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Hurricane Season 2011: Tropical Storm Nock-ten (Northwest Pacific Ocean)
07.29.11
 
AIRS infrared image of Tropical Storm Nock-ten on July 29, 2011 at 05:59 UTC (1:59 a.m. EDT). › View larger image
NASA's Aqua satellite passed over Tropical Storm Nock-ten on July 29, 2011 at 05:59 UTC (1:59 a.m. EDT) as it was approaching a landfall over Hainan Island, China. The infrared image showed the most powerful, high thunderstorms with cold cloud tops (purple) southeast of Hainan. Cloud temperatures were colder than -63 Fahrenheit (-52 Celsius).
Credit: NASA/JPL, Ed Olsen
Tropical Storm Nock-Ten Now Headed to Final Landfall in Vietnam

Infrared satellite imagery from NASA's Aqua satellite saw the strong thunderstorms and heavy rainfall that surrounded the center of Tropical Storm Nock-Ten as it was making landfall in Hainan Island on July 29.

According to China's Xinhuanet news almost 28,000 people were evacuated from Hainan province before Tropical Storm Nock-Ten made landfall over the southern part of the island on the afternoon (local time/China) of July 28. Gusty winds and heavy rains accompanied the landfall with winds of 62 mph (100 kmh) in Longlou Township.

The Atmospheric Infrared Sounder (AIRS) instrument passed over Tropical Storm Nock-Ten on July 29, 2011 at 05:59 UTC (1:59 a.m. EDT) as it was approaching a landfall over Hainan Island, China. AIRS data showed the most powerful, high thunderstorms with cold cloud tops southeast of Hainan Island at the time, and the cloud temperatures were colder than -63 Fahrenheit (-52 Celsius). As it made landfall, AIRS infrared imagery showed that the low level circulation center was covered by cold, dense overcast.

Already at 5:59 UTC on July 29, the western-most extent of Nock-Ten's clouds had extended over Vietnam as a precursor to its arrival in the next day.

At 1500 UTC (11 a.m. EDT/11 p.m. local time China), Tropical Storm Nock-Ten's maximum sustained winds had been knocked down to 40 knots (46 mph). Nock-Ten's center was about 245 miles east-southeast of Hanoi, Vietnam near 19.2 north and 109.8 East.

Nock-Ten is expected to intensify a little as it crosses the waters of the Gulf of Tonkin before making a third and final landfall in central Vietnam this weekend. Once it makes landfall, it is expected to move inland and dissipate.

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



July 28, 2011

AIRS captured this infrared image of Nock-ten on July 28 at 0517 UTC (1:47 a.m. EDT). › View larger image
NASA's Aqua satellite passed over the eastern side of Tropical Storm Nock-ten and the AIRS instrument captured this infrared image of the storm's cold cloud tops (purple) and strong thunderstorms on July 28 at 0517 UTC (1:47 a.m. EDT). Hainan Island, China is located to the west and can be seen on the left side of the image.
Credit: NASA/JPL, Ed Olsen
NASA Eyes Tropical Storm Nock-Ten's Heavy Rains for Hainan Island and Vietnam

Infrared satellite imagery from NASA's Aqua satellite shows bands of strong thunderstorms wrapping around the center of Tropical Storm Nock-Ten as it makes its way through the South China Sea and two landfalls on Hainan Island and in Vietnam.

Bands of strong thunderstorms that make up tropical storm Nock-ten were visible in an infrared image captured on July 28 by the Atmospheric Infrared Sounder (AIRS) instrument that flies on NASA's Aqua satellite. The colder the cloud tops, the higher the thunderstorms and the stronger they are, and cloud top temperatures over a large area of Nock-ten were colder than -63 Fahrenheit (-52 Celsius) and the cloud tops likely extended into the tropopause. High, strong thunderstorms like those also can generate heavy rainfall, up to 2 inches (50 mm) per hour. Those in Nock-ten's path can expect heavy rainfall, local flooding, gusty winds and rough surf along coastal areas.

AIRS imagery has shown that the convection within Nock-ten has intensified as it moves through the warm waters of the South China Sea. It is expected to strengthen a little more with the warm sea surface temperatures feeding it, and wind shear remaining light.

