From
Dr Masters:
An area of disturbed weather with heavy thunderstorm activity has developed along a broad trough of surface low pressure in the western Caribbean between Mexico's Yucatan Peninsula and Cuba. Satellite imagery shows a steadily increasing amount of heavy thunderstorm activity, but no signs of a surface circulation. NHC canceled the Hurricane Hunter flight scheduled for this afternoon, and has not scheduled a mission for Saturday.
NHC no longer thinks highly enough of this system to offer their suite of early model tracks, but the latest runs of the GFS, NOGAPS, and UKMET models all indicate that the disturbance will move north then northeastward over the weekend, bringing heavy rains of 2-4 inches over Central Cuba, extreme South Florida, and the northwest Bahama Islands. Some isolated amounts of up to 6 inches are possible over Cuba and the Bahamas. All of these models indicate the possibility that a tropical or subtropical depression could form by Sunday near South Florida or the Bahamas. There is enough wind shear that an extratropical storm could form, instead, though.
Wind shear over the disturbance has decreased from 20-25 to 10-20 knots today, and is forecast to remain at similar levels for the next 48 hours. There is some dry air one can see on
Water vapor satellite loops over the western Caribbean and southern Gulf of Mexico slowing development of the system, and this will continue to be a factor that will slow development over the next two days. Surface pressures are not falling over the region, and thus any development is going to be slow to occur. I give the system a 20% chance of becoming a depression. Wind shear is a very high 20-40 knots from central Florida northwards, which should act to keep the top winds of any storm that does form below 50 mph.