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Hurricane Season 2009: Typhoon Melor (Western Pacific)
10.09.09
 
October 9, 2009

AIRS image of Melor> View larger image
NASA's Aqua satellite AIRS instrument captured remnants of Extra-tropical Storm Melor on October 8 at 11:59 a.m. EDT. Melor appears as a large amorphous area (blue) located over Hokkaidō (large island that resembles a sideways anvil) and the Kuril island chain as it continued moving out to sea. The lack of purple in this image indicates a weak storm without strong thunderstorms. Credit: NASA JPL, Ed Olsen
Extra-Tropical Storm Melor in the Northern Pacific Ocean

Extra-Tropical Storm Melor swept through Japan yesterday, October 8, delaying airline flights and bringing gusty winds to the main island. Around noontime EDT, NASA satellite imagery saw Melor's remnants were raining on Hokkaido and the Habomai Islands.

Hokkaido and the Habomai islands were buffeted by strong winds and high waves. Hokkaidō is Japan's second largest island and north of the big island. Sapporo is the capital city in Hokkaidō and is best-known for hosting the 1972 Olympics. The Habomai islands are located off the northern coast of Japan's Hokkaido Island, and are part of the Kuril Island chain. Those islands are also known as the Northern Territories in Japan.

NASA's Aqua satellite's Atmospheric Infrared Sounder (AIRS) instrument captured remnants of Extra-tropical Storm Melor on October 8 at 11:59 a.m. EDT. At that time, Melor appeared as a large amorphous area located over Hokkaidō and the Kuril island chain, as Melor continued moving out to sea. AIRS imagery revealed that there were no extremely high thunderstorms, and cloud temperatures were warmer than -63F (the threshold that indicates high, powerful thunderstorms).

As Melor swept through Japan, it did take four lives, and injured more than 100 people. On the big island, north of Toyko, a tornado was reported to have destroyed a post office, downed trees and powerlines and caused other damages.

Melor still had 89 mph wind gusts as it exited Japan on Friday, October 9, and is expected to weaken to a tropical depression as is tracks northeastward along Russia's Kuril island chain. The extratropical remnants of Typhoon are now in the western North Pacific Ocean. It was the first typhoon to make landfall in Japan in two years.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



October 8, 2009

Typhoon Melor had winds between 104 and 98 mph. The strongest winds are pink and purple. > View larger image
NASA's QuikScat satellite captured the winds of Super Typhoon Melor on October 7 at 5:35 a.m. (Tokyo time).Typhoon Melor had winds between 104 and 98 mph. The strongest winds are pink and purple, forming a rough circle in the center of the storm.
Credit: NASA JPL/David Long, Brigham Young Univ.
NASA's QuikScat Sees a Weaker Typhoon Melor Near Japan

Typhoon Melor was a weakening Category 2 typhoon on the morning of October 7, 2009, when the QuikSCAT satellite collected the observations used to make this image. The image depicts the wind field associated with the storm. The strongest winds are pink and purple, forming a rough circle in the center of the storm. Much of the rest of the storm is made up of a broad field of moderately strong winds, shown in red. Barbs illustrate wind direction, spiraling around the center of the storm. White barbs point to areas of heavy rain.

QuikSCAT collected these wind measurements at 5:35 a.m. (Tokyo time) on October 7 (20:35 UTC, October 6). At that time, Typhoon Melor had winds between 167 kilometers per hour (104 miles per hour or 90 knots) and 157 km/hr (98 mph or 85 knots), according to the Joint Typhoon Warning Center. The storm was moving towards Japan and was forecast to make landfall around 9:00 a.m. on October 8, local time.

QuikSCAT monitors wind speed with a radar that sends out pulses of microwave energy and listens for the echo after the pulse bounces off the wind-roughened ocean surface. Scientists translate radar signals into estimates of wind speed by matching the radar echoes to physical measurements collected from buoys at the same time and place.

