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NASA Catches Speedy Tropical Cyclone Eunice Transitioning
Tropical Cyclone Eunice has been spinning around in the Southern Indian Ocean for the last week and by Feb. 1 as NASA's Terra satellite passed overhead, the storm was transitioning into an extra-tropical cyclone.
A tropical cyclone becomes extra-tropical when its warm core becomes a cold core, like a typical mid-latitude low pressure area.
On Jan. 31, 2015 at 09:00 UTC (4 a.m. EST), the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Aqua satellite captured a visible image of Tropical Cyclone Eunice and the storm appeared circular with strong thunderstorms wrapped around the center. The next day, Feb. 1, 2015 at 05:20 UTC (12:20 a.m. EST), MODIS aboard NASA's Terra satellite captured a visible image of Eunice. In that image, Eunice appeared to be elongated from north to south.
The Joint Typhoon Warning Center (JTWC) issued the final warning on Tropical Cyclone Eunice on Feb. 2 at 1500 UTC (10 a.m. EST). At that time, Eunice's maximum sustained winds were near 55 knots (63.2 mph/101.9 kph). It was centered near 30.4 south latitude and 92.5 east longitude, about 1,278 nautical miles (1,471 miles/2,367 km) west-southwest of Learmonth, Australia. Eunice was speeding to the southeast at 40 knots (46 mph/74 kph).
The JTWC noted that the system is encountering increasing vertical wind shear and cooler sea surface temperatures as it rapidly approaches a baroclinic zone where it will weaken and dissipate. The National Oceanic and Atmospheric Administration defines a baroclinic zone as a region in which a temperature gradient exists on a constant pressure surface. Baroclinic zones are favored areas for strengthening and weakening systems. Wind shear is also a characteristic of a baroclinic zone, and can tear a storm apart, which will be the case with Eunice over the next several days.
Rob Gutro
NASA's Goddard Space Flight Center
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Jan. 30, 2015 - NASA Gathers Wind, Rain, Cloud Data on Major Tropical Cyclone Eunice
NASA's RapidScat, GPM and Terra satellite have been actively providing wind, rain and cloud data to forecasters about Tropical Cyclone Eunice. The storm reached Category 5 status on the Saffir-Simpson scale on January 30.
Tropical cyclone Eunice became the fourth tropical cyclone of the 2015 Southern Indian Ocean season when it formed well east of Madagascar on January 27, 2014.
The Global Precipitation Measurement or GPM core satellite flew directly over the eye of Tropical Cyclone Eunice on January 28, 2015 at 1049 UTC (5:49 a.m. EST). GPM's Microwave Imager (GMI) found that rain was falling at a rate of only 30.2 mm (about 1.2 inches) per hour in storms around Eunice's eye. GPM's Radar (Ku band) was used in a 3-D view to show vertical structure of precipitation within the tropical cyclone. The data showed the highest thunderstorm heights reached heights of close to 14km (8.7 miles).
On Jan. 29, 2015, the RapidScat instrument that flies aboard the International Space Station scanned Tropical Cyclone Eunice from 12:38 UTC to 14:11 UTC gathering wind speed data. RapidScat showed that the strongest winds were occurring on the southwestern quadrant of the storm at a rate of 25 to 30 meters per second (55.9 to 67.1 mph/90 to 108 kph).
NASA's Terra satellite flew over Tropical Cyclone Eunice and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard captured a clear visible image of its tiny 6 nautical-mile (6.9 miles/11.1 km) wide eye on Jan. 30 at 05:30 UTC.
At 1500 UTC (10 a.m. EST), Tropical Cyclone Eunice was a major hurricane with maximum sustained winds up to 140 knots (161.1 mph/259.3 kph). It was centered near 19.5 south latitude and 68.9 east longitude, about 763 nautical miles (878 miles/1,413 km) south-southwest of Diego Garcia. Eunice is moving south-southeast at 9 knots (10.3 mph/ 16.67 kph).
