Featured Images

Text Size

Hurricane Season 2011: Tropical Depression Ma-on (Western No. Pacific Ocean)
07.25.11
 
This image is based on data from the Multisatellite Precipitation Analysis produced at Goddard Space Flight Center. › View larger image
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.
Credit: NASA Earth Observatory/Jesse Allen
Rainfall from Typhoon Ma-on

Ma-on formed over the western Pacific Ocean in early July, traveled west then north, and made a U-turn along the shore of Japan. En route to Japan, the storm strengthened into a Category 4 typhoon, and dropped heavy precipitation.

This color-coded image shows rainfall amounts from July 14 to 21, 2011. The lightest rainfall amounts (less than 50 millimeters or about 2 inches) appear in pale green. The heaviest amounts (more than 300 millimeters or about 12 inches) appear in dark blue. The heaviest rainfall occurs over the Pacific Ocean south of Japan, including an area immediately off the coast.

Superimposed on the rainfall amounts is a storm track for Ma-on. Darker shades of orange indicate greater storm strength. Dates on the storm track indicate Ma-on’s location as of midnight UTC on each date. Ma-on peaked late in the day on July 15, and weakened considerably on July 21.

Ma-on was downgraded to a tropical storm before it reached Japan, but the storm still brought heavy rains and strong winds to the country. On July 21, The Japan Times reported that Ma-on disrupted air and rail transportation. Meanwhile, officials blamed the storm for more than 50 injuries and at least one death. Authorities warned residents to remain alert for floods and landslides as Ma-on moved off.

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 Goddard Space Flight Center, Greenbelt, Md.



July 22, 2011

TRMM rainfall totals are shown here for the period July 14-21, 2011 for southeastern Japan in association Ma-On. › View larger image
TRMM rainfall totals are shown here for the period 14 to 21 July 2011 for southeastern Japan in association with the passage of Ma-On. Appropriate storm symbols denote the storm's track and intensity. Rainfall totals are the highest over Shikoku where Ma-On made landfall. Most of the island received at least 160 mm of rain (~6 inches, shown in green) while the far eastern portion received upwards of 320 mm (~13 inches, shown in orange).
Credit: SSAI/NASA, Hal Pierce
NASA Measures Heavy Rain in Southern Japan from Typhoon Ma-on

Typhoon Ma-On formed from an area of disturbed weather in the northwest Pacific halfway between Wake Island and the Northern Marianas on the 11th of July 2011.

The system slowly developed and became a typhoon two days later on the 13th as it continued tracking westward. Ma-On then reached its maximum intensity on the 15th with sustained winds estimated at 115 knots (~132 mph), making it a Category 4 typhoon, before turning northward towards southern Japan. Ma-On began to weaken as it neared the southeast coast of Japan where it briefly made landfall in southern Tokushima Prefecture on the Japanese Island of Shikoku as a minimal typhoon with sustained winds reported at 75 mph before recurving back out to sea.

Despite its minimal intensity, however, the storm brought very heavy rain to parts of southeastern Japan.

With its array of passive microwave and active radar sensors, the Tropical Rainfall Measuring Mission satellite (better known as TRMM) was launched back in 1997 with the primary purpose of measuring rainfall in the Tropics from space. For increased coverage, 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, Greenbelt, Md. is used to monitor rainfall over the global Tropics.

TMPA rainfall totals were compiled for the period of July 14 to 21, 2011 for southeastern Japan in association with the passage of Ma-On. Rainfall totals are the highest over Shikoku where Ma-On made landfall. Most of the island received at least 160 mm of rain (~6 inches) while the far eastern portion received upwards of 320 mm (~13 inches). Locally a record 850 mm of rain (~34 inches) was reported in a 24-hour period in the village of Umaji in the Kochi Prefecture. So far one person has died as a result of the storm, which is expected to continue to weaken as it pulls away from Japan and pass well to the east of the damaged Fukushima power plant.

