Typhoon Xangsane bears down on Vietnam

Vietnam has ordered mass evacuations of 200,000 coastal residents in the path of Typhoon Xangsane, now a very dangerous Category 3 typhoon over the South China Sea. This is the largest evacuation in Vietnam for a typhoon in 30 years. Xangsane is expected to hit Vietnam on Sunday morning as a major typhoon. Authorities are most concerned for the welfare of about 4,000 fisherman still at sea in the path of the typhoon; in May, 234 Vietnamese fishermen were killed or unaccounted for after Supertyphoon Chanchu passed east of Vietnam on its way to a landfall in China. Da Nang on the central coast of Vietnam has had its winds rise to 29 mph with higher gusts today, and may receive a direct hit from Xangsane.

The Philippine Islands continue to clean up from Xangsane today, and the death toll stands at 94 with at least another 60 people missing. Over 15,000 homes were damaged or destroyed, and power is still out to 20% of the island of Luzon's 43 million people. The death toll from the storm was not as high as many other typhoons to strike the country in recent years, since Xangsane moved though fairly quickly--15 mph--and didn't have time to dump as much rain as usual for a typhoon. Peak rain amounts (Figure 1) were about 10 inches, and rainfall amounts closer to 15 inches are required to trigger the kinds of major flash flooding and mud slides that often kill so many in the Philippines.


Figure 1. Rainfall from Typhoon Xangsane over the Philippines as measured by NASA's TRMM satellite. 250mm is about 10 inches. Image credit: NASA TRMM Project.

Hurricane Isaac
Hurricane Isaac became the season's fifth hurricane this morning, thanks to some lighter wind shear, warmer waters, and moister air. Isaac has another day or two of favorable conditions before cooler waters and high wind shear weaken the hurricane. Isaac is expected to pass near southeast Newfoundland on Monday as a tropical storm with 55 mph winds.

Elsewhere in the tropics
A non-tropical low pressure system is expected to form in the mid-Atlantic south of the Azores Islands by Wednesday, and this system may make the transition to a tropical storm as it drifts south over the open Atlantic late in the week. There are no other threat areas to discuss--the tropical wave (97L) that we were tracking yesterday, north of Puerto Rico, has fallen apart.

I'll have an update Sunday morning.

Jeff Masters