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Hurricane Season 2012: Tropical Storm Kirogi (Northwestern Pacific Ocean)
08.09.12
 
AIRS image of Tropical Storm Kirogi› Larger image
NASA's Aqua satellite passed over Tropical Storm Kirogi on August 9 at 0241 UTC. The AIRS instrument captured an infrared image of the cloud temperatures that showed a concentrated area of strongest storms (purple) and heaviest rainfall around west of the center of circulation. AIRS shows cool waters in the direction Kirogi is heading, which will sap the storm's strength. Credit: NASA JPL, Ed Olsen
NASA Sees Tropical Storm Kirogi Headed For Cooler Waters

Sea surface temperatures cooler than 80 degrees Fahrenheit can sap the strength from a tropical cyclone and Tropical Storm Kirogi is headed toward waters below that threshold on its track through the northwestern Pacific Ocean, according to data from NASA's Aqua satellite.

NASA's Aqua satellite passed over Tropical Storm Kirogi on August 9 at 0241 UTC. The Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of the cloud temperatures that showed a concentrated area of strongest storms and heaviest rainfall west of the center of circulation. Vertical wind shear is currently at 10-15 knots, which is helping to prevent the storm from intensifying. The center of circulation also appears elongated from northwest to southeast in satellite imagery, which is a sign the storm is weakening. Whenever a tropical storm's center cannot "stack up" in the atmosphere, it begins to weaken.

On August 9, 2012 at 11 a.m. EDT (1500 UTC), Tropical Storm Kirogi had maximum sustained winds near 35 knots (40 mph/64.8 kmh). It was located about 550 nautical miles (633 miles/1,019 km) east-southeast of Misawa, Japan, near 38.5 North and 151.9 East. Kirogi was moving to the northwest at 20 knots (23 mph/37 kmh).

AIRS data indicates that the sea surface temperatures in the direction that Kirogi is moving are too cool to maintain a tropical cyclone. Kirogi is forecast to track over sea surface temperatures cooler than 25 Celsius once it nears 38 degrees north later on August 9, which will weaken the storm. The forecasters at the Joint Typhoon Warning Center note that the cooler waters will also help transform Kirogi's warm core to a cold core, making the storm into an extra-tropical one as it heads toward the two southernmost Kuril Islands.

Text Credit: Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, Md.



Aug. 8, 2012

MODIS image of Kirogi› Larger image
This visible image of Tropical Storm Kirogi was captured from NASA's Aqua satellite on August 8, 2012 at 0202 UTC (10:02 p.m. EDT/Aug.7). The strongest storms appear west and east of the center, which appears to have an eye. Credit: NRL/NASA.
NASA Sees Powerful Bands of Thunderstorms Surrounding Tropical Storm Kirogi

Tropical Storm 13W has been renamed Tropical Storm Kirogi as it continues to spin in the western North Pacific Ocean. NASA's Aqua satellite passed over the tropical storm and noticed bands of thunderstorms on the western and eastern sides of the center.

A visible image of Tropical Storm Kirogi was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies onboard NASA's Aqua satellite. In an image captured on August 8, 2012 at 0202 UTC (10:02 p.m. EDT/Aug.7) the strongest storms appear west and east of the center, which appears to have an eye. Since then the strongest storms appeared to be over the southern edge of the center. Satellite data also shows that the low-level center of circulation appears to be elongating as a result of wind shear. Elongation of a tropical cyclone's center is a sign of weakening.

At 11 a.m. EDT (1500 UTC) on August 8, 2012, Tropical Storm Kirogi's maximum sustained winds were near 35 knots (40 mph/62 kmh). It was located about 885 nautical miles east-southeast of Misawa, Japan near 33.1 North latitude and 156.7 East longitude. It was moving to the northwest near 13 knots (15 mph/24 kmh).

Kirogi is expected to continue tracking to the northwest over the next several days and the forecasters at the Joint Typhoon Warning Center.

Text Credit: Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, Md.