On July 22, the Joint Typhoon Warning Center issued their final advisory on Tropical Depression Ma-on. Ma-on was located about 435 miles south-southeast of Tokyo, Japan near 28.9 North and 142.7 East. It was moving near 11 knots (12 mph) to the south-southeast and had maximum sustained winds near 20 knots (23 mph/37 kmh). Ma-on is dissipating to the south of Japan in an area of high wind shear.

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

Text credit:Steve Lange, SSAI/NASA Goddard Space Flight Center, Greenbelt, Md.



July 21, 2011

On July 19, Ma-on was dropping heavy rainfall over southern areas of the Japanese Island of Honshu. › View larger image
Two days ago, on July 19, the TRMM satellite passed over Ma-on when it was a strong tropical storm with winds near 69 mph. At that time, Ma-on was dropping heavy rainfall over southern areas of the Japanese Island of Honshu. A red tropical storm symbol shows the location of Ma-on's center of circulation.
Credit: NASA/SSAI, Hal Pierce
AIRS captured Tropical Depression Ma-on's on July 20 at 16:35 UTC (12:35 p.m. EDT). › View larger image
The AIRS instrument on NASA's Aqua satellite captured this infrared image of Tropical Depression Ma-on's cloud temperatures on July 20 at 16:35 UTC (12:35 p.m. EDT). The strongest thunderstorms and convection (center, purple) were on the southern side of the storm.
Credit: NASA/JPL, Ed Olsen
Ma-on Tropically Depressed and Back at Sea on NASA Imagery

NASA infrared imagery showed cloud top temperatures that revealed the former Typhoon Ma-on weakened into a tropical depression as it continues to pull away from Japan.

Very cold cloud top temperatures indicate strong convection and strong thunderstorms (that power a tropical cyclone). Infrared satellite imagery from the Atmospheric Infrared Sounder instrument on NASA's Aqua satellite showed that the only area of very cold thunderstorm cloud-top temperatures was south of Tropical Depression Ma-on's center.

At 5 a.m. EDT on July 21, Tropical Depression Ma-on's maximum sustained winds were near 30 knots (34 mph/55 kmh). At that time, it was 300 nautical miles (345 miles/555 km)south of Yokosuka, Japan, near 30.4 North and 141.2 East. It was moving away to the southeast near 14 knots (16 mph/26 kmh). Ma-on continues to move into the open waters of the western North Pacific Ocean.

Ma-on has had a history of dropping heavy rainfall, and that continues over the open ocean. Two days ago, on July 19, the Tropical Rainfall Measuring Mission (TRMM) satellite passed over Ma-on when it was a strong tropical storm with winds near 60 knots (69 mph/111 kmh). At that time, Ma-on was dropping heavy rainfall over southern areas of the Japanese Island of Honshu.

Today, July 21, satellite imagery indicates that Ma-on's low-level center of circulation was filling with clouds, which indicates that the storm continues to weaken. The center of circulation is exposed to outer winds. Another satellite shows that the strongest winds in Ma-on are displaced from the center, an indication that some wind shear is affecting the tropical cyclone.

Ma-on is now moving into an area of decreasing wind shear and is still in warm waters, so it could intensify before weakening again in the next day or two when it enters cooler waters. It is forecast to turn to the northeast and slowly transition into an extra-tropical storm over the weekend.

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






July 20, 2011

AIRS showed warmer cloud tops (blue) in thunderstorms around the center than the day before › View larger image
NASA's Aqua satellite passed over the western half of Tropical Storm Ma-on on July 20 at 04:29 UTC (12:29 a.m. EDT). NASA's AIRS infrared imagery showed warmer cloud tops (blue) in thunderstorms around the center than the day before, indicating the storm had weakened.
Credit: NASA/JPL, Ed Olsen
NASA Sees a Weakened Tropical Storm Ma-on Moving on

NASA infrared satellite imagery noticed warmer cloud temperatures in Tropical Storm Ma-on as it moves into the Western North Pacific Ocean and away from the main island of Japan today.

