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Hurricane Season 2011: Tropical Storm Aere (Western North Pacific Ocean)
05.17.11
 
This color-coded image shows TRMM satellite estimated rainfall amounts with the heaviest amounts in dark blue.› View larger image
This color-coded image shows TRMM satellite estimated rainfall amounts from May 5 to 12, 2011. The lowest rainfall amounts (less than 75 millimeters, or 3 inches) appear in pale green, and the heaviest amounts (more than 600 millimeters, or 24 inches) appear in dark blue. The heaviest rainfall forms a kind of bull’s eye over the easternmost islands, southeast of Manila. Rainfall amounts fall farther away from this area, but rain still affects a broad swath across the central Philippines.
Credit: NASA Earth Observatory. Jesse Allen/TRMM
NASA's TRMM Satellite Measures Heavy Rains from Tropical Storm Aere

Tropical Storm Aere formed in early May 2011, just east of the Philippines. Channel News Asia and Unisys Weather reported that the storm made landfall on May 8. By May 13, the Philippine government reported that the storm’s death toll in that nation stood at 31. Besides strong winds, the storm brought torrential rains that caused flash floods and landslides.

A color-coded image was created using data from NASA's Tropical Rainfall Measuring Mission (TRMM) satellite by Jesse Allen at NASA's Goddard Space Flight Center, Greenbelt, Md. The image shows estimated rainfall amounts from May 5 to 12, 2011. In the image, the lowest rainfall amounts (less than 75 millimeters, or 3 inches) appear in pale green, and the heaviest amounts (more than 600 millimeters, or 24 inches) appear in dark blue. The heaviest rainfall forms a kind of bull’s eye over the easternmost islands, southeast of Manila. Rainfall amounts fall farther away from this area, but rain still affects a broad swath across the central Philippines.

Over the course of its existence, Tropical Storm Aere traveled in a large arc. The storm passed over the northern Philippines, and passed east of Taiwan before curving back toward the northeast. Aere dissipated south of Japan.

Tropical storms and damaging rains frequently affect the Philippines, Typhoon Megi, Tropical Storm Conson, and Tropical Storm Ketsana being just a few of the storms to cause widespread damage. Torrential rains can also affect the islands even without the influence of named storms, such as heavy rains in January 2011.

This image is based on data from the Multisatellite Precipitation Analysis produced at Goddard Space Flight Center, which estimates rainfall by combining measurements from many satellites and calibrating them using rainfall measurements from the Tropical Rainfall Measuring Mission (TRMM) satellite.

Text Credit: Michon Scott, NASA's Earth Observatory/NASA's Goddard Space Flight Center, Greenbelt, MD



May 12, 2011

Yellow and green areas indicate moderate rainfall, falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour.› View larger image
This image of rainfall from NASA's TRMM satellite on May 11 at 1349 UTC (9:49 a.m. EDT) shows that Tropical Storm Aere is south of Japan (top of image) in the Northwestern Pacific. The small yellow and green areas are moderate rainfall, falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour.
Credit: NASA/SSAI, Hal Pierce
NASA's TRMM Satellite Sees Less Intense Rainfall in Tropical Storm Aere

Tropical Storm Aere is now moving parallel to Japan's east coast and undergoing extra-tropical transitioning. NASA's TRMM satellite passed overhead from space yesterday and captured Aere's rainfall rates and noticed they were waning.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite captured an image of rainfall happening within Tropical Storm Aere in the northwestern Pacific Ocean on May 11 at 1349 UTC (9:49 a.m. EDT). Most of the rainfall in the TRMM data appeared to be light with some isolated areas of moderate rainfall, falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour.

The final warning on Tropical Storm Aere was issued by the Joint Typhoon Warning Center yesterday, May 11 at 2100 UTC 5:00 p.m. EDT. At that time, it was centered about 230 miles SSE of Sasebo, Japan near 29.8N and 132.0E. It had maintained its strength despite extra-tropical transitioning and had maximum sustained winds near 35 knots (40 mph/64 kmh).

