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97L fizzles; new Bahamas disturbance develops

By: Dr. Jeff Masters, 2:17 PM GMT on July 21, 2009

A strong tropical wave (97L), now located just south of Puerto Rico, has grown disorganized today. Sustained winds as high as 26 mph were observed on Barbados, and 35 mph winds were observed on St. Lucia yesterday when 97L passed through the Lesser Antilles Islands. Wind gusts to 45 mph and heavy rain can be expected in the Dominican Republic and Puerto Rico this afternoon, and in Haiti and the southeastern Bahama Islands on Wednesday. However, 97L is under too much wind shear to develop, and shear will remain in the high 25 - 35 knot range over the disturbance over the next two days.

Figure 1. Today's disturbances to watch.

A new tropical disturbance has formed north of the central Bahama Islands, about 600 miles east of Miami. The thunderstorm activity is not yet very intense, but does cover a moderately large area. This morning's QuikSCAT pass showed winds of 20 - 25 mph, and no evidence of a circulation trying to form. This region is under about 20 - 25 knots of wind shear, and has the potential for some slow development over the next few days as it moves slowly northwards. The GFS and ECMWF models hint at the possibility that this system may attempt to organize into a tropical depression by Friday, off the coast of North Carolina.

I'll have an update Wednesday.

Jeff Masters


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