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Hurricane Season 2007: Dean (Atlantic)
08.23.07
 
A NASA Satellite Captured the Life and Death of Hurricane Dean

AIRS Sequence of images showing Hurricane Dean


Hurricane Dean, who slammed into the Yucatan Peninsula as a mighty Category 5 hurricane on the Saffir-Simpson scale and moved into the Gulf of Campeche to make a second landfall in Mexico as a Category 2 hurricane last week, is now a bad memory.

This is a series of infrared images of Hurricane Dean from August 17-23, created by data from the Atmospheric Infrared Sounder on NASA's Aqua satellite. These AIRS images show 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 hurricane. 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). This infrared image shows large areas of strong convection surrounding the core of the storm (in purple).




Tropical Depression Dean's Rains Moving Over Southwestern Mexico

Tropical Depression Dean
Click image for animation.

Tropical Depression Dean was bringing heavy rains over southwestern Mexico as he continued his west-southwestward track on Thursday, August 23.

On August 23 at 9:00 a.m. EDT, the Mexican Weather Service reported Tropical Depression Dean was located at 19.9 degrees north latitude and 103.9 degrees west longitude. That's about 100 kilometers (62 miles) south-southwest of Guadalajara. Dean is moving to the west-southwest near 33 kilometers per hour (20 mph) Dean's maximum sustained winds are estimated around 35 km/hour (22 mph) with gusts to 45 km/hr (28 mph).

This movie showing Dean was created with data from Geostationary Operational Environmental Satellite (GOES-12), which is operated by the National Oceanic and Atmospheric Administration. The movie begins on August 21, 10:45 a.m. EDT (14:45 UTC) when Dean was over the Yucatan Peninsula. It ends on August 23 at 10:45 a.m. EDT (14:45 UTC) when Dean moved into southwestern Mexico (out of range of the satellite view). The movie was created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.

The Mexican Weather Service forecast calls for heavy rainfall from Dean, between 10 to 20 inches, especially in the mountainous areas. Those areas include: Puebla, Hidalgo, and San Luis Potosí. Heavy rainfall between 3 and 6 inches (70 to 150 mm) is also expected in these areas: Tamaulipas, Veracruz, Nuevo Leo'n, Querétaro, Mexico, Federal District, Tlaxcala, Guanajuato, Jalisco, Michoacán, Oaxaca, Morelos, and Guerrero.

Rob Gutro
Goddard Space Flight Center
Animation Credit: NOAA/NASA GOES Project




Dean Moves Over Central Mexico

Tropical Storm Dean

Weaned from its strength-giving source of energy over the Gulf of Mexico's warm waters, Hurricane Dean, now downgraded to a tropical storm, moves into southern and central Mexico in this August 22 image from the Atmospheric Infrared Sounder on NASA's Aqua satellite. The cold cloud tops of the storm are shown in blue and purple. Dean is expected to produce heavy rainfall throughout the region.

Image credit: NASA/JPL

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Hurricane Dean Makes Second and Final Landfall in Mexico

GOES Image of Hurricane Dean


After crashing onto Mexico's Yucatan Peninsula the morning of August 21, the National Hurricane Center reported that Hurricane Dean made landfall for the second time in Mexico near the town of Tecolutla at about 11:30 a.m. CDT (16:30 UTC) on Wednesday, August 22. Tecolutla is just east of Gutierrez Zamora and about 40 miles south-southeast of Tuxpan.

Dean's first landfall was as a powerful Category 5 hurricane with maximum sustained winds of 165 mph. During this landfall near Tecolutla, Dean was packing maximum sustained winds of 100 mph. That made Dean a Category 2 hurricane on the Saffir-Simpson scale.

This image of Hurricane Dean was created with data from Geostationary Operational Environmental Satellite (GOES-12), which is operated by the National Oceanic and Atmospheric Administration. The image was created on August 22 at 1:10 p.m. EDT (17:10 UTC) by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.

At 1:00 p.m. CDT on August 22, Dean sustained winds had already decreased to 85 mph, as he continued to move inland after making landfall just one and one-half hours earlier. At that time, Dean was downgraded to a Category One hurricane. His eye was located near latitude 20.5 degrees north and longitude 97.3 degrees west, near the town of Poza Rica, Mexico. The estimated minimum central pressure is 982 millibars and Dean was moving west at 19 mph.