Cyclone-strength wind speeds are rare, however, and scientists generally don’t have enough matching buoy observations to convert wind speeds above roughly 50 knots. Intense rain rippling the ocean’s surface can also interfere with the radar signal. Because of these limitations, QuikSCAT images don’t show absolute, maximum wind speeds. Instead, they give forecasters a valuable picture of the wind structure within the storm, for example, revealing whether a storm has a strong or a weak eye and how large an area is experiencing tropical-storm-strength winds.

Text credit: Holli Riebeek, NASA's Earth Observatory



Melor had a nearly complete inner eyewall, surrounded by a nearly complete outer eyewall of moderate rain. > View larger image
TRMM captured Category 4 Typhoon Melor at 14:29 UTC on October 5, 530 miles southeast of Okinawa. Melor had a nearly complete inner eyewall (the innermost bright green ring indicates moderate rain), surrounded by a nearly complete outer eyewall of moderate rain (wider concentric ring of bright green). This is only found in very powerful, mature tropical cyclones. The white area is a nearly symmetrical cirrus cloud shield indicating Melor was in a favorable environment..
Credit: SSAI/NASA, Hal Pierce
TRMM revealed Melor lost its symmetrical structure with most of the rain now to the north of the center. > View larger image
TRMM captured another image of Melor at 20:06 UTC October 6 moving north-northeast towards southern Japan. TRMM revealed Melor lost its symmetrical structure with most of the rain (blue, green and red areas, indicating light, moderate and heavy rain, respectively) now to the north of the center (white area surrounded by blue near the bottom). The area of light to moderate rain (blue and green areas, respectively) across the top of the image is associated with a stationary front draped across southern Japan.
Credit: SSAI/NASA, Hal Pierce
NASA's TRMM Satellite Captures Typhoon Melor as it Reaches Japan

Melor began as a tropical depression back on the 29th of September 2009 about 1000 miles (~1600 km) east-southeast of Guam in the Northern Mariana Islands. Over the next couple of days, the system steadily intensified, first into a tropical storm on the 30th, then into a typhoon on the morning of the 1st of October. At which time, Melor underwent a rapid intensification cycle and quickly reached Category 4 intensity on the night of the 1st with sustained winds estimated at 115 knots (~132 mph) by the Joint Typhoon Warning Center (JTWC) as it moved toward the west-northwest in the direction of the Northern Marianas. Melor underwent minor fluctuations in intensity before passing through the Northern Marianas Islands on the afternoon (local time) of the 3rd where it caused only relatively minor damage. After clearing the islands, Melor strengthened once again, becoming the 3rd super typhoon of the year as it crossed through the central Philippine Sea. Melor reached its peak intensity on the 4th when its sustained winds were estimated at 145 knots (~167 mph) by JTWC.

The Tropical Rainfall Measuring Mission satellite (better known as TRMM) has served as a valuable platform for monitoring tropical cyclones since its launch back in 1997, especially over remote parts of the ocean. TRMM captured an image of Melor at 14:29 UTC on October 5, 2009 as the storm was moving west-northwest about 530 miles (~850 km) southeast of Okinawa. The image shows the horizontal distribution of rain intensity inside the storm. The rain rates were obtained from the TRMM Microwave Imager (TMI) and are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). At the time of that image, although it was a little off of its peak intensity, Melor was still a powerful Category 4 super typhoon with maximum sustained winds estimated at 135 knots (~155 mph) by JTWC. TRMM showed that Melor appears to be in the process of undergoing an eyewall replacement cycle as evidenced by the distinct double eyewall structure. Melor had a nearly complete inner eyewall, which is surrounded by a nearly complete outer eyewall of moderate rain. This type of feature is only found in very powerful, mature tropical cyclones. Also apparent is the nearly symmetrical cirrus cloud shield, which indicates that Melor was still in a favorable low wind shear environment. But, that all changed quickly as the steering currents finally began to recurve Melor toward the north the next day, and in the process, Melor began to weaken steadily.

