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Hurricane Season 2007: Dora (Western Pacific)
01.30.07
 
Dora Fading Away, Forecasters Focus on New Storm

Although Tropical Cyclone Dora still has a defined center of circulation, most of the deep, thick clouds and intense thunderstorms have dissipated. The weakening trend is expected to continue and Dora will likely transition into an extratropical system by late Fri., Feb. 9. As her remnants travel south-southwest over the weekend, strong wind shear (changing wind speed and direction with height) should prevent any redevelopment.

At 4:00 a.m. EST (0900 UTC) on Fri., Feb. 9, Dora was located near 26.3 degrees south latitude and 62.2 degrees east longitude, or about 475 miles southeast of Le Reunion, and was moving toward the south at 6 knots (7 mph). Maximum sustained winds were near 30 knots (35 mph), with gusts to 40 knots (46 mph). Wave heights close to the center of the storm were roughly 12 feet.

While Dora is fading away, forecasters are closely watching the development of another tropical cyclone, also in the Indian Ocean. Tropical Cyclone 13S is expected to slowly strengthen over the next two days and recent satellite imagery indicates that deep thunderstorms are beginning to form near the circulation center. By Sun., Feb. 11, the budding cyclone may be absorbed by the remnants of Tropical Cyclone Dora, especially if it makes an expected turn to the south.

At 4:00 a.m. EST (0900 UTC) on Fri., Feb. 9, Tropical Cyclone 13S was located near 15.1 degrees south latitude and 54.1 degrees east longitude, or about 375 miles north-northwest of La Reunion. It was moving east-northeast at 9 knots (10 mph). Maximum sustained winds were near 35 knots (40 mph), with gusts to 45 knots (52 mph).

Satellite image of Tropical Cyclone Dora on 2


This satellite image of Tropical Cyclone Dora taken at 12:30 a.m. EST (0530 UTC) on Fri., Feb. 9, shows a storm that remains rather well-organized, with a defined center (red marking). However, notice the lack of deep, thick clouds (bright white) that are often associated with strong thunderstorms and high winds. The thickest clouds are also shifted away from the circulation center. Image credit: JTWC/SATOPS.



Unshakable Dora Remains a Tropical Cyclone in the Indian Ocean

TRMM image of Tropical Cyclone Dora
Click image to enlarge

Despite a brief flare of intense thunderstorms near its center of circulation, tropical cyclone Dora continues to show signs of gradual weakening over the Indian Ocean. Satellite imagery and other data suggest the cyclone will soon experience increased wind shear (changing wind speed and direction) that should hasten dissipation. Before dissolving by Fri., Feb. 9, Dora should make a turn to the southwest as a ridge (elongated, broad area of high pressure) builds to her south.

At 4:00 a.m. EST (0900 UTC) on Thurs., Feb. 8, Dora was located near 25.0 degrees south latitude and 63.0 degrees east longitude, or about 465 miles east-southeast of Le Reunion, and was moving toward the south at 9 knots (10 mph). Maximum sustained winds were near 35 knots (40 mph), with gusts to 45 knots (52 mph). Wave heights close to the center of the storm were near 14 feet.

This image of Tropical Cyclone Dora, taken by the Tropical Rainfall Measuring Mission (TRMM) satellite at 9:54 p.m. EST on Mon., Feb. 5 (0254 UTC Tues., Feb. 6) shows a top-down-view of rain intensity. Estimated rain rates of 25 to 40 millimeters (0.98 to 1.57 inches) per hour were common, but areas of extreme rainfall (greater than 50 millimeters, or 1.97 inches per hour) were no longer present. TRMM is a joint mission between NASA and the Japanese space agency JAXA.



Tropical Cyclone Dora Dissipating in Indian Ocean

As Tropical Cyclone Dora travels the open waters of the Indian Ocean and encounters strong wind shear (changing wind speed and direction), she continues to weaken. Recent satellite imagery shows that most of the cyclone's deepest thunderstorms have been shifted away from the center of circulation. Forecasters expect Dora to completely dissipate by late Thurs., Feb. 8, and should not threaten any major land masses.

At 4:00 a.m. EST (0900 UTC) on Wed., Feb. 7, Dora was located near 21.9 degrees south latitude and 63.0 degrees east longitude, or about 425 miles east of Le Reunion, and was moving toward the west-southwest at 5 knots (6 mph). Maximum sustained winds were near 35 knots (40 mph), with gusts to 45 knots (52 mph). Wave heights close to the center of the storm were near 18 feet.

Quikscat image of Tropical Cyclone Dora


Powerful winds spiral towards the center of Tropical Cyclone Dora in this image made from data captured at 8:20 a.m. EST (1320 UTC) on Mon., Feb. 5, by the SeaWinds scatterometer on NASA’s QuikSCAT satellite. At the time, Dora had maximum sustained winds of 65 knots (75 mph). The satellite records wind speed and direction 10 meters (32.8 feet) above the ocean’s surface. Wind speed is represented by color, with the strongest winds in purple and the calmest in blue. The barbs indicate both wind direction and rainfall. Areas of heavy rain are marked with white barbs. The strongest winds and heaviest rainfall, indicated in red and purple, surround the eye of the storm. Image credit: NASA/JPL. Caption credit: Mike Bettwy, RSIS/Goddard Space Flight Center.



