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Hurricane Season 2009: Tropical Storm Lana (Eastern Pacific)
08.04.09
 
August 4, 2009

Lana Dissipates in the Central Pacific

On Tuesday, August 4, 2009, Tropical Depression Lana had already dissipated into a remnant low pressure area in the Central Pacific Ocean. The Central Pacific Hurricane Center was no longer issuing advisories on the system, so Lana has folded into the pages of hurricane history.



August 3, 2009

NASA's CloudSat Captures a Sideways Look a Fading Lana

This sideways image of Tropical Storm Lana came from NASA's CloudSat satellite on Aug. 2. > View larger image
This sideways image of Tropical Storm Lana came from NASA's CloudSat satellite on Aug. 2 when its high clouds were almost 9 miles high and colder than -76F!
Credit: NASA/JPL/Colo. State Univ/NRL-Monterey
NASA satellites do some really cool things, like take a sideways look at a slice of a tropical depression. That's what CloudSat did with Lana in the Central Pacific.

As Lana passed south of the Hawaiian Islands this past weekend, its maximum sustained winds peaked around 65 knots (74 mph), making it a Category One hurricane for a brief period before it ran into adverse atmospheric conditions that weakened the storm quickly.

By Monday, August 3, 2009 at 5 a.m. EDT, Lana's sustained winds were down to 30 knots and her minimum central pressure had gone up to 1010 millibars. Weakening winds and rising air pressure are signs of a weakening storm. Lana was located near 14.5 degrees north latitude and 162.0 west longitude and headed west near 13 knots (15 mph).

When NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Lana the day before, Sunday, August 2, it was still a tropical storm with high clouds higher than 14 kilometers (8.7 miles) high. CloudSat measured the highest, coldest cloud temperatures near minus 60 degrees Celsius (minus 76 degrees Fahrenheit)! Those high clouds indicated that there were some strong thunderstorms still occurring on Sunday, August 2. At the time when CloudSat swept over Lana, its maximum sustained winds were near 45 knots (52 mph) and pressure was 1008 millibars.

Less than 24 hours later, satellite data showed that Lana lacked "deep convection" – that is, rapid rising air that helps to build the powerful thunderstorms that fuel the tropical storm. Thus, Lana was re-classified as a weaker tropical depression. Forecasters believe that by August 4, Lana will start dissipating, and by August 5, she'll be a remnant low pressure area in the Central Pacific.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



July 31, 2009

Two Satellites Take In TD#6-E's Transformation into Tropical Storm Lana

A combined satellite image of Tropical Storm Lana from the GOES-11 satellite and QuikScat. > View larger image
This is a combined satellite image of Tropical Storm Lana from the GOES-11 satellite and QuikScat. It shows Lana's wind speeds in different colors and wind direction are indicated by small barbs. White barbs point to areas of heavy rain. The highest wind speeds, are shown in red indicate winds over 50 knots (57 mph)
Credit: NASA/NRL/JTWC
The sixth tropical depression in the eastern Pacific strengthened into Tropical Storm Lana this morning, and is expected to reach hurricane strength by the weekend. Lana will pass far to the south of the Hawaiian Islands over the weekend.

NASA satellites provide a great deal of information to forecasters, and seeing how the clouds organize in a storm or the ability to peer through them and actually clock how fast the winds are spinning, help forecasters to know if a storm is strengthening or weakening. That's exactly what the GOES-11 satellite and NASA's QuikScat satellite have done this morning with the latest image created by the U.S. Navy's Joint Typhoon Warning Center (JTWC).

GOES-11, the Geostationary Operational Environmental Satellite provided infrared imagery of Lana's cloud cover at night. It showed that the storm has become well-organized. QuikScat uses microwave technology to measure winds in a storm, like x-ray vision.

The JTWC combined both the GOES-11 and QuikScat images from the early morning hours of July 31 to get a comprehensive look at Lana. The image revealed that Lana's winds were up to 50 knots (57 mph) and pressure was 997 millibars.

At 5 a.m. EDT, July 31, Lana's maximum sustained winds were near 60 mph, and she's forecast to strengthen over the next 24 hours. Lana was located near 13.3 north and longitude 144.6 west, about 825 miles east-southeast of Hilo, Hawaii. Lana's minimum central pressure was 997 millibars and she was moving west-northwest near 20 mph. Lana is generating 16 foot high waves at sea.

Wind shear will play into Lana's life over the weekend. Currently, Lana is in a good environment to keep growing as the wind shear is weak. Wind shear is winds blowing at different levels of that atmosphere that can tear a storm apart. Lana is forecast to move closer to an area that has stronger upper-level southerly and southwesterly winds that will inhibit her growth and start to weaken the storm quickly.

GOES-11 is operated by the National Oceanic and Atmospheric Administration, and images are created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. QuikScat is managed out of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



July 30, 2009

Sixth Tropical Depression Forms in Eastern Pacific

TD#6-E's clouds organizing, and sustained winds near 30 knots (34 mph). > View larger image
This combined GOES-11/ASCAT image shows TD#6-E's clouds organizing, and sustained winds near 30 knots (34 mph). The image was created at 2:17 a.m. EDT
Credit: JTWC/NRL
The sixth tropical depression formed in the Eastern Pacific late in the morning hours on July 30, Eastern Daylight Time. The depression, "TD#6-E" containing showers and thunderstorms associated with a tropical wave, organized before it crossed into the Central Pacific Ocean today.

