Posted by JAC on 4/17/2009, 4:07 pm, in reply to "Hot Tower firing"

Tropical cyclones can extend hundreds of miles from one side to another, and the human eye can't possibly see an entire storm, but a NASA satellite can. NASA's Tropical Rainfall Measuring Mission (TRMM) not only sees the storm, but the rainfall inside of it, and scientists can visualize storms, including clouds and rainfall in 3-D. That's what NASA scientists have done with Cyclone Bijli located in the Bay of Bengal. The 3-D TRMM Precipitation Radar instrument helped create a 3-D image of Bijli on April 16. It shows a well organized storm with intense thunderstorms reaching above 15 kilometers (9.3 miles) high in the western edge of a partially closed eyewall. Those high clouds known as "hot towers" are indicative of a strengthening storm. Bijli is expected to make landfall as a tropical storm over the weekend. TRMM acts like a "rain gauge in space" and can estimate rainfall in storms. On April 16, TRMM flew over Bijli and captured this image of rainfall happening throughout the storm. The TRMM rainfall analysis shows bands of intense rainfall in the western side of Tropical Cyclone Bijli. The storm's center is located near the yellow, green and red areas, which indicate rainfall between 20 and 40 millimeters (.78 to 1.57 inches) per hour. The red areas are considered moderate rainfall. On Friday, April 17, Cyclone Bijli was raining on northeastern coastal India and Bangladesh, and headed toward a landfall in southern Bangladesh. At 0900 UTC (5 a.m. EDT) on April 17, Bijli's center was about 130 miles south-southwest of Kolkata, India. That's near 20.4 degrees north latitude and 89.0 degrees east longitude. The storm was moving east-northeast near 12 knots (13 mph), and packing sustained winds near 50 knots (57 mph). Bijli is forecast to intensify slowly as it heads east. The Joint Typhoon Warning Center, the organization that forecasts cyclones in that area of the world, forecasts that Bijli will attain 60 knots (69 mph) just before landfall. That means it isn't expected to attain hurricane strength, and will likely make landfall as a strong tropical storm. Landfall is expected near or south of Chittagong, Bangladesh sometime on April 18. The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of Bijli on Apr. 17 at 6:59 UTC (2:59 a.m. EDT). The infrared image shows Bijli's cold clouds in purple and blue. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone. In the area false colored as purple, that's where meteorologists would also find the "hot tower" clouds that the TRMM satellite sees. At the time of this image, Cyclone Bijli's northeastern clouds and rains had already extended into Bangladesh. Bangladesh and Burma (Myanmar) can expect their coasts to be battered with high waves and gusty winds to tropical storm strength from now through Bijli's landfall. Tropical storm-force winds extend out to 65 miles from the center. Bijli is expected to make landfall on April 12 in southern Bangladesh, south of the city of Chittagong. Text credit: Rob Gutro, NASA's Goddard Space Flight Center