Dean is expected to produce storm total rainfall of 5 to 10 inches over parts of southern and central Mexico with maximum amounts of up to 20 inches. These rains could cause life-threatening flash floods and mudslides.

Dean is expected to continue weakening until he dissipates over the mountains of central Mexico during the overnight period of August 22 and early morning hours of August 23.

Image credit: NOAA/NASA GOES Project.


A Weakened Dean Heads Into the Gulf of Mexico

Hurricane Dean

After barrelling through Mexico's Yucatan Peninsula, a weakened Hurricane Dean emerges into the Gulf of Mexico in this latest image from the Atmospheric Infrared Sounder on NASA's Aqua satellite. Dean is expected to regain some strength before making landfall again in central Mexico.

Image credit: NASA/JPL

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Texas-Sized Powerful Hurricane Dean Hits Mexico's Yucatan

GOES image of Hurricane Dean


The National Hurricane Center reported that Hurricane Dean made landfall around 4:30 a.m. EDT, Tuesday, August 21, 2007 about 35 miles north of the city of Chetumal in Mexico's Yucatan Peninsula. Although the spot where Dean's eye made landfall is rural, and not very populated, Dean came ashore as a Category 5 hurricane, packing maximum sustained winds of 165 mph.

This image of Hurricane Dean was created with data from Geostationary Operational Environmental Satellite (GOES-12), which is operated by the National Oceanic and Atmospheric Administration. The image was created on August 21 at 9:10 a.m. EDT (13:10 UTC) by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.

At 8:00 a.m. EDT, Dean, a large Category Three hurricane, almost the size of Texas, had maximum sustained winds of 125 mph (205 km/hr) while moving over the Yucatan Peninsula. His eye was located near latitude 18.9 degrees north and longitude 88.7 degrees west or about 40 miles (60 kilometers (km)) northwest of Chetumal, Mexico and about 135 miles (220 km) east-southeast of Campeche, Mexico. The estimated minimum central pressure is 935 millibars.

NASA's CloudSat Satellite Gets a Sideways View of Dean

CloudSat image of Hurricane Dean from August 17
CloudSat image of Hurricane Dean from August 19


Scientists now have the ability to see what a hurricane looks like sideways, thanks to NASA's CloudSat Satellite. CloudSat's Cloud Profiling Radar captured these profiles of Hurricane Dean on August 17 and August 19 as he was heading toward the Yucatan. These images show the how the storm looks horizontally and vertically. The colors indicate the intensity of the reflected radar energy. The top of Dean's clouds are higher than 14 kilometers (almost 9 miles high).

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 this area 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 Dean Headed?

Dean is moving west-northwest near 20 mph (32 km/hr) and is expected to move on a west-northwestward to westward motion today and tonight. On the forecast track, Dean's center will reach the southern Bay of Campeche late this afternoon and still remain a hurricane.

A hurricane watch is in effect for the Gulf coast of Mexico from north of Veracruz to Tampico. A hurricane watch means that hurricane conditions are possible within the watch area, generally within 36 hours. Interests elsewhere in the southern Gulf of Mexico should closely monitor the progress of Dean.

What Conditions are Expected?

The National Hurricane Center noted in its 8:00 a.m. EDT report, "Storm surge flooding and waves will gradually diminish along the east coast of the Yucatan Peninsula today. Within the hurricane warning area in the Bay of Campeche, storm surge flooding of 6 to 8 feet above normal tide levels is possible, along with large and dangerous battering waves."

Dean is expected to produce storm total rainfall of 5 to 10 inches over the Isthmus of Tehuantepec and Yucatan Peninsula of Mexico, Belize, Guatemala, and northern Honduras with maximum amounts of up to 20 inches. These rains could cause life-threatening flash floods and mud slides.




A NASA-view of Dean's Rainfall

TRMM Image of Hurricane Dean from August 18, 2007


This image of Hurricane Dean shows it as a powerful Category 4 hurricane as it was passing through the eastern Caribbean south of Puerto Rico and the Dominican Republic. The image was taken by the Tropical Rainfall Measuring Mission (or TRMM) satellite at 13:45 UTC (9:45 am EDT) on August 18, and shows the horizontal pattern of rain intensity within Dean.