Aug. 7, 2012

On August 7, AIRS instrument captured an infrared image of 13W and showed very limited strong storms › View larger image
NASA's Aqua satellite passed over Tropical Storm 13W on August 7 at 0253 UTC. The AIRS instrument captured an infrared image of the cloud temperatures that showed very limited strong storms (purple) and most of the precipitation was to the east of the center of circulation.
Credit: NASA JPL, Ed Olsen
Infrared NASA Imagery Shows a Weaker Tropical Storm 13W

Infrared satellite imagery from shows how cold cloud top temperatures are in a tropical cyclone, and recent imagery from NASA's Aqua satellite shows the cloud-top temperatures have been warming in Tropical Storm 13W. Warming cloud top temperatures indicate less strength, and Tropical Storm 13W is weakening.

NASA's Aqua satellite passed over Tropical Storm 13W on August 7 at 0253 UTC. The Atmospheric Infrared Sounder (AIRS) instrument that flies onboard Aqua captured an infrared image of the storm's cloud temperatures that showed very limited strong thunderstorms make up the tropical cyclone and most of the precipitation was to the east of the center of circulation. The AIRS imagery also shows that the bands of thunderstorms around the center are fragmented.

On August 7 at 1500 UTC (11 a.m. EDT), Tropical Storm 13W's (TS13W) maximum sustained winds were near 35 knots (40.2 mph/64.8 kmh). TS13W was located 745 nautical miles (857 miles/1,380 km) north-northwest of Wake Island, near 30.2 North and 160.5 East. It was moving to the northwest near 9 knots (10.3 mph/16.6 kmh).

The Joint Typhoon Warning Center forecasters noted that Tropical Storm 13W "Continues to maintain a warm core and will likely dissipate before transitioning to a subtropical or extra-tropical system."

Text Credit: Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, Md.



Aug. 6, 2012

AIRS showed the strongest storms (purple) and heaviest rainfall north and east of the center of 13W's circulation. › View larger image
NASA's Aqua satellite passed over Tropical Storm 13W on August 6 at 0205 UTC (Aug. 5 10:05 a.m. EDT). The AIRS instrument captured an infrared image of the cloud temperatures that showed the strongest storms (purple) and heaviest rainfall north and east of the center of circulation.
Credit: NASA/JPL, Ed Olsen
NASA's Aqua Satellite Shows Strongest Side of Tropical Storm 13W

When NASA's Aqua satellite captured an infrared view of the northwestern Pacific's latest tropical storm, Tropical Storm 13W, the data revealed the bulk of the heavy rainfall on the northern side of the center.

NASA's Aqua satellite passed over Tropical Storm 13W on August 6 at 0205 UTC (Aug. 5 10:05 a.m. EDT). The Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of the cloud temperatures that showed the strongest storms (purple) and heaviest rainfall north and east of the center of circulation.

Infrared imagery shows temperature and the higher the cloud tops, the colder they are as they reach higher in the troposphere (lowest atmospheric layer). When cloud top temperatures are very cold, it's an indication of strong uplift in the atmosphere. The cloud top temperatures north and east of Tropical Storm 13W's center of this low were near -63 Fahrenheit (-52 Celsius), and indicated powerful uplift and high cloud tops.

At 1500 UTC (11 a.m. EDT) on August 6, Tropical Storm 13W had maximum sustained winds near 45 knots (51.7 mph/83.3 kmh). It was located about 550 nautical miles (632 miles/1019 km) north-northwest of Wake Island near 28.2 North and 162.5 East. It was moving to the north-northwest at 13 knots (15 mph/24 kmh).

Forecasters at the Joint Typhoon Warning Center expect that the tropical storm should maintain intensity while staying at sea over the next several days. Vertical wind shear is expected to decrease and sea surface temperatures are near 26.6 Celsius (80 Fahrenheit), which is needed to maintain a tropical cyclone. The tropical storm is expected to track to the north-northwest and move into drier air, which will prevent further intensification.

Text Credit: Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, Md.