Good morning! A lot of activity in the tropical Atlantic this morning and the eastern tropical Pacific. We have monsoonal moisture moving out of the Pacific, across central America and into the Caribbean. At the same time, the remnants of Tropical Storm Matthew are spinning across the southern Bay of Campeche/mainland Mexico and a new area of low pressure appears to be forming near the Cayman Islands this morning. This all adds up to a very unique pattern with lots of rising motion and energy spread out across a good chunk of the Caribbean and far eastern Pacific Ocean. While the satellite view looks imposing, this "spread out" nature of the energy may actually work in our favor and prevent a terribly well organized system from ever developing.
The first part of the forecast to deal with is the low forming west of Jamaica this morning. It is forming underneath an upper level high and is located over some very high heat content water -- so organization should not be a problem here. But the limiting factor is its competing against a lot of rising motion elsewhere in the Caribbean and this will help keep any strengthening slow. Also, just north of the disturbance, over the southern Gulf, wind shear is high because of the trough digging into the southeast United States -- another limiting factor. As a result, most of our models show a relatively weak system lifting northward toward Florida at mid-week along the front expected to be draped across Florida. One uncertainty is how far east this low tracks -- the farther east it tracks, the drier it will be in southwest Florida. That's a question we'll try to answer better by midday but, at this point, we expect a fairly rainy mid-week period -- and a system that will be far more a rainy one than a windy one. You can see the differences in the 2nd and 3rd maps above -- total 84 hour precip in the GFS and NAM model. The NAM (farther west) is much wetter than the GFS.
Behind this first system or wave, we may get a respite of dry air late week and early this weekend. Then, the remnants of Matthew may get involved to help create a new area of low pressure in the northwest Caribbean which could also move toward south Florida by late in the weekend and early next week. Either way, it promises to be quite active in the Caribbean over the next week to ten days. Our models have handled the idea of an active period this week very well (going back 14-17 days ago) -- the details of this active pattern are just starting to come into focus but there are still many questions.