On May 12, gale warnings remain in effect along the eastern coasts of the main island of Japan. The sub-prefectures of Nakadori Hokubu, Nakadori Chubu, Nakadori Nambu, Hamadori Hokubu, Hamadori Chubu, Hamadori Chubu, Hamadori Nambu, Aizu Hokubu, Aizu Chubu, and Aizu Nambu all had advisories today for heavy rain, thunderstorms and dense fog as Tropical Storm Aere passes east of them (center remaining at sea).

At 12:41 p.m. EDT on May 12, most of Tropical Storm Aere's rainfall was over the open waters of the Northwestern Pacific Ocean, far to the east of Toyko. However, the northern extent of the storm was bringing rainfall north of Toyko to Fukishima and Sendai. Aere's rainfall also extended much farther north to Aomori.

Aere is now moving rapidly northeast and undergoing extra-tropical transitioning in the northwestern Pacific Ocean. Over the next day it is forecast to continue moving north-northeast past Toyko and Sendai remaining centered over the open waters of the Northwestern Pacific Ocean.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 11, 2011

This AIRS infrared image of Aere revealed limited areas of strong convection with cloud-top temperatures as cold as -63F/-52C.› View larger image
NASA's Aqua satellite passed over the western half of Tropical Storm Aere on May 11 at 05:05 UTC (1:05 a.m. EDT) and the AIRS instrument onboard captured an infrared image of the storm. The image revealed limited areas of strong convection (purple) with cloud-top temperatures as cold as -63F/-52C.
Credit: NASA/JPL, Ed Olsen
NASA Sees an "Aere" Extra-Tropical Transitioning

Tropical Storm Aere has started transitioning into an extra-tropical storm as it makes it way north-northeast in the Northwestern Pacific Ocean. Infrared imagery from NASA's Aqua satellite showed that cloud tops are warming, indicating a weakening storm.

Maximum sustained winds were still holding near 35 knots (40 mph/64 kmh). It was about 325 nautical miles (374 miles/601 km) south of Sasebo, Japan near 28.4 North and 130.7 East. It was moving east-northeastward near 20 knots (23 mph/36 kmh) and generating 15-foot (4.5 meter) high waves. The peak wind reported at Kadena Air Base during the passage of the storm was 37 knots (43 mph/68 kmh).

Satellite imagery during the morning of May 11 showed that the low-level circulation was still organized as the storm tracks along the west coast of Okinawa.

NASA's Aqua satellite passed over the western half of Tropical Storm Aere on May 11 at 05:05 UTC (1:05 a.m. EDT). Infrared data from NASA's Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite has shown that cloud-top temperatures have warmed since yesterday. Cloud-top temperatures are important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the colder the cloud tops and the more powerful the thunderstorms. The coldest cloud top temperatures are typically as cold as or colder than -63F/-52C. The area of high, powerful thunderstorms today is smaller than it was on May 10 indicating that convection (rapidly rising air that forms the thunderstorms) is weakening.

Increased wind shear is also now taking its toll on Tropical Storm Aere as are cooler sea surface temperatures as it continues to move north. Those two factors will continue to weaken the storm.

The Joint Typhoon Warning Center noted that computer model guidance shows that Aere will weaken into a "low-gale force mid-latitude low as it tracks seaward of the Kanto Plain."

