Three instruments on NASA's Aqua satellite captured views of
Typhoon Lupit on its western track toward the Philippines and are
helping forecasters get an idea of its strength and behavior. Lupit
strengthened quickly in 24 hours from a tropical depression to a
typhoon, between October 15 and 16.
From 12:41a.m. to 12:45 a.m. EDT (12:45 p.m. Asia/Manila Time)
on October 16, NASA's Aqua satellite was capturing important data
on Typhoon Lupit, so that forecasters in the U.S. Navy's Joint
Typhoon Warning Center (who forecasts tropical cyclones in the
Western Pacific) could make a forecast. In the Philippines,
meteorologists are referring to the storm by the name "Ramil."
Aqua's Moderate Imaging Spectroradiometer (MODIS) instrument,
Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding
Unit (AMSU) instrument captured visible, infrared and microwave
images of Typhoon Lupit.
Infrared imagery measures temperatures and not only can it see
cold, high cloud tops in tropical cyclones, but also the warm ocean
waters that power the cyclones (if the sea surface temperatures are
over 80F(26.6 C)). Cold cloud top temperatures provide clues about
the power of the thunderstorms in a tropical cyclone. The colder
the clouds are, the higher they are, and the more powerful the
thunderstorms are that make up the cyclone. Lupit's cloud
temperatures were colder than minus 63 Fahrenheit (-52.78 C),
indicating very cold, high, strong thunderstorms within.
The ocean waters beneath Typhoon Lupit are over 80F (26.6 C),
the threshold to maintain tropical cyclones, so they're helping to
strengthen the storm.
AIRS data is also coupled with data from AMSU create microwave
images of storms. The AMSU image uses the radiances of the 89 GHz
channel, and the cold areas in those images indicate where there is
precipitation or ice in the cloud tops.
By using both the infrared and microwave satellite imagery,
forecasters at the Joint Typhoon Warning Center (JTWC) were able to
see inside the storm. The JTWC discussion on October 16 said
"Typhoon Lupit has developed an impressive convective structure
evident in a microwave image, [from 4:59 a.m. EDT] as well as in
recent animated infrared imagery which shows a tightly wrapped
system with a banding eye. Lupit's intensification to typhoon
strength has been enabled by excellent poleward outflow into the
mid-latitude westerlies."
At 11 a.m. EDT (11 p.m. Asia/Manila Time) on October 16, Typhoon
Lupit's maximum sustained winds were near 74 mph. Lupit's center
was 400 nautical miles (643 kilometers) north of Palau, near 14.4
North latitude and 133.8 East longitude. Lupit was moving west at
20 mph (32 km/hr) and generating 17-foot-high waves.
Over the weekend, Typhoon Lupit is expected to continue moving
generally in a west-northwest direction. The northern Philippines
will likely feel the first effects of Lupit by 8:00 a.m. EDT (1200
UTC, or 8 p.m. Asia/Manila Time) on October 20. Storm-weary
residents in Luzon, the Philippines should make preparations over
the weekend.
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