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Hurricane Season 2010: Tropical Storm Oli (Southern Pacific Ocean)
02.04.10
 
February 4, 2010

Oli's rain bands were causing additional rainfall in distant Bora Bora and Tahiti. > View larger image
The TRMM satellite flew almost directly over Tropical Cyclone Oli on February 3 at 0741 UTC (2:41 a.m. ET). The image shows that Oli had a large circulation and that its converging rain bands were causing additional rainfall in distant Bora Bora and Tahiti.
Credit: NASA/SSAI, Hal Pierce
An AIRS image on Feb. 4 showed that French Polynesia and Tahiti were on the outer edges of powerful Cyclone Oli. > View larger image
An infrared AIRS image (from NASA's Aqua satellite) on Feb. 4 at 11:23 UTC (6:23 a.m. ET) showed that French Polynesia and Tahiti were on the outer edges of powerful Cyclone Oli. Purple indicates strong thunderstorms with heavy rainfall, and very high storms with cloud temperatures to -63F.
Credit: NASA/JPL, Ed Olsen
Cyclone Oli Reaches Category Four Strength On Its Way to Open Waters

Oli has exploded in strength and as of February 4 it was a Category 4 cyclone with peak sustained winds of 132 mph (115 knots/213 km/hr). NASA's Aqua and TRMM satellites observed Oli's clouds grow colder and rainfall become heavier over the last day. Residents of French Polynesia should watch for local weather advisories.

The Tropical Rainfall Measuring Mission or TRMM satellite is like a rain gauge in space. It's managed by NASA and the Japanese Space Agency, and can measure rainfall in a cyclone from its orbit above the Earth. Yesterday, the TRMM satellite flew almost directly over Tropical Cyclone Oli and revealed that Oli had a large circulation and that its converging rain bands were causing additional rainfall in distant Bora Bora and Tahiti. In some areas of the storm, rain was falling at more than 2 inches (50 millimeters) per hour.

Earlier today, February 4, NASA's Aqua satellite flew over Oli and showed very high thunderstorm cloud tops, so high they were colder than -63F (-52C), and dropping heavy rainfall.

At 10 a.m. ET (1500 UTC) February 4, Tropical Cyclone Oli was located about 250 miles west-southwest of Bora Bora, ear 18.6 South and 152.4 West. Cyclone (hurricane) force winds extend only to about 35 miles (56 kilometers) from the center. From there, tropical storm-force winds extent out as far as 145 miles, so Bora Bora and Tahiti will likely experience breezy conditions and winds likely below tropical storm force (because they are farther out). Oli keeps moving south-southeast near 10 mph (9 knots/16 km/hr). Oli continues to cause very high seas, up to 23 feet (7 meters).

French Polynesia had not posted any warnings as of 12 p.m. ET on February 4 (17:00 UTC), but residents can expect dangerous surf and on-and-off showers and thunderstorms, some with heavy rainfall and gusty winds.

On February 4 during the morning hours (Eastern Time) sustained winds have been averaging about 30 mph (48 km/hr), and temperatures are hovering around 80F (29C). Earlier, some heavy rain was reported. For updated weather observations in Tahiti, go to: http://weather.noaa.gov/weather/current/NTAA.html.

Oli is expected to strengthen more until late in the day on February 5, then will start weakening. Oli is expected to transition into an extra-tropical system over the weekend.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



February 3, 2010

The area of purple in the middle of the storm indicates strong thunderstorms with cloud temperatures colder than -63F. > View larger image
NASA's Aqua satellite AIRS instrument captured the western half of Cyclone Oli on Feb. 3 at 12:17 UTC (7:17 a.m. ET). The area of purple in the middle of the storm indicates strong thunderstorms with cloud temperatures colder than -63F.
Credit: NASA/JPL, Ed Olsen
Now a Hurricane, Oli Passing Bora Bora

Tropical cyclone Oli has attained hurricane strength today, February 3, with maximum sustained winds near 74 mph.

At 10 a.m. ET (1500 UTC), Oli was located approximately 200 nautical miles west-northwest of Bora Bora, near 15.9 South and 154.9 West. It was moving east at 14 mph (12 knots).

The Atmospheric Infrared Sounder instrument (AIRS) on NASA's Aqua satellite captured infrared images of Oli as it passed by early this morning.

Infrared satellite imagery showed that Oli has become better organized, thus its new hurricane status. Oli has well defined banding (arms of thunderstorms that wrap into the low level circulation center of the storm.