A well-defined eye (small dark center) marks the center of Dean. This is immediately surrounded by a small, tight band of very intense rain to the north and west that is part of the eyewall (innermost dark red arc). The eyewall is surrounded by outer rain bands (wider green and red arcs indicating moderate to heavy rain). The sharp curvature of these rain features means that Dean's circulation is well-developed and very strong. At the time of this image, Dean's maximum sustained winds were estimated at 130 knots (150 mph) by the National Hurricane Center. Dean intensified into a very powerful Category 5 storm in the western Caribbean as it bore down on the Yucatan Peninsula.

TRMM is a joint mission between NASA and the Japanese space agency JAXA. Image credit: NASA/JAXA/SSAI/Steve Lang.




A Mean Dean Takes Aim on Mexico's Yucatan

Quikscat view of Hurricane Dean


Hurricane Dean, expected to become a Category Five storm with maximum sustained winds of at least 135 knots (155 miles per hour), steams through the western Caribbean on its way to a projected landfall in Mexico's Yucatan Peninsula. In this August 20 image from NASA's QuikScat satellite, white arrows showing wind direction are superimposed on color images of wind speed.

Image credit: NASA/JPL

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Extremely Dangerous Hurricane Dean Headed for the Yucatan Peninsula

Hurricane Dean is a Category 4 hurricane, and may strengthen to a Category 5 storm before closing in on the Yucatan Peninsula's east coast tonight, Monday, August 20. Residents and visitors to Mexico's Yucatan Peninsula have been making preparations or leaving early from their vacations to return home.

NASA Satellite Watching Hurricane Dean Speeding Through the Caribbean

AIRS Progression of Images from August 17 to August 20 of Hurricane Dean


This is a series of infrared images of Hurricane Dean from August 17-20, created by data from the Atmospheric Infrared Sounder on NASA's Aqua satellite. These AIRS images show 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 hurricane. 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). This infrared image shows large areas of strong convection surrounding the core of the storm (in purple).

In this first AIRS satellite image from August 17, 1:48 p.m. EDT (17:48 UTC), Dean had just passed over the Lesser Antilles and was moving westward. In the second AIRS image on August 18, at 2:29 p.m. EDT (18:29 UTC) Dean is shown as the purple area on the right side of the image (box), and Dean's clouds, winds and rain are covering Haiti and the Dominican Republic, while Jamaica lies in Dean's path.

The third image, from August 19 at 2:41 a.m. EDT (06:41 UTC) shows Dean due south of Cuba, and his eye was clearly visible. A visible eye is an indication of a strong storm. At this time, Dean was a Category 4 hurricane on the Saffir-Simpson scale. The fourth image is from Monday, August 20, 2007 at 3:23 a.m. EDT (7:23 UTC) showing Dean moving westward and closing in on the Yucatan Peninsula.

Image Credit: NASA/JPL (High Resolution Images: + Aug 17 | + Aug 18 | + Aug 19 | + Aug 20)

Where is Dean on Monday, August 20, 2007?

Dean was located 385 miles east of Belize City and headed west, at 11:00 a.m. EDT (1500 Zulu) near latitude 17.9 north and longitude 82.4 west. Dean was a powerful Category 4 hurricane on the Saffir-Simpson scale, packing maximum sustained winds of 150 mph with higher gusts. Dean has the potential to become Category 5 storm (the strongest category) because of the very warm waters in the Gulf of Mexico. Warm waters power hurricanes.

Dean is moving toward the west near 20 mph and a westward or west-northwestward motion is expected over the next 24 hours. Estimated minimum central pressure is 925 millibars.

Dean is a large hurricane. Hurricane force winds extend outward up to 60 miles (95 km) from the center, and tropical storm force winds extend outward up to 205 miles (335 km).

Where are the Warnings and Watches?

At 11:00 a.m. EDT (1500 UTC) the government of Mexico has issued a hurricane warning for the west coast of the Yucatan Peninsula from south of Progresso southward to Ciudad Del Carmen. The government of Belize has extended the hurricane warning southward from Belize City to the border with Guatemala. A hurricane warning is now in effect for all of Belize. The government of Mexico has issued a tropical storm warning from north of Cancun to Progresso. For up-to-date tropical storm watches and warnings, visit the National Hurricane Center web site at: www.nhc.noaa.gov.

What Can Dean Do to Mexico?