Eunice is expected to begin weakening after today as it moves into cooler sea surface temperatures and encounters strong vertical wind shear. The Joint Typhoon Warning Center forecast indicates that the storm will weaken to an extra-tropical storm by February 3 over open waters of the Southern Indian Ocean.
GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency called JAXA.
The ISS-RapidScat instrument flies aboard the International Space Station and measures Earth's ocean surface wind speed and direction. ISS-RapidScat images are created by Analyst Doug Tyler at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. NASA JPL manages ISS-RapidScat.
Hal Pierce/Rob Gutro
SSAI/NASA's Goddard Space Flight Center
[image-77]Jan. 29, 2015 - Tropical Cyclone Eunice Still Churning in the Southern Indian Ocean
The MODIS instrument that flies aboard NASA's Aqua satellite captured this image of Tropical Cyclone Eunice in the South Indian Ocean, well south of Diego Garcia and the Cocos Islands. Its location is 637 nautical miles south-southwest of these islands. The storm is currently tracking south-southeastward at 10 knots.
Eunice's microwave eye is well-defined in this image and the banding around its center is tightly wrapped. The eye is 5 nautical miles across. The intensity of the storm has increased to 115 knots. The storm is encountering favorable conditions for its continued intensity and is tracking south-southeastward and is expected to continue this past for the next 24 hours. At that point it is expected that the storm will shift east-southeastward due on the Ninetyeast Ridge underwater seamount chain which becomes more west-to-east oriented. Favorable continuing conditions will likely allow the storm to increase to a peak intensity of 140 knots. Current maximum sea wave height is 30 feet. After peak intensity the storm will slowly dissipate.
Eunice is not threatening any land masses at this time.Lynn Jenner
NASA's Goddard Space Flight Center
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Jan. 28, 2015 - NASA Panorama of Two Southern Indian Ocean Tropical Cyclones
The MODIS instrument that flies aboard two NASA satellites captured images of Tropical Cyclone Diamondra and Tropical Cyclone Eunice in the South Indian Ocean, and two separate images were combined to make one panorama of the two storms.
The Moderate Resolution Imaging Spectroradiometer or MODIS instrument flies aboard NASA's Aqua and Terra satellites. Those satellites fly in formation behind each other as the circle the Earth. An image from the MODIS instrument aboard each satellite was used to create a panorama from January 28, 2015 at 08:30 UTC (3:30 a.m. EST) showing both storms. Tropical Cyclone Eunice is the more powerful of the two storms and is west of Diamondra.
On Jan. 28, 2015 at 0900 UTC (4 a.m. EST), Tropical cyclone Diamondra was centered near 19.2 south latitude and 79.3 east longitude, about 827 nautical miles (951.7 miles/1,532 km) south-southeast of Diego Garcia. Diamondra was moving to the east-southeast at 9 knots (10.3 mph/16.6 kph) and had maximum sustained winds still near 45 knots (51.7 mph/83.3 kph) as they were on Jan. 27. Forecasters at the Joint Typhoon Warning Center (JTWC) expect the storm to intensify to 55 knots (63.2 mph/101.9 kph) before running into conditions that will weaken it quickly. JTWC expects those conditions to dissipate the storm in three days.
Tropical cyclone Eunice is the powerhouse of the two storms with maximum sustained winds near 85 knots (97.8 mph/157.4 kph) at hurricane force. JTWC forecasters expect Eunice to continue strengthening over the next couple of days and peak near 125 knots (143.8 mph/231.5 kph) before weakening.
It was centered 622 nautical miles (715.8 miles/1,152 km) southwest of Diego Garcia near 14.2 south latitude and 64.8 east longitude. Eunice was moving to the southeast at 4 knots (4.6 mph/7.4 kph).
Neither storm threatens any land areas.
Rob Gutro
NASA's Goddard Space Flight Center
