Tag: Mekkhala 2020

Aug. 11, 2020 – NASA Finds Mekkhala Coming Apart After Landfall in Southeastern China

NASA-NOAA’s Suomi NPP satellite provided forecasters with a visible image of former Typhoon Mekkhala shortly after it made landfall in southeastern China. Wind shear had torn the storm apart.

Mekkhala made landfall in Fujian, southeastern China, bringing strong winds and torrential rain. According to the China Meteorological Agency, the typhoon came ashore in coastal areas of Zhangpu County at around 7:30 a.m. local time on Aug. 11 (7:30 p.m. EDT on Aug. 10). The storm generated at least 170 mm (6.7 inches) of rainfall in Zhangpu County by the middle of the day on Aug. 11.

At 11 p.m. EDT on Aug. 10 (0300 UTC, Aug. 11) the Joint Typhoon Warning Center (JTWC) issued their final bulletin on Mekkhala. At that time, the storm was centered near latitude 24.1 degrees north and longitude 117.7 degrees east, about 216 nautical miles west-southwest of Taipei, Taiwan. Mekkhala’s maximum sustained winds were near 70 knots (81 mph/129 kph) at landfall. It continued to move to the north-northwest.

Wind Shear Tearing at Mekkhala

The shape of a tropical cyclone provides forecasters with an idea of its organization and strength. When outside winds batter a storm, it can change the storm’s shape and push much of the associated clouds and rain to one side of it which is what wind shear does.

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.

Suomi NPP’s Satellite View

On Aug. 11, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite showed a somewhat shapeless storm. Satellite imagery showed that Typhoon Mekkhala was quickly becoming sheared, with the outer low-level bands of thunderstorms on the north side of the system exposed, but with deep convection and strong thunderstorms remaining in place over and south of the center.

The JTWC expects Mekkhala to dissipate within the next day or two.

NASA Researches Tropical Cyclones

Hurricanes/tropical cyclones are the most powerful weather events 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 more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America’s leadership in space and scientific exploration.

By Rob Gutro 
NASA’s Goddard Space Flight Center

Aug. 10, 2020 – NASA Finds Strong Storms in Developing Tropical Storm Mekkhala

After Tropical Depression 07W formed close to the western Philippines, it moved away and strengthened into a tropical storm in the South China Sea. NASA’s Terra satellite provided a look at the strength of the storms that make up the tropical cyclone.

On Aug. 9 at 11 p.m. EDT (Aug. 10 at 0300 UTC), Tropical Depression 07W formed near latitude 16.8 degrees north and longitude 118.3 degrees east, about 204 nautical miles northwest of Manila, Philippines.

When it formed it was close enough to the Philippines to generate warnings. Tropical cyclone wind signal #1 was posted for western portions of Ilocos Norte and Sur, La Union, western parts of Pangasinan, and northern part of Zambales. Those warnings were dropped by Aug. 10 as the system moved west and away from the Philippines.

Infrared imagery gathered on Aug. 9 at 10:20 a.m. EDT (1420 UTC) was from the Moderate Resolution Imaging Spectroradiometer or MODIS instrument. MODIS flies aboard NASA’s Terra satellite. MODIS gathered temperature information about 07W’s cloud tops. Infrared data provides temperature information, and the strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures.

MODIS found the most powerful thunderstorms were around the center of circulation, and several other areas around the center where temperatures were as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 Celsius). Those areas were surrounded by thunderstorms slightly less high in the atmosphere, but still powerful rainmakers with cloud top temperatures as cold as or colder than minus 70 degrees Fahrenheit (minus 56.6 Celsius). Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

Tropical Depression 07W became a tropical storm at 5 a.m. EDT (0900 UTC) on Aug, 10 and was renamed Tropical Storm Mekkhala. Mekkhala is known locally in the Philippines as Ferdie. The storm’s maximum sustained winds had increased to 35 knots (40 mph). It was centered near latitude 20.2 degrees north and longitude 118.7 degrees east, about 332 nautical miles south-southwest of Taipei, Taiwan. Mekkhala was moving to the north.

The Joint Typhoon Warning Center expects that Mekkhala will continue to move north before moving ashore in southern China.

Tropical cyclones/hurricanes are the most powerful weather events 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