Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 8:02 PM GMT on September 28, 2005
The tropical disturbance in the western Caribbean sea, southwest of Jamaica, is now strengthening. The amount of deep convection has increased considerably since this morning, and this system now appears well on its way to becoming Tropical Depression 19 by tomorrow. A reconnaissance airplane is scheduled to visit the area Thursday morning at 8 am EDT.
Wind shear over the disturbance remains in the 5 - 10 knot range, which is in the slightly to moderately favorable range for tropical storm development. This wind shear is forecast to decrease the next two days. Upper level outflow channels have opened to the northeast and southwest, and a small upper-level anticyclone is over the system, helping ventilate the air pushed to the upper atmosphere by the strong updrafts in the storm's deep convection.
The disturbance is moving at about 13 mph to the west-northwest. This motion is forecast to slow down over the next few days, which will keep the system in the western Caribbean through Friday night. None of the computer forecast models develop the system, so their tracks of the disturbance are dubious. The GFS model takes the disturbance across western Cuba on Saturday. The BAMM model takes the system across the Yucatan Peninsula and into the southwest Gulf of Mexico. This seems more reasonable, given the strong ridge of high pressure developing over the Gulf of Mexico.
Figure 1. Early run of the BAMM model takes the Caribbean disturbance into the Yucatan Peninsula. The GFDL model disippates the system immediately.
The ITCZ is active in the region extending from the African coast westwards for 1000 miles. Some of the global computer models are forecasting that a tropical storm will develop along this area later this week. There are currently no suspect areas to focus on, though.
Hawaii and Baja
Hawaii is watching Tropical Storm Kenneth, which is expected to pass though the Islands Friday and Saturday. Kenneth should only be a tropical depression by then, but may bring heavy rains and the threat of flash flooding to the islands. Tropical depressions that have passed though the islands in previous years have caused serious flooding problems.
The Baja Peninsula is watching newly-formed Tropical Depression 15E, which may threaten the Baja Peninsula as a tropical storm by Sunday.
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