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Hurricane Season 2011: Tropical Storm Harvey (Atlantic Ocean)
08.22.11
 
AIRS infrared image showing Harvey's remnants dissipating on August 22 at 7:29 UTC (4:29 a.m. EDT).› View larger image
This infrared image from the AIRS instrument on NASA's Aqua satellite shows Tropical Depression Harvey's remnants dissipating on August 22 at 7:29 UTC (4:29 a.m. EDT). Harvey made landfall in Belize and moved over Guatemala. Isolated strong thunderstorms appear in purple, blue indicates weaker thunderstorms with warmer cloud top temperatures.
Credit: NASA/JPL, Ed Olsen
NASA Infrared Eye Sees Warmer Cloud Tops in a Dissipating Tropical Depression Harvey

Cloud top temperatures in the remnants of Tropical Depression Harvey have warmed according to infrared data on NASA's Aqua satellite and that means the storm is weakening over extreme southern Mexico today. Heavy rainfall is still expected in southern Mexico as Harvey continues to weaken.

Cloud top temperatures are observed by infrared instruments that fly aboard satellites. The Atmospheric Infrared Sounder (AIRS) instrument flies onboard NASA's Aqua satellite and takes infrared "pictures" of temperature data around the world. When Aqua flew over Tropical Depression Harvey this morning, August 22, AIRS infrared data showed that cloud top temperatures had warmed in the last 24 hours. Warmer cloud tops mean that the top of the clouds are not as high as they were before (because the air gets colder the higher you go in the troposphere).

By 11 a.m. EDT on August 22, the National Hurricane Center noted that Tropical Depression Harvey had dissipated over the Sierra Madre of Mexico. Harvey's maximum sustained winds were down to 25 mph (45 kmh). It was centered about 105 miles (170 km) southwest of Veracruz, Mexico near 18.1 North and 97.3 West. It was moving to the west near 13 mph (20 kmh) and had a minimum central pressure of 1008 millibars.

Despite Harvey's dissipation as a tropical depression, its remnants are still expected to generate some heavy rainfall, as indicated in the NASA AIRS infrared image. Some of the higher thunderstorms (with the coldest cloud top temperatures) were still capable of dropping heavy rainfall.

NASA AIRS infrared data shows a large area of convection (rapidly rising air that form the thunderstorms that make up a tropical depression), and that convection, although much weaker, contains a lot of low-level moisture. The convection and associated rainfall is expected to move further inland over south-central Mexico over the next day or two, according the National Hurricane Center (NHC). Once it interacts with the mountainous areas, rainfall may be enhanced and become heavier.

The NHC noted that additional rainfall between 2 and 4 inches are possible today in the Mexican states of Veracruz, Oaxaca, Hidalgo, Puebla and Tiaxcala. Some of those stronger thunderstorms could add to those rainfall totals, so isolated amounts of up to 6 inches are possible. That means flash flooding and mudslides in areas of higher terrain are a possibility.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



image of storms Harvey and Irene created from satellite data › View larger image
The GOES-13 satellite saw Tropical Depression Harvey over the Bay of Campeche prepping for landfall No. 2 in Mexico on Sunday, August 21, at 6 p.m. EDT.
Credit: NASA/NOAA GOES Project
GOES-13 Satellite Has a Busy Weekend in Tropics With Harvey and Irene

System 98L exploded into Tropical Storm Irene on Saturday, August 20 at 7 p.m. EDT east of the Leeward Islands. Meanwhile, Tropical Storm Harvey made landfall in Belize.

On Sunday, August 21, a satellite image from the Geostationary Operational Environmental Satellite called GOES-13 showed Tropical Storm Irene's clouds over Puerto Rico. Maximum sustained winds were near 50 mph and Irene is expected to be a hurricane on Monday, August 22, but is forecast to weakening after its center moves over Dominican Republic. Watches and Warnings were posted on Sunday, August 21 and continue through the eastern Caribbean. Current forecasts suggest Irene will again reach hurricane status before making landfall in southern Florida later this week.

