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Hurricane Season 2009: Chan-hom (South China Sea)
05.11.09
 
May 11, 2009

Tropical Storm Kujira brought up to 900 mm rainfall (~36 inches) and Chan-hom brought about 150 mm of rain (~6 inches). A TRMM rainfall map from Apr. 27-May 8 shows Tropical Storm Kujira brought up to 900 mm (~36 in. shown by the darker brown). Chan-hom brought about 150 mm (~6 inches) (in green) over northern Luzon.
Credit: NASA/Hal Pierce
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Chan-hom forms off of the southeast coast of Vietnam on May 3, 2009 Chan-hom forms off of the southeast coast of Vietnam on May 3, 2009.
Credit: NASA/Hal Pierce
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Rainfall seen in Tropical Storm Chan-hom as it was heading into the central South China Sea on May 5 Rainfall seen in Tropical Storm Chan-hom as it was heading into the central South China Sea on May 5.
Credit: NASA/Hal Pierce
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NASA’S TRMM SATELLITE CAPTURES RAINFALL FROM TWO TYPHOONS THAT SOAKED PHILIPPINES

Within a week's time, the northern Philippines were hit by two tropical cyclones that left behind more than 42 inches of rainfall to various areas, and NASA’s Tropical Rainfall Measuring Mission satellite captured those measurements from space. Less than a week ago, then Tropical Storm Kujira inundated parts of southern Luzon in the northeast-central Philippines with torrential rains. Recently Typhoon Chan-hom (known locally as "Emong") made landfall on the northwest coast of Luzon, bringing strong winds, heavy rains and yet more flooding to the beleaguered island.

The Tropical Rainfall Measuring Mission satellite (better known as TRMM) can be used to calibrate rainfall estimates from other satellites. The TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center in Greenbelt, Md. is used to monitor rainfall over the global Tropics. TMPA rainfall totals were calculated and created on an image for the period April 27 to May 8, 2009, which captures the rainfall from both tropical cyclone events. The most extreme rainfall totals, located over southern Luzon in the northeast-central part of the islands are associated with then Tropical Storm Kujira and are on the order of 900 mm or more (~36 inches, shown by the darker brown). The totals from Chan-hom are considerably less on the order of 150 mm (~6 inches) and are located over the northern part of Luzon (shown in green). The large difference in rainfall between the two storms is due to the difference in their forward motion and not their intensity--Kujira was only a tropical storm at the time while Chan-hom was a typhoon.

TRMM captured an image of Chan-hom after it formed off of the southeast coast of Vietnam on the evening (local time) of May 3, 2009 as a tropical depression. It was upgraded overnight to a minimal tropical storm as it slowly drifted northward. Chan-hom continued to drift northward on May 4, paralleling the coast of Vietnam, with a slight increase in intensity. The system continued to gradually intensify on May 5 before turning westward across the central South China Sea in the direction of Luzon in the northern Philippines. TRMM was launched way back in November of 1997 with the objective of measuring rainfall over the Tropics. Armed with a combination of passive microwave and active radar sensors, TRMM has been providing unique images and valuable information on tropical cyclones for over 11 years.

TRMM also captured Tropical Storm Chan-hom as it was heading into the central South China Sea. The image was taken at 20:09 UTC May 5, 2009 (4:09 am May 6 Manila time). It shows the horizontal pattern of rain intensity (top down view) within the storm. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), a unique space-borne precipitation radar, while those in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). At the time of this image, the Chan-hom was a moderate tropical storm with sustained winds estimated at 55 knots (63 mph) by the Joint Typhoon Warning Center. The center of circulation is located in the middle of the circular cloud shield (circular white area) and just to the north of the heavy rain area (dark red area) in the center of the image. This heavy rain area is actually part of a southern eyewall (a northern eyewall has not yet formed). Although not yet fully developed, the strong curvature in the surrounding rainbands indicates that Chan-hom has a well-developed circulation. The intense rain near the center can be a precursor to strengthening; it indicates that large amounts of heat (known as latent heat) are being released into the core of the system, driving its circulation.

On the night of May 6, Chan-hom became a typhoon as it continued to march west-northwestward across the South China Sea towards the northern Philippines. By early afternoon on May 7, it was a category 2 storm with sustained winds estimated at 85 knots (98 mph). Chan-hom made landfall later that day around 7 pm (local time) on Thursday the 7th on the west coast of Luzon near the town of Bolinao at the entrance to the Lingayen Gulf. So far the storm has been blamed for 26 dead with several more still missing. Twelve people were killed in around Bolinao where Chan-hom made landfall and the rest in the mountainous region to the northeast of Bolinao mainly from landslides in the form of large boulders.

