Hurricane Season 2011: NASA Sees Heavy Rain in Hurricane Irene

Before Irene even reached hurricane status, a NASA satellite saw heavy rainfall and hot towering thunderstorm clouds around the storm's center this weekend. That heavy rainfall is expected as Irene continues to track through the Caribbean today. The Tropical Rainfall Measuring Mission (TRMM) satellite passed over Irene when it was a tropical storm on August 21, 2011 at 0024 UTC (8:24 p.m. EDT August 20). Data collected with this orbit showed that Irene contained numerous powerful thunderstorms with TRMM's Precipitation Radar revealing that some thunderstorm towers near the center of the storm were reaching to heights above 15 km (~9.3 miles).

Those "hot towers" are called "hot" because they rise to such altitude due to the large amount of latent heat. Water vapor releases this latent heat as it condenses into liquid. Back in 2004, researchers Owen Kelley and John Stout of NASA's Goddard Space Flight Center, Greenbelt, Md., found that a tropical cyclone with a hot tower in its eyewall was twice as likely to intensify within the next six hours than a cyclone that lacked a tower. Irene had those hot towers and did intensify into a hurricane.

The National Hurricane Center noted on August 22 that Irene is expected to produce total rainfall accumulations of 5 to 10 inches across Puerto Rico, The Virgin Islands, the Dominican Republic, Haiti, the Southeastern Bahamas and The Turks and Caicos Islands. Isolated maximum amounts of rainfall may reach up to 20 inches.

NASA To Fly Into Hurricane Research This Summer

Three NASA aircraft will begin flights to study tropical cyclones on Aug. 15 during the agency's first major U.S.-based hurricane field campaign since 2001. The Genesis and Rapid Intensification Processes mission, or GRIP, will study the creation and rapid intensification of hurricanes. One of the major challenges in tropical cyclone forecasting is knowing when a tropical cyclone is going to form. Scientists will use the data from this six-week field mission to better understand how tropical storms form and develop into major hurricanes.

Mission scientists will also be looking at how storms strengthen, weaken and die. "This is really going to be a game-changing hurricane experiment," said Ramesh Kakar, GRIP program scientist at NASA Headquarters in Washington. "For the first time, scientists will be able to study these storms and the conditions that produce them for up to 20 hours straight. GRIP will provide a sustained, continuous look at hurricane behavior at critical times during their formation and evolution."

GRIP is being led by Kakar and three project scientists: Scott Braun and Gerry Heymsfield of NASA's Goddard Space Flight Center in Greenbelt, Md., and Edward Zipser of the University of Utah in Salt Lake City. Three NASA satellites will play a key role in supplying data about tropical cyclones during the field mission. The Tropical Rainfall Measuring Mission, or TRMM, managed by both NASA and the Japan Aerospace Exploration Agency, will provide rainfall estimates and help pinpoint the locations of "hot towers" or powerhouse thunderstorms in tropical cyclones.