Extremely cold cloud top temperatures in thunderstorms are an indication of the strength they possess, and infrared satellite data from NASA revealed that the cloud top temperatures of the thunderstorms in Ma-on have warmed over the last day. That tells forecasters that the convection (rapidly rising air that forms thunderstorms that make up the tropical cyclone) have been losing their strength, so the storm is not as strong as it was. That will change, however, as Ma-on is no longer interacting with land.

NASA's Aqua satellite passed over the western half of Tropical Storm Ma-on on July 20 at 04:29 UTC (12:29 a.m. EDT). The Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite captured an infrared image that revealed weaker convection because of the interaction with land. Now that Ma-on is moving away from land, convection is beginning to re-form over the low-level circulation center.

At 1200 UTC (8 a.m. EDT) Tropical Storm Ma-on had maximum sustained winds near 55 knots (63 mph/101 kmh). It was located about 150 nautical miles (172 miles/277 km) southwest of Yokosuka, Japan near 32.9 North and 138.5 East. It was moving to the east-southeast near 9 knots (10 mph/16 kmh).

Although moving away, Ma-on continues to generate dangerous ocean swells along the beaches. It is also moving into warm waters and a weaker wind shear, so some re-strengthening is forecast by the Joint Typhoon Warning Center.

Ma-on is expected to move southeast and then curve to the northeast in the next two days.

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




July 19, 2011

The TRMM satellite captured the rainfall rates occurring within Typhoon Ma-on (before it weakened) on July 19. › View larger image
The TRMM satellite captured the rainfall rates occurring within Typhoon Ma-on (before it weakened) on July 19. The red areas are heavy rainfall, falling at a rate of 2 inches (50 mm) per hour. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches (20-40 mm) per hour.
Credit: NASA/SSAI, Hal Pierce
Infrared image of Tropical Storm Ma-on was captured by AIRS on July 19  at 0347 UTC › View larger image
This infrared image of Tropical Storm Ma-on was captured from the AIRS instrument on NASA's Aqua satellite on July 19 at 0347 UTC (11:47 p.m. EDT on July 18) and it revealed a large area of very cold cloud top temperatures (purple) from strong thunderstorms to the east and south of the center.
Credit: NASA/JPL, Ed Olsen
NASA Satellites Show Heavy Rainfall at Southeastern Coast of Japan

Some of the strongest thunderstorms within Typhoon Ma-on are now affecting the southeastern coast of Japan and appeared on satellite imagery from two NASA satellites. Rough surf, gusty winds and heavy rainfall is affecting eastern coastal Japan today.

NASA's Aqua satellite passed over Typhoon Ma-on early on July 19, at 0347 UTC (11:47 p.m. EDT on July 18) and imagery from the Atmospheric Infrared Sounder (AIRS) instrument showed a large area of very cold cloud top temperatures from strong thunderstorms to the east and south of the center. As Ma-on moved near the island of Shikoku today, infrared satellite data showed the cloud tops warmed (dropped in height). That's because Ma-on was interacting with the land and wind shear increased, weakening the strength of convection (that builds the thunderstorms).

The other satellite that noticed the heavy rainfall associated with Typhoon Ma-on is operated by both NASA and the Japanese Space Agency. That's appropriate because the heavy rains are falling over southeastern Japan. The Tropical Rainfall Measuring Mission (TRMM) satellite observed rainfall rates in Ma-on on July 18, 2011 at 2306 UTC (7:06 p.m. EDT) and again on July 19, 2011 at 0221 UTC (July 18 at 10:21 p.m. EDT).

The rainfall analysis used TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data from both orbits. The rainfall from early July 19 shows that bands of very heavy rainfall of over 50 mm (~2 inches) were falling over both of the Japanese island of Shikoku and Honshu. At that time, Ma-on's winds had weakened to about 67 kts (~77 mph) making it a category 1 typhoon on the Saffir/Simpson scale.