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 10, 2011

This image of rainfall from NASA's TRMM satellite on May 10 shows Aere is east of Taiwan in the Northwestern Pacific.› View larger image
This image of rainfall from NASA's TRMM satellite on May 10 at 0811 UTC (4:11 a.m. EDT) shows that Tropical Storm Aere is east of Taiwan in the Northwestern Pacific. The red areas on the northeastern side of Aere's circulation represent heavy rainfall (falling at about 2 inches/50 mm per hour). The yellow and green areas are moderate rainfall, falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour. The image also showed that Aere had what appeared to be a "tail" of precipitation falling southeast over Luzon, northern Philippines.
Credit: NASA/SSAI, Hal Pierce
TRMM 3-D image Aere on May 8 showed powerful thunderstorms within the center of circulation that topped 15 kilometers.› View larger image
This 3-D image of Tropical Storm Aere on May 8 at 0823 UTC (4:23 a.m. EDT) revealed that there were some very powerful thunderstorms within the center of circulation that topped 15 kilometers (over 9 miles high- in red). That area had heavy rainfall of up to 2 inches (50 mm) per hour.
Credit: NASA/SSAI, Hal Pierce
Infrared image of Tropical Storm Aere was captured by satellite on May 9 at 17:29 UTC.› View larger image
This infrared image of Tropical Storm Aere was captured by the Atmospheric Infrared Sounder on NASA's Aqua satellite on May 9 at 17:29 UTC. The strongest convection (purple) has cloud top temperatures near -63F/-52C. Aere appears somewhat elongated in this image.
Credit: NASA/JPL, Ed Olsen
NASA Sees Towering Thunderstorms, Heavy Rainfall in Tropical Storm Aere

Tropical Storm Aere appears to be headed toward Kadena Air Base in the northwestern Pacific Ocean, and NASA satellites have found towering thunderstorms and heavy rainfall occurring in some areas of the storm. Aere's center is forecast to stay just to the east of the island tomorrow, but will bring heavy surf, gusty winds and heavy rainfall.

When NASA and the Japanese Space Agency's Tropical Rainfall Measuring Mission (TRMM) satellite passed over Tropical Storm Aere on May 10 at 0811 UTC (4:11 a.m. EDT) it captured the rainfall rates within the storm as it lay east of Taiwan in the Northwestern Pacific. On the northeastern side of Aere's circulation TRMM found areas of heavy rainfall (falling at about 2 inches/50 mm per hour). Moderate rainfall encompassed a large area, falling at a rate between .78 to 1.57 inches (20 to 40 mm) per hour. The image also showed that Aere had what appeared to be a "tail" of precipitation falling southeast over Luzon, northern Philippines.

The following animation of the 3-D image of Tropical Storm Aere on May 8 shows very powerful thunderstorms within the center of circulation that topped 16 kilometers (almost 10 miles high- in red). That area had heavy rainfall of up to 2 inches (50 mm) per hour. The animation takes the viewer around the storm. (Credit: NASA/SSAI, Hal Pierce)



Tropical storm Aere was the first tropical cyclone to hit the Philippines in 2011 and was responsible for the deaths of least 22 people. Aere, also known as Bebeng in the Philippines islands, formed east of the Philippines on May 6, 2011. Data collected by the TRMM satellite on May 8, 2011 at 0823 UTC (~4:23 p.m. Local time) were used to create an image of rainfall. At that time Aere had wind speeds estimated at about 50 knots (~58 mph). TRMM Precipitation Radar data from this orbit were used to also create a 3-D image that shows the vertical structure within Aere. The 3-D image showed that some thunderstorms within Aere's center reached heights of about 16 km (~9.9 miles).

On May 10 at 1500 UTC (11 a.m. EDT), Tropical Storm Aere's maximum sustained winds were near 35 knots (40 mph/64X kmh). It was about 330 nautical miles (380 miles/611 km) southwest of Kadena Air Base, Okinawa, Japan, near 22.9 North and 124.4 East. It was moving northeast near 19 knots (22 mph/35 kmh) and generating 15-foot (4.5 meter) high waves. The southern and eastern sides of Okinawa are likely more susceptible to high surf.

Convection (rapidly rising air that forms the thunderstorms the make up the tropical storm) is continuing in the northeastern quadrant of Aere, however, an upper-level trough (elongated area of low pressure) moving toward the western side of the storm is suppressing thunderstorms development over the western edge of circulation. Satellite data also indicates that the low-level center of circulation appears partially exposed to wind shear, and that wind shear is displacing most of the convection east of the center.

Aere is moving in a northeasterly direction and is currently to the east of Taiwan. The system will maintain strength as it passes to the south of Japan and then undergo extra-tropical transitioning.

