NASA infrared image of Tropical Storm Chanthu shows convection missing on west side

Jul 20, 2010
NASA's AIRS instrument infrared imagery of Chanthu from July 19 at 18:05 UTC showed strong convection (purple) from northeast to southwest. Credit: NASA/JPL, Ed Olsen

The fourth tropical depression of the western Pacific Ocean strengthened into a tropical storm and was named Chanthu today. Infrared imagery from the Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured areas of strong convection from northeast to southwest, but convection isn't showing on the storm's west side.

At 1500 UTC (11 a.m. EDT) on July 20, Tropical Storm Chanthu's were near 46 mph (40 knots). Chantu was located about 240 nautical miles south of Hong Kong, China, near 18.6 North and 114.3 East. It was moving west-northwestward near 8 mph (7 knots), and is forecast to make a landfall south of Hong Kong by 1800 UTC (3 p.m. EDT) tomorrow, July 21 or 3 a.m. local time/Hong Kong on July 22.

The Hong Kong Observatory has posted Standby Signal, No. 1. That means that a tropical cyclone now centred within about (~500 miles) 800 kilometers of Hong Kong.

from NASA's AIRS instrument on July 19 at 18:05 UTC (2:05 p.m. EDT) showed strong (rapidly rising air that forms the thunderstorms that power a tropical cyclone) from northeast to southwest. By July 20, convection had become fragmented, which indicated to forecasters at the Joint Typhoon Warning Center (JTWC) that any further strengthening will be limited.

The JTWC forecast notes that although the eastern side of the storm is showing convection, the western side is lacking it. This morning's JTWC report noted "Convection has been somewhat dampened on the western periphery of the circulation due to an upper level trough (elongated area of low pressure) positioned over the extreme-western South China Sea."

Two factors will play into the strength of Tropical Storm Chanthu over the next two days as it nears landfall: dry air and increased . Both of those factors will help weaken Chantu on its journey to a landfall in China.

Explore further: Quakes destroy or damage 83 houses in Philippines

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Kiribati leader visits Arctic on climate mission

Sep 20, 2014

Fearing that his Pacific island nation could be swallowed by a rising ocean, the president of Kiribati says a visit to the melting Arctic has helped him appreciate the scale of the threat.

NASA catches a weaker Edouard, headed toward Azores

Sep 19, 2014

NASA's Aqua satellite passed over the Atlantic Ocean and captured a picture of Tropical Storm Edouard as it continues to weaken. The National Hurricane Center expects Edouard to affect the western Azores ...

User comments : 0