On July 28, at 1500 UTC (11 a.m. EDT) Tropical Storm Nock-ten was already raining on Hainan Island and headed toward another landfall in Vietnam. Its center was still 464 nautical miles east-southeast of Hanoi, Vietnam near 18.2 North and 113.0 East. Nock-ten's sustained winds are near 55 knots (63 mph/101 kmh) and it is moving in a westerly direction at 12 knots (14 mph/22 kmh).

The Joint Typhoon Warning center forecasters expect that the center of Nock-ten will make landfall over Hainan Island, China before July 29 at 1500 UTC (11 a.m. EDT) and weaken a little as it moves over land. However, once it re-emerges over water in the Gulf of Tonkin, it may strengthen a little before making final landfall in Vietnam.

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



July 27, 2011

TRMM data was used to create a 3-D image of Tropical Storm Nock-ten's rainfall and cloud heights on July 26. › View larger image
The Tropical Rainfall Measuring Mission (TRMM) satellite data was used to create a 3-D image of Tropical Storm Nock-ten's rainfall and cloud heights as it passed overhead on July 26. Nock-ten had towering convective storms near their centers of circulation that extended to heights above 15km (~9.3 miles) with heavy rainfall, falling at 2 inches (50 mm) per hour.
Credit: NASA/SSAI, Hal Pierce
TRMM captured the rainfall rates of Tropical Storm Nock-ten on July 26. › View larger image
TRMM captured the rainfall rates of Tropical Storm Nock-ten on July 26. The heaviest rainfall appears in red, falling at almost 2 inches (50 mm) per hour. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour.
Credit: NASA/SSAI, Hal Pierce
NASA Measures Heavy Rain in Tropical Storm Nock-Ten Over Philippines

NASA satellite data has shown that Tropical Storm Nock-ten has been a big rainmaker across the Philippines for the last two days and is now tracking into the South China Sea.

The Tropical Rainfall Measuring Mission (TRMM) satellite data was used to create a 3-D image of Tropical Storm Nock-ten's rainfall and cloud heights as it passed overhead on July 25. Nock-ten had towering convective storms near their centers of circulation that extended to heights above 15km (~9.3 miles) with heavy rainfall, falling at 2 inches (50 mm) per hour.

The 3-D view was made from TRMM's Precipitation Radar (PR) data collected on July 25, 2011 at 1631 UTC (12:31 p.m. EDT). Nock-ten had towering convective storms near the center of circulation that extended to heights above 15 kilometers (~9.3 miles). These tall towers are associated with convective bursts and can be a sign of future strengthening because they indicate areas where energy is being released into the developing tropical storms. Even on July 25, tropical storm Nock-ten was affecting the eastern Philippines.

Warnings are still in effect in the Philippines today, July 27, as Nock-ten makes its exit. The Public storm warning signal #1 is in effect in the Luzon provinces of Aurora, Apayao, Cagayan, Pangasinan, Nueva Ecija, Northern Quezon, Zambales, Pampanga, Tarlac, Bulacan, Bataan, Rizal and Metro Manila. In addition, Public storm warning signal #2 is in effect for the Luzon provinces of Ilocos Norte & Sur, Abra, Kalinga, Isabela, Mt. Province, Ifugao, La Union, Benguet, Nueva Viscaya and Quirino.

According to the Manila Sun Star news, the third day of heavy rains from Nock-ten (locally named Juaning) caused flooding in the northeastern Philippines and is responsible for 24 deaths.

At 1500 UTC (11 a.m. EDT) on July 27 infrared imagery from the Atmospheric Infrared Sounder instrument on NASA's Aqua satellite indicated that Nock-ten's center moved off the coast of western Luzon. Tropical Storm Nock-ten's maximum sustained winds were still near 50 knots (57 mph/92 kmh). It was centered about 170 miles (273 km) north-northwest of Manila, near 17.4 North and 120.4 East. Tropical storm-force winds extend out to 70 miles (112 km) from the center. Nock-ten was moving to the northwest at 14 knots (16 mph/26 kmh), and is making its way out of Luzon and into the South China Sea.

The forecasters at the Joint Typhoon Warning center expect Nock-ten to strengthen and make a second landfall crossing over Hainan Island, China and finally landfalling in Vietnam.

