[SatNews] Hurricane Danielle became the first major hurricane of the 2010 Atlantic hurricane season overnight as it made its way through the central Atlantic — NASA's Tropical Rainfall Measuring Mission satellite, known as TRMM, provided an "eagle eye" view of the rainfall and clouds in powerful Danielle.

Danielle, which had been a Category 2 storm the day before with sustained winds estimated at around 95 knots (~110 mph) by the National Hurricane Center, quickly intensified overnight and by morning was a power Category 4 hurricane on the Saffir-Simpson scale with sustained winds of 115 knots (132 mph). Two images were taken from TRMM at 06:46 UTC (2:46 a.m. EDT) on August 27. The first image showed a top-down view of the horizontal pattern of rain intensity within the storm. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), and those in the outer swath are from the TRMM Microwave Imager (TMI).The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS), and are created at NASA Goddard. TRMM is managed by NASA and the Japanese Space Agency, JAXA.

TRMM revealed that Danielle has a well-formed eye surrounded by sharply curved rainbands — all signs of mature storm with an intense circulation. TRMM also reveals that there are very powerful thunderstorms in Danielle's eye wall dropping extreme amounts of rain, especially in the northwest quadrant, falling as much as 2 inches per hour. TRMM data is also used to create 3D images of tropical cyclones (the generic name for tropical depressions, tropical storms, hurricanes or typhoons). A 3D view of Danielle was created at NASA Goddard using data from the TRMM PR. An area of deep convective towers were prominently visible in Danielle's center in the 3D image from August 27 at 2:46 a.m. EDT. These tall towers are the key to Danielle's intensification. They are associated with the strong thunderstorms responsible for the areas of intense rain. These storms within a storm are releasing vast amounts of heat into the core of Danielle. This heating, known as latent heating, is what is driving the storm's circulation and intensification.

Danielle was still a powerful Category 4 hurricane on the Saffir-Simpson scale on Friday, August 27, at 11 a.m., EDT. She had maximum sustained winds near 135 mph, and was moving northwest near 12 mph. Danielle's center was about 480 miles southeast of Bermuda near 26.9 North and 59.8 West. Her minimum central pressure is 946 millibars. Although Danielle is not expected to be directly affected by the hurricane, Danielle will create large and dangerous surf conditions in Bermuda over the weekend. Those large ocean swells will also begin affecting the U.S. east coast beginning this weekend into next week. Beachgoers along the U.S. eastern seaboard should be aware of dangerous rip currents as a result of Danielle's passage. Danielle is expected to remain a major hurricane until it recurves east of Bermuda and then weaken as it moves northeastward over cooler waters in the central Atlantic. (Text credit: Steve Lang/NASA SSAI and Rob Gutro/NASA's Goddard Space Flight Center, Greenbelt, Md.)