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Hurricane Season 2010: Tropical Depression 1F (Southern Pacific Ocean)
November 26, 2010

First Tropical Depression Forms in the SW Pacific, Fiji on Alert

NASA's TRMM satellite saw moderate rainfall (orange) in Tropical Depression 1F in the Southwestern Pacific. › View larger image
NASA's TRMM satellite saw moderate rainfall (orange) in Tropical Depression 1F in the Southwestern Pacific Ocean on Nov. 26 at 1202 UTC (7:02 a.m. EST). Rain was falling as much as 1 inch per hour. This image is a combination of TRMM data and infrared data from the MetSat satellite.
Tropical depression 1F has formed in the southwestern Pacific Ocean, and a NASA satellite revealed that it already has moderate rainfall as it continues to get organized. The Tropical Rainfall Measuring Mission or TRMM satellite passed over Tropical Depression 1F on November 26 at 1202 UTC (7:02 a.m. EST) and captured rainfall rates near 1.0 inches per hour in the southern half of the storm. TRMM's pathway over the depression only covered the southern half of it, so there was no data available for the rainfall rates in the northern half. TRMM is a joint mission between NASA and the Japanese Space Agency, JAXA.

Fiji is an island nation in Melanesia in the South Pacific Ocean about 1,240 miles (2000 km) northeast of New Zealand's North Island, located in the southwestern Pacific Ocean. Fiji comprises an archipelago of more than 332 islands. Of those, 110 islands are permanently inhabited. The two major islands of Fiji are called Viti Levu and Vanua Levu.

The Nadi Tropical Cyclone Center is the organization that forecasts tropical cyclones in that region of the world. It was officially designated by World Meteorological Organization in 1995 as a Regional Specialized Meteorological Center (RSMC) with activity specialization in tropical cyclones tasked to provide "first-level" information in tropical cyclones in the South-West Pacific Ocean.

The RSMC issued a warning for parts of Fiji as Tropical Depression 1F is expected to organize and strengthen. At 1350 UTC (7:50 a.m. EST) on Nov. 26, the center of Tropical Depression 1F was located near 16.1 South and 171.4 East. That's about 447 miles (720 kilometers) west-northwest of Nadi, Fiji. It is moving east-southeast at 10 mph (8 knots).

Satellite data has confirmed that Tropical Depression 1F has become better organized this morning and convection (rapidly rising air that forms the thunderstorms that power the tropical cyclone) has increased since Nov. 25. Maximum sustained winds are estimated between 30 and 35 knots (18-22 mph).

It is expected to become a tropical cyclone over the weekend as wind shear is expected to weaken and the depression tracks through warm waters. Sea surface temperatures in the depression's path are near 30 degrees Celsius (86 Fahrenheit). Tropical cyclones need sea surface temperatures of at least 80 F (27 C) to develop and strengthen, so the waters are warm enough to further development as long as the wind shear allows. Tropical Depression 1F is expected to move southeastward over the weekend.

The RSMC has issued warnings for parts of Fiji. Gale warning 007 was issued on Nov. 26 at 1319 UTC (8:19 a.m. EST), which is 1:19 a.m. local time/Fiji on Nov. 27. A Tropical Storm Alert is in effect for Fiji. A strong wind warning is also in effect for Fiji. The RSMC noted that as Tropical Depression 1F continues to intensify "it may bring damaging gale force winds over the western parts of Fiji by later Sunday (local time)." The RSMC noted that rainfall will become more frequent and heavy with thunderstorms. Flooding in low lying and coastal areas can be expected on Saturday.

Other areas of Fiji can expect moderate easterly winds to gradually become northerly and intensify later Sunday. Showers and thunderstorms are expected to become more frequent and heavy rainfall may also produce flash flooding of low-lying areas. For more updates on Tropical Depression 1F from the Fiji Meteorological Society, go to http://www.met.gov.fj//.

Text Credit: Rob Gutro
NASA Goddard Space Flight Center, Greenbelt, MD