NASA spots wide band of strong thunderstorms south of Tropical Storm Usagi's center

Sep 18, 2013 by Rob Gutro
The AIRS instrument aboard NASA's Aqua satellite captured this infrared image of Tropical Storm Usagi on Sept. 16 at 16:59 UTC/12:59 a.m. EDT. The image showed the highest storms and coldest cloud top temperatures (purple) around and south of the center. Credit: NASA JPL, Ed Olsen

Infrared data provides a look at cloud top temperatures in tropical cyclones and there were very cold cloud tops in the thunderstorms banding around the south of newborn Tropical Storm Usagi's Center.

On Sept. 16, low pressure System 99W strengthened into Tropical Depression 17W. The depression became Tropical Storm Usagi very late in the day.

The Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite captured an infrared image of Tropical Storm Usagi on Sept. 16 at 16:59 UTC/12:59 a.m. EDT. The image showed the highest storms and coldest cloud top temperatures around and south of the center of circulation. The cloud top temperatures exceeded -63F/-52C in those areas, indicating high thunderstorms, with the potential for heavy rainfall.

The Joint Typhoon Warning Center or JTWC is the forecast organization for this tropical storm. JTWC noted that animated revealed the low-level circulation center was consolidating, although partially exposed to outside winds. The circulation center has become more tightly wrapped and a central dense overcast feature has started to build along the southern edge of the center.

When NASA's Tropical Rainfall Measuring Mission satellite called TRMM passed overhead on Sept. 17 at 1050 UTC/6:50 a.m. EDT, the TRMM Microwave Imager, or TMI showed that the low-level center was continuing to consolidate and wrap more tightly, while thunderstorms and convection continued to strengthen.

On Tuesday, Sept. 17 at 1500 UTC/11 a.m. EDT Usagi had near 40 knots//46 mph/74 kph. Usagi was centered near 17.6 north and 130.6 east, about 559 nautical miles/643 miles/1,035 km south-southeast of Kadena Air Base. Usagi was moving to the west at 5 knots/5.7 mph/9.2 kph.

The Joint Typhoon Warning Center forecast takes Usagi west toward the northern Philippines but turning to the northwest before reaching the country, and heading toward Taiwan.

Explore further: Soil nutrients may limit ability of plants to slow climate change

Related Stories

NASA infrared imagery indicates Pewa weakened

Aug 23, 2013

Cloud top temperatures warmed up on NASA infrared imagery, indicating that the uplift in Tropical Storm Pewa was waning. By Aug. 23, Pewa was reduced to a tropical depression. Infrared imagery also showed ...

NASA sees Tropical Storm Pewa temporarily weaken

Aug 20, 2013

Tropical Storm Pewa weakened temporarily while facing adverse atmospheric conditions in the Northwestern Pacific, and NASA's Aqua satellite captured the storm in infrared light.

Recommended for you

Ocean currents impact methane consumption

15 hours ago

Large amounts of methane - whether as free gas or as solid gas hydrates - can be found in the sea floor along the ocean shores. When the hydrates dissolve or when the gas finds pathways in the sea floor to ...

Study shines new light on the source of diamonds

20 hours ago

A team of specialists from four Australian universities, including the University of Western Australia, has established the exact source of a diamond-bearing rock for the first time.

Source of Earth's ringing? French team views ocean waves

20 hours ago

Three researchers in France have authored "How ocean waves rock the Earth: Two mechanisms explain microseisms with periods 3 to 300 s," published in Geophysical Research Letters, a journal of the Americ ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.