TRMM captured another image of Melor at 20:06 UTC 6 October (5:06 am 7 October Japan standard time) as it was moving north-northeast towards southern Japan. In the second image, rain rates in the center of the swath were obtained from the TRMM Precipitation Radar (PR), the only spaceborne precipitation radar of its kind. That TRMM image revealed that Melor has lost its symmetrical structure with most of the rain now to the north of the center. This is due to the southwesterly winds that are pushing the storm to the north. The area of light to moderate rain across the top of the TRMM image of October 6 is associated with a stationary front draped across southern Japan. Melor's circulation and moisture are expected to merge with this front and bring heavy rain and strong winds as the system moves northeastward over the main island of Honshu. At the time of this last image, Melor was a Category 2 typhoon with sustained winds estimated at 90 knots (104 mph) by JTWC.

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

Text credit: Steve Lang, SSAI /Goddard Space Flight Center



October 7, 2009

Infrared image of Parma (lower left) and Melor (top right) on October 7 › Larger image
NASA's Aqua satellite captured cold thunderstorm cloud tops of both Parma (lower left) and Melor (top right) in this infrared image October 7. Parma continues to rain on northern Luzon in the Philippines, while Melor is now bringing rains and winds over southern Japan. Credit: NASA JPL, Ed Olsen

AIRS visible image of Tropical Storm Parma (lower left) and Typhoon Melor (top right) on October 7 › Larger image
NASA's Aqua satellite captured this visible image of Tropical Storm Parma (lower left) and Typhoon Melor (top right) on October 7. Credit: NASA/JPL, Ed Olsen

MODIS image of Typhoon Melor as it was approaching Japan (outline of Japan at top of image) on October 6 › Larger image
The Moderate Imaging Spectroradiometer instrument on NASA's Terra satellite captured this image of Typhoon Melor as it was approaching Japan (outline of Japan at top of image) on October 6 at 9:40 p.m. EDT. Credit: NASA MODIS Rapid Response Team
Melor and Parma Mean Double Trouble in the Western Pacific

There's double-trouble in the Western Pacific with one typhoon and one tropical storm bringing soaking rains, dangerous surf and gusty winds to two different locations. Typhoon Melor is affecting the east coast of Japan and watches and warnings are up today. Further south, Tropical Storm Parma continues to rain on Luzon in the northern Philippines.

Typhoon Melor is currently affecting southern Japan and bringing gusty winds, heavy rains and high waves there. High Wave and Gale Watches and warnings have been posted in Japan in the prefectures of Miyazaki and Kagoshima today. For current watches and warnings posted in Japan: http://www.jma.go.jp/en/warn/110_table.html

At 11 a.m. EDT, Typhoon Melor had sustained winds near 75 knots (86 mph). It was located 350 nautical miles southwest of Tokyo, Japan, near 32.7 North and 135.4 East. Melor is moving northeast near 25 knots (28 mph) and is generating 30-foot high waves. At 11 a.m. EDT, the storm was almost due south of the city of Wakayama.

Melor is currently becoming extra-tropical as it approaches Honshu. It will accelerate northeast to the west of Tokyo and reemerge over the Pacific as a strong non-tropical low pressure system.

At 11 a.m. EDT on October 7, Parma had been downgraded to a tropical storm with sustained winds near 35 knots (42 mph). Parma was located 225 nautical miles north-northeast of Manila, Philippines, near 18.1 North and 122.4 East. Parma has tracked north-northeastward at 4 mph. Parma is still generating waves up to 22 feet high.

Parma's forecast track is still somewhat questionable, as different computer forecast models take Parma on different tracks. However, forecasters at the U.S. Navy's Joint Typhoon Warning Center are forecasting Parma to slowly crawl from northeastern Luzon back across the northern island and finally into the South China Sea sometime on October 9. The slow movement across the northern Philippines means more unwelcome rain in the region over the next several days.

