NASA Eyes Category 4 Hurricane Felicia and a Stubborn Enrique Felicia is the storm that rules the Eastern Pacific Ocean this week, but Enrique refuses to give up. Felicia is a major hurricane with sustained winds near 140 mph, and Enrique is still hanging onto tropical storm status with 50 mph sustained winds. Both cyclones are close to each other and two NASA satellites captured them together.

On August 6 at 5 a.m. EDT, powerful Felicia is still a category four hurricane on the Saffir-Simpson hurricane scale. She’s far out to sea, about 1,480 miles west-southwest of the southern tip of Baja California near 15.5 north and 131.2 west. She’s moving west- northwest near 10 mph, and is expected to speed up and start to weaken in the next couple of days because of colder waters in her path. Felicia’s minimum central pressure is 937 millibars.

Boys can be stubborn, and Enrique is proving that, even though he’s a tropical storm with a boy’s name. Despite Enrique’s close proximity to Felicia, he’s maintaining sustained winds near 50 mph. At 5 a.m. EDT, Enrique’s center was 345 miles behind Felicia’s, near 20.7 north and 125.9 west. He’s speeding northwest near 17 mph into cooler waters which is going to weaken him over the next day or two. Enrique’s minimum central pressure is 1,000 millibars, much higher than Felicia’s indicating a much weaker storm.

The higher the atmospheric pressure the weaker the tropical cyclone. NASA’s Terra satellite flew over Felicia and Enrique and using the Moderate Imaging Spectroradiometer (MODIS) instrument captured them side-by-side on August 5 at 3 p.m. EDT. The satellite image clearly showed an eye in powerful Hurricane Felicia, while Tropical Storm Enrique’s eye was not clear. Terra wasn’t the only satellite to capture Felicia and Enrique battling it out for territory in the Eastern Pacific Ocean. NASA’s Aqua satellite also flew overhead and its Atmospheric Infrared Sounder (AIRS) instrument captured the frigid cloud temperatures in both storms.

Felicia’s clouds are colder and higher than Enrique’s clouds, because Using AIRS and other infrared imagery to determine cloud temperature, the National Hurricane Center noted in their discussion on August 6, that Felicia’s “eye has been warming and has become more well-defined over the past few hours but at the same time the cold cloud tops around the eye have also been warming.” That’s an indication that Felicia will start waning in strength.

Infrared satellite image showing Hurricane Felicia’s cold clouds and thunderstorms Still from GOES Project movie of Hurricane Felicia’s track through the Eastern Pacific Ocean NASA satellite imagery has helped forecasters see that Hurricane Felicia is running into cooler waters and increasing wind shear, two things have taken her strength down a peg or two. Felicia will continue to weaken further over the weekend as she heads to Hawaii where landfall isn’t expected until late Monday or early Tuesday. By Friday, Aug. 7 at 11 a.m. EDT (5 p.m. Hawaiian Time), Felicia had weakened from a Category four hurricane on the Suffer-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 mill bars. Rising air pressure means a weakening storm, and that’s good news for the big island of Hawaii.

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.