Text Credit: Hal Pierce, NASA/SSAI, and Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 9, 2011

Aqua infrared view of Tropical storm Aere › View larger image
This time series of imagery from NASA's Aqua satellite show Tropical Storm Aere's progress over the weekend on May 6 at 16:59 UTC, May 7 at 05:29 UTC, and Monday, May 9 at 05:17 UTC. Aere continues to track to the north today. The purple areas indicate the strongest thunderstorms and areas of heaviest rainfall. They are the coldest cloud temperatures (highest, strongest thunderstorms) and are as cold as or colder than -63F/-52C.
Credit: NASA JPL, Ed Olsen
NASA Satellite Sees Tropical Storm Aere Leave Deadly Path in Philippines

NASA's Aqua satellite flew over what has grown into Tropical Storm Aere every day this past weekend, as it dropped heavy rainfall, created mudslides and took lives in the eastern Philippines. Infrared satellite imagery from Aqua revealed the strong thunderstorms responsible for the heavy rainfall.

In a time series of imagery from NASA's Aqua satellite, the Atmospheric Infrared Sounder (AIRS) instrument showed Tropical Storm Aere's progress over the weekend on May 6 at 16:59 UTC, May 7 at 05:29 UTC, and Monday, May 9 at 05:17 UTC. Infrared data basically takes the temperature of a tropical cyclone's clouds and the coldest areas indicate the strongest thunderstorms and areas of heaviest rainfall. Those coldest cloud temperatures (highest, strongest thunderstorms) and are as cold as or colder than -63F/-52C.

On May 6, when Aere was a tropical depression (03W) it appeared to be more concentrated with the heaviest rainfall and strongest thunderstorms over open ocean. By Saturday, May 7, those heavy rains overspread land areas. On Monday, May 9, the circulation seemed to become weaker and convection (rapidly rising air that forms the thunderstorms) seemed to appear more scattered and has decreased in AIRS imagery.

Warnings are still in effect in the Philippines as Aere continues to move north. Public storm warning signal #1 is in effect in the following provinces: Luzon: Quirino, Ifugao, Mt. Province, Kalinga, Apayao and Batanes. Public storm warning signal #2 is in effect for: Luzon: Cagayan, Babuya and Calayan.

The four fatalities caused by Tropical Storm Aere occurred in Balatan, Camarines Sur where a landslide took three lives, and another person drowned in floodwaters in Leyte. Radio reports also noted that nine people at the Manila airport were injured when lightning struck a plane on the tarmac on May 7.

On May 9 at 1500 UTC (11:00 a.m. EDT), Tropical Storm Aere, formerly known as Tropical Depression 03W continued to bring rainfall to the Philippines. Its center was about 215 miles (346 km) north-northeast of Manila near 18.0 North and 122.3 East. It was moving north near 9 knots and had maximum sustained winds near 40 knots (46 mph/74 kmh). Aere, known locally in the Philippines as "Bebing," was creating rough waves on eastern-facing shores, as wave heights were reaching up to 13 feet (4 meters).

Aere is now moving along the east coast of Luzon Island and the Joint Typhoon Warning Center forecasts the tropical storm to soon move into the open waters south of Taiwan and then move northeast through the Northwestern Pacific Ocean. Aere is expected to become extratropical south of Japan.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 6, 2011

TRMM noticed that the storm's rainfall was still concentrated on the western side of circulation.› View larger image
TRMM captured the rainfall rates of Tropical Depression 03W (TD03W) on Friday, May 6 at 0837 UTC (4:37 a.m. EDT). TRMM noticed that the storm's rainfall was still concentrated on the western side of circulation, although the northern and eastern areas of the storm were also showing rainfall. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches (20-40 mm) per hour. The tiny red areas are heavy rainfall at almost 2 inches (50 mm) per hour.
Credit: NASA/SSAI, Hal Pierce
AIRS captured the cold, strong thunderstorms (purple) surrounding the center of Tropical Depression 03W.› View larger image
On May 6 at 4:41 UTC NASA's Aqua satellite captured the cold, strong thunderstorms (purple) surrounding the center of Tropical Depression 03W. Those areas had cloud-top temperatures of -63F/-52C.
Credit: NASA/JPL, Ed Olsen
NASA Satellites See Moderate Rainfall in Tropical Depression 03W, Affecting the Philippines