Warnings are posted in the Philippines today. Public storm warning signal 1 is in force in Batanes Group of Islands, Cagayan, Babuyan Island, Calayan Island, Ilocos Norte & Sur, Apayao, Abra, Kalinga, Mountain Province, Isabela, Ifugao, Nueva Vizcaya, Northern Aurora and Benguet.

An instrument on NASA's Aqua satellite captured both typhoons in one image. The Atmospheric Infrared Sounder (AIRS) captured both Parma and Melor in a visible and infrared image October 7 at 0453 UTC (12:53 a.m. EDT) as Parma continues to rain on northern Luzon in the Philippines, while Melor is now bringing rains and winds over southern Japan.

The infrared imagery revealed that the cloud tops of Parma are not as cold as they are in Melor, indicating that Parma is a much weaker storm. Typhoon Melor has some strong thunderstorms, where temperatures are colder than -63 Fahrenheit.

Infrared imagery has also shown that Tropical Storm Parma has made its track over Luzon, and is now back over the open waters of the Philippine Sea. Although Parma's track over land weakened the storm, the open waters are expected to power the storm's convection and thunderstorms back up. In fact, infrared imagery has shown that convection is already redeveloping near the low level center of the storm.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



October 6, 2009

AIRS image of Typhoon Melor at 1:30 p.m. local time October 6 › View larger image
The AIRS instrument on NASA's Aqua satellite captured an infrared image of Typhoon Melor at 1:30 p.m. local time October 6. The infrared image shows the coldest cloud tops are 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.
Credit: NASA/JPL, Ed Olsen
Typhoon Melor Starting to Weaken, But Affecting Japan's Kadena Island

Kadena Island is a small island in the Western Pacific, south of Japan, and today its feeling the affects of Typhoon Melor as the storm continues to move toward it.

Kadena Air Base, a United States Air Force base is located in the towns of Kadena and Chatan and the city of Okinawa, in Okinawa Prefecture, Japan.

Melor has already started to weaken because of upper level winds battering the storm, but as of 11 a.m. EDT on October 6, Melor had maximum sustained winds near 110 knots (126 mph). It was located 165 miles east-southeast of Okinawa, Japan, near 25.2 North and 130.6 East. It was moving north-northwest near 17 mph. Tropical storm-force winds extend as far out as 175 miles form the center, and hurricane-force winds extend as far as 95 miles from the center.

Data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite captured an infrared image of Typhoon Melor at 1:30 p.m. local time October 6. AIRS infrared images show the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures are associated with high, cold cloud tops that make up the top area of Typhoon Melor. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). Surrounding thunderstorms are not as high and not as cold at around 240 degrees Kelvin, or minus 27F.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the ocean and land surfaces, revealing warmer temperatures. Those are important for forecasters to know as well, because it takes ocean surface water temperatures of at least 80 degrees Fahrenheit to power a storm. The waters in Melor's path are near that threshold. AIRS data is also used to create an accurate 3-D map of atmospheric temperature, water vapor and clouds and all of those factors also help forecasters gauge what's going to happen with the storm.

Forecasters are also keeping a close eye on local radar. To see local radar from Kadena, click here.

The storm is curving to a northeasterly course and that is expected to take Melor ashore in Japan south of Kyoto. Residents of Japan should be on watch for Melor's arrival.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



October 5, 2009

MODIS image of Melor> Click for larger image
The MODIS instrument on NASA's Terra satellite captured an image of Super Typhoon Melor in the Western Pacific Ocean during the early morning hours of October 5, 2009. Melor has intensified to Super Typhoon strength and is currently equivalent to category 5 on the Saffir Simpson scale. Credit: NASA MODIS Rapid Response Team
Two NASA Satellites Capture Monster Super Typhoon Melor

NASA's Terra and Aqua satellites flew over Super Typhoon Melor early today, October 5 and captured some impressive images of the storm's clouds on a track toward Japan. The Western Pacific Ocean has the edge on super typhoons, and Melor's maximum sustained winds near 161 mph are more proof.