On Sunday, August 21 at 8 p.m. EDT, Tropical Depression Harvey was over the Bay of Campeche and was expected to re-strengthen into a tropical storm. It was located 50 miles northeast of Coatzacoalcos, Mexico. A GOES-13 satellite image captured at 6 p.m. EDT pm August 21 showed Harvey's cloud cover as a circular area. Maximum sustained winds were near 30 mph, and Harvey was moving to the west-northwest near 14 mph. Tropical storm warning is in effect for the coast of southern Mexico from Punta El Lagarto To Barra De Nautia. Harvey's rainfall forecast ranges from 2 to 4 inches and isolated amounts to 10 inches. Tropical storm-force winds expected to reach the coast of southern Mexico with the warning area Monday morning.

System 98L exploded into Tropical Storm Irene on Saturday, August 20. This GOES-13 Video shows Tropical Storm Harvey making landfall in Belize (just beneath the Yucatan Peninsula) and moving into the Bay of Campeche Aug. 21, 2011, while Irene moved in from the east toward Puerto Rico (right). (Credit: NASA/NOAA GOES Project)

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



August 19, 2011

GOES-13 captured Tropical Storm Harvey on August 19 at 1731 UTC (1:31 p.m. EDT).› View larger image
GOES-13 captured Tropical Storm Harvey still at the Honduran coastline on August 19 at 1731 UTC (1:31 p.m. EDT). The western edge of Harvey was over the coastlines of Guatemala and Honduras. Higher, stronger thunderstorms around Harvey's center were visible in the image, as they cast shadows on the lower, surrounding thunderstorms.
Credit: NASA/NOAA GOES Project
Belize Under Warning: Tropical Depression 8 Now Tropical Storm Harvey

Tropical Depression 8 strengthened into a tropical storm during the mid-day hours on August 19, and the GOES-13 satellite saw towering thunderstorms within the storm's center. Belize is now under a tropical storm warning as Tropical Storm Harvey is expected to be over the Belize coast by August 20.

The National Hurricane Center revised the track and the strength of this tropical cyclone around mid-day on August 19 after hurricane hunter aircraft flew overhead and collected data. As a result, Tropical Storm Harvey is now expected to take more time over water than previously forecast and that means more time to strengthen over the warm waters of the western Caribbean Sea.

The GOES-13 satellite captured an image of Tropical Storm Harvey's clouds still at the Honduran coastline on August 19 at 1731 UTC (1:31 p.m. EDT). NOAA operates the GOES satellites and NASA created the image that showed the western edge of Harvey was over the coastlines of Guatemala and Honduras. Higher, stronger thunderstorms around Harvey's center were visible in the image, as they cast shadows on the lower, surrounding thunderstorms.

The new forecast track for Harvey takes his center passing near the Bay Islands of Honduras tonight and over the coast of Belize Saturday or Saturday night.

At 2 p.m. EDT on August 19 Harvey's maximum sustained winds increased to 40 mph. Tropical-storm-force winds extend outward up to 40 miles from the center mostly to the north. Now, additional strengthening is forecast before the center of Harvey reaches Belize.

Just three hours before he was a tropical depression with winds near 35 mph. Harvey's center is located about 155 miles east of Isla Roatan, Honduras near 16.3 North and 84.2 West. Harvey is moving west near 10 mph and is expected to travel west to west-northwest in the next couple of days.

