NASA sees Tropical Cyclone Tuni becomes extra-tropical

November 30, 2015

NASA's GPM core satellite and NOAA's GOES-West satellite saw the Southern Pacific Ocean's Tropical Storm Tuni was being battered by wind shear and had lost its tropical characteristics.

On Nov. 28, the RapidScat instrument aboard the International Space Station saw Tropical Cyclone Tuni's maximum sustained winds near 27 meters per second (60.4 mph/97.2 kph) southeast of the center.

At 0900 UTC (4 a.m. EST) on Nov. 29, Tuni's maximum sustained winds were near 40 knots (46 mph/74 kph). It was located about 132 miles south of Pago Pago, American Samoa. Later in the day at 2100 UTC (4 p.m. EST) the Joint Typhoon Warning Center issued their final bulletin on Tropical Cyclone Tuni. At that time, Tuni's maximum sustained winds were down to 35 knots (40 mph/62 kph). It was centered near 17. 9 degrees south latitude and 169.3 degrees west longitude, about 231 miles south-southeast of Pago Pago, American Samoa. Tuni was becoming extra-tropical as it moved to the southeast at 14 knots (16.1 mph/25.9 kph).

Northwesterly wind shear had increased and had pushed the strongest storms, and clouds southeast of the center of Tuni's circulation.

NOAA's GOES-West satellite captured at visible image of the storm at 2152 UTC (4:52 p.m. EST) and showed that the bulk of clouds were pushed far southeast of the center. NASA/JAXA's Global Precipitation Measurement Mission or GPM core satellite passed over Tropical Cyclone Tuni and measured the rate in which rain was falling within the storm. GPM found heavy rain, falling at a rate of more than 1.4 inches (35.5 mm) per hour southeast of the center. Images from both satellites were combined at the Naval Research Laboratory in Washington, D.C. to provide a total picture of the storm.

By Nov. 30, Tuni had become extra-tropical while weakening over the open waters of the southern Pacific Ocean. When a storm becomes extra-tropical it 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.

NASA/Goddard Space Flight Center

Related Cyclone Articles from Brightsurf:

NASA sees Tropical Cyclone Herold's eye
NASA's Aqua satellite passed over the Southern Indian Ocean and captured an image of a well-developed Tropical Cyclone Herold at hurricane strength, east of Madagascar.

A new method to improve tropical cyclone intensity forecasts
There are many reasons for model errors in numerical weather forecasting of tropical cyclone intensity.

No storm in a teacup -- it's a cyclone on a silicon chip
University of Queensland researchers have combined quantum liquids and silicon-chip technology to study turbulence for the first time, opening the door to new navigation technologies and improved understanding of the turbulent dynamics of cyclones and other extreme weather.

NASA finds tropical cyclone 02S consolidating
NASA's Aqua satellite captured an image of Tropical cyclone 02S and the visible image showed that the storm was getting better organized.

NASA finds Tropical Cyclone's Vayu getting stretched
When NASA's Aqua satellite passed over the Northern Indian Ocean, it captured an infrared image that revealed Tropical Cyclone Vayu was elongating.

NASA takes Tropical Cyclone's Vayu's temperature
NASA's Aqua satellite passed over the Northern Indian Ocean and took the temperature of Tropical Cyclone Vayu as it moved northward in the Arabian Sea.

NASA catches development of Tropical Cyclone 02A
Visible imagery from NASA's Terra satellite provided confirmation of the development of Tropical Cyclone 02A in the Arabian Sea, Northern Indian Ocean.

NASA goes infrared on powerful Tropical Cyclone Fani
NASA's Aqua satellite focused an infrared eye on a very powerful Tropical Cyclone Fani as it approached landfall in northeastern India.

NASA finds a more circular Tropical Cyclone Lorna
NASA-NOAA's Suomi NPP satellite passed over the Southern Indian Ocean and captured a visible image of what appeared to be a more organized Tropical Cyclone Lorna.

NASA catches Tropical Cyclone Pola near Fiji
Tropical Cyclone Pola was passing near the Southern Pacific country of Fiji when NASA's Aqua satellite analyzed the storm in infrared light and found it strengthening.

Read More: Cyclone News and Cyclone Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to