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

July 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: NASA sees strong thunderstorms in potential tropical cyclone near Hong Kong

Related Stories

Recommended for you

Ice sheets may be more resilient than thought

September 3, 2015

Sea level rise poses one of the biggest threats to human systems in a globally warming world, potentially causing trillions of dollars' worth of damages to flooded cities around the world. As surface temperatures rise, ice ...

Clues from ancient Maya reveal lasting impact on environment

September 3, 2015

Evidence from the tropical lowlands of Central America reveals how Maya activity more than 2,000 years ago not only contributed to the decline of their environment but continues to influence today's environmental conditions, ...

Climate ups odds of 'grey swan' superstorms

August 31, 2015

Climate change will boost the odds up to 14-fold for extremely rare, hard-to-predict tropical cyclones for parts of Australia, the United States and Dubai by 2100, researchers said Monday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.