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Dolly (Atlantic/Gulf of Mexico)
September 4, 2014

NASA Sees Dolly's Remnants Bringing Showers to the Rio Grande Valley

[image-126][image-142][image-158]Tropical Storm Dolly fizzled out quickly on September 3 after making landfall in eastern Mexico, and NASA's Aqua satellite saw some of the remnants moving into southern Texas. NASA's TRMM satellite analyzed the rainfall occurring in the storm as it was approaching landfall.

NASA's Aqua satellite captured the remnants of Tropical Depression Dolly over northeastern Mexico on Sept. 3 at 19:40 UTC (3:40 p.m. EDT). The image, captured by the Moderate Resolution Imaging Spectroradiometer or MODIS instrument showed the center of Dolly over northeastern Mexico with a band of thunderstorms north of the center of circulation, spiraling over the Texas/Mexico border.

The Tropical Rainfall Measuring Mission or TRMM satellite flew over Tropical Storm Dolly early on September 3, 2014 at 0844 UTC (3:33 a.m. CDT). TRMM's Microwave Imager (TMI) collected with that orbit showed that Dolly was dropping light to moderate rainfall near the dissipating storm's center of circulation. Moderate to heavy rainfall, falling at a rate of over 30 mm (about 1.2 inches) per hour, was seen in a strong band of showers moving ashore north of Dolly's center.

The previous day, September 2, the TRMM satellite had a good daylight look at Dolly at 1616 UTC (11:16 a.m. CDT). At that time, strong north-northwesterly vertical shear was pushing powerful convective (rising air that condenses and forms thunderstorms) thunderstorms to the south of the tropical cyclone's center. Some of these storms were dropping rain at a rate of almost 83 mm (3.3 inches) per hour. At NASA's Goddard Space Flight Center in Greenbelt, Maryland, that data was used to create a 3-D image that showed those intense storms. The data used to create the 3-D image was derived from TRMM's Precipitation Radar (PR) reflectivity data values. The 3-D image showed that some tops of these storms towered to heights of over 15km (about 9.3 km), indicating strong uplift of air.

The National Hurricane Center (NHC) issued the final advisory on Dolly on Wednesday, September 3 at 11 a.m. EDT (1500 UTC). At that time, Dolly had dissipated about 90 miles (145 km) west-southwest of Tampico, Mexico near 21.7 north latitude and 99.2 west longitude. At that time, Dolly's maximum sustained winds dropped to 30 mph (45 kph) and weakening quickly. It was moving to the west at 8 mph (13 kph).

Dolly's remnants are bringing rainfall to southern Texas today, September 4, 2014. The National Weather Service in Brownsville, Texas noted that low-to-mid-level moisture remains high across the Rio Grande Valley with the remnants of Tropical Depression Dolly across northeast Mexico. That moisture will trigger isolated and scattered thunderstorms across parts of the Valley today.

Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Maryland

 

 

 

 

 

 

 

 

 


3 Sept. 2014 - NASA's HS3 Hurricane Mission and Terra Satellite Take on Tropical Storm Dolly

NASA has Tropical Storm Dolly covered by satellite and the remotely piloted Global Hawk aircraft. Both captured data on Dolly before it made landfall in eastern Mexico.

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The MODIS or Moderate Resolution Imaging Spectroradiometer instrument aboard NASA's Terra satellite took an image of Tropical Storms Norbert in the Eastern Pacific and Dolly in the Gulf of Mexico at 1:30 p.m. EDT on Sept. 2.  The image showed Dolly is a much more organized storm than Norbert, and revealed Dolly's strongest, towering thunderstorms around the center of circulation. Norbert is close to the western coast of Mexico, so the country has tropical storms to the east and west.  The image was created by the NASA MODIS Rapid Response Team at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

At 11 p.m. EDT on September 2, Dolly made landfall between Tampico and Cabo Rojo, near latitude 21.9 north and longitude 97.7 west.

One of NASA's unmanned Global Hawk aircraft number 872 surveyed Tropical Storm Dolly during the night-time hours of September 2 as part of NASA's latest hurricane airborne mission known as the Hurricane and Severe Storm Sentinel, or HS3 mission.