A tropical storm warning is in effect for the Bay Islands of Honduras and Belize coast. A tropical storm watch is in effect for the coasts of Honduras, Guatemala, and the southeastern coast of the Yucatan Peninsula from Punta Gruesa southward to Chetumal. Updates on the track and intensity of Harvey can be found at: www.nhc.noaa.gov.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



GOES-13 captured Tropical Depression 8 at the Honduran coastline on August 19 at 1431 UTC (10:31 a.m. EDT).› View larger image
GOES-13 captured Tropical Depression 8 at the Honduran coastline this morning, August 19 at 1431 UTC (10:31 a.m. EDT). The western edge of TD8 was already over the coastlines of Guatemala and Honduras. Higher, stronger thunderstorms around TD8's center were visible in the image, as they cast shadows on the lower, surrounding thunderstorms.
Credit: NASA/NOAA GOES Project
NASA's Aqua satellite passed over Tropical Storm Don at 8:17 UTC (4:17 a.m. EDT) on July 29.› View larger image
NASA's Aqua satellite passed over Tropical Storm Don at 8:17 UTC (4:17 a.m. EDT) on July 29. The infrared image revealed a large area of powerful, high thunderstorms with cold cloud tops (purple) surrounding the center where cloud temperatures were colder than -63 Fahrenheit (-52 Celsius).
Credit: NASA/JPL, Ed Olsen
NASA Satellites See Heavy Rains for Central America from Tropical Depression 8

The eighth tropical depression of the Atlantic Ocean hurricane season formed from the low pressure System 93L on August 19 at 8 a.m. EDT and satellite data from NASA shows strong rainmaking potential as the depression moves out of the Caribbean and inland this weekend.

Infrared satellite data gives forecasters a good idea at the strength and height of thunderstorms, and the rainfall potential that they carry with them. When NASA's Aqua satellite passed over Tropical Depression 8 (TD8) today, August 19 at 6:59 UTC (2:59 a.m. EDT) the Atmospheric Infrared Sounder (AIRS) took the temperature of the cloud tops using infrared technology. AIRS data revealed a large area of powerful, high thunderstorms with cold cloud tops surrounding the center where cloud temperatures were colder than -63 Fahrenheit (-52 Celsius). The higher the thunderstorm cloud-top, the colder it is, and the more powerful they are, and typically, the heavier the rainfall.

The National Hurricane Center (NHC) today noted that TD8 is expected to produce total rainfall accumulations of 3 to 5 inches across Honduras, Guatemala, and Belize. Isolated amounts as high as 8 inches are possible in local areas, and these heavy rains could produce flash flooding and mudslides, especially over higher terrain.

As TD8 continues its western track, a tropical storm warning is in effect for the coast of the Bay Islands of Honduras. A tropical storm watch is in effect for Honduras, Guatemala, the Belize coast from Dangriga Town southward to the Guatemala border, and for the southeastern coast of the Yucatan Peninsula. Because of the depression's close proximity to land the NHC expected little to no strengthening over the next 24 to 36 hours before landfall.

The Geostationary Operational Environmental Satellite called GOES-13 took a visible image of Tropical Depression 8 on August 19 at 1431 UTC (10:31 a.m. EDT). The western edge of TD8 was already over the coastlines of Guatemala and Honduras. Higher, stronger thunderstorms around TD8's center were visible in the image, as they cast shadows on the lower, surrounding thunderstorms.

The image was created at NASA's GOES Project, located at NASA Goddard Space Flight Center in Greenbelt, Md. NOAA manages the GOES-13 satellite and NASA uses its data to create images and animations.

At 11 a.m. EDT TD8's maximum sustained winds were near 35 mph. It was located about 195 miles (310 km) east of Isla Roatan, Honduras and about 315 miles (505 km) east-southeast of Belize City, Belize. That's near 16.1 north and 83.7 west. The depression is moving toward the west near 10 mph (17 kmh) and is expected to continue moving in a general westward direction over the next couple of days. The National Hurricane Center noted that "On the forecast track, the center of TD8 will pass near the Bay Islands of Honduras tonight and move across the coast of Belize Saturday (August 20) or Saturday night." For updates on the storm, go to the NHC forecast page: www.nhc.noaa.gov.

As Tropical Depression 8 moves west through Central America this weekend, residents should be prepared for heavy rainfall, mudslides and flash flooding.

