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Dorian (wasTD4) (Atlantic Ocean)
August 5, 2013

08.05.13 - NASA Saw Dorian, the Zombie Storm, Fall Apart Again[image-206]

Dorian weakened to a remnant low pressure area the previous week and lingered off the Florida coast and in the Bahamas. Then on Aug. 3 at 5 a.m. EDT/0900 UTC the Zombie storm was reborn as a tropical depression.
At that time, Tropical Depression Dorian's maximum sustained winds reached near 35 mph/55 kph with higher gusts.  Dorian's center was just 85 miles/140 km east-northeast of Cape Canaveral, Florida, near latitude 28.7 north and longitude 79.2 west. The zombie storm was moving north near 6 mph/9 kph.

Just 24 hours later, the zombie storm "died" again, becoming a remnant low pressure area once again. Dorian's remnants were merging with a frontal trough (elongated area of low pressure), located a couple of hundred miles off the coast of North Carolina.

NOAA's GOES-13 satellite captured a visible image of the final demise of zombie Dorian's remnants on Aug. 4 at 1401 UTC (10:01 a.m. EDT). The remnants, coupled with the cloud cover appeared more like a frontal boundary, stretching northeast to southwest. The GOES data was processed into this image by NASA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md.

The cold front marks the final death knell of this zombie storm, and the National Hurricane Center now gives Dorian's remnants a near "zero percent chance" or re-developing in the next 5 days.

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


07.30.13 - Satellite Shows Ex-Tropical Storm Dorian's Remnants Elongated[image-190]

Former Tropical Storm Dorian has been hanging around the Caribbean Sea for a couple of days, and appears stretched out on satellite imagery.

NOAA’s GOES-13 satellite has been capturing images of the movement of Dorian since it was born.  NASA’s GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md. created an image of the storm using GOES-13 satellite data on July 30 at 1415 UTC/10:15 a.m. EDT. Dorian's remnants appear elongated from north to south on the GOES-13 image. The showers and thunderstorms are disorganized and extend a few hundred miles east and northeast of the Turks and Caicos Islands.

The National Hurricane Center or NHC noted that upper-level winds are not expected to favor re-development over the next couple of days, as Dorian's remnants move west to northwest. The remnant low is moving 10 to 15 mph, and is expected to bring showers and gusty winds across Turks and Caicos as it moves into portions of the Bahamas.

The NHC gave Dorian's remnants a 20 percent chance for regeneration over the next couple of days.

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


07.29.13 - NASA Keeping an Eye on Dorian's Remnants

[image-174]

NASA and NOAA satellites continue to keep a close eye on the remnants of Tropical Storm Dorian as they make their way through the eastern Caribbean Sea.

On Saturday, July 27 at 11 a.m. EDT, Dorian was still a tropical storm, but that didn't last. Dorian was near 18.5N and 52.1W, about 720 miles (1,160 km) east of the Northern Leeward Islands. Dorian's maximum sustained winds were near 40 mph (65 kph) and it was moving to the west at 23 mph (37 kph).  

By July 28, Dorian weakened to a remnant low pressure area. It was producing showers and thunderstorms that extended a few hundred miles northeast of the Northern Leeward Islands. Dorian's remnants passed north of the Leeward Islands on July 28.

On Monday, July 29, remnants of Doran and a trough (elongated area) of low pressure were generating disorganized clouds and thunderstorms a couple of hundred miles north of Puerto Rico. Those clouds were seen by NOAA's GOES-13 satellite. The GOES-13 satellite image captured on July 29 at 14:45 UTC (10:45 a.m. EDT) shows that Dorian seems to have regained a more rounded appearance. However, the National Hurricane Center noted that the disturbance still does not appear to have a closed low-level circulation and surface pressures remain high across the area.  If pressure drops, it would be a sign that the low pressure area is consolidating, but that was not occurring during the morning of July 29.

GOES satellites are managed and operated by NOAA, and the GOES image was created by NASA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md.

