Hurricane Felicia eyeing Hawaii while weakening on weekend

By Friday, Aug. 7 at 11 a.m. EDT (5 p.m. Hawaiian Time), Felicia had weakened from a Category four hurricane on the Saffir-Simpson scale to a Category two hurricane with sustained winds near 100 mph. Additional weakening is expected over the weekend, and forecasters at the National Hurricane Center are forecasting that by Monday, Aug. 10 Felicia will be a tropical storm.

Felicia is moving west-northwest near 13 mph and will turn toward the west over the weekend. Her minimum central pressure continues rising and is currently 973 millibars. Rising air pressure means a weakening storm, and that's good news for the big island of Hawaii.

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This infrared satellite image shows Hurricane Felicia's cold clouds (depicted in purple and blue) and thunderstorms in the eastern Pacific Ocean on Aug 7, 2009. The tight circular shape indicates she's still a powerful hurricane. Credit: NASA JPL, Ed Olsen

Over the weekend as Felicia continues her track toward Hawaii, she's running into cooler waters that will continue sapping her strength. Hurricanes need warm waters of at least 80 degrees Fahrenheit to maintain strength. In addition, vertical wind shear (winds that can weaken and tear a storm apart) will increase from the west.

AIRS captured an infrared image of Hurricane Felicia tracking through the Eastern Pacific Ocean on August 7 at 6:59 a.m. EDT showing a tight circular shape, indicating she's still a powerful hurricane.

AIRS provides visible, infrared and microwave images of tropical storms. Infrared imagery shows the temperature of the cloud tops which gives a hint about the power of the thunderstorms in a tropical cyclone. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone.

NASA also creates imagery from a satellite operated by the National Oceanic and Atmospheric Administration and created a movie of Hurricane Felicia's track through the Eastern Pacific Ocean. Images from Aug. 5 through Aug. 7 from the Geostationary Operational Environmental Satellite (GOES-11) were put together as a movie. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. created the movie that clearly shows Felicia as a powerful Category Four hurricane with a very visible eye.

Interests in the Hawaii should monitor Felicia's progress closely over the weekend.

Source: NASA/Goddard Space Flight Center