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Henri being torn apart by shear

By: Dr. Jeff Masters, 7:21 PM GMT on October 07, 2009

Tropical Storm Henri is getting ripped apart by wind shear, and is much less organized than it was early this morning. About 25 knots of wind shear continues to eat into storm, and visible satellite loops show that the shear has exposed Henri's low level center to view. Henri's heavy thunderstorms have been shrinking in areal coverage and intensity, and are steadily moving away from the center--all signs of a highly sheared tropical storm that has little time left to live.

All of the reliable global computer models show weakening and dissipation of Henri by Thursday, due to high wind shear. Wind shear in the vicinity of Henri's remains is predicted to fall to the moderate range by Saturday, so we will have to be concerned with regeneration after Henri dissipates. It appears likely that moisture from Henri will affect Puerto Rico by Friday night, the Dominican Republic on Saturday, and Haiti on Sunday. It is too early to tell if Henri's remains will be capable of causing flooding rains in these regions.

Figure 1. Afternoon satellite image of Henri (top) and a new tropical wave we're watching (bottom). The tropical wave south of Henri, just off the coast of South America, has become more organized this afternoon. The thunderstorm activity has grown more concentrated near 8N 50W, with a hint of some low-level spiral banding starting to form. This wave is under about 10 knots of wind shear, but is too close to the Equator to be able to take advantage of the Earth's spin to help it spin up into a tropical depression very quickly. Also, the wave will suffer from interaction with the coast of South America on Thursday. NHC is giving this disturbance a low (less than 30% chance) or developing into a tropical depression by Friday.

Typhoon Melor
Typhoon Melor has made landfall on Japan's Honshu Island south of Osaka as a Category 1 typhoon with 85 mph winds. Hamamatsu reported sustained winds of 54 mph last hour, and tropical storm force wind gusts will be common along much of the south coast of Honshu as the typhoon passes. You can follow the landfall of Melor with our interactive wundermap for the region.

Jeff Masters


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