Environmental conditions are expected to be only marginally conducive for regeneration to occur, and the National Hurricane Center gives Dorian's remnants a medium chance, about 40 percent of becoming a tropical cyclone again. The remnant low is moving to the west and is expected to move to the west-northwest in the next two days. As it continues moving it is expected to move across the Turks and Caicos Islands and the Bahamas on Tuesday and Wednesday, July 30 and 31.

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


07.26.13 - NASA's Various Views of Tropical Storm Dorian

NASA satellites analyzed Tropical Storm Dorian in infrared light, giving scientists an idea of the storm's structure, cloud heights and cloud temperatures.

A Suomi-NPP Satellite View[image-96]

NASA-NOAA's Suomi-NPP satellite flew over Tropical Storm Dorian on July 25 at 03:52 UTC (July 24 at 11:52 p.m. EDT). At that time the Visible Infrared Imager Radiometer Suite or VIIRS instrument that flies aboard the satellite captured a night-time, infrared image of Tropical Storm Dorian. VIIRS data showed that the thunderstorms that surround the center of circulation were as cold as 195 to 200 kelvin. Those frigid temperatures indicate very high thunderstorms shooting to the top of the troposphere (lowest layer of atmosphere).

VIIRS, a scanning radiometer, collects visible and infrared imagery and radiometric measurements. VIIRS data is used to measure cloud and aerosol properties, ocean color, sea and land surface temperature, ice motion and temperature, fires, and Earth's albedo.

An Aqua Satellite View[image-97]

The Atmospheric Infrared Sounder or AIRS instrument also captures infrared data and captured data on Dorian hours after VIIRS. AIRS flies aboard NASA's Aqua satellite and flew over Dorian on July 25 at 15:59 UTC (11:59 a.m. EDT). AIRS data showed that Dorian maintained strong thunderstorms around its center. AIRS also showed an extended band of fragmented thunderstorms wrapping into Dorian's center from the south and southwest.

AIRS data also showed that Dorian had moved back into warmer sea surface temperatures between 300 (80F/26.8C) and 310 Kelvin (98.3F/36.8C).

TRMM Satellite View[image-98]

When NASA and the Japan Space Agency's Tropical Rainfall Measuring Mission or TRMM satellite passed over Dorian on July 26 at 01:39 UTC (9:39 p.m. EDT on July 25), the instruments aboard measured the rainfall rates occurring within the storm.  Mostly light to moderate rainfall was found near Dorian's center of circulation by TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments. TRMM imagery is created at NASA's Goddard Space Flight Center in Greenbelt, Md. where TRMM precipitation data is placed atop a visible/infrared image from TRMM's Visible and InfraRed Scanner to form a complete picture.

Where is Dorian?[

At 5 a.m. EDT (0900 UTC) on Friday, July 26, Dorian's maximum sustained winds had slowed to 50 mph (85 kph). The National Hurricane Center or NHC noted that Dorian has become less organized. Dorian was centered near 17.1 north latitude and 41.5 west longitude, about 1,425 miles (2,290 km) east of the Northern Leeward Islands. Dorian is moving to the west-northwest at 20 mph (32 kph). There were no warnings or watches in effect as of 5 a.m. EDT.

NHC noted that Dorian's disorganization is possibly due to a combination of southwesterly vertical wind shear and mid to upper-level dry air seen in water vapor imagery.

As the AIRS data showed on July 25, the convective area (showers and thunderstorms) has become elongated from north to south.

Dorian is expected to continue moving west-northwest and in 4 or 5 days (by Monday, July 29); NOAA forecasts take the storm over Hispaniola.

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


July 25, 2013 - NASA Puts Tropical Storm Dorian in the Infrared Spotlight[image-95]

The newest tropical storm to form in the Atlantic was put in NASA's "infrared spotlight." NASA's AIRS instrument uses infrared imaging to analyze tropical cyclones and captured an image of newborn Tropical Storm Dorian. 