Moderate rainfall abounds in newly strengthened Tropical Depression 03W near the Philippines, according to data from NASA's Tropical Rainfall Measuring Mission satellite. NASA's Aqua satellite confirmed the data through cold cloud-top temperatures and rain continues to fall in the Philippines today where the storm has been given the local name "Bebeng."

System 93W strengthened into Tropical Depression Three early on May 6 and is forecast to move toward Luzon late into the weekend. At 1500 UTC (11 a.m. EDT) on May 6, the center of TD03W was located east of Visayas about 460 nautical miles east-southeast of Manila, the Philippines near 11.9 North and 138.0 East. It was moving toward the northwest at 3 knots. Maximum sustained winds are near 30 knots.

On May 6, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) had not issued any warnings in the Philippines. The forecast from PAGASA on Friday, May 6 noted that clouds and scattered showers would affect the Bicol Region, Visayas and northern Mindanao, with thunderstorms developing over the Bicol Region and Visayas. Some of the rainfall could be heavy in those areas and may trigger flash flooding and landslides.

The Tropical Rainfall Measuring Mission (TRMM) satellite, managed by NASA and the Japanese Space Agency flew over Tropical Depression 03W (TD03W) on Friday, May 6 at 0837 UTC (4:37 a.m. EDT). TRMM noticed that the storm's rainfall was still concentrated on the western side of circulation, although the northern and eastern areas of the storm were also showing rainfall. Only a couple of very small areas of heavy rainfall were seen in the TRMM image around the northeastern fringes of circulation. In those small, isolated areas rain was falling at about 2 inches (50 mm) per hour. Rainfall around the rest of the storm was moderate, falling at rates between 20 and 40 millimeters (.78 to 1.57 inches) per hour.

TRMM images are pretty complicated to create. They're made at NASA's Goddard Space Flight Center in Greenbelt, Md. At Goddard, rain rates in the center of the swath (the satellite's orbit path over the storm) are created from the TRMM Precipitation Radar (PR) instrument. The TRMM PR is the only space borne radar of its kind. The rain rates in the outer portion of the storm are created from a different instrument on the satellite, called the TRMM Microwave Imager (TMI). The rain rates are then overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). For more information about TRMM, visit: http://www.trmm.gsfc.nasa.gov/.

NASA's Aqua satellite flew over TD03W on May 6 at 4:41 UTC (12:41 a.m. EDT) and the Atmospheric Infrared Sounder (AIRS) instrument onboard captured an infrared image the storm. The AIRS image showed TD03W as a slightly elongated storm with some very cold cloud top temperatures indicating some high cloud tops and strong thunderstorms. The coldest cloud-tops were as cold as or colder than -63F (-52C).

Infrared and microwaves satellite imagery showed that although the low-level circulation center is slightly elongated, it is consolidating and there are bands of thunderstorms wrapping into the center. Convection (rapidly rising air that form the thunderstorms that power TD03W) has increased near the center.

Forecasters at the Joint Typhoon Warning Center expect TD03W to continue intensifying slowly before making landfall on Monday, May 9 - then weaken over Luzon.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 5, 2011

AIRS infrared image from May 4 showing large areas of strong convection on System 93W's west and southern edges.› View larger image
This infrared image taken from the AIRS instrument on NASA's Aqua satellite on May 4 at 17:11 UTC ( 1:11 p.m. EDT) shows large areas of strong convection (purple) on System 93W's west and southern edges, where thunderstorms have very cold cloud-top temperatures (-63F/-52C).
Credit: NASA/JPL, Ed Olsen
NASA Satellites See System 93W Still Strengthening, Affecting Philippines

It seems to be a matter of time before System 93W strengthens into a tropical storm and infrared satellite imagery from NASA's Aqua satellite seems to go along with that idea. Aqua imagery showed some strong convection particularly on the west side of the low pressure area today, and rain is already falling in parts of the Philippines.

