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Hurricane Season 2012: Tropical Depression Doksuri (Western North Pacific Ocean)
07.02.12
 
AIRS captured Tropical Storm Doksuri on June 29 at 0559 UTC over 100 miles south-southeast of Hong Kong, China. › View larger image
NASA's AIRS instrument (on the Aqua satellite) captured this infrared image of Tropical Storm Doksuri on June 29 at 0559 UTC (1:59 a.m. EDT) over 100 miles south-southeast of Hong Kong, China. The strongest thunderstorms have high, cold cloud tops of -63F (-52C).
Credit: NASA/JPL, Ed Olsen
NASA Saw Heavy Rain Potential In Tropical Storm Doksuri Before China Landfall

NASA's Aqua satellite's infrared instrument showed some strong thunderstorms with heavy rain in Tropical Storm Doksuri before it made landfall in South China this past weekend.

Tropical Storm Doksuri made landfall in South China's Guangdong province on June 30, and brought those heavy rains and gusty winds along with it. When it came ashore, it brought maximum wind gusts up to 60 km per hour in coastal regions in Guangdong, according to China Daily.

The Atmospheric Infrared Sounder (AIRS) instrument that flies onboard NASA's Aqua satellite captured an infrared image of Tropical Storm Doksuri on June 29 at 0559 UTC (1:59 a.m. EDT), when it was still over 100 nautical miles (115 miles/185 km) south-southeast of Hong Kong, China. The strongest thunderstorms had high, cold cloud tops of -63F (-52C) and were areas that had the potential of heavy rainfall. As Doksuri headed for landfall, increased wind shear weakened the system. After landfall, Doksuri weakened quickly.

The Joint Typhoon Warning Center issued its final bulletin on Doksuri on June 30 at 0300 UTC (June 29 at 11 p.m. EDT/U.S.), when it was about 55 nautical miles (63 miles/102 km) west-southwest of Hong Kong, China, near 22.7 North and 111.9 East. Doksuri's maximum sustained winds were 35 knots (40 mph/65 kmh) at the time, so it was still a tropical storm, although it weakened into a depression quickly afterward.

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



June 29, 2012
MODIS shows Doksuri is becoming elongated, due to strong vertical wind shear from the northeast. › View larger image
When NASA's Terra satellite flew over Tropical Storm Doksuri on June 28 at 11 p.m. EDT/U.S. the MODIS instrument onboard captured a visible image of the storm that shows the storm is becoming elongated, due to strong vertical wind shear from the northeast.
Credit: NASA MODIS Rapid Response Team
AIRS captured this infrared image of Doksuri on June 28 at 1729 UTC northwest of Luzon, Philippines. › View larger image
NASA's AIRS instrument (on the Aqua satellite) captured this infrared image of Tropical Storm Doksuri on June 28 at 1729 UTC (1:29 p.m. EDT) northwest of Luzon, Philippines. The strongest thunderstorms have high, cold cloud tops of -63F (-52C).
Credit: NASA/JPL, Ed Olsen
NASA Sees Tropical Storm Doksuri Headed for China Landfall

Doksuri strengthened back into a tropical storm as it passed north of Luzon and is close to making a landfall in China. NASA's Terra satellite captured an image of the storm approaching the China coast on June 29 and NASA's Aqua satellite measured the temperatures in its warming cloud tops.

When NASA's Terra satellite flew over Tropical Storm Doksuri on June 29 at 0300 UTC (June 28 at 11 p.m. EDT/U.S.) the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard captured a visible image of the storm. The MODIS image shows that the storm is becoming elongated, due to strong vertical wind shear from the northeast.

The Atmospheric Infrared Sounder (AIRS) that flies on NASA's Aqua satellite noticed that cloud top temperatures were warming in Doksuri when it passed overhead. Warming cloud top temperatures mean that the cloud heights are dropping because there's not as strong an uplift in the atmosphere. The higher the cloud tops are, the stronger the thunderstorms (that usually come with heavier rainfall). When cloud tops warm and drop, that's a sign that the storm is weakening.

Doksuri is moving around the outer edge of a sub-tropical ridge (elongated area) of high pressure located to the north of the storm. High pressure spins clockwise, thus, Doksuri is moving in a westerly direction.

On June 29 at 0600 UTC (4 a.m. EDT/U.S), Doksuri's maximum sustained winds were near 40 knots (46 mph/74 kmh). It was located 170 nautical miles (195.6 miles/314.8 km) southeast of Hong Kong, near 20.0 North and 116.0 East. It is moving west at 13 knots (~15 mph/24 kmh). Doksuri is expected to continue to steadily weaken as it heads for the coast.

Currently a stand-by signal 1 is currently in force in Hong Kong.

Doksuri is moving through the Gulf of Tonkin. Doksuri's center is expected to make landfall far south of Hong Kong sometime on June 30, and dissipate over land within two days.

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



June 28, 2012
Infrared data from AIRS iindicated the there were still some strong (purple) showers and thunderstorms within Doksuri. › View larger image
NASA's Aqua satellite passed over Tropical Storm Dokuri on June 27 on 0435 UTC (12:35 a.m. EDT). Infrared data from the AIRS instrument onboard, indicated the there were still some strong (purple) showers and thunderstorms within.
Credit: NASA/JPL, Ed Olsen
Tropical Depression Dokuri Weaker, But Still Potent

Tropical Storm Dokuri weakened into a tropical depression today, but NASA infrared satellite imagery is still showing some areas of strong convection and thunderstorms in the storm and they're being pushed away from the center.