Dean's powerful winds can cause severe damage to structures and trees. The National Hurricane Center notes that storm surge flooding of 9 to 11 feet above normal tide levels is possible near and to the north of where Dean makes landfall along the east coast of the Yucatan Peninsula. Storm total rainfall amounts of 5 to 10 inches can be expected over the Yucatan Peninsula with maximum amounts of up to 20 inches. Rains could cause life-threatening flash floods and mud slides.

The Saffir-Simpson Scale identifies these effects from a Category 4 hurricane: Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally 13-18 feet above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km).

What Happened to Jamaica, Haiti and Martinique?

As the storm swept past Jamaica, Haiti and Martinique this past weekend, it made its mark. In Jamaica, there were power outages, landslides, debris-strewn roadways, and packed storm shelters. Airports were closed there on Saturday. Dean brought strong winds and heavy rainfall to Haiti, and two people were reported killed from storm related events. Agricultural damage has also been reported. In the Dominican Republic a boy was killed after being swept away by huge storm-generated waves and two people were reported dead in Martinique. At the time of this story, reports were still coming in.




Major Hurricane Dean Headed Towards Gulf of Mexico

Satellite image of Hurricane Dean
Click image to enlarge.

On Friday afternoon, August 17, Hurricane Dean became a powerful category three hurricane on the Saffir-Simpson scale with maximum sustained winds of 125 mph. Dean's winds increased throughout the day on Friday, and are expected to strengthen Dean into a category four hurricane over the weekend.

This satellite image from NASA's QuikSCAT satellite was taken on August 17 at 2:55 p.m. EDT and depicts the wind speeds in Hurricane Dean. This image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, are shown in purple.

At 17:45 UTC (1:45 p.m. EDT) on Aug. 17, Dean's center was located near 14.8 north latitude and 63.6 west longitude, and moving west at 22 mph. That's about 175 miles west of Martinique and about 300 miles southeast of San Juan, Puerto Rico.

The maximum sustained winds were 125 mph with higher gusts. The national hurricane center noted that Dean is a major category three hurricane on the Saffir-Simpson hurricane scale, and additional strengthening is forecast during the next 24 hours. Minimum central pressure was 961 millibars at 1:45 p.m. EDT on Friday.

What's in Store?

Late on Friday, August 17, 2007, bands of heavy squalls were still affecting portions of the Lesser Antilles and are approaching Puerto Rico and the U.S. and British Virgin Islands. Tropical Storm warnings remain in effect for these locations as well as many others in the vicinity. Current forecast models take Dean over Jamaica during the morning hours on Sunday, so residents must make preparations immediately.

Storm total amounts of 1 to 2 inches can be expected from Dean over Puerto Rico and the Dominican Republic with maximum amounts up to 5 inches. Additional rainfall accumulations of 1 to 2 inches are expected in the Lesser Antilles with isolated maximum amounts of 10 inches in mountainous areas. These rains could cause life-threatening flash floods and mudslides. Dean is forecast to make his way into the Gulf of Mexico during the morning hours on Monday, August 20. Forecast models place Dean due south of Cuba at that time.

Rob Gutro
Goddard Space Flight Center
Image credit: NASA/JPL





Hurricane Dean Lashing Martinique and Dominica Going to Eastern Caribbean

Satellite image of Hurricane Dean
Click image to enlarge.

At 7:00 a.m., Friday, August 17, 2007 Hurricane Dean was bringing strong winds, heavy rains and surf to Martinique, St. Lucia and the Windward Islands.

Hurricane Warnings and Watches have been posted throughout the region. For up-to-the-minute warnings and watches, visit the National Hurricane Center's web page.

NASA's Aqua satellite captured Dean with the Atmospheric Infrared Sounder (AIRS) instrument. AIRS has three different ways to look at hurricanes and tropical storms. It can see them in infrared light (indicating heat), using microwaves, and visibly, like a photograph. The top image is a visible image from AIRS, showing Dean in the Caribbean on August 16 at 12:59 p.m. EDT (16:59 UTC).

At 7:00 a.m. EDT the center of Hurricane Dean was located near latitude 14.4 north and longitude 61.7 west or 50 miles (80 km) west-southwest of Martinique. Dean is moving toward the west near 23 mph (37 km/hr) and this general motion is expected to continue with some decrease in forward speed during the next 24 hours. This motion should take the center of Dean away from the Lesser Antilles later today.

