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Hurricane Season 2010: Tropical Storm Dianmu (Northwest Pacific Ocean)
08.13.10
 
August 13, 2010

Dianmu's elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm. > View larger image
This NASA infrared image of Dianmu on August 11 at 16:29 UTC (12:29 p.m. EDT) shows her elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm.
Credit: NASA/JPL, Ed Olsen Friday the 13 Unlucky for Dianmu

Friday the 13th has proven unlucky for the once tropical storm Dianmu.

The tropical storm known as Dianmu crossed over northern Japan yesterday and today is just a remnant low pressure area fading in the Northwestern Pacific Ocean today, August 13.

The last position of Dianmu's center was noted from the Japan Meteorological Service on August 12 at 18:45 UTC (2:45 p.m. EDT), when the center of the low was located near 40.1 North and 146.0 East. The low was moving to the east-northeast near 30 knots (34 mph). The remnant low will be "lucky" to make it to the weekend.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center


August 12, 2010

Dianmu's elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm. > View larger image
This NASA infrared image of Dianmu on August 11 at 16:29 UTC (12:29 p.m. EDT) shows her elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm.
Credit: NASA/JPL, Ed Olsen Depression Dianmu Dying Down in Sea of Japan

Once a tropical storm, Dianmu is still traveling in a northeasterly direction through the Sea of Japan, but has diminished to a tropical depression with maximum sustained winds near 34 mph.

Dianmu is being battered by increasing vertical wind shear and cooler sea surface temperatures as it completes a transition into an extra-tropical storm. At 0300 UTC on August 12 (11 p.m. EDT on August 11) the Joint Typhoon Warning Center forecasters in Hawaii issued their final warning on the storm. At that time, Dianmu was located about 285 nautical miles west-southwest of Misawa, Japan, near 38.7 North and 137.1 East.

Sea surface temperatures of at least 80 degrees Fahrenheit are needed to support a tropical cyclone, but warmer temperatures are needed for intensification. The Joint Typhoon Warning Center noted that warmer temperatures are not in Dianmu's area and that temperatures are between 75 and 78F (24-26 Celsius).

Satellite data indicated that most of the deepest convection (and thunderstorm activity) has moved to the eastern quadrant of Dianmu.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center


August 11, 2010

Dianmu's elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm. > View larger image
This NASA infrared image of Dianmu on August 11 at 16:29 UTC (12:29 p.m. EDT) shows her elongated center in the Sea of Japan, with most of the convection (blue, purple) to the eastern part of the storm.
Credit: NASA/JPL, Ed Olsen NASA's Aqua Satellite Sees Dianmu Enter the Sea of Japan

NASA captured infrared imagery of Dianmu entering the Sea of Japan today, August 11. Tropical Storm Dianmu made a quick track over South Korea and has already emerged in the Sea of Japan. She's on track for crossing northern Japan and then moving into the North Western Pacific Ocean.

The Atmospheric Infrared Sounder (AIRS) instrument onboard NASA's Aqua satellite captured an infrared image of Dianmu on August 11 at 4:29 UTC (12:29 a.m. EDT). That showed her center exiting South Korea and entering the Sea of Japan. The strongest areas of convection (rapidly rising air that form the thunderstorms that power the tropical storm) appeared around Dianmu's center. The next AIRS image on 16:29 UTC (12:29 p.m. EDT) showed Dianmu as an elongated system with most of the convection to the eastern part of the storm.

At 1500 UTC (11 a.m. EDT) on August 11, Dianmu had maximum sustained winds near 46 mph (40 knots). It was 500 nautical miles west-southwest of Misawa, Japan, and moving east-northeast near 20 mph. it is generating 15-foot high waves in the Sea of Japan today.

Dianmu is transitioning into an extra-tropical storm as it encounters increasing vertical wind shear and cooler sea surface temperatures. Those are two factors that weaken a tropical cyclone. Dianmu is expected to make landfall over north Honshu, Japan on August 12.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center


August 10, 2010

Dianmu (05W) approaching Korea on August 10 (China is on the left side of the image, and Taiwan is at the bottom left). > View larger image
NASA's Terra satellite captured a visible image of Tropical Storm Dianmu (05W) approaching Korea on August 10 at 2:10 UTC. China is visible on the left side of the image, and Taiwan is visible at the bottom left.
Credit: NASA/MODIS Rapid Response Team NASA Eyes Tropical Storm Dianmu Approaching Korea

NASA's Terra satellite captured an impressive visible image of Tropical Storm Dianmu as it continues to travel through the East China Sea and is headed for a landfall in South Korea.