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"We saw winds at low levels (near 850 millibars) up to about 35 to 40 knots (40 to 46 mph) and a reasonably depicted cyclonic circulation," said HS3 Principal Investigator, Dr. Scott Braun of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The data at 150 millibars (high in the atmosphere) shows the strong outflow from the storm to the east and southeast."

In the image, the dropsonde data gathered from NASA's Global Hawk were adjusted over the satellite image of the storm to compensate for the storm's movement. As a result, although the image makes dropsonde data look as if it were over eastern Mexico, there were no drops over the country. The data was just shifted to match the satellite image. All dropsondes were dropped over the Gulf of Mexico.

NASA's HS3 mission returned to NASA Wallops Flight Facility, Wallops Island, Virginia for the third year to investigate the processes that underlie hurricane formation and intensity change in the Atlantic Ocean basin. HS3 is a collaborative effort that brings together several NASA centers with federal and university partners.

By 8 a.m. EDT (1200 UTC) on September 3, Dolly had weakened to a depression with maximum sustained winds near 35 mph (55 kph). The National Hurricane Center (NHC) expects Dolly to weaken quickly and dissipate by the end of the day on September 3. Dolly was centered near latitude 21.7 north and longitude 98.8 west, about 65 miles (110 km) west-southwest of Tampico, Mexico. Dolly was moving toward the west near 8 mph (13 kph) and is expected to continue in that direction for the next day or so taking Dolly farther inland.

As with any tropical cyclone that makes landfall, heavy rainfall is always a concern. The NHC expects Dolly to produce rainfall amounts of 5 to 10 inches with isolated maximum amounts of 15 inches across much of Tamaulipas and Nuevo Leon...as well as northern Veracruz and eastern San Luis Potosi, Mexico through Wednesday evening.  This rainfall is expected to cause life-threatening flash floods and mud slides in areas of mountainous terrain.

Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Maryland

 


3 Sept. 2014 - NASA Satellites Calling Here You Come Again, Tropical Storm Dolly

Tropical Storm Dolly visited Mexico six years ago, and NASA satellite data is calling "Here you come again," reminiscent of the famous country singer's hit song, as another storm named Dolly heads for a second landfall in Mexico. 

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In July of 2008, Tropical Storm Dolly made landfall on Mexico's Yucatan Peninsula of Mexico before making a second and final landfall in south Texas. Now, six years later, Tropical Storm Dolly returns thanks to the six year list of revolving hurricane names, and once again Dolly is making landfall in eastern Mexico. NASA's Aqua satellite caught Dolly developing over the Yucatan and poised for a second landfall in eastern Mexico today, September 2. 

On Sept. 1 at 12:45 p.m. EDT NASA's Terra satellite caught an image of the low pressure area that would become Tropical Storm Dolly, while it was moving over the Yucatan Peninsula.  By September 2, the low developed into a tropical storm.  The image, taken by the Moderate Resolution Imaging Spectroradiometer or MODIS instrument, showed the low pressure area as somewhat shapeless as it passed over the Yucatan. Once it slid west and entered the warm waters of the Bay of Campeche, it began to develop more.

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An animation of visible and infrared satellite imagery from NOAA's GOES-East satellite was created by the NASA/NOAA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The animation showed the birth and movement of Dolly from August 31 to September 2.  On August 31, Dolly was not yet named and was a low pressure area from the western Caribbean Sea that moved over the Yucatan Peninsula. The animation shows the development of the storm as the low moved across the Bay of Campeche. 

The Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite captured infrared data on Tropical Storm Dolly on Sept. 2 at 3:59 a.m. EDT as it neared the east coast of Mexico. The data was made into a false-colored image at NASA's Jet Propulsion Laboratory in Pasadena, California. The AIRS image showed the strongest thunderstorms were on the eastern side of the center of circulation, where cloud tops stretched toward the top of the troposphere. Cloud tops in that area were as cold as -63F/-52C, indicative of high, strong thunderstorms. NASA research shows that thunderstorms with cloud top temperatures that cold have the potential for dropping heavy rainfall.