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



July 26, 2011

MODIS captured Nock-ten on July 26, 2011 at 02:30 UTC as its center was moving over the Philippines. › View larger image
This visible image of Tropical Storm 10W, now called Nock-ten was captured on July 26, 2011 at 02:30 UTC (July 25 at 10:30 p.m. EDT) as its center was moving over the Philippines. The image was taken from the Moderate Resolution Imaging Spectroradiometer (MODIS) that flies on NASA's Terra satellite (it also flies on NASA's Aqua satellite).
Credit: NASA/MODIS
NASA Sees Tropical Storm Nock-ten Knocking the Philippines

Tropical Storm Nock-ten, formerly tropical depression 10W continues raining on the Philippines, and a NASA satellite image shows the extent of the storm's clouds.

A visible image of Tropical Storm 10W, now called Nock-ten was captured on July 26, 2011 at 02:30 UTC or 10:30 a.m. local Asia/Manila time (July 25 at 10:30 p.m. EDT) as its center was moving over the Philippines. The image was taken from the Moderate Resolution Imaging Spectroradiometer (MODIS) that flies on NASA's Terra satellite (it also flies on NASA's Aqua satellite). The center of circulation in the image appears to be near the Cataduanes Island on the eastern side of the Philippines, in the Philippine Sea.

By 1200 UTC (8 p.m. local Asia/Manila time), surface weather reports from Catanduanes confirmed the low level circulation center passed north of the site. The center of Nock-ten is forecast to cross just north of Manila later today, July 26 and early July 27.

At 12:00 UTC (8 a.m. EDT) on July 26, Nock-ten's maximum sustained winds were near 35 knots (40 mph/65 kmh) making it a minimum tropical storm. It was located about 110 nautical miles east of Manila near 14.7 North and 122.6 East. Nock-ten was moving to the west-northwest at 5 knots (6 mph/9 kmh). It is expected to keep moving in that direction because it is following the outside of a ridge (elongated area) of high pressure located north of Luzon (which is north of the storm).

Residents of the central Philippines can expect heavy rainfall, gusty winds and some localized flooding as Nock-ten sweeps across land today and tomorrow. According to the Joint Typhoon Warning Center, Nock-ten should weaken as it moves over land, but re-energize once it enters the South China Sea on July 27.

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



July 25, 2011

Infrared image of Tropical Depression 10W taken by the AIRS instrument on July 25  at 0441 UTC (12:41 a.m. EDT) › View larger image
This infrared image of Tropical Depression 10W was taken from the AIRS instrument on NASA's Aqua satellite on July 25 at 0441 UTC (12:41 a.m. EDT) and it revealed a large area of very cold cloud top temperatures (purple) from strong thunderstorms over the central Philippines.
Credit: NASA JPL, Ed Olsen
Tropical Depression 10W Bringing Rain to the Philippines

The tenth tropical depression formed in the western North Pacific Ocean this past weekend, and brought rains to the central Philippines as seen on infrared imagery from a NASA satellite.

When NASA's Aqua satellite passed over Tropical Depression 10W on July 25 at 0441 UTC (12:41 a.m. EDT), the infrared image captured by the Atmospheric Infrared Sounder (AIRS) instrument revealed a large area of very cold cloud top temperatures (-63F/-52C) from strong thunderstorms over the central Philippines. A second area of strong thunderstorms on the eastern side of circulation was over the Philippine Sea.

On July 25 at 0600 UTC (2 a.m. EDT) Tropical Depression 10W's maximum sustained winds were near 30 knots (34 mph/55 kmh). It was about 335 nautical miles (385 miles/ 620 km) east of Manila, Philippines near 13.8 North and 126.4 East. Tropical Depression 10W (TD10W) is moving to the northwest at 9 knots (10 mph/17 kmh).

Satellite imagery has shown that the bands of thunderstorms feeding into the center of TD10W's circulation. TD10W continues to become more organized. The system is in an area of low to moderate wind shear which is enabling it to become better organized.

At 11 a.m. EDT on July 25, a weather station in Daet, Philippines was reporting thunderstorms and rain, with winds from the west at 11 mph. Daet is the capital municipality in the Camarines Norte province. The local forecast calls for TD10W to affect the city through the day on July 26.

The Joint Typhoon Warning Center forecasters expect TD10W to slowly intensify over the next two days and make landfall northeast of Hong Kong later this week.

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