Typhoon Melor tracked through the channel between Saipan and Agrihan on Saturday night, and became a Super Typhoon on Sunday. Melor's winds dropped to 130 mph just before it passed near the island of Saipan this weekend and it was far enough away to not cause any major damage, according to local news reports. Downed trees and heavy rain were experienced Saturday afternoon and overnight into Sunday (local time), but no major flooding was reported.

On October 5 at 5 a.m. EDT (0900 UTC), Super Typhoon Melor's winds were up to 161 mph, and it was located approximately 585 nautical miles southeast of Okinawa, near 19.6 North and 134.3 East. Melor is moving west-northwestward at 19 mph.

NASA's Terra satellite flew over Melor during the early morning hours on October 5. The Moderate Imaging Spectroradiometer (MODIS) instrument on Terra provided a dramatic image of Melor at Category 5 strength on the Saffir-Simpson scale with maximum sustained winds near 161 mph!

AIRS image of Melor> Click for larger image
Aqua's Atmospheric Infrared Sounder (AIRS) instrument captured Melor's high thunderstorm cloud temperatures (in purple) that were colder than minus 63 Fahrenheit. This image from October 4 at 12:29 EDT clearly shows Melor's eye. Credit: NASA JPL, Ed Olsen
NASA's Aqua satellite flew over Super Typhoon Melor mid-day on October 4 and captured an infrared image of the monster typhoon. Aqua's Atmospheric Infrared Sounder (AIRS) instrument and Moderate Imaging Spectroradiometer (MODIS) analyzed temperatures in Melor's clouds. AIRS revealed the cold high thunderstorm cloud temperatures were colder than minus 63 Fahrenheit indicating a very strong tropical cyclone.

Forecasters at the U.S. Navy's Joint Typhoon Warning Center have amended the forecast track for Melor, and take the super typhoon on a path resembling the letter "C" in the Western Pacific Ocean. The storm is forecast to swing just east of Kadena island Japan, then turn northeast (because westerly winds will push it northeast) and its center is now expected to brush Tokyo before it swings northeast back into the open Western Pacific.

There's good news about the storm's strength however. Melor will slowly weaken as a because of increased vertical wind shear (winds blowing sometimes at different directions, at different levels of the atmosphere that can tear a storm apart) and cooler waters. When Melor is south of Tokyo, it's expected to interact with a baroclinic boundary (i.e. a front) and become extratropical.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



October 2, 2009

The AIRS infrared images are false-colored to show Melor's highest, cold clouds in purple and blue. > View larger image
The AIRS infrared images are false-colored to show Melor's highest, 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 tropical storm.
Credit: NASA/JPL, Ed Olsen
Super Typhoon Melor Crossing Guam This Weekend

Melor has become a Super Typhoon with sustained winds near 130 mph, and is crossing Guam and its islands this weekend. Warnings and watches are already up for the region.

A typhoon warning is in force for Saipan and Tinian. A typhoon watch is in force for Rota and Agrihan, and a tropical storm warning is in effect for Guam, Rota and Agrihan, meaning that tropical storm conditions are expected within 24 hours.

NASA's Aqua satellite flew over Super Typhoon Melor on October 1 at 15:59 UTC (1:59 a.m. Guam local time), and captured in infrared image of the storm's clouds using the Atmospheric Infrared Sounder (AIRS) instrument. AIRS takes the temperature of the storm's highest, cold clouds and revealed very high, powerful thunderstorms. Those cloud tops were as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the tropical storm.

The National Weather Service (NWS) in Guam issued a special statement about Super Typhoon Melor, and warned residents not to focus on where Melor's center is located, because the storm is very large and dangerous winds extend far from the center. The NWS statement reads "Islands hundreds of miles from the typhoon eye will experience tropical storm-force winds. Melor is expected to intensify and move toward the Marianas. The onset of damaging winds is expected in the northern Marianas after Midnight tonight (local time)." For updated information: http://www.prh.noaa.gov/guam/localHazards.php.