NASA's Atmospheric Infrared Sounder instrument also known as AIRS, flies aboard the Aqua satellite. AIRS uses infrared light and shined that light on Tropical Storm Dorian on July 25 at 03:29 UTC (11:29 p.m. EDT, July 24). Infrared data helps determine temperature, such as the cloud top and sea surface temperatures. AIRS data revealed that Dorian's strongest storms and heaviest rains were around its center and in a band of thunderstorms south of the center. Those areas had cloud top temperatures near -63F/-52C, indicating very high thunderstorms.

Forecasters at the National Hurricane Center kept a close eye on Dorian over the last 24 hours as it traversed cooler sea surface temperatures, and survived. Dorian is now moving over and toward warmer waters.[image-91]

The official position of Tropical Storm Dorian at 11 a.m. EDT (1500 UTC), was about 1,800 miles (2,900 km) east of the northern Leeward Islands, near 16.0 north and 35.9 west, according to the National Hurricane Center or NHC. The NHC noted that Dorian's maximum sustained winds were near 60 mph (95 kph) and some fluctuations in intensity are expected in the next couple of days. The tropical-storm-force winds extend outward up to 60 miles (95 km) from the center, making Dorian about 120 miles (190 km) in diameter.  

Dorian was moving toward the west-northwest near 17 mph (28 kph) and that general motion is expected to continue today, followed by a gradual turn toward the west on Friday, July 26. The estimated minimum central pressure is 999 millibars.

The NHC expects Dorian to continue to move west-northwest across the Atlantic.

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

 

 

 

 

 


July 24, 2013 - NASA's TRMM Satellite Sees Tropical Storm Dorian Forming[image-78]

On July 23, 2013 at 0253 UTC,NASA's TRMM satellite captured an image of the tropical wave that spawned Tropical Storm Dorian and revealed that it had become much more organized that it was on July 22, 2013 at 1703 UTC when TRMM previously passed over the storm.

Analyses of rainfall from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) were overlaid on Visible and InfraRed Scanner (VIRS) data. A combination visible and infrared VIRS image is shown overlaid with precipitation in the early evening at 1703 UTC. An enhanced infrared image alone, from TRMM's VIRS instrument, was used as an underlay in the early morning 0253 UTC view on the right. The area covered by the TRMM PR instrument is shown as a slightly lighter shade.

The National Hurricane Center (NHC) upgraded the low pressure center to tropical depression four (TD04) on July 24, 2013 at 0900 UTC (5 a.m. EDT) and then to tropical storm Dorian at 1500 UTC (11 a.m. EDT). Dorian is the fourth named tropical storm in the 2013 Atlantic hurricane season. Dorian is predicted to remain a tropical storm with winds no greater than 40 knots (46 mph) while moving into the central Atlantic.

On average, the 4th named storm doesn't occur until around August 23rd, an indication that the 2013 season  is off to a fast start. The fact that tropical storm Dorian formed near the Cape Verde Islands is also somewhat unusual. Although they can occur in July, Cape Verde-type storms typically don't form until August and September, and 2013 has almost had one earlier in July--Tropical Storm Chantal.

Text credit:  Steve Lang/Hal Pierce
SSAI/NASA Goddard Space Flight Center


July 23, 2013 - NASA Sees Newborn Eastern Atlantic Tropical Depression[image-51]

The fourth tropical depression of the Atlantic Ocean hurricane season was born west of the Cape Verde Islands in the Eastern Atlantic Ocean on July 24. NOAA's GOES-13 satellite provides continuous views of the Atlantic Ocean basin and captured an image of the newborn storm.

At 5 a.m. EDT on July 24, the National Hurricane Center announced the birth of Tropical Depression 4 or TD4. At that time TD4 had maximum sustained winds near 35 mph (55 kph). It was centered about 310 miles (500 km) west-southwest of the Cape Verde Islands, near 13.9 north and 28.1 west. TD4 was moving to the west-northwest at 20 mph (32 kph) and had a minimum central pressure of 1008 millibars.

