Cyclone Oli reaches category 4 strength on its way to open waters

Cyclone Oli reaches category 4 strength on its way to open waters
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

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 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 () force winds extend only to about 35 miles (56 kilometers) from the center. From there, 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 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.

Citation: Cyclone Oli reaches category 4 strength on its way to open waters (2010, February 4) retrieved 8 December 2022 from https://phys.org/news/2010-02-cyclone-oli-category-strength.html
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