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 , 2:42 PM GMT on September 29, 2006
The tropical wave over the northernmost Lesser Antilles Islands (designated 97L by the NHC yesterday) has weakened. The wave is north of Puerto Rico this morning, and could bring some heavy rains to that island today. The system is very small and disorganized, and the 10-15 knots of wind shear over it will probably not allow such a small system to develop. You can follow the progress of 97L today on long range Puerto Rico radar.
Figure 1. Preliminary models tracks for Invest 97L.
The Philippine Islands continue to count the dead and assess the damage left by Typhoon Xangsane, which roared over the main Philippine Island of Luzon Wednesday, passing directly over the capital city of Manila. At least 60 are dead and another 60 missing, with many hard-hit areas still to be heard from, due to failed communications and washed out roads. The majority of the victims died in mudslides, flash floods, and building collapses. Xangsane cut power to all 43 million people on the island of Luzon, making it one of the most extensive blackouts due to natural disaster in world history. Power had been restored to about 40% of the island this morning. Xangsane (from the Laotian word for Elephant) hit as a Category 4 typhoon with 145 mph winds before weakening during its passage over land. It has reintensified today into a Category 4 typhoon over the South China Sea, and is expected to deliver a heavy blow to Vietnam on Sunday.
Figure 2. Rainfall from Typhoon Xangsane over the Philippines as measured by NASA's TRMM satellite. The pink color represents about ten inches of rain. Image credit: NASA TRMM Project.
Tropical Storm Isaac continues to look unimpressive, thanks to dry air on the south side being drawn in, wind shear from an upper level low, and passage over some cool ocean waters stirred up by hurricanes Gordon and Helene. All of these influences should diminish a bit over the next day, which may allow Isaac the opportunity to do some modest intensification. The storm is not a threat to any land areas, and should recurve out to sea this weekend.
Elsewhere in the tropics
A strong cold front has pushed off the North American coast, and is serving as the focus of some thunderstorm development from the Bahamas southwestward through the waters south of Florida. We'll have to watch this region over the coming days for some possible development. However, the computer models are no longer forecasting development along this old front.
Next week, a non-tropical low pressure system is expected to form in the mid-Atlantic south of the Azores Islands, and this system may make the transition to a tropical storm like Delta, Epsilon, and Zeta did last year.
I'll have an update Saturday morning, and I'll post my outlook for October on Monday. We might be done with landfalling hurricanes for the year!
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