How far do Melor's winds extend? Tropical storm-force winds of (39 mph) 34 knots or higher occur within 185 to 225 miles of the center, while typhoon (hurricane)-force winds of (73 mph) 64 knots or higher occur within 60 miles of the center.

The National Weather Service forecast for Guam, specifically where Andersen Air Force Base is located is as follows: Today (Saturday, October 2)...Damaging winds. Northwest winds 25 to 30 mph shifting to the west 30 to 40 mph in the afternoon. Cloudy. Scattered showers and isolated thunderstorms in the morning...then numerous locally heavy showers and isolated thunderstorms in the afternoon. Highs around 83. Tonight (Saturday Night...Damaging winds. Southwest winds 35 to 45 mph. Cloudy with numerous locally heavy showers and isolated thunderstorms. Lows around 77. For live National Weather Service radar at the Andersen Air Force Base, Guam: http://radar.weather.gov/radar.php?rid=GUA&product=NCR&overlay=11101111&loop=yes.

Super Typhoon Melor had maximum sustained winds near 132 mph (115 knots) on October 2 at 1500 UTC (at 1 a.m. Saturday, October 2). It was located 305 miles east-northeast of Saipan, near 15.0 North and 149.9 East. Melor is moving northwest near 9 mph and is creating 29-foot high waves.

After passing Guam, Melor is forecast to steer northeast and approach central Japan.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



October 1, 2009

QuikScat imagery is false-colored to show different wind speeds; the highest winds are always shown in purple. > View larger image
QuikScat saw Melor's winds on September 30 at 7:39 UTC. QuikScat imagery is false-colored to show different wind speeds, the highest winds are always shown in purple, indicating winds over 40 knots (46 mph). Small barbs are used in the images to indicate wind direction and point to areas of heavy rain.
Credit: NASA/JPL, Pedro Falcon III
The AIRS instrument showed the large extent of Melor's cold clouds and rains (in blue and purple). > View larger image
The AIRS instrument showed the large extent of Melor's cold clouds and rains (in blue and purple) as it neared Guam on October 1 at 3:47 UTC. The colder the clouds, the higher they are, and the stronger the thunderstorms. Purple indicates higher clouds than blue.
Credit: NASA/JPL, Ed Olsen
Marianas on Alert: Melor Joins the Typhoon Group

Being a typhoon seems to be the "in thing" lately for tropical cyclones in the Western Pacific, and Melor is now one of the "in crowd." NASA's QuikScat and Aqua satellites helped the U.S. Navy's Joint Typhoon Warning Center confirm that Melor now has sustained winds near 115 knots. The Marianas Islands have posted watches and warnings anticipating Melor's arrival.

On October 1 at 15:00 Zulu Time (1 a.m. October 2, Pacific/Guam Time), Typhoon Melor was located approximately 420 nautical miles east of Guam, near 14.4 North and 151 East. That also puts Melor 355 miles east of Saipan, and 360 miles east of Tinan. Melor has tracked northwestward at 6 mph while continuing to intensify. Melor is generating high surf, with waves as high as 26 feet.

A tropical storm warning is now in effect for Rota, Tinian and Saipan. That means tropical storm conditions are now happening there.

A typhoon watch remains in effect for Rota, Tinian and Saipan, and a tropical storm watch remains in effect for Guam. A watch means that conditions are expected to occur in 48 hours. Updated Watches and Warnings can be found at: http://forecast.weather.gov/wwamap/wwatxtget.php?cwa=gum&wwa=tropical%20storm%20warning.

The National Weather Service in Guam issued the following statement: "Melor will be a large and dangerous system before it reaches the Marianas. The radius of damaging winds already extends far from the center. The onset of damaging winds is possible in the northern Marianas early Saturday morning and Saturday afternoon on Guam."