NASA and the Japanese Space Agency's Tropical Rainfall Measuring Mission (TRMM) satellite, which measures rainfall from space, noticed an eye developing and deep convection has continued developing over the center of the storm.

Oli was kicking up waves 20 feet high in the open ocean.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



February 2, 2010

NASA's AIRS instrument captured an infrared image of Oli's cloud temperatures on February 2 at 0041 UTC. > View larger image
NASA's Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of Oli's cloud temperatures on February 2 at 0041 UTC. High thunderstorm cloud tops surrounded Oli's center as cold as minus 63F. There is a separate band of clouds associated with Oli to the north.
Credit: NASA/JPL, Ed Olsen
Tropical Storm Oli Kicking Up Waves in South Pacific

Tropical Storm Oli is headed between the islands of Bora Bora and Raratonga in the South Pacific, while maintaining its intensity as a tropical storm. Infrared satellite data from NASA's Aqua satellite reveals that Oli is a large storm, so those islands will experience gusty winds, some moderate to heavy rainfall, and heavy swells along their coasts.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite flew over Oli on February 2 at 0041 UTC (Feb. 1 at 7:41 p.m. ET) and captured its extensive area of cloud cover. AIRS measured the temperatures of the clouds and found a large area of high thunderstorm cloud tops around the storm's center, as cold as minus 63 Fahrenheit. Those high, cold cloud tops indicate strong thunderstorms and heavy rainfall.

Infrared satellite imagery also showed that convection (rising air that creates thunderstorms) continues to flare up and dissipate near Oli's low level circulation center. In the satellite image captured earlier today, there is a separate larger band of deeper convection and thunderstorms located to the north of Oli's center. That band has started to elongate from east to west, indicating weakening of the storm is possible in the next day or two.

At 1500 UTC (10 a.m. ET) on February 2, Oli had maximum sustained winds near 52 mph (45 knots) with higher gusts. It was located about 480 nautical miles west of Bora Bora, near 14.8 South and 159.5 West. Oli has tracked eastward at 11 mph (10 knots).

The tropical cyclone warning for Suwarrow has been cancelled, as has the tropical cyclone alert for the Southern Cook Islands. However, a strong wind warning remains in force for the Northern Cook Islands.

Over the next couple of days, Oli is forecast to move southeast and pass between Bora Bora and Tahiti to the north and Raratonga to the south.

For Cook Island forecast updates from the Cook Islands Meteorological Service: http://www.cookislands.pacificweather.org/.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



February 1, 2010

Oli appears to be well-defined. > View larger image
GOES-11 captured an infrared look at Oli's clouds on Feb.1 at 1652 UTC (11: 52 a.m. ET). The storm appears to be well-defined.
Credit: NOAA/JTWC
Tropical Storm Oli Forms in the Southern Pacific

The twelfth tropical cyclone in the Southern Pacific Ocean has formed today, February 1, 2010, and because of its proximity to the Fiji islands, it has been dubbed "Oli." The GOES-11 satellite passed over Oli early this morning and captured an infrared image of the storm's clouds.

GOES-11, or the Geostationary Operational Environmental Satellite, is operated by the National Oceanic and Atmospheric Administration and provides visible and infrared satellite imagery. Some of the imagery is created through the NASA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. GOES-11 flew over Oli at 11:52 a.m. ET today, February 1, and noticed a well-organized tropical storm.

Oli's name may also be referred to as Tropical Cyclone 12P in the news. The Fiji islands have their own list of tropical cyclone names, which may be confusing, because the Joint Typhoon Warning Center will typically use the number of the storm. The Joint Typhoon Warning Center is currently referring to Oli as "12P" for the twelfth tropical cyclone in the Southern Pacific Ocean.

At 10 a.m. ET, February 1, Tropical Storm Oli (12P) had maximum sustained winds near 57 mph (50 knots) up from 40 mph from 12 hours ago. Oli is moving east at 23 mph (20 knots). It was located about 540 nautical miles north-northwest of Rarotonga, near 13.5 degrees South and 162.9 degrees West.

Oli is currently in an area of low wind shear. High wind shear can tear a storm apart, while low wind shear allows storms to strengthen, if the sea surface temperatures are over 80 degrees Fahrenheit (and they are where Oli is located). Over the next four days, however, Oli will move into those cooler waters and wind shear is forecast to pick up. So, forecasters expect some strengthening in the short term, but Oli will hit a wall after day four.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center