On Monday, May 11, the Joint Typhoon Warning Center issued its final warning on Chan-hom as it has been downgraded into a tropical depression. At 0900 Zulu Time (5 a.m. EDT), Chan-hom’s center was about 265 nautical miles south of Okinawa, Japan, near 21.8 north and 126.7 east. It was moving northwestward near 4 knots (5 mph). It is now in waters cooler than the 80F threshold that is needed to keep the storm going, and is expected to dissipate by 5pm EDT today.

TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center and Steve Lang, SSAI



May 8, 2009

AIRS image of Chan-Hom
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NASA's Aqua satellite captured this image of Chan-Hom with the AIRS instrument. Credit: NASA JPL, Ed Olsen
Chan-Hom Back at Sea, But Expected to Fizzle Over Weekend

Tropical Storm Chan-Hom survived its landfall in the Philippines and managed to make its way back out to sea. However, it's not expected to survive until Monday, May 11.

On Friday, May 8, 2009 at 1500 Zulu (11 a.m. EDT) Chan-Hom had maximum sustained winds near 40 knots (46 mph) and was moving east near 16 knots (18 mph). Chan-Hom was located about 361 miles east-northeast of Manila, Philippines, near 16.8 north and 126.8 east. It's still kicking up 11 foot high waves, and tropical storm force winds extend as far as 55 miles from its center. NASA's Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured a visible and infrared image of Chan-Hom on May 7 at 17:11 UTC (1:11 p.m. EDT). In the infrared image, Chan-Hom is seen in the two areas in blue and purple.

As Tropical Storm Chan-Hom has moved east and weakened in the last 12 hours, the infrared satellite imagery has showed that the circulation around its center was very poorly organized. There are only isolated areas of convection (rising air creating thunderstorms). Further, some of the bands of thunderstorms located to the southeast of the storm (the blue and purple colored clouds to the southeast of the other area of the same) are disconnected from the center of the storm. That also shows disorganization.

The infrared image clearly shows a large temperature difference between the storm's cloud-tops and the warm ocean temperatures. In this image, the orange temperatures are 80F (300 degrees Kelvin) or warmer. The storm's lowest temperatures (in purple) are associated with high, cold cloud tops. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F.

Chan-Hom is forecast to steer north. It is already encountering an increasingly unfavorable environment of wind shear (winds that tear a storm apart) and cooler water temperatures. It is expected to dissipate over the waters east of Taiwan.

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



May 7, 2009

Chan-Hom Made Landfall in the Philippines

Rains and gusty winds are being felt in Manila, the Philippines today as Typhoon Chan-Hom made landfall on the western side of the main island.

TRMM shows intense rainfall in Chan-Hom's southeastern side (in red) TRMM shows intense rainfall in Chan-Hom's southeastern side (in red).
Credit: NASA/SSAI, Hal Pierce
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Chan-Hom's cold thunderstorm cloud tops appear in purple in this false-colored AIRS satellite image Chan-Hom's cold thunderstorm cloud tops appear in purple in this false-colored AIRS satellite image
Credit: NASA JPL, Ed Olsen
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At 11 p.m. local time in Manila, the city had thunderstorms with winds from the west-southwest (the direction Chan-Hom is coming from) near 12 mph. Quezon City, to the northeast of Manila is not expected to see the thunderstorms later in the day Friday and could see up to an inch of rain from Chan-Hom.

On Thursday, May 7 at 1500 Zulu Time (11 p.m. local time Manila), Chan-Hom's center was located near La Union, Philippines, near 16.7 north and 120.4 east. It was moving 12 knots (13 mph) in a northeasterly direction. Sustained winds were around 93 mph (150 km/h), making it a strong Category One hurricane on the Saffir-Simpson scale.

Public storm warning signals (1, 2, and 3) are in effect in the following Philippine provinces: "Signal no 3:" Pangasinan, Northern Zambales, Tarlac, Nueva Vizcaya, Benguet, La Union, Ilocos Sur, Ilocos Norte, Ifugao, Mt. Province, Kalinga, Apayao, Abra. Under Signal no 2: Rest of Zambales, Pampanga, Nueva Ecija, Quirino, Isabela, Cagayan, Babuyan, Batanes. Under Signal no 1: Lubang Island, Bataan, Bulacan, Cavite, Rizal, Northern Quezon, Aurora, Metro Manila.

NASA and the Japanese Space Agency JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite acts like a "rain gauge in space" and can estimate rainfall in storms. On May 5, TRMM flew over Chan-Hom when it was off the coast of Vietnam and captured this image of rainfall happening throughout the storm. The TRMM rainfall analysis shows bands of intense rainfall in the southeastern side of Typhoon Chan-Hom. The storm's center is located near the yellow, green and red areas, which indicate rainfall between 20 and 40 millimeters (.78 to 1.57 inches) per hour. The red areas are considered moderate rainfall.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured a visible and infrared image of Chan-Hom on May 6 at 18:05 UTC (6:05 p.m. EDT). The storm's center is the purple circle to the west of the Philippines.