Maximum sustained winds are near 100 mph (160 km/hr) with higher gusts. Dean is a category two hurricane on the Saffir-Simpson Scale. Stronger winds, especially in gusts are likely over elevated terrain near the path of the center. Some strengthening is forecast during the next 24 hours. Minimum central pressure was 970 millibars.

Satellite image of Hurricane Dean
Click image to enlarge.

The image above shows how the DEAN looks through an AIRS Infrared window channel on August 16 at 12:59 p.m. EDT (16:59 UTC). Window channels measure the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures in dark purple are associated with high, cold cloud tops that make up the top of the hurricane. The infrared signal does not penetrate through clouds, so the purple color indicates the cool cloud tops of the storm. The infrared image doesn't yet indicate an eye at the center of the storm (it would be indicated by a red dot in the middle).

In cloud-free areas, the infrared signal is retrieved at the Earth's surface, revealing warmer temperatures except over open water (which appears colder due to lower emissivity). Cooler areas are pushing to purple and warmer areas are pushing to red. Green generally indicates the presence of clouds.

What is Dean Doing to the Region?

Storm surge flooding of 2 to 4 feet above normal tide levels, along with large and dangerous battering waves are possible near Dean's center. Rainfall totals will range from 2 to 5 inches with up to 10 inches in mountainous areas in Lesser Antilles. Across Puerto Rico, storm total amounts of 1 to 2 inches can be expected, with some areas receiving up to 5 inches, posing the threat for life-threatening flash floods and mudslides.

Satellite image of Hurricane Dean
Click image to enlarge.

In this image created from the AIRS microwave sensor, the large blue swath to the north of the center of Dean (seen as the tight swirl) is a relatively clear area. If there is clear air over land it will show up hot (orange) because of the heat that the land emits (back into space). Green generally indicates the presence of clouds. The blue areas around the eye are indicative of very high, cold cloud tops crowned by ice. These cloud towers are indicative of strong convection and rain - these are strong high altitude thunderstorms in the eye wall.

Over the weekend of August 18-19, interests in the central and western Caribbean including Jamaica and the Cayman Islands should closely monitor the progress of Dean.

The National Hurricane Center forecast brings Dean just south of Cuba early Monday, August 20, and across the Yucatan late Tuesday. Residents along the Gulf of Mexico should closely monitor the progress of Dean over the weekend of August 18-19. You can find updates at www.nhc.noaa.gov.

Rob Gutro (additional text from NHC reports)
Goddard Space Flight Center
Image credits: NASA





Dean Gathers Steam in Central Atlantic

Tropical Storm Dean


Tropical Storm Dean continues to intensify in the central Atlantic about 1,450 kilometers (900 miles) east of the Lesser Antilles. In this August 15 infrared image from the Atmospheric Infrared Sounder on NASA's Aqua satellite, high, cold cloud tops at the top of the storm are shown in purple, while warmer, cloud-free areas are shown in orange/red.

Image credit: NASA/JPL

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Tropical Storm Dean, Strengthening and Eyeing the Lesser Antilles

TRMM Image of Tropical Storm Dean


Tropical Storm Dean is causing people in the string of islands in the Atlantic Ocean known as the Lesser Antilles to prepare for his arrival. At 10:00 a.m. EDT, on August 15, Tropical Storm Dean is strengthening over the central Atlantic Ocean and could become a hurricane by Thursday, August 16.

Dean is moving quickly westward, and heading to the Lesser Antilles. His center was located near latitude 12.4 north and longitude 46.0 west, or about 1045 miles east of the Lesser Antilles. Dean has picked up forward steam and was moving west near 20 mph and is forecast to continue moving at this speed over the next day. Dean's maximum sustained winds are near 60 mph, with higher gusts. The National Hurricane Center has forecast some strengthening over the next 24 hours as Dean gets closer to the islands. The minimum central pressure is 997 millibars.

The image above was made from the Tropical Rainfall Measuring Mission (TRMM) satellite data received on August 15, 2007 at 9:20 a.m. EDT (1320 UTC) and shows the horizontal pattern of rain intensity within Dean.

Although Dean is still a relatively small storm, it appears to be fairly well-organized. TRMM detected an eye in the rain field (the white center in the middle of the upper-right-most rain area). There is also good curvature evident in the rain bands surrounding the center (green arcs indicating moderate intensity rain), which is a further indication that Dean already has a well-formed circulation. At the time of this image, Dean was still a tropical storm with sustained winds estimated at 50 knots (58 mph) by the National Hurricane Center.

