Western Caribbean disturbance could bring heavy rains to Florida

An area of disturbed weather (94L) with heavy thunderstorm activity has developed in the western Caribbean between Mexico's Yucatan Peninsula and Cuba. This disturbance has the potential to form into a tropical depression by Sunday as it drifts northwards into the Gulf of Mexico. Wind shear over the northwest Caribbean is a not-so-healthy-for-development 20-25 knots, but is forecast to decrease somewhat over the next 48 hours. There is some dry air over the western Caribbean and southern Gulf of Mexico, but water vapor satellite loops show that the thunderstorm activity starting to fire up in association with the disturbance is steadily moistening the atmosphere. However, surface pressures are rising over the region, and thus any development is going to be slow to occur. The 7:21am EDT QuikSCAT satellite wind map show no surface circulation, and neither do satellite loops. Top winds from QuikSCAT were in the 20-30 mph range. However, winds were only about 15 mph at the Yucatan Basin buoy, and this is more representative of the winds associated with the disturbance.


Figure 1. Visible satellite image of the western Caribbean disturbance.


Figure 2. Early model tracks for the western Caribbean disturbance.

None of the computer models forecast that this system will become a tropical storm, but the GFS model is indicating that an extratropical storm will form from this system early next week once it moves over Florida. The situation looks similar to what happened with Tropical Storm Barry, and we could get a hybrid subtropical storm forming in the Gulf on Saturday or Sunday, as the system passes over some very deep warm waters associated with the "Loop Current" that feed the Gulf Stream. There will be a lot of wind shear (20-40 knots) over the northern Gulf of Mexico over the next seven days, which should prevent any system that forms from having winds stonger than about 60 mph. A tropical, subtropical or extratropical storm with winds topping out at 50 mph is 20% probable, though, and Florida may be the beneficiary of another good rain-making storm.

A Hurricane Hunter flight was scheduled to visit the system at 2pm EDT this afternoon, but has been canceled. The flight has not been re-scheduled for Saturday. I'll have an update on this system this afternoon, and will include my rest of June outlook for hurricane season.

Jeff Masters