addition, the track model intensity guidance forecasts steady strengthening with some of the guidance forecasting this system to become a hurricane before it reaches the coast of Nicaragua and Honduras on Thursday.
All-In-All, I Think That there is a very good chance that Invest 99-L will become a tropical depression and probably a tropical storm over the next 2 to 3 days. It remains to be seen how close Invest 99-L will get to Jamaica on Tuesday night, but I think it is quite possible that it could come close enough to bring gusty winds and squalls to the island during Tuesday night and Wednesday morning.
Beyond this, it seems likely given the upper level weather pattern that this system should head for Central America by Thursday with tropical storm conditions a possibility across the southern Yucatan Peninsula, Belize, Honduras, Nicaragua, El Salvador and Guatemala and Yucatan during Thursday.