Looking at the conditions in the next couple of days NHC forecasters say that Dean should encounter warmer sea surface temperatures along the forecast track and the wind shear (winds that can weaken a storm) is forecast to be light during the forecast period. So computer guidance calls for steady strengthening. Further, the NHC forecasts that Dean is likely to head toward the Gulf of Mexico early next week.

For more information about how TRMM looks at rainfall, visit NASA's TRMM website at: http://trmm.gsfc.nasa.gov/. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Image credit: NASA/JAXA/Hal Pierce/SSAI




Tropical Storm Dean Forms in the Atlantic

GOES image of Tropical Storm Dean


Tropical Storm Dean was "born" today, August 14th, midway between Africa and the Lesser Antilles, in the deep tropics of the Atlantic Ocean.

As of yesterday, Dean was the fourth tropical depression in the Atlantic Ocean this season, and this morning, strengthened into a tropical storm.

According to the National Hurricane Center, at 11:00 am EDT (1500z), on Tuesday, August 14, 2007, the center of Tropical Storm Dean (formerly Tropical Depression Four) was located near latitude 11.7 north and longitude 39.4 west. That's about 1030 miles (1660 km) west of the southernmost Cape Verde Islands and about 1490 miles (2400 km) east of the lesser Antilles.

Currently, maximum sustained winds are near 35 knots (40 mph) with higher gusts. Dean is moving toward the west near 20 knots (23 mph) and this general motion is expected to continue during the next 24 hours. Estimated minimum central pressure is 1004 millibars.

This satellite image Tropical Storm Dean was created with images from Geostationary Operational Environmental Satellite, (GOES-12), which is operated by the National Oceanic and Atmospheric Administration. The image was created on August 14 at 11:32 a.m. EDT by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. Dean is visible in the bottom right-hand corner of the image.

Dean to Strengthen

Over the next 2 days, strengthening is forecast for Dean. Some computer models suggest that Dean could be near the Lesser Antilles in the next five days as a hurricane with sustained winds to 110 knots (126 mph), which would be a strong Category 3 hurricane on the Saffir-Simpson scale. Meanwhile, over the next 2-3 days, Dean is expected to continue to track westward, and he'll likely slow in movement. Interests in the Lesser Antilles should take precautions and prepare if Dean should track as expected.

Image credit: NASA GOES Project/NOAA




Fourth Atlantic Tropical Depression Forms

Cloudsat Image of TD Four


The fourth tropical depression in the Atlantic Ocean has formed 2000 miles east of the Lesser Antilles.

According to the National Hurricane Center, at 11:00 am EDT (1500z), on Monday, August 13, 2007, the center of tropical depression four was located near latitude 12.0 north and longitude 31.6 west. That's about 520 miles (840 km) west-southwest of the southernmost Cape Verde Islands and about 2000 miles (3220 km) east of the lesser Antilles.

Currently, maximum sustained winds are near 35 mph (55 km/hour) with higher gusts, and forecasters expect some strengthening in the next day. If the depression strengthens into a tropical storm, it would be named Dean.

The depression is moving toward the west near 21 mph and this general motion is expected to continue during the next 24 hours. Estimated minimum central pressure is 1005 millibars.

NASA's CloudSat satellite has proven useful in hurricane research. CloudSat's Cloud Profiling Radar captured a profile across Tropical Depression Four on at 3:23 UTC, Monday August 13th (11:23 p.m. EDT Sunday, August 12). The top image shows an infrared view of the depression from the Moderate Resolution Imaging Spectroradiometer instrument on NASA's Aqua satellite, with CloudSat's ground track shown as a red line. The bottom image is the vertical cross section of radar reflectivity along this path. The colors indicate the intensity of the reflected radar energy. The top of Tropical Depression Four's clouds reach up to 14 kilometers, or approximately 8.7 miles high.

Forecast tracks currently take the storm over the Lesser Antilles and southeast of Puerto Rico early Saturday morning, August 18 and strengthen it to hurricane status.

Image credit: NASA/JPL/Colorado State University/Naval Research Laboratory-Monterey. Story Summary: Rob Gutro (via NHC reports), NASA Goddard Space Flight Center.

 
 
Rob Gutro
NASA Goddard Space Flight Center

(From NHC Reports)