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By September 2 at 8 a.m. EDT (1200 UTC) the center of Tropical Storm Dolly was located near latitude 23.0 north and longitude 95.7 west. That puts Dolly's center about 145 miles (230 km) east-southeast of la Pesca, Mexico. Dolly was moving toward the west-northwest near 13 mph (20 kph) and the center of the storm is expected to approach the coast by tonight, September 2, and move inland tomorrow. 

Maximum sustained winds have increased to near 50 mph (85 kph) and the National Hurricane Center (NHC) noted that some strengthening is possible until Dolly makes landfall. Tropical-storm-force winds extend outward up to 115 miles (185 km) mostly northeast through southeast of the center.

A tropical storm warning is in force from Tuxpan to Barra el Mezquital. The NHC noted that rainfall totals of 3 to 6, locally up to 10 inches are possible in southern Tamaulipas, northern Veracruz and eastern San Luis Potosi. Those heavy rains will likely cause flash flooding and mudslides in regions of mountainous terrain and that threat will continue as Dolly moves inland.

Rob Gutro
NASA's Goddard Space Flight Center, Greenbelt, Maryland

Terra satellite image from 1-Sep-2014 of low-pressure system that became Tropical Storm Dolly
On Sept. 1 at 12:45 p.m. EDT NASA's Terra satellite caught this image of the low pressure area that would become Tropical Storm Dolly, while it was moving over the Yucatan Peninsula.
Image Credit: 
NASA Goddard's MODIS Rapid Response Team
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This animation from NOAA's GOES-East satellite from Aug. 31-Sept. 2 shows the movement of a low pressure area from the western Caribbean Sea over the Yucatan Peninsula as it becomes Tropical Storm Dolly.
Image Credit: 
NASA/NOAA GOES Project
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MODIS instrument aboard NASA's Terra satellite took this image of Tropical Storms Norbert (bottom left)  in the Eastern Pacific and Dolly (right) in the Gulf of Mexico at 1:30 p.m. EDT on Sept. 2, 2014
The MODIS instrument aboard NASA's Terra satellite took this image of Tropical Storms Norbert (bottom left) in the Eastern Pacific and Dolly (right) in the Gulf of Mexico at 1:30 p.m. EDT on Sept. 2.
Image Credit: 
NASA Goddard's MODIS Rapid Response Team
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infrared image of Tropical Storm Dolly on Sept. 2, 2014, at 3:59 a.m. EDT
The AIRS instrument aboard NASA's Aqua satellite captured this infrared image of Tropical Storm Dolly on Sept. 2 at 3:59 a.m. EDT as it neared the east coast of Mexico. Purple areas indicate the strongest thunderstorms.
Image Credit: 
NASA JPL, Ed Olsen
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Wind plots of Tropical Storm Dolly
NASA's unmanned Global Hawk aircraft flew over Tropical Storm Dolly on Sept. 2 and gathered data. The plot shows wind speeds and wind barbs at 850 and 150 millibars. It showed Winds at low levels up to about 35 to 40 knots and a reasonably depicted cyclonic circulation.
Image Credit: 
NASA Goddard/Scott Braun
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satellite image of tropical storm
NASA's Aqua satellite captured the remnants of Tropical Depression Dolly over northeastern Mexico on Sept. 3 at 19:40 UTC (3:40 p.m. EDT).
Image Credit: 
NASA Goddard MODIS Rapid Response Team
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tropical storm overlaid with rainfall data in blue and green
NASA's TRMM satellite flew over Dolly on Sept. 3 at 3:33 a.m. CDT. Moderate to heavy rainfall, falling at a rate of over 1.2 inches per hour, was seen in a strong band of showers moving ashore north of Dolly's center.
Image Credit: 
NASA/SSAI, Hal Pierce
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3d overlay of rainfall data mapped on a tropical storm
On Sept. 2, TRMM saw some thunderstorms towered to heights of over 15km (about 9.3 km), dropping rain at a rate of almost 83 mm (3.3 inches) per hour.
Image Credit: 
NASA/SSAI, Hal Pierce
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Page Last Updated: September 4th, 2014
Page Editor: Rob Garner