Two disturbances to watch off of the coast of Florida
The most serious threat in the tropics today is a large area of disturbed weather extending from Miami eastward over the Bahama Islands. Shear values are still probably a little too high--about 10-15 knots--to permit a tropical depression to form in this region today. However, the shear is rapidly decreasing, having fallen 10 knots in the past 24 hours, and is forecast to be 5-10 knots tomorrow. At this level, a tropical depression could form Monday or Tuesday. Several computer models, including the UKMET and NOGAPS, forecast that a strong tropical storm will form here and move slowly northward, threatening the Carolinas late in the week. The GFS model does not develop the system.
A second disturbance with a well-defined circulation visible on both visible satellite images and QuikSCAT data is located about 600 miles east of West Palm Beach, Florida. A concentrated area of deep convection has developed on the south side of the circulation center, and continues to build. Shear values in the region have dropped to 5-10 knots and continue to drop, and the conditions appear favorable for a tropical depression to form by tomorrow. The system is expected to move north and may threaten Bermuda. Figure 1.
Forecast track of tropical low 600 miles east of West Palm Beach, FL.
The Thursday GFS forecast
was remarkably accurate--it correctly predicted tropical development in both of these areas, four days in advance! African tropical waves
The tropical wave we've been watching cross the Atlantic for the past week is still out there, at 10N 53W, 500 miles east of the islands. This system is still too far south to develop significantly, but steering currents should start to push the system just far enough north for it to avoid being destroyed by passage over South America. We will continue to watch this system as it moves westward at 15 mph. Hurricane Maria
Oh yes, there is a hurricane out there! Maria has a nice looking eye starting to develop, and should be a pretty sight on satellite images the next few days as she heads northward and then northeastward out to sea. Maria should make it to Category 2 and possibly Category 3 status before cold water and wind shear three days from now start taking their toll.