At 1500 UTC (11 a.m. EDT) on July 19, Typhoon Ma-on's maximum sustained winds were near 55 knots. Tropical storm-force winds extended out to 140 miles from the storm's center. Ma-on was moving to the northeast near 10 knots. It was about 300 miles west-southwest of Yokosuka, Japan near 33.3 North and 134.2 East. At that time, it was brushing the island of Shikoku's southern coast near Muroto Point. Shikoku one of four islands in the four main islands of Japan, and is the smallest. It is located south of Honshu.

Ma-on is expected to continue weakening and is now expected to recurve to the east-southeast and head back to sea sometime on July 20.

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




July 18, 2011

On July 18 the heaviest rainfall and strongest convection from Ma-on were still over open waters (purple). › View larger image
NASA's Aqua satellite captured this infrared image of Typhoon Ma-on from the AIRS instrument on July 18 at 04:41 UTC (12:41 a.m. EDT). The heaviest rainfall and strongest convection were still over open waters (purple).
Credit: NASA/JPL, Ed Olsen
NASA Infrared Imagery Shows Typhoon Ma-on's Strongest Storms Over Open Ocean

Typhoon Ma-on continues to move toward the main island of Japan today, and NASA's Aqua satellite noticed that the strongest storms were fortunately still over open ocean. Ma-on is a large storm, over 450 miles in diameter and tropical storm-force winds extend to half that distance.

NASA's Aqua satellite flew over Typhoon Ma-on on July 18 at 04:41 UTC (12:41 a.m. EDT) and the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of the storm's cloud top temperatures and surrounding sea temperatures. At the time of the overpass, the heaviest rainfall and strongest convection were still over open waters. The AIRS data showed that the coldest cloud tops were around the center of Ma-on's circulation. Coldest cloud tops indicate the highest clouds and strongest thunderstorms, where rainfall rates are approximately 2 inches/50 mm per hour.

Infrared satellite imagery also showed a ragged eye has become cloud-filled, and cloud top temperatures are warming, indicating that convection is weakening (convection helps build the thunderstorms that power the tropical cyclone). Meanwhile, microwave imagery from NASA's Aqua satellite and other satellites indicate that dry air is now wrapping into the southwestern quadrant of the storm, which will also weaken convection.

Typhoon Warnings have been posted for several southern and eastern facing areas of Japan. The warnings call for heavy rain, thunderstorms, local flooding, gale-force winds and high waves. For updated warnings, visit the Japan Meteorological Agency website: http://www.jma.go.jp/en/warn/.

According to the Joint Typhoon Warning Center, the organization that forecasts typhoons in that area of the world, "The outer rainbands are extending into Kyushu and Shikoku, and surface reports from the coast of Kyushu indicate that over the northeastern quadrant, gale force winds extend nearly 200 nautical miles from the center."

Typhoon Ma-on had maximum sustained winds near 75 knots (86 mph/139 kmh) at 1500 UTC (11 a.m. EDT) on July 18 (1:40 p.m. on Tuesday, July 19 local time/Japan). Those typhoon-strength winds extend out 50 miles (80 km) from the center, while tropical storm-force winds extend as far as 220 miles (354 km) from the center. It was located about 550 nautical miles (632 miles/1019 km) southwest of Tokyo near 30.2 North and 133.0 East. It was moving to the north at 14 knots (16 mph/26 kmh).

Ma-on continues to move north and is forecast to curve east. The Joint Typhoon Warning Center is forecasting a brief landfall in southeastern Japan, south of Kyoto mid morning (local time/Japan) on July 20.

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




July 15, 2011

This image of Typhoon Ma-on from MODIS clearly shows Ma-on's eye, although it has some high clouds in it. › View larger image
This image of Typhoon Ma-on from the MODIS instrument aboard NASA's Aqua satellite clearly shows the storm's eye, although it has some high clouds in it. The image was taken at 04:15 UTC (12:15 a.m. EDT) on July 15 as Typhoon Ma-on continues moving west in the western Pacific Ocean.
Credit: NASA Goddard/MODIS Rapid Response Team, Jeff Schmaltz
AIRS infrared image of the storm, identifying the coldest cloud tops, and the strongest thunderstorms (in purple). › View larger image
NASA's Aqua satellite passed over Ma-on on July 14 at 03:23 UTC and captured an infrared image of the storm, identifying the coldest cloud tops, and the strongest thunderstorms (in purple). The infrared image also revealed an eye.
Credit: NASA/JPL, Ed Olsen
Typhoon Ma-on's Eye Seen in NASA Satellite Images

The eye of a tropical cyclone is an indication of a strong storm, and Typhoon Ma-on's eye was apparent in visible and infrared imagery captured by NASA's Aqua satellite. Ma-on just achieved Category Four status on the Saffir-simpson scale that measures hurricane intensity.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies aboard NASA's Aqua satellite took an image of Typhoon Ma-on that clearly shows the storm's eye, although it has some high clouds in it. The image was taken at 04:15 UTC (12:15 a.m. EDT) on July 15 as Typhoon Ma-on continues moving west in the western Pacific Ocean.

When NASA's Aqua satellite passed over Ma-on on July 14 at 03:23 UTC, the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of the storm. The infrared image showed a large area of coldest cloud tops and the strongest thunderstorms mostly south of the center of circulation, and also revealed an eye at that time.

On July 15 at 0900 UTC (5 a.m. EDT), Typhoon Ma-on's winds were stronger than they were the day before. Maximum sustained winds are now at 115 knots (132 mph/213 kmh). Ma-on is located about 250 nautical miles south of Iwo To, Japan near 20.7 North and 140.9 East.

The strongest thunderstorms in Ma-on are still located south of the center of circulation. Visible, microwave and infrared imagery all show a well-defined eye within the storm.

Ma-on is moving to the west-northwest along the southern edge of a subtropical ridge (elongated area) of high pressure. This weekend people on Iwo To, Chici Jima and Kadena Air Base can experience rough seas and gusty winds and rains.

Ma-on is then expected to move to the north, then northeast as it curves around the western edge of the ridge. That would put Ma-on on track to skirt the eastern edge of the big island of Japan early next week.

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




TRMM animated rainfall rates from Typhoon Ma-on on July 14, 2011 at 0525 UTC (1:25 a.m. EDT). › View TRMM animation
Rainfall rates from Typhoon Ma-on were animated on an image from the MODIS instrument on NASA's Aqua satellite on July 14, 2011 at 0525 UTC (1:25 a.m. EDT) . The rainfall rates were obtained from the TRMM satellite and showed heavy rainfall (red) around the center of circulation, with exception of the eastern side.
Credit: SSAI/NASA, Hal Pierce
The TRMM satellite flew over Ma-on on July 14, 2011 and noticed heavy rainfall around the center of circulation. › View larger image
The TRMM satellite flew over Ma-on on July 14, 2011 at 0525 UTC (1:25 a.m. EDT) and noticed heavy rainfall (red) around the center of circulation, with exception of the eastern side.
Credit: SSAI/NASA, Hal Pierce
TRMM Satellite Sees Very Heavy Rainfall in Typhoon Ma-On

The Tropical rainfall Measuring Mission satellite known as TRMM can measure rainfall from space, and data that it sent back to meteorologists reveal that the rain fall rate in Typhoon Ma-on are high.

The TRMM satellite passed almost directly above powerful typhoon Ma-on on July 14, 2011 at 0525 UTC (1:25 a.m. EDT). The TRMM orbit revealed that Ma-on was extremely well organized with numerous bands of intense thunderstorms around a well defined eye.

The rainfall analysis was created at NASA's Goddard Space Flight Center in Greenbelt, Md. using data from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR). It showed that the heaviest rainfall of over 50 mm/hr (~ 2 inches) was located in the southwestern quadrant of Ma-on's eye wall.

Ma-on is predicted to become an even more dangerous super typhoon with wind speeds of 135 kts (155 mph) on July 17, 2011 while approaching the islands of southern Japan.

Text credit:Hal Pierce, SSAI/NASA Goddard Space Flight Center, Greenbelt, Md.




















MODIS image showing Typhoon Ma-on on July 14 moving through the western North Pacific Ocean. › View larger image
This image was captured by the MODIS instrument that flies aboard NASA's Aqua satellite. It shows Typhoon Ma-on at 03:30 UTC on July 14 (11:30 p.m. EDT on July 13) moving through the western North Pacific Ocean, over the Northern Mariana Islands.
Credit: NASA Goddard/MODIS Rapid Response Team, Jeff Schmaltz
NASA Satellite Sees Typhoon Ma-on Soaking Guam

NASA satellite data shows Typhoon Ma-on soaking Guam, and the National Weather Service office there has issued an urban and small stream flood advisory for all of Guam until 2 a.m. CHST (local time) and a coastal hazard message and small craft advisories because of high waves and gusty winds.

Over the last couple of days, NASA satellite data from both the Tropical Rainfall Measuring Mission (TRMM) and Atmospheric Infrared Sounder (AIRS) that flies aboard Aqua detected powerful thunderstorms within Ma-on. Those thunderstorms contained heavy rainfall, falling at a rate of 2 inches/50 mm per hour. As NASA's Aqua satellite flew over Ma-on on July 14 (11:30 p.m. EDT on July 13), the Moderate Resolution Imaging Spectradiometer (MODIS) instrument captured a visible image of Typhoon Ma-on moving over the Northern Mariana Islands.

At 1500 UTC (11 a.m. EDT/1 a.m. Guam local time) on July 14, Typhoon Ma-on had maximum sustained winds near 95 knots (109 mph/175 kmh). It was located over the northern Marianas islands, about 250 nautical miles southeast of Iwo To, Japan near 20.3 North and 144.5 East. It was moving west near 11 knots (13 mph/20 kmh).

The National Weather Service flood advisory for today, July 14 at 11 a.m. Eastern Daylight Time (1 a.m. local time/Guam on July 15) noted that "additional rainfall amounts of 1 to 2 inches are possible during the next several hours. Recent heavy rains have left the ground saturated."

High surf conditions are also expected in Guam, Rota, Tinian and Saipan over the next several days. At 3:50 p.m. CHST (local time in Guam) on July 14 the National Weather Service (NWS) also issued a high surf advisory that will remain in effect through 6 a.m. (local time) on Sunday, July 17 as Ma-on passes through the region. The NWS advisory states that "Surf will build to hazardous at 7 to 9 feet along west facing reefs tonight and Friday. Surf will peak at 9 to 11 feet Friday night and Saturday, and should fall below 9 feet on Sunday." Beaches and exposed reefs are places to avoid through the advisory period, especially those facing the west as Ma-on continues to move in that direction. Rip currents are also possible.

There is also a small craft advisory in effect for the coastal waters of Guam, Rota, Tinian and Saipan until 6 p.m. (local time) Sunday as seas are expected to rise to 10 to 12 feet accompanied by winds between 20 and 25 knots (23-29 mph/37-46 kmh) through Saturday night.

Updated weather forecasts and advisories from the NWS for Guam can be found at: http://www.prh.noaa.gov/pr/guam/.

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



July 13, 2011

AIRS showed Ma-on is steadily organizing and the strongest thunderstorms were on the southeastern side. › View larger image
When NASA's Aqua satellite passed over the eastern half of Typhoon Ma-on on July 13 at 14:53 UTC (10:53 a.m. EDT) it captured an infrared image of the temperatures of the eastern half of the cyclone's cloud tops that showed the storm is steadily organizing and the strongest thunderstorms (purple) were on the southeastern side.
Credit: NASA/JPL, Ed Olsen
NASA Satellite Imagery Confirms Ma-on Now a Typhoon

A large area of very cold, high thunderstorm cloud tops surround the center and the southeastern quadrant of the newly dubbed Typhoon Ma-on in the western North Pacific Ocean.

When NASA's Aqua satellite passed over the eastern half of Typhoon Ma-on on July 13 at 14:53 UTC (10:53 a.m. EDT) it captured an infrared image of the temperatures of the eastern half of the cyclone's cloud tops that showed the storm is steadily organizing. Ma-on became a typhoon earlier on July 13, 2011.

The Atmospheric Infrared Sounder (AIRS) instrument provided data on the clouds that showed they were very high and as cold as or colder than -63 Fahrenheit (-52 Celsius) the AIRS data threshold indicating strong thunderstorms around the center of circulation and in a large band of thunderstorms around the southeast of the center (the only quadrant of the storm with good outflow).

The forecasters at the Joint Typhoon Warning Center noted that the strong convection in the southeastern side of the storm was "robbing the core of energy" and had enabled faster intensification of the storm. In earlier imagery on July 18, an eye was visible when satellites passed over the center.

At 1500 UTC (11 a.m. EDT) on July 18, Typhoon Ma-on's maximum sustained winds were near 80 knots with higher gusts. The storm was about 570 nautical miles east-southeast of Iwo To, Japan near 19.8 North and 150.3 East. It was moving west at 11 knots and generating seas over 17 feet high.

Ma-on is continuing to intensify slowly, due to less than favourable atmospheric conditions. The storm will continue to move west-northwest, across the open Pacific. Later in the forecast period, Ma-on will veer north and is expected to make landfall in Japan in the course of next week, without weakening much beforehand.

Ma-on is expected to remain at sea over the next several days. On the 14th it will be well to the north of the island of Saipan, and by the 15th, it is forecast to be well south of Iwo To and Chichi Jima. However, those two islands will likely experience heavy surf from the east and south, showers and thunderstorms and gusty winds from the outer edges of the storm.

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



July 12, 2011

Animation showing the rainfall occurring within Ma-on on July 12, 2011. › View animation
This animation shows the rainfall occurring within the storm on July 12, 2011. Click here to see an animation that shows TMI and PR rainfall being drawn over an image from TRMM's Visible and InfraRed Scanner (VIRS).
Credit: NASA/SSAI, Hal Pierce
Rainfall occurring in Ma-on when it was Tropical Depression 08W on July 11 at 0637 UTC (2:37 a.m. EDT). › View larger image
This is the rainfall occurring in Ma-on when it was Tropical Depression 08W on July 11 at 0637 UTC (2:37 a.m. EDT). The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour. Red areas are heavy rainfall at almost 2 inches per hour.
Credit: NASA/SSAI, Hal Pierce
3-D look at the cloud heights and rainfall occurring in Ma-on when it was Tropical Depression 08W on July 11. › View larger image
This is a 3-D look at the cloud heights and rainfall occurring in Ma-on when it was Tropical Depression 08W on July 11 at 0637 UTC (2:37 a.m. EDT). The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches per hour. Red areas are heavy rainfall at almost 2 inches per hour. The highest clouds were over 9 miles (15 km) high.
Credit: NASA/SSAI, Hal Pierce
TRMM Satellite Sees Intensification as Depression Becomes Tropical Storm Ma-on

Rainfall measurements taken from space have shown heavy rain within the newly named "Tropical Storm Ma-on" in the western North Pacific.

The Tropical Rainfall Measuring Mission (TRMM) satellite measures rainfall from space and noticed there were several areas where rains were heavy over the last two days. Heavy rain rates are about 2 inches/50 millimeters per hour. TRMM is a satellite that is managed by both NASA and the Japanese Space Agency.

Tropical storm Ma-on (formerly tropical depression 08W) developed east of the Marianas in the northern Pacific Ocean yesterday, July 11. It has continued to become more powerful in the last 24 hours Ma-on had wind speeds of about 35 knots (~40 mph/65 kmh) when TRMM saw the storm on July 12, 2011 at 0640 UTC (2:40 a.m. EDT).

Rainfall data from TRMM are used to create visualizations at NASA's Goddard Space Flight Center in Greenbelt, Md. Hal Pierce created various images using TRMM data that helped show where the strongest rainfall and most powerful thunderstorms are located within the tropical cyclone. TRMM Microwave Imager (TMI) and Precipitation Radar (PR) data were used in a rainfall analysis that was drawn on a Visible/Infrared (VIRS) image. The TMI data showed that Ma-on had heavy rainfall around the storms center of circulation and also in a large feeder band (of thunderstorms) converging into the eastern side of the storm.

At 1500 UTC (11 a.m. EDT) on July 12, Tropical Storm Ma-on's maximum sustained winds were near 35 knots (40 mph/65 kmh). It was located in the open waters of the western North Pacific, about 800 miles east-southeast of Iwo To, Japan, near 18.9 North and 154.4. East. It was moving to the west near 11 knots (12.6 mph/20 kmh).

On Monday July 11, 2011, TRMM had passed over Ma-on when it was weaker and still Tropical Depression 08W. It passed overhead at 0637 UTC (2:37 a.m. EDT) and showed that numerous convective thunderstorms were dropping moderate to heavy rainfall over a large area of the Pacific Ocean near 18.1N 157.3E.

TRMM data was also used to create a 3-D image that shows the structure of tropical depression 08W. Several thunderstorm towers within 08W reached heights of at least 15 kilometers (~9.3 miles) high.

Ma-on is predicted to gradually strengthen over the next five days. Ma-on is then expected to be a powerful typhoon with wind speeds of 95 kts (~109 mph) and be located in the open waters of the Pacific Ocean south of Japan.

Text credit:Hal Pierce, SSAI/NASA Goddard Space Flight Center, Greenbelt, Md.













July 11, 2011

AIRS captured TD08 showing the strongest thunderstorms (in purple) on the eastern and southern sides of it. ›View larger image
NASA's Aqua satellite passed over Tropical Depression 08W and captured an infrared image of the storm, identifying the coldest cloud tops, and therefore, the strongest thunderstorms (in purple), on the eastern and southern sides of it.
Credit: NASA JPL, Ed Olsen
New Tropical Depression 08W Has Strong T-Storms on 2 Sides

Infrared satellite data is helpful to forecasters in determining where the strongest thunderstorms are in a tropical cyclone through temperature. NASA satellite imagery confirmed those strongest storms in newborn Tropical Depression 08W were located on the southern and eastern sides of the storm.

Tropical Depression 08W formed in the western North Pacific Ocean during the morning hours (Eastern Daylight Time) on July 11. Its maximum sustained winds are near 30 knots (34 mph). It is currently located over open waters near 18.2 North and 157.3 East. That's about 775 nautical miles east-northeast of Andersen Air Base. It's moving to the west at about 3 knots (4 mph).

NASA's Aqua satellite passed over Tropical Depression 08W (TD08W) and captured an infrared image of the storm, identifying the coldest cloud tops, and therefore, the strongest thunderstorms, on the eastern and southern sides of it. The other interesting thing that the infrared data showed is that the center of the storm's circulation is somewhat elongated. When a storm is elongated, it doesn't tend to intensify as quickly as if it were rounded. Think of the performance of a storm like a tire. It would be like driving on a tire that's not exactly round. It would take you a lot longer to get somewhere, just as an elongated low pressure area is not spinning as efficiently as it could, allowing it to organize as quickly.

TD08W is in an area of low wind shear and warm waters, so those are two factors that will enable it to strengthen. The forecasters at the Joint Typhoon Warning Center noted all of these factors and the strong thunderstorms on the two sides of the storm, and created their forecast. The forecast calls for intensification over the next several days so it is likely going to reach tropical storm status in the next day.

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