At 1500 UTC (11 a.m. EDT) on August 10, Dianmu has maximum sustained winds near 5 knots (62 mph) and is about 270 nautical miles south-southwest of Seoul, South Korea. That's near 33.5 North and 126.2 East. Dianmu has tracked north-northeastward at 10 mph and is generating 16 foot high waves.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra satellite captured a visible image of Tropical Storm Dianmu approaching Korea on August 10 at 2:10 UTC (August 9 at 10:10 p.m. EDT). The image clearly showed an eye, and most of the cloud banding was on the eastern and southern side of the storm which correlates with microwave satellite imagery.

Satellite microwave imagery showed a clearly defined center in Dianmu, and there was convective banding in all quadrants wrapping into the center. That indicates a well-formed storm. The strongest convection (rapidly rising air that forms thunderstorms that power the tropical cyclone) is in the eastern part of the storm.

The Joint Typhoon Warning Center forecasts Dianmu to cross over South Korea, then cross northern Japan near the city of Misawa on August 12 before entering into the northwestern Pacific Ocean. Shortly after Dianmu makes landfall in South Korea, it is expected to begin extratropical transitioning and continue to weaken. For updates on Dianmu, go to the Joint Typhoon Warning Center's web site: http://www.usno.navy.mil/JTWC.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center


August 9, 2010

The bulk of Dianmu's thunderstorms (as cold as -63 F) are north, east and south of the center which appears as a small circle. > View larger image
NASA's AIRS Instrument captured this infrared image of Dianmu's cold, strong thunderstorms (purple) on August 9 at 12:35 a.m. EDT. The bulk of high cold thunderstorms (as cold as -63 F) are north, east and south of the center which appears as a small circle.
Credit: NASA/JPL, Ed Olsen NASA AIRS and AMSU Imagery Show Tropical Storm Dianmu Strengthening

NASA's Aqua satellite was flying overhead after Tropical Depression 05W formed east of the island of Ishigakijima, Japan, then strengthened into Tropical Storm Dianmu. Two instruments on Aqua provided an infrared and microwave look at Dianmu and caught signs that the tropical storm was strengthening on its way toward South Korea. The name Dianmu is the name of the goddess of thunder and lightning in Chinese folklore.

Early on August 8, Dianmu formed in the Northwestern Pacific Ocean and by 2100 UTC (5 p.m. EDT) Dianmu had maximum sustained winds near 35 knots (40 mph) and was about 180 miles southwest of Okinawa, Japan.

On August 9 at 04:35 UTC (12:35 a.m. EDT), the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of Tropical Storm Dianmu. The AIRS infrared image showed very cold cloud-top temperatures and showed banding of strong thunderstorms around the north, east and south of the center of circulation. Those cloud tops were so high that they were colder than -63 Fahrenheit. The center of circulation was also clearly visible in the infrared image and appeared as a small circle.

Another instrument on NASA's Aqua satellite that provided data is the Advanced Microwave Scanning Radiometer- EOS (AMSR-E). Over the ocean, AMSR-E microwave frequencies probe through smaller cloud particles to measure the microwave emissions from larger raindrops. AMSR-E provides improved measurements of rainfall rates. The AMSR-E image showed a banding low-level eye that indicates that Dianmu is intensifying.

At 1500 UTC (11 a.m. EDT), Dianmu's maximum sustained winds were near 52 mph (45 knots). It was located about 180 nautical miles northwest of Okinawa, Japan. That's near 29.2 North and 125.3 East. Dianmu is moving north at 17 mph and creating 18-foot high waves. Forecasters at the Joint Typhoon Warning Center in Pearl Harbor, Hawaii forecast Dianmu to continue on a northward track in the Northwestern Pacific Ocean.

A ridge of high pressure sitting east of Japan is causing the storm to track north and it will continue in that direction for the next day. The Joint Typhoon Warning Center expects Dianmu to intensify because upper level winds will diminish.

By Wednesday, August 11, Dianmu will reach South Korea, so residents should make preparations now.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center
 
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