Typhoon Rammasun Explosively Re-Intensifies on Way to China, Vietnam

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Typhoon Rammasun, seen here in a computer model simulation of its wind field, is strengthening and nearing Hainan Island, China on July 17, 2014.

Image: Earth.nullschool.net

By Andrew Freedman2014-07-17 16:24:47 UTC

Typhoon Rammasun, which heavily damaged parts of the northern Philippines earlier this week, is once again rapidly intensifying as it spins its way toward a second and third landfall. And once again, tropical weather forecasters at the Joint Typhoon Warning Center (JTWC), which is run by the U.S. Navy and Air Force, seem to be several steps behind the curve in predicting the storm's intensity.

As of Thursday morning Eastern Time, the JTWC had pegged the storm's estimated maximum sustained winds to be that of a Category One storm on the Saffir Simpson Hurricane Scale.

See also: Typhoon Slams Philippines, But Manila Escapes Catastrophe

But after the storm took advantage of light upper level winds in the atmosphere, which allowed its towering thunderstorms to build and organize, as well as the warm waters of the South China Sea, which gives the storm its energy, it underwent a six-hour period of what one meteorologist called "explosive" intensification.

This means that instead of facing a Category One storm, China's Hainan Island, which is Rammasun's next landfall target, will be dealing with a major typhoon instead, with much greater impacts. A similar situation played out in the Philippines on Tuesday and Wednesday.

At 11 a.m. ET, the JTWC upgraded Rammasun to a Category Two storm, with sustained winds of 110 miles per hour, although its winds may be considerably higher than that, according to meteorologist Ryan Maue of WeatherBell Analytics, a private sector weather company.

The JTWC's official forecast calls for the storm to make landfall on the northern part of Hainan Island, China, home to about 9 million people, on Friday with 100 mile per hour sustained winds. The storm is then expected to weaken as it curves to the west-southwest, coming in for a third landfall northeast of Hanoi, Vietnam on Saturday.

If the track forecast proves to be accurate — and track forecasts are generally more accurate than intensity forecasts for tropical weather systems — the Chinese coastal city of Zhanjiang, which is north of Hainan Island, may see strong winds and a damaging storm surge, since it will be located in the storm's more dangerous right front quadrant.

Typhoon Rammasun track forecast as of July 17, 2015.

In this area, winds would be stronger because they blow in the same direction as the storm is moving, giving them added intensity. In addition, the onshore airflow in the right front quadrant of the storm means the storm surge there is far greater than on the southern side of the storm's counterclockwise circulation.

Meanwhile, cleanup efforts are underway in the Philippines, where the death toll from Rammasun, which was known as Glenda there, has risen to 38. Millions are without power in Manila and outlying areas after trees and power lines were torn down by strong winds, but the worst case scenario of major flooding in the low-lying city was not realized in part because the storm weakened slightly and took a slight jog away from Manila at the last minute, sparing the city from even worse impacts.

The storm was one of the strongest ever to directly hit Manila, even in its slightly weakened state.

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Topics: Climate, hurricane, typhoon, typhoon Rammasun, US & World, World