QuikScat saw Melor's winds swirling inside its clouds by using microwaves to peer into them. It flew over Melor and captured an image on September 30 at 7:39 UTC. QuikScat can actually determine the speed of a tropical cyclone's rotating winds using microwave technology. QuikScat imagery is false-colored to show different wind speeds, the highest winds are always shown in purple, indicating winds over 40 knots (46 mph). Small barbs are used in the images to indicate wind direction and point to areas of heavy rain.

While QuikScat took a look at Melor's winds, the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite identified the storm's icy cloud temperatures. Those temperatures help determine the height the clouds and thunderstorms. The colder the clouds, the higher they are, and the stronger the thunderstorms. The satellite images, which false-color clouds based on their temperature, showed a large extent of cloud cover. In AIRS images, purple indicates the highest thunderstorms (and strongest), and blue areas are the second coldest and highest clouds.

Melor is approaching the island of Saipan, and is forecast to swing north of there on its journey northwest.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



September 30, 2009

Satellite imagery showed Melor had two large areas of high, cold, thunderstorm cloud tops around its center. > View larger image
The Aqua satellite flew over Tropical Storm Melor at 1 p.m. local (Guam) time, September 30 and infrared satellite imagery also showed Melor had two large areas of high, cold, thunderstorm cloud tops around its center, indicating it is likely developing an eye.
Credit: NASA/JPL, Ed Olsen
20W Grows into Tropical Storm Melor, Threatens Guam

Guam just got through Tropical Depression 18W and is still contending with heavy surf from the storm. Now, Tropical Depression 20W has strengthened into a tropical storm named "Melor" and that storm is headed toward Guam. It is expected to start affecting Guam in the next two days.

Tropical Storm Melor was packing sustained winds near 80 mph (70 knots) on September 30 at 1500 UTC (11 a.m. EDT) or October 1 at 3 a.m. local time in Guam. Its center was located about 495 miles east-southeast of Saipan near 12.9 north and 153.9 east. It was moving west-northwest near 9 mph.

Melor's tropical storm-force winds extend up to 50 miles from the center, and its generating waves up to 17 feet high. Melor is still intensifying and is forecast to move west-northwest toward Guam. Melor is expected to reach typhoon strength.

The Aqua satellite flew over Tropical Storm Melor at 1 p.m. local (Guam) time, September 30 and the Atmospheric Infrared Sounder (AIRS) instrument provided valuable infrared data on its cloud top temperatures. They're important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the more powerful it is, and the data helped forecasters see Melor's cloud tops were as cold as or colder than minus 63 degrees Fahrenheit (F). The infrared satellite imagery also showed Melor had two large areas of high, strong, thunderstorm cloud tops around its center, indicating it is likely developing an eye and strengthening.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



September 29, 2009

Image of Tropical Depression 20W (left) shortly after it was > View larger image
A visible image from NASA's Aqua satellite of Tropical Depression 20W (left) shortly after it was "born" on September 28. The western half of the storm was out of the satellite's view (white area).
Credit: NASA/JPL, Ed Olsen
20W Born: A Fourth Tropical Cyclone in the Western Pacific This Week

There are now four tropical cyclones stirring in the Western Pacific: Ketsana, 18W, 19W and now Tropical Depression 20W. The twentieth tropical cyclone of the Western Pacific Ocean formed in the overnight hours of September 28-29.

On Tuesday, September 29 at 11 a.m. EDT, Tropical Depression 20W(TD20W) had maximum sustained winds near 34 mph and was located 820 miles east-southeast of the island of Saipan. That's near 10.5 north and 158.9 east. TD20W was moving west-northwest near 13 mph, and was generating waves 9 feet high.

On its current track, TD20W threatens to bring heavy rains and gusty winds to the Federal States of Micronesia. It is expected to intensify into a tropical storm on its track over the next several days.

NASA's Aqua satellite flew over Tropical Depression 20W shortly after it was "born" on September 28 at 10:17 p.m. EDT (September 29, at 2:17 UTC) and the AIRS instrument captured a visible image of it coming together.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center