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Hurricane Season 2006: Ileana (Eastern Pacific)
08.24.06
 
Hurricane Ileana Weakening in the Eastern Pacific: No Land Threat

Hurricane Ileana is weakening in the eastern Pacific, according to the National Hurricane Center, in their storm discussion on Friday, Aug. 25.

Two Satellite Views: Top and Sideways

GOES
Click image to enlarge.


These two images are from two different satellites, giving a top-down and sideways view of Hurricane Ileana as she spins in the eastern Pacific on Aug. 23, 2006. The top image is from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite (GOES) to give an idea of how the storm looked from the top. This data was processed by NASA's GOES Project at the Goddard Space Flight Center, Greenbelt, Md. The bottom images are from CloudSat.

Looking at the Storm Like a Cake

The black line that dissects the GOES satellite image (top) shows the part of the storm that the CloudSat satellite looked through in a sideways "slice." If you think of the GOES image as a cake, you're looking at the cake from the top. After you cut the cake in half and look at it sideways, that's just like how CloudSat sees the storm.

In the CloudSat image, you can see that CloudSat looked right over Ileana's open eye, as it appears empty (dark). The red and purple areas indicate large amounts of cloud water. The blue areas along the top of the clouds indicates cloud ice, while the wavy blue lines on the bottom center of the image indicate intense rainfall. Notice that the solid line along the bottom of the panel, which is the ground, disappears in these areas of intense precipitation. It is likely that in the area the precipitation rate exceeds 30mm/hr (1.18 inches/hour) based on previous studies.

Where is Hurricane Ileana and What is Her Future?

The National Hurricane Center (NHC) forecast for Hurricane Ileana as of 5:00 a.m. EDT (9:00 UTC) on Aug. 25, places Ileana's center near 21.3 North and 116.7 West. Ileana's movement is toward the west-northwest at 6 knots (7 mph). Ileana's estimated minimum central pressure is 980 millibars, and maximum sustained winds are 75 knots (86 mph) with gusts to 90 knots (103 mph). The NHC discussion indicated that Ileana is weakening, and using infrared satellite imagery and water vapor images, they see that Ileana's eye has expanded and opened up toward the northeast, a sign of weakening. Image credit: NASA/JPL/The Cooperative Institute for Research in the Atmosphere (CIRA), Colorado State University/NOAA


Hurricane Ileana Weakening in the Eastern Pacific

On Thurs. Aug. 24 at 2:00 a.m. PDT local time (0900 UTC) the National Hurricane Center (NHC) reported Hurricane Ileana was packing maximum sustained winds of 109 mph (95 knots) with gusts to 132 mph (115 knots) in the open eastern Pacific Ocean. At that time, Ileana was located near 19.9 North latitude and 114.2 West longitude. Ileana was moving toward the west-northwest near 9 knots (11 mph), and minimum central pressure was 950 millibars.

What's in Store for Ileana?

The NHC reported in their 2 a.m. discussion on Aug. 24 that Hurricane Ileana had began to weaken. Enhanced infrared satellite imagery (see the "Cloud" image here) shows that the eye has expanded and cloud top temperatures have warmed, indicating weakening. Forecasters don't expect Ileana to re-intensify, as she is moving into cooler waters. By late Sun. Aug. 27, Ileana could weaken to a tropical depression.

At the time the data were taken from which these images were made on Aug. 22 at 1:11 p.m. PDT (20:11 UTC) Ileana was still intensifying. Peak winds were 100 knots and the minimum pressure 960 millibars. Major convection/rain bands can be seen in the northeast quadrant of the storm.

An Inside Satellite Look at Ileana's Clouds

This is an infrared image of Hurricane Ileana in the Eastern Pacific, from the Atmospheric Infrared Sounder on NASA's Aqua satellite on August 22, 2006. This is an infrared image of Hurricane Ileana in the Eastern Pacific, from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite on August 22, 2006. This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud- free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).



Where is Ileana's Heaviest Rainfall?

This image is created from microwave radiation emitted by Earth's atmosphere and received by the instrument. The second image is created from microwave radiation emitted by Earth's atmosphere and received by the instrument. It shows where the heaviest rainfall is taking place (in blue) in the storm. Blue areas outside of the storm where there are either some clouds or no clouds, indicate where the sea surface shines through.









What Does Ileana Look Like to the Eye?

Hurricane Ileana captured by the visible light near infrared sensor on the AIRS instrument. Hurricane Ileana captured by the visible light / near- infrared sensor on the AIRS instrument. This is what Ileana looks like to the naked eye. Image Credit: NASA/JPL -- Caption Credit: NASA/JPL/ Rob Gutro Goddard

















Hurricane Season Kicking Up on Both Coasts

Image of two concurrent tropical storms/hurricanes taken by the GOES satellite.
Click image to enlarge.


Tropical Depression Four formed in the far eastern Atlantic Ocean the evening of Aug. 21, 2006, is headed into the open Atlantic, and is expected to strengthen. There are now two storms in the eastern Pacific Ocean, Hector and now Ileana.

This is an image from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite (GOES) on Tues. Aug. 22. This data was processed by NASA's GOES Project Science Office at the Goddard Space Flight Center, Greenbelt, Md. In this GOES satellite image of the northern hemisphere, Tropical Depression #4 (TD4) can be seen on the far right off the African coast. On the far left, off the southwestern coast of Mexico, is Tropical Storm Ileana.



Ileana and Hector Churn in the Eastern Pacific

Meanwhile in the eastern Pacific Ocean, there are two systems that the National Hurricane Center is watching, although both are not expected to affect land. Tropical Storm Ileana as of 2:00 a.m. PDT (9:00 UTC) on Aug. 22, was located off the south-western Mexican coast near 14.0 North and 105.6 West. Ileana can be seen in this satellite image, churning to the left of Mexico. Ileana's movement is toward the west-northwest at around 12 knots (14 mph). Ileana's maximum sustained winds were 45 knots (52 mph) with gusts to 55 knots (63 mph).

Tropical Storm Hector has been struggling in the last couple of days, but the National Hurricane Center predicts dissipation by Aug. 23 or 24 as Hector enters cooler waters and stable air. At 2:00 a.m. PDT on Aug. 22, Hector was located far west of Ileana in the open ocean, near 22.4 North and 136.5 West. Hector isn't visible on this satellite image, because he's hidden by the curvature of the Earth and far to the left of Ileana. Hector's movement is toward the west-northwest at around 4 knots (5 mph). Hector's maximum sustained winds were 35 knots (40 mph) with gusts to 45 knots (52 mph). Credit: NASA GSFC/NOAA. Caption: Rob Gutro, NASA GSFC.