The infrared image shows Chan-Hom's cold clouds in purple and blue. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone. Cyclone Chan-Hom's northeastern clouds and rains are already over Luzon, the Philippines.

The Philippines can expect coastal areas to be battered with high waves and gusty winds to tropical storm strength from now through Chan-Hom's landfall.

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



May 6, 2009

NASA's Aqua MODIS instrument captures a stunning visible image of Tropical Storm Chan-Hom NASA's Aqua MODIS instrument captures a stunning visible image of Tropical Storm Chan-Hom.
Credit: NASA/MODIS Rapid Response C
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Tropical Storm Chan-Hom Stirring Up 20 Foot Waves En route to Luzon

Chan-Hom is kicking up high waves in the South China Sea, according to the Joint Typhoon Warning Center (JTWC) as it heads for a landfall in Luzon, the Philippines.

On May 6 at 15:00 Zulu Time (11 a.m. EDT), Chan-Hom was packing maximum sustained winds near 60 knots (69 mph), only four miles per hour shy of hurricane strength. It was located near 14.8 north and 115.4 east, or 335 nautical miles wet of Manila, Philippines. Chan-Hom is moving east-northeast near 10 knots (11 mph), and is kicking up waves to 20 feet high.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite took this picture of Tropical Storm Chan-Hom at 1:55 a.m. EDT (5:55 UTC) on May 6, 2009.

Chan-Hom is expected to intensify only slightly before making landfall sometime on Friday north of the Gulf of Lingayen and cross over Luzon.

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



May 5, 2009

Visible image of Chan-Hom was captured byNASA's Terra satellite Credit: NASA/JTWC
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Tropical Storm Chan-Hom Maintaining Strength

Satellites have confirmed that Tropical Storm Chan-Hom has been maintaining its strength over the last twelve hours in the South China Sea. Meanwhile, Chan-Hom continues on its track toward the island of Luzon in the Philippines where it is expected to make landfall near the end of the week.

This visible image of Chan-Hom was captured as NASA's Terra satellite flew overhead from its vantage point in space. The Moderate Imaging Spectroradiometer or MODIS instrument captured the data. It was taken on May 5 at 0344 Zulu Time. That translates to 11:44 p.m. EDT on May 4. At the time, Chan-Hom had sustained winds near 55 knots (63 mph) and a minimum central pressure near 982 millibars. Twelve hours later on May 5, its sustained winds were still near 63 mph, and it was moving north-northwest near 6 knots (7 mph) on track to Luzon.

At 11:44 a.m. EDT, May 5, Chan-Hom was located about 505 nautical miles west of Manila, the Philippines, which places it near 13.2 degrees north and 112.6 degrees east.

Chan-Hom is forecast to make landfall three days from now near Lingayen Gulf, Philippines and should rapidly weaken due to land interaction. Remnants of Chan-Hom are expected to drift into the Philippine Sea and dissipate afterward.

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



May 4, 2009

Visible image of Chan-Hom This is a visible image of Tropical Cyclone Chan-hom in the early morning hours of May 4, from NASA's Aqua satellite.
Credit: NASA JPL/Ed Olsen
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Tropical Storm Chan-hom Poses Threat to the Philippines

Residents of the Philippines just bid farewell to Tropical Cyclone Kurija but are preparing themselves for a landfall from Tropical Storm Chan-hom later this week.

Tropical Storm Chan-hom was the second tropical cyclone to form over the weekend of May 2-3, and developed in the South China Sea about 200 miles southeast of Nha Trang, Vietnam. Meanwhile, Tropical Cyclone Kurija developed to its northeast and is now heading into the open waters of the western Pacific Ocean.

On Monday, May 4, at 5 a.m. EDT (0900 Zulu Time) Tropical storm Chan-hom had maximum sustained winds near 55 knots (63 mph) and it was moving slowly through the South China Sea at 3 mph in a north-northeasterly direction. Chan-hom was now 545 miles west-southwest of Manila, the Philippines. That's near 10.9 degrees north latitude and 112.4 degrees east longitude.

Infrared image of Chan-Hom An infrared image of Chan-hom from NASA's AIRS Instrument, shows it in the South China Sea.
Credit: NASA JPL/Ed Olsen
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NASA's Aqua satellite flew over the storm on May 5, at 1:59 a.m. EDT, and the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite captured an infrared and visible image.

The AIRS infrared image shows the temperature of Chan-hom's cloud tops and the surface of the Earth (where there are no clouds). The coldest cloud temperatures are in purple (where the strongest convection is occurring). Those areas in purple have some of the strongest thunderstorms. The second coolest temperatures are in blue, which make up the clouds outside of the center of circulation. The warmer temperatures of the ocean and land are shown orange and red.

Forecasters at the Joint Typhoon Warning Center said that Chan-hom will slowly intensify as it continues to move northeast across the South China Sea towards the island of Luzon, the Philippines where it is expected to make landfall on Thursday, May 6.

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