Forecasters Tracking Two Tropical Cyclones in Southern Hemisphere

As Tropical Cyclone Dora weakens in the open waters of the Indian Ocean, forecasters are busy tracking a new cyclone that threatens Australia.

At 4:00 a.m. EST (0900 UTC) on Tue., Feb. 6, Dora was located near 20.4 degrees south latitude and 64.8 degrees east longitude, or about 525 miles east of Le Reunion, and was moving toward the south-southwest at just 4 knots (5 mph). Maximum sustained winds were near 55 knots (63 mph), with gusts to 70 knots (81 mph). Wave heights close to the center of the storm were near 30 feet.

Dora continues to weaken as the strongest thunderstorms are torn from the storm center due to increasing wind shear (changing wind speed and direction with height). Environmental conditions surrounding Dora are not expected to change, so forecasters anticipate additional weakening as the cyclone tracks slowly toward the southwest over the next day.

While Dora may be completely dissolved by late Thurs., Feb. 8, another tropical cyclone - Nelson - is gaining strength in the Gulf of Carpentaria in the South Pacific. At 10:00 a.m. EST (1500 UTC) on Tues., Feb. 6, Nelson was near 16.6 degrees south latitude and 140.6 degrees east longitude, or 315 miles west of Cairns, Australia. Storm movement was to the east at 6 knots (7 mph). Maximum sustained winds had risen to 45 knots (52 mph) with gusts to 55 knots (63 mph). Recent satellite imagery shows Nelson has become more consolidated and will continue to slowly intensify before making landfall in northeast Australia by early Wed., Feb. 7.

An Inside Satellite Look at Dora's Clouds

This infrared satellite image of Tropical Cyclone Dora, from the Atmospheric Infrared Sounder on NASA's Aqua satellite, taken Sat., Feb. 3, captures Dora near her peak intensity.


This infrared satellite image of Tropical Cyclone Dora, from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite, taken Sat., Feb. 3, captures Dora near her peak intensity. It shows the temperature of 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. In locations without clouds, the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

What Does Dora Look Like to the Eye?

This satellite image of Tropical Storm Dora shows what Dora looked like to the naked eye.


This satellite image of Tropical Storm Dora, also on Sat., Feb. 3, was taken by the visible light/near-infrared sensor on the AIRS instrument. It shows what Dora looked like to the naked eye. Image credit: NASA/JPL. Caption credit: Mike Bettwy, RSIS/Goddard Space Flight Center



Bout of Storminess in Southern Hemisphere Continues

TRMM image of Tropical Cyclone Dora on Feb. 5, 2007.
Click image to enlarge

As Tropical Cyclone Dora churns in the Indian Ocean, forecasters have been busy monitoring other storminess in the South Pacific.

At 4:00 a.m. EST (0900 UTC) on Mon., Feb. 5, Dora was located near 19.2 degrees south latitude and 65.9 degrees east longitude, or about 640 miles northeast of Le Reunion, and was moving toward the west at just 3 knots (3.4 mph). Maximum sustained winds were near 65 knots (75 mph), with gusts to 80 knots (92 mph). Wave heights near the center of the storm have decreased to 31 feet.

Dora is facing more wind shear (changing wind speed and direction with height), taking the cyclone's most powerful thunderstorms away from her center. These conditions are expected to persist and forecasters say considerable weakening is likely over the next two days. A low-pressure system near Madagascar should begin to steer Dora back on a more southerly path within 12 hours.

As Dora began weakening over the weekend, another tropical cyclone - this time in the South Pacific - was showing signs of intensification, but has since lost much of its punch. At 10:00 p.m. EST on Sun., Feb. 4 (0300 UTC Mon., Feb. 5), tropical cyclone 11P was about 495 miles east-southeast of Nadi, Fiji, and was quickly tracking east-southeast at 30 knots (35 mph). Maximum sustained winds had decreased to 30 knots (35 mph). As the system encounters increasing wind shear, it is expected to fade completely within a day.

This satellite image of Tropical Cyclone Dora, taken by the Tropical Rainfall Measuring Mission (TRMM) at 10:50 p.m. EST on Sun., Feb. 4 (0350 UTC Mon., Feb. 5) shows a top-down-view of rain intensity. Estimated rain rates of 25 to 40 millimeters (0.98 to 1.57 inches) per hour were common to the east of Dora's center. TRMM is a joint mission between NASA and the Japanese space agency JAXA. Caption credit: Mike Bettwy, RSIS/Goddard Space Flight Center



Tropical Cyclone Dora May Be Reaching Her Peak

Satellite image of Tropical Cyclone Dora taken on February 2, 2007.


Dora has intensified into a significant tropical cyclone but continues to pose no threat to major land masses, and may soon begin to weaken as she travels over the Indian Ocean.