NASA's Aqua satellite passed over Tropical Storm Dokuri on June 27 on 0435 UTC (12:35 a.m. EDT). Infrared data from the Atmospheric Infrared Sounder (AIRS) instrument onboard indicated there were still some strong showers and thunderstorms within the system. Those cloud top temperatures were colder than -63 Fahrenheit (-52 Celsius), indicating strong uplift in the atmopshere, and thunderstorms within Dokuri that have the capability for heavy rainfall.

Infrared data shows a fully-exposed low level-circulation center. The strongest convection (rising air that creates thunderstorms that make up the system)are being pushed to the southwest due to strong northeasterly vertical wind shear.

Warnings are up in the Philippines as Doksuri (known there as Dindo) continues to move north of Luzon today. Public storm warning signal #1 is in effect in Abra, Kalinga, Isabela, Ilocos Sur, Mt. Province, Ifugao, La Union, Benguet, Pangasinan, Nueva Vizcaya and Quirino. Public storm warning signal #2 is also in effect for Cagayan, Calayan Group of Islands, Babuyan Group of Islands, Batanes Group of Islands, Apayao, Ilocos Norte.

On June 28, 2012 at 1500 UTC (11 a.m. EDT), Tropical Storm Doksuri had maximum sustained winds near 35 knots. It was located approximately 335 nautical miles north of Manila, Philippines, near 20.4 North and 120.7 East. It was moving to the west-northwestward at 17 knots. The strongest convection and thunderstorms were located over northern Luzon at this time, and are moving off the northwestern coast of the Philippines.

Doksuri has weakened as it passes to the north of Luzon. Doksuri is expected to continue tracking west and make landfall near Hong Kong in two days.

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



June 27, 2012
This image of rainfall rates within Tropical Storm Doksuri were obtained with NASA's TRMM satellite on June 26. › View larger image This image of rainfall rates within Tropical Storm Doksuri were obtained with NASA's TRMM satellite on June 26. The yellow, green and blue areas indicate light-to-moderate rainfall between 20 and 40 millimeters (.78 to 1.57 inches) per hour. The red area is considered heavy rainfall at 2 inches/50 mm per hour and is occurring in one area near the center of circulation.
Credit: NASA/SSAI, Hal Pierce
Tropical Storm Doksuri Has Small Area of Heavy Rainfall

NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite flew over Tropical Storm Doksuri as it continued moving through the western North Pacific Ocean, and measured its rainfall rates.

TRMM data showed one small area of heavy rainfall near Dokuri’s center of circulation when it passed overhead on June 26, 2012 at 2229 UTC (6:29 p.m. EDT).

On June 27 at 1500 UTC (11:00 a.m. EDT), Doksuri had maximum sustained winds near 40 knots (46 mph/74 khm). It was located about 395 nautical miles east-northeast of Manila, Philippines near 17.7 North and 126.5 East. It is moving to the north-northwest near 14 knots (16 mph/26 kmh).

Doksuri is expected to pass to the north of Luzon as vertical wind shear increases (which will weaken the storm). It is expected to make landfall near Hong Kong over the weekend of June 30-July 1.

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



June 26, 2012
This infrared image of Doksuri from MODIS was captured on June 26 at 0228 UTC. › View larger image
This infrared image from the MODIS instrument onboard NASA's Terra satellite was captured on June 26 at 0228 UTC. The higher thunderstorms around the center of Tropical Depression Doksuri are casting shadows on the lower, less potent storms surrounding them.
Credit: NASA/NRL
NASA Satellite Spots Newborn Tropical Depression Doksuri in W. Pacific

Another tropical depression was born in the western North Pacific, and NASA's Terra satellite captured an infrared image of the newborn cyclone. Tropical depression Doksuri, known in the Philippines as Dindo, was born during the early hours of June 26, 2012 in the western North Pacific Ocean.

The Moderate Imaging Spectroradiometer (MODIS) instrument onboard NASA's Terra satellite as captured an infrared image of the newborn storm on June 26 at 0228 UTC. The image revealed higher thunderstorms around the center of Tropical Depression Doksuri that were casting shadows on the lower, less potent storms surrounding them. The bands of thunderstorms wrapping into the center of the circulation appear fragmented on infrared imagery. Satellite imagery also shows that the southwestern quadrant has a large area of strong convection (rising air that forms thunderstorms that make up the tropical cyclone) and thunderstorms.

At 1500 UTC (11 a.m .EDT) it was located 545 nautical miles (627 miles/1,009 km) east of Manila, Philippines, near 14.6 North and 130.3 West. It was moving to the west at 10 knots (11.5/18.5 kph)and had maximum sustained winds near 30 knots (34.5 mph/55.5 kph). It is expected to intensify as it is in an area of warm sea surface temperatures, and wind shear is expected to relax. Doksuri is forecast to pass north of Lumon Island, then skirt the coast of China.

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