From Crown Weather - Monday:
Invest 93L Located To The East Of The Lesser Antilles:
Satellite imagery this morning showed some deep convection developing around what was Invest 93L now located between 50 and 55 West Longitude. Analysis of ocean water temperatures reveals that this disturbance has just entered ocean water temperatures warmer than 84 degrees Fahrenheit. The combination of a more favorable upper level environment and these warmer ocean water temperatures are likely the reasons for the marked increase in convection this morning. A view of the water vapor satellite loops shows that there is a lot of dry air surrounding this disturbance and any development that does occur will be slow to happen.
Neither the GFS or European model guidance forecasts development of 93L and they both keep it a tropical wave which eventually tracks into Central America on Friday. Now, the NAM model has been fairly insistent on forecasting the development of this system. The current forecast run of the NAM model forecasts that 93L will track across Barbados today and then across the southern Leeward Islands and the Windward Islands tonight into Tuesday, which I do agree with. The NAM model then forecasts that this disturbance will develop into a tropical cyclone as we get into Wednesday and for it to strengthen into a moderate tropical storm on Thursday with it beginning to impact Jamaica during Thursday afternoon.
The NOGAPS model forecasts that 93L will develop into a tropical cyclone once it reaches the west-central Caribbean just south of Jamaica on Thursday and then forecasts it to impact Central America and Belize as a fairly weak tropical storm this coming weekend.
Here are my thoughts on 93L: Even though we are seeing a marked increase in convection this morning that development of Invest 93L will be slow to occur and the NAM model’s forecast should not be trusted. Why?? The eastern Caribbean is essentially a desert in the mid and upper levels of the atmosphere and once this disturbance starts trying to develop and intensify it will likely suck in this dry air and weaken. So, I really do not think 93L will become a tropical depression over at least the next couple of days, however, it will bring strong gusty winds, choppy seas and heavy rainfall across Barbados, the Windward Islands and the southern Leeward Islands from today through Tuesday.
I do think that 93L will find a more favorable environment for development once it reaches the central and western Caribbean later this week and this is when we may see it organize into a tropical depression or a tropical storm. Given this, it would probably track west-northwestward right into Central America and Belize this coming weekend as a tropical depression or perhaps a tropical storm.
As it stands right now, 93L is not a immediate concern and there is the possibility that it may never develop. With that said, this disturbance will be watched closely this week and I will keep you all updated on the latest.