Forecasters are also watching two other low pressure areas in the Atlantic Ocean this weekend as both have a medium chance for development. One is a low about 900 miles east of the Lesser Antilles that is showing organization. The other is a low in the far eastern Atlantic, located between the Cape Verde Islands and Africa with a large area of thunderstorms.

Text Credit: Rob Gutro, NASA Goddard Space Flight Center, Greenbelt, Md.



August 18, 2011

AIRS image of System 93L taken on August 17 at 18:05 UTC (2:05 p.m. EDT).› View larger image
This infrared image of System 93L's cold cloud tops was taken on August 17 at 18:05 UTC (2:05 p.m. EDT). Some of those cloud tops over open ocean were so high that they were as cold as -63 Fahrenheit (-52 Celsius), a threshold in infrared imagery that suggests strong thunderstorms with heavy rainfall.
Credit: NASA/JPL, Ed Olsen
GOES-13 image of System 93L from August 18 at 1331 UTC (8:31 a.m. EDT).› View larger image
This GOES-13 satellite image from August 18 at 1331 UTC (8:31 a.m. EDT) shows System 93L as a small rounded area of clouds in Caribbean Sea, south of Jamaica. The low appears to be almost as large as nearby Hispaniola.
Credit: NASA/NOAA GOES Project
Infrared NASA Data Shows System 93L Finally Tropically Assembling

Infrared satellite imagery from NASA today reveals that a low pressure area in the Atlantic Ocean is coming together after almost a week of struggling. System 93L may become a tropical depression later today or tomorrow.

Several NASA satellites have been monitoring cloud extent, temperatures and heights, rainfall and winds in the low pressure area called System 93L since August 11 when it was located 450 miles southwest of the southernmost Cape Verde Islands, near 11.3 North and 30.3 West. At that time, The Tropical Rainfall Measuring Mission (TRMM) satellite's Microwave Imager and Precipitation Radar showed that the low pressure area, located southwest of the Verde Islands, contained lines of heavy rainfall.

System 93L is associated with a tropical wave and has moved west through the Atlantic since then.

On August 17 at 18:05 UTC (2:05 p.m. EDT) when NASA's Aqua satellite swept over System 93L from its perch in space, the Atmospheric Infrared Sounder (AIRS) instrument took an infrared image of the low pressure area's cloud top temperatures. AIRS data showed that the strongest convection and thunderstorms appeared to be in the northern and eastern sides of the center. Some of those cloud tops over open ocean were so high that they were as cold as -63 Fahrenheit (-52 Celsius), a threshold in infrared imagery that suggests strong thunderstorms with heavy rainfall.

On August 18 in the morning hours (Eastern Daylight Time), satellite imagery shows that System 93L's showers were about 200 miles south-southwest of Jamaica and are becoming better organized. A satellite image from NOAA's Geostationary Operational Environmental Satellite called GOES-13 satellite image this morning, August 18 at 1331 UTC (8:31 a.m. EDT) shows System 93L as a small rounded area of clouds in Caribbean Sea, south of Jamaica. The low appears to be almost as large as nearby Hispaniola.

Falling atmospheric pressure in the region is another indicator that a tropical depression could be forming, and the National Hurricane Center (NHC) gives System 93L an 80% chance of developing later today or tomorrow. If it does strengthen into a tropical storm, it would be dubbed "Harvey."

As System 93L continues to move to the west, the NHC advises interests along the coasts of Honduras, Nicaragua, Belize and Mexico's eastern Yucatan peninsula to keep watch on its movement.

Meanwhile, forecasters are looking far to the east for the next potential low pressure system. A large tropical wave, located about 875 miles west of the Cape Verde Islands in the eastern Atlantic Ocean is generating some shower activity. Over the next couple of days, the NHC expects conditions to improve for development. As of today, however, the system has a 10% chance of developing in the next 48 hours.

Text Credit: Rob Gutro, NASA Goddard Space Flight Center, Greenbelt, Md.