At 4:00 a.m. EST (0900 UTC) on Fri., Feb. 2, Dora was located near 17.9 degrees south latitude and 68.1 degrees east longitude, or about 740 miles east-northeast of Le Reunion, and was moving toward the south at 6 knots (7 mph). Maximum sustained winds were near 90 knots (104 mph), with gusts to 110 knots (127 mph). Wave heights near the center of the storm have grown to an estimated 35 feet.

A ridge (elongated area of high pressure) near Madagascar has turned Dora slightly southwestward, but approaching low-pressure systems will soon weaken the ridge and steer Dora back to the south. As the cyclone ingests stable, drier air, it will weaken slowly throughout the weekend, but should remain quite organized. By early Sun., Feb. 4, forecasters expect maximum sustained winds to decrease to 80 knots (92 mph).

This satellite image of Dora, taken at 12:30 a.m. EST (0530 UTC) on Fri., Feb. 2, shows a strong and well-organized tropical cyclone. Note the defined eye and nearly symmetric shape. The area of cloudiness to the east of the cyclone may help induce weakening. Image credit: JTWC/SATOPS/EUMETSAT.



Dora Deepening Into a Powerful Tropical Cyclone

TRMM image of Tropical Cyclone Dora
Click image to enlarge
Tropical Cyclone Dora is gradually gaining strength, but currently poses no threat to major land masses as it travels across the open waters of the Indian Ocean.

At 4:00 a.m. EST (0900 UTC) on Thurs., Feb. 1, Dora was located near 15.0 degrees south latitude and 67.4 degrees east longitude, or about 760 miles east-northeast of Le Reunion, and was moving toward the south-southeast at 6 knots (7 mph). Maximum sustained winds were near 75 knots (86 mph), with gusts to 90 knots (104 mph). Wave heights near the center of the storm have grown to an estimated 32 feet.

Forecasters expect Dora to continue on a southerly track, steered by a high-pressure system to her east. As a ridge (elongated region of high pressure) builds over Madagascar in about 24 hours, Dora may begin making a turn toward the north-northeast. While the cyclone will be traveling into a more stable, dry air mass, Dora will remain well-organized and should continue to slowly intensify. Most forecast computer models agree on additional strengthening, with maximum sustained winds reaching up to 95 knots (109 mph) by Sat., Feb. 3.

This satellite image of Tropical Cyclone Dora, taken by the Tropical Rainfall Measuring Mission (TRMM) at 12:54 a.m. EST (0554 UTC) on Thurs., Feb. 1, shows a top-down-view of rain intensity. Estimated rain rates of 25 to 40 millimeters (0.98 to 1.57 inches) per hour were common near and to the east of Dora's center. TRMM is a joint mission between NASA and the Japanese space agency JAXA.



Tropical Cyclone Dora Continues to Churn in the Indian Ocean

Image of tropical cyclone Dora


As forecast, Tropical Cyclone Dora is gaining strength, but remains nearly stationary in the Indian Ocean.

At 4:00 a.m. EST (0900 UTC) on Tue., Jan. 30, Dora was located near 12.8 degrees south latitude and 65.2 degrees east longitude, or about 750 miles northeast of Le Reunion, and was drifting to the south-southwest. Maximum sustained winds were near 55 knots (63 mph), with gusts to 70 knots (81 mph). Wave heights near the center of the storm were estimated at 26 feet.

Forecasters expect the cyclone to steadily intensify over the next 36 hours as wind shear (changing wind speed and direction with height) remains relatively light and storm outflow improves. Dora will likely reach its maximum intensity by early Thurs., Feb. 1, with sustained winds possibly reaching 90 knots (104 mph). Movement will continue toward the south-southwest, with a potential increase in forward speed.

This satellite image shows Tropical Cyclone Dora at 12:30 a.m. EST (0530 UTC) on Tues., Jan. 30. Bright white areas indicate deep, thick clouds. The system appears to have a symmetric shape, indicative of a strong cyclone. The red marking indicates the location of the cyclone's center.



Arthur Dissolves, Yet Another Tropical Cyclone Forming

Tropical Cyclone Forming Image above: This image shows the anticipated path and strength of tropical cyclone 10S over the next 48 hours. It indicates that the cyclone should intensify and reach typhoon strength (filled pink circles). Previous cyclone positions are in black; forecast positions are in pink. Dashed lines outline the region ships are urged to avoid. Image credit: JTWC.

Just hours after tropical cyclone Arthur fell apart in the South Pacific, a new tropical cyclone is forming - this time in the Indian Ocean.

At 4:00 a.m. EST (0900 UTC) on Mon., Jan. 29, tropical cyclone 10S was located near 12.1 degrees south latitude and 66.6 degrees east longitude, or about 440 miles southwest of Diego Garcia, with a forward motion toward the south-southwest at 11 knots (13 mph). Maximum sustained winds were near 40 knots (46 mph), with gusts to 50 knots (58 mph). Wave heights near the center of the storm were estimated at 16 feet.

Forecasters expect the cyclone to rapidly intensify as wind shear (changing wind speed and direction with height) remains relatively light and storm organization and outflow improve. By early Wed., Jan. 31, the cyclone is forecast to contain sustained winds of up to 90 knots (104 mph).

 
 
Mike Bettwy
Goddard Space Flight Center