NOAA's eastern Geostationary Operational Environmental Satellite known as GOES-13 captured a visible image of Tropical Depression 4 in the far eastern Atlantic Ocean on July 24 at 11:45 UTC (7:45 a.m. EDT). The image was created by the NASA GOES Project located at NASA's Goddard Space Flight Center in Greenbelt, Md.

The image showed that the storm had become more organized overnight, and strong convection (rising air that forms thunderstorms that make up the tropical depression) had increased in coverage and become more concentrated around the center.

The National Hurricane Center noted that TD4 may strengthen slightly and reach tropical storm status later in the day or on July 25 before running into drier air and cooler waters. Dry air absorbs the moisture needed to form thunderstorms, and tropical cyclones need water temperatures of at least 80F/26.6C to maintain strength.

If TD4 strengthens into a tropical storm it would be renamed Dorian.

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

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[image-36]
Tropical Depression 4
NOAA's GOES-13 satellite captured this view of Tropical Depression 4 in the far eastern Atlantic Ocean on July 24 at 11:45 UTC (7:45 a.m. EDT).
Image Credit: 
NASA GOES Project
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[image-51]
On July 23, 2013 at 0253 UTC,NASA's TRMM satellite captured an image of the tropical wave that spawned Tropical Storm Dorian and revealed that it had become much more organized that it was on July 22, 2013 at 1703 UTC when TRMM previously passed over the storm.
Image Credit: 
SSAI/NASA Hal Pierce
Image Token: 
[image-78]
TRMM image of Dorian
NASA's TRMM satellite flew over tropical storm Dorian on July 24 at 1648 UTC and the TMI and PR instruments saw light to moderate rainfall (blue/green) near the center of circulation. Precipitation is shown overlaid on a visible/infrared image from TRMM's Visible and InfraRed Scanner (VIRS).
Image Credit: 
SSAI/NASA Hal Pierce
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[image-91]
AIRS image of Dorian
The AIRS instrument aboard NASA's Aqua satellite captured this infrared image of Tropical Storm Dorian on July 25 at 03:29 UTC (11:29 p.m. EDT, July 24). Strongest storms and heaviest rains are around the center and in a band of thunderstorms south of the center with cloud top temperatures near -63F/-52C (purple).
Image Credit: 
NASA JPL/Ed Olsen
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[image-95]
This night-time, infrared image of Tropical Storm Dorian was taken from the VIIRS instrument aboard the Suomi-NPP satellite on July 25 at 03:52 UTC. The red and purple areas are very high thunderstorms.
Image Credit: 
UWI-Madison/NASA-NOAA
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[image-96]
AIRS image of Dorian
On July 25 at 11:59 a.m. EDT, AIRS data showed Dorian had strong thunderstorms (purple) around its center and in a fragmented band wrapping into the center from the south.
Image Credit: 
NASA/JPL, Ed Olsen
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[image-97]
TRMM image of Dorian
The TRMM satellite passed over Dorian at 9:39 p.m. EDT on July 25, and saw mostly light to moderate rainfall (blue/green) near the center.
Image Credit: 
NASA/SSAI, Hal Pierce
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[image-98]
GOES-13 captured this image of Dorian's remnants (far right) located north of Puerto Rico on July 29 at 10:45 a.m. EDT.
NOAA's GOES-13 satellite captured this image of Dorian's remnants (far right) located north of Puerto Rico on July 29 at 10:45 a.m. EDT.
Image Credit: 
NASA GOES Project
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[image-174]
remains of a hurricane east of Cuba
NOAA’s GOES-13 satellite captured this image on July 30 at 10:15 a.m. EDT that showed showers and thunderstorms associated with Dorian's remnants north of Hispaniola.
Image Credit: 
NASA's GOES Project
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[image-190]
GOES-13 image of Dorian remnants
NOAA's GOES-13 satellite captured a visible image of the final demise of zombie storm, Dorian as it weakened back to a remnant low pressure area on Aug. 4 at 1401 UTC (10:01 a.m. EDT).
Image Credit: 
NASA's GOES Project
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Page Last Updated: August 5th, 2013
Page Editor: Lynn Jenner