An infrared image taken from the AIRS (Atmospheric Infrared Sounder) instrument on NASA's Aqua satellite on May 4 at 17:11 UTC (1:11 p.m. EDT) showed large areas of strong convection on System 93W's west and southern edges, where thunderstorms have very cold cloud-top temperatures (-63F/-52C). That strong convection remained on the low's western side on May 5.

On May 5, System 93W's circulation center appears to be near 11.1 North and 128.3 East, about 475 nautical miles (546 miles/879 km) east-southeast of Manila, the Philippines. The surface winds are still estimated between 15 and 20 knots (17-23 mph/28-37kmh). System 93W is still in warm waters that will assist in its strengthening as it continues moving to the northwest near 8 knots (9 mph/15 kmh).

The eastern Philippines are already experiencing some light rains from System 93W. At 12 p.m. EDT on May 5, the city of Legazpi (capital of the province of Albay), Philippines reported light rain with a temperature of 25C/ 77F. The minimum central pressure was 29.80 inches and falling and winds were blowing from the northeast at 5 mph (4 knots). Thunderstorms are in the forecast for Friday, May 6 and Saturday May 7, as System 93W moves closer.

The low-level circulation center still appears to be somewhat loosely organized, but there are some banding of thunderstorms wrapping into System 93W's center. The upper level winds are cooperating for further development, and currently the Joint Typhoon Warning Center gives this low a good prognosis for developing into a tropical storm.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD



May 4, 2011

System 93W captured by AIRS on May 4  showing the coldest, strongest thunderstorms (purple) around the center of the low.› View larger image
This infrared image of System 93W on May 4 at 01:53 UTC was captured by NASA's Aqua satellite. The coldest, strongest thunderstorms (purple) surrounded the center of the low.
Credit: NASA/JPL, Ed Olsen
This AIRS visible image of System 93W suggests that the storm is about 800 miles wide.› View larger image
This visible image of System 93W from NASA's Aqua satellite was captured on May 4 at 01:53 UTC and suggests that the storm is about 800 miles wide.
Credit: NASA/JPL, Ed Olsen
Tropically-Speaking - NASA Satellite Imagery Shows Big System 93W Developing

System 93W is a large low pressure area in the Western North Pacific Ocean that appears poised for tropical development in NASA satellite imagery. Improved circulation and warm sea surface temperatures provide some hints of a strengthening storm.

The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured both an infrared and visible image of System 93W on May 4 at 01:53 UTC (May 3 at 9:53 p.m. EDT). The width of the AIRS image track is 1056 miles (1700 km), the width of System 93W appears to be approximately 800 miles (1,287 km) from west to east.

The AIRS imagery showed an improved low-level circulation center and unorganized, but deep convection. Convection is rapidly rising air that forms the thunderstorms that power a tropical cyclone.

The strongest convection appeared around the center of System 93W's circulation where cloud-top temperatures were measured to be as cold as or colder than -63F/-52C. Cloud-top temperatures are important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the colder the cloud tops and the more powerful the thunderstorms.

Today, May 4, the low pressure area was located about 180 nautical miles east of Mindanao, the Philippines today, near 9.4 North and 129.0 East. Its surface winds are estimated between 15 and 20 knots. The system is moving west-northwestward at 11 knots (~12 mph/20 kmh).

The Joint Typhoon Warning Center (JTWC) noted that a buoy about 100 nautical miles to away reported a minimum central pressure of 1005 millibars. With sea surface temperatures near 84F (29C), the waters are warm enough to support development into a tropical storm. Wind shear is also low, which will help with development. The JTWC gives System 93W a good chance for development into a tropical storm over the next 24 hours.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD