Tag: Bualoi 2019

Oct. 25, 2019 -NASA-NOAA Satellite Shows Wind Shear Affecting a Changing Typhoon Bualoi

NASA-NOAA’s Suomi NPP satellite passed over the Northwestern Pacific Ocean revealed that Typhoon Bualoi continued to look asymmetric because of ongoing wind shear. The Joint Typhoon Warning Center issued the final bulletin on Bualoi as it was beginning the transition into an extra-tropical cyclone.

On Oct. 25, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite captured a visible image of the structure of Bualoi. The storm appeared elongated from southwest to northeast, indicating that it had begun its transition into an extra-tropical cyclone. The image was generated by NASA Worldview, Earth Observing System Data and Information System (EOSDIS), at NASA’s Goddard Space Flight Center in Greenbelt, Md.

What Wind Shear Does to a Tropical Cyclone

In general, wind shear is a measure of how the speed and direction of winds change with altitude. Tropical cyclones are like rotating cylinders of winds. Each level needs to be stacked on top each other vertically in order for the storm to maintain strength or intensify. Wind shear occurs when winds at different levels of the atmosphere push against the rotating cylinder of winds, weakening the rotation by pushing it apart at different levels.

What does Extra-tropical Mean?

When a storm becomes extra-tropical it means that a tropical cyclone has lost its “tropical” characteristics. The National Hurricane Center defines “extra-tropical” as a transition that implies both poleward displacement (meaning it moves toward the north or south pole) of the cyclone and the conversion of the cyclone’s primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force.

Bualoi’s Final Advisory

When the Joint Typhoon Warning Center issued their final bulletin on Bualoi at 5 a.m. EDT (0900 UTC), the storm was centered near latitude 33.7 degrees north and longitude 148.0 degrees east, about 421 nautical miles east of Yokosuka, Japan. The storm was speeding to the northeast at 25 knots (28 mph/44 kph) and had maximum sustained winds near 65 knots (75 mph/120 kph).

Forecasters at the Joint Typhoon Warning Center said that Bualoi was moving north-northeast and will continue to weaken. The storm is forecast to make its transition to an extra-tropical cyclone well to the east of Japan by the end of the day on Oct. 25.

Hurricanes are the most powerful weather event on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

By Rob Gutro
NASA’s Goddard Space Flight Center

Oct. 24, 2019 – Satellite Analysis Reveals and Asymmetric Typhoon Bualoi

NASA-NOAA’s Suomi NPP satellite and NASA’s Aqua satellite both passed over the Northwestern Pacific Ocean and both used infrared light to obtain temperature data and shape information on Typhoon Bualoi.

The shape of a storm says a lot about what is happening to it. Symmetrical storms are stronger, more organized storms. It is like a spinning tire that is well rounded. It can spin faster. Asymmetric storms cannot rotate as fast as symmetrical storms. It is similar to a flat tire cannot go as fast as a rounded tire. Satellite data provides a look at the symmetry of storms and found that Typhoon Bualoi is now an asymmetric storm, indicating it is weakening.

Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures. This data is helpful to forecasters because storms are not uniform around tropical cyclones and it helps pinpoint where the strongest storms are located.

On Oct. 23 at 12:12 p.m. EDT (1612 UTC), the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP found strongest thunderstorms west of center had cloud top temperatures as cold as 190 Kelvin (minus 117 degrees Fahrenheit/minus 83.1 Celsius). NASA research has shown that cloud top temperatures that cold indicate strong storms have the potential to generate heavy rainfall.

William Straka III, a researcher at the University of Wisconsin – Madison, Space Science and Engineering Center (SSEC) created imagery of the storm using the Suomi-NPP satellite. The strongest thunderstorms were on the western side of the eye, while the eastern side showed tropospheric gravity waves created by overshooting cloud tops into the stratosphere. An overshooting cloud top is a dome-like protrusion above a cumulonimbus anvil cloud, often penetrating into the lower stratosphere. It indicates a very strong updraft in the convective cloud or thunderstorm.

Gravity waves are the mark of a powerful storm. They are created when air moving around the atmosphere gets pushed to another place as in the case of tropical cyclones. Powerful thunderstorms around a tropical cyclone’s center can move air up and down and generate these waves in quick, short bursts. They can be seen as ripples in some imagery of clouds in a tropical cyclone.

“The brightness temperature showed an asymmetrical orientation with the circulation being hidden in the convection. Also, the southern part of the storm seems to have some dry air intruding in on it, simply based on the infrared appearance,” Straka said.

When NASA’s Aqua satellite passed over Typhoon Bualoi, the Atmospheric Infrared Sounder or AIRS instrument aboard captured an image of the storm on Oct. 23 at 11:29 p.m. EDT (0329 UTC). Aqua found that the strongest thunderstorms around west of center had cloud top temperatures as cold as or colder than 210 Kelvin (minus 81.6 degrees Fahrenheit/minus 63.5 Celsius). The Joint Typhoon Warning Center said that animated enhanced infrared satellite imagery depicts decaying deep convective banding wrapping into a ragged eye.

On Oct. 24 at 11 a.m. EDT (1500 UTC), Typhoon Bualoi was located near latitude 29.4 degrees north and longitude 143.5 degrees east. That is about 670 nautical miles south of Misawa, Japan. Bualoi was moving to the north-northeast with maximum sustained winds near 90 knots (103 mph/167 kph).

The Joint Typhoon Warning Center noted that Bualoi is moving north-northeast and will continue to weaken. The storm will become extra-tropical east of Japan within 24 hours.

Hurricanes are the most powerful weather event on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

By Rob Gutro
NASA’s Goddard Space Flight Center

Oct. 23, 2019 – NASA Analysis Shows Heavy Rain in Typhoon Bualoi

Typhoon Bualoi continues to move through the Northwestern Pacific Ocean and the Global Precipitation Measurement mission or GPM core satellite measured rainfall rates throughout the storm.

The GPM’s core satellite passed over Typhoon Bualoi on Oct. 22 at 12:11 p.m. EDT (1611 UTC). GPM found the heaviest rain around the eye, falling at a rate of over 50 mm (about 2 inches) per hour. Forecasters at NOAA’s National Hurricane Center or NHC incorporate the rainfall data into their forecasts.

At 5 a.m. EDT (7 p.m. ChST/0900 UTC) the center of Typhoon Bualoi was located near latitude 23.5 degrees north and longitude 142.0 degrees east. The National Weather Service in Tiyan, Guam noted that it is about 405 miles northwest of Agrihan. Bualoi is now moving north-northwest at 13 mph and will continue a gradual turn to the north tonight and then toward the north-northeast through Thursday night.  Maximum sustained winds have decreased to 115 mph and Bualoi is expected to continue this weakening trend the next several days. Bualoi is expected to gradually increase in forward speed as it heads farther into the north Pacific east of Japan.

Both the Japan Aerospace Exploration Agency (JAXA) and NASA manage GPM.

Hurricanes are the most powerful weather event on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For updated forecasts, visit: https://www.weather.gov/gum/Cyclones

By Rob Gutro
NASA’s Goddard Space Flight Center

Oct. 22, 2019 – NASA Finds Heavy Rain Potential in Typhoon Bualoi Over Marianas

Typhoon Bualoi was lashing the Marianas Islands in the Northwestern Pacific Ocean when NASA’s Aqua satellite passed overhead and analyzed the cloud top temperatures to give forecasters insight into the storm’s rain potential.

On Oct. 22, a Tropical Storm Warning remained in effect for the islands of Agrihan, Pagan and Alamagan in the Northern Mariana Islands.

One of the ways NASA researches tropical cyclones is by using infrared data that provides temperature information. Cloud top temperatures identify where the strongest storms are located. The stronger the storms, the higher they extend into the troposphere, and the colder the cloud top temperatures.

Tropical cyclones do not always have uniform strength, and some sides have stronger sides than others, so knowing where the strongest sides of the storms are located helps forecasters. NASA then provides data to tropical cyclone meteorologists so they can incorporate the data in their forecasts.

On Oct. 22 at 0335 UTC (Oct. 21 at 11:35 p.m. EDT) NASA’s Aqua satellite analyzed the storm using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder 210 Kelvin (purple) which is minus 81 degrees Fahrenheit (minus 63.1 degrees Celsius) around the center. NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.

The AIRS infrared imagery also hinted at an eye, but the eye was more apparent in the AIRS microwave imagery. The Joint Typhoon Warning Center estimated that the eye is about 8 nautical miles wide.

At 11 a.m. EDT (1 a.m. CHST local time/1500 UTC) NOAA’s National Weather Service (NWS) in Tiyan, Guam noted that the center of Typhoon Bualoi was located near latitude 19.7 degrees north and longitude 143.2 degrees east. That puts the eye about 175 miles west-northwest of Agrihan, and about 440 miles north-northwest of Guam.

Bualoi is moving northwest at 16 mph. It is expected to make a slight turn toward the north-northwest with a slight decrease in forward speed over the next 24 hours. Maximum sustained winds have increased to 145 mph. Bualoi is forecast to intensify through Thursday and then begin weakening as it moves in a northerly track.

Hurricanes are the most powerful weather event on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

The AIRS instrument is one of six instruments flying on board NASA’s Aqua satellite, launched on May 4, 2002.

For updated forecasts, visit: https://www.weather.gov/gum/Cyclones

By Rob Gutro
NASA’s Goddard Space Flight Center  

Oct. 21, 2019 – NASA Finds Typhoon Bualoi Rapidly Intensified

Typhoon Bualoi rapidly intensified over 24 hours and quickly developed an eye and powerful thunderstorms.

On Oct. 21, the eye of Typhoon Bualoi was just over 50 miles from the island of Saipan when NASA-NOAA’s Suomi NPP satellite passed overhead. Saipan is the largest island of the Northern Mariana Islands. The Marianas are a commonwealth of the United States in the western Pacific Ocean.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite provided forecasters with an image of Bualoi revealing a clear eye surrounded by powerful thunderstorms. The Joint Typhoon Warning Center (JTWC) noted at 11 a.m. EDT on Oct. 21, that Tropical Depression 22W (Bualoi) rapidly intensified by 35 knots (40 mph/65 kph) over the past 24 hours from 70 knots (81 mph/129 kph) at 8 a.m. EDT (1200 UTC) on Oct. 20 to the current intensity of 105 knots (120 mph/194 kph).

JTWC also noted “Animated enhanced infrared imagery depicts a 15 nautical mile round eye embedded in a compact, asymmetric convective core.”

Satellite imagery helps forecasters understand if a storm is organizing or weakening. The shape of a tropical cyclone provides forecasters with an idea of its organization and strength, and NASA-NOAA’s Suomi NPP satellite provided a visible image of the storm to forecasters.

Bualoi formed on Oct. 19 as Tropical Depression 22W and strengthened into a tropical storm later that day. It became a typhoon on Oct. 20.

Warnings and Watches

On Monday, October 21, 2019, the National Weather Service in Tiyan, Guam noted that a Typhoon Warning remains in effect for Tinian and Saipan. Damaging winds of 39 mph or more are expected through this morning. A Tropical Storm Watch remains in effect for the islands of Agrihan, Pagan and Alamagan in the Northern Mariana Islands. Damaging winds of 39 mph or higher are possible today.

Status of Typhoon Bualoi on Oct. 21

At 11 a.m. EDT (1 a.m. CHST, local time/1500 UTC), Typhoon Bualoi was centered near latitude 15.8 degrees north  and longitude 146.4 degrees east. That puts the eye about 65 miles northeast of Saipan, 75 miles northeast of Tinian, 130 miles south-southeast of Alamagan, and about 195 miles northeast of Guam.  Maximum sustained winds have increased to 120 mph. Bualoi is forecast to intensify through Wednesday.

Bualoi is moving northwest at 12 mph. It is expected to maintain this general course and speed over the next 24 hours.

Hurricanes are the most powerful weather event on Earth. NASA’s expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For updated forecasts. visit:  https://www.weather.gov/gum/Cyclones

By Rob Gutro 
NASA’s Goddard Space Flight Center