The U.S. Navy's Joint Typhoon Warning Center created a composite satellite image that combines infrared imagery of TD#6-E's clouds from the Geostationary Operational Environmental satellite, GOES-11 with wind data from the European Space Agency's "ASCAT" scatterometer. ASCAT is an advanced scatterometer instrument aboard the European Space Agency's MetOps satellite, and is similar to NASA's QuikScat instrument. Its primary function is to provide measurements of wind velocity over the world's oceans using radar. The image shows the cloud cover of the tropical depression organizing, and the sustained winds near the center of circulation near 30 knots (34 mph). The image was created at 2:17 a.m. EDT.

At 11 a.m. EDT on July 30, TD#6-E's center was located near 12.0 north latitude and 139.7 west longitude, about 1,155 miles east-southeast of Hilo, Hawaii. It has sustained winds near 35 mph, and is expected to strengthen into a tropical storm later today or tomorrow. Its moving westward near 18 mph and will continue in that direction. Estimated minimum central pressure is 1008 millibars.

GOES-11 is operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project that creates GOES imagery is located at NASA's Goddard Space Flight Center, Greenbelt, Md.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



Chances Upped for a Developing Depression

A large swirl of clouds taking on the shape of a tropical depression. > View larger image
A GOES-11 image from July 30, shows a large swirl of clouds taking on the shape of a tropical depression (lower right) and Hawaii far to its northwest (upper right).
Credit: NASA GOES Project
The one remaining area of showers and thunderstorms in the eastern Pacific now has a better chance of becoming a tropical depression as it moves toward the Central Pacific Ocean. The "Central Pacific Ocean" begins around 140 degrees west longitude, and continues west to the International Dateline.

The clouds, showers and thunderstorms that are associated with a tropical wave near 1,200 miles east-southeast of the Hawaiian Islands are getting their act together. That is, the upper-level winds are enabling them to organize around an area of low pressure. That means a tropical depression may be forming!

The National Hurricane Center said on July 30 that there is now "a medium chance…30 to 50 percent…of this system becoming a tropical cyclone during the next 48 hours." The area of disturbed weather is moving west about 15 mph. As it continues west, it will move into the Central Pacific Ocean. Once in that region, the National Hurricane Center turns over the monitoring of the system to the Central Pacific Hurricane Center (CPHC), located in Honolulu, Hawaii. Forecasters at the CPHC already have their eyes on this system and are tracking it on an hourly basis. For information about the CPHC, visit: http://www.prh.noaa.gov/hnl/cphc/ .

The GOES-11 or Geostationary Operational Environmental (GOES) satellite captured the clouds associated with the disturbance on Thursday, July 30. The image shows a large swirl of clouds taking on the shape of a tropical depression, and Hawaii far to its northwest.

GOES is operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the satellite images from the GOES satellites.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



July 29, 2009

And Then There Was One…Possibility in the Eastern Pacific

The large cluster of clouds has a > View larger image
GOES-11 captured the area of thunderstorms on July 29 at 11:00 a.m. EDT. The large cluster of clouds in the lower left side of the GOES satellite image is the area that has a "less than 30 percent chance" of development.
Credit: NASA GOES Project
On Tuesday, July 28, there were two areas of showers and thunderstorms being watched for potential development in the eastern Pacific Ocean. A day later, on July 29, the only area that has a slim chance of development now lies 1,500 miles east south-east of the Hawaiian Islands.

The area that lost its chance for development was located several hundred miles from Manzanillo, Mexico on July 28, and wind shear has wiped that chance away.

The Geostationary Operational Environmental (GOES) satellite, GOES-11 captured an image of the thunderstorms and clouds associated with the area of clouds and showers further out to sea, that has a chance of development. GOES-11 passed over the area on Thursday, July 29 at 11 a.m .EDT. The disturbance is part of a tropical wave moving westward between 10 and 15 mph. The National Hurricane Center gives the area "less than a 30 percent chance" of developing into something tropical.

GOES is operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the satellite images from the GOES satellites.

Elsewhere in the eastern Pacific tropical cyclone formation isn't expected for another two days.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



July 28, 2009

GOES-11 Eyeing Two E. Pacific Areas for Tropical Development

> View larger image
GOES-11 captured two low pressure areas on July 28 at 11:00 a.m. EDT (1500 UTC). The satellite image is marked "Area 1" for the showers associated with the tropical wave near mainland Mexico, and "Area 2" for the other area over 1,000 miles farther west.
Credit: NASA GOES Project
Two areas of thunderstorms in the eastern Pacific developed today, July 28, 2009 and both have less than a 30 percent chance of developing into a tropical depression.

The Geostationary Operational Environmental (GOES) satellite, GOES-11 captured a satellite snapshot of the two areas of thunderstorms on Tuesday, July 28 at 11 a.m. EDT. The satellite image shows the two clusters of showers and thunderstorms in the eastern Pacific. The first area is near mainland Mexico and the other far to the west in the open waters.

The first area of showers and thunderstorms that the National Hurricane Center is keeping an eye on is closest to land, although still several hundred miles south-southwest of Manzanillo, Mexico. Those showers are associated with a tropical wave. Currently there are no signs of organization, and if it happens it is expected to be slow to develop. That tropical wave is moving west to west-northwest near 10-15 mph.

The second cluster of showers and thunderstorms that have a low chance of development are much farther from land. In fact, they're located about 1,400 miles southwest of the southern tip of Baja California. That cluster of storms is also poorly organized, and it continues moving westward near 10-15 mph.

Tropical waves are elongated areas of low pressure, also called a "trough." They consist of clouds and thunderstorms and stretch from north to south and move west across the eastern Pacific Ocean. They can lead to the formation of tropical cyclones in the northeast Pacific basin.

GOES is operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the satellite images from the GOES satellites.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center