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Update of SW Pacific TC guidance for the 2010-11 season

There is an expectation of normal or above normal tropical cyclone (TC) activity for most islands west of the International Date Line in the southwest Pacific during the remainder of the 2010-11 season (February–April). Although risk is reduced east of the International Date Line, all communities should remain alert and prepared.

There is an expectation of normal or above normal tropical cyclone (TC) activity for most islands west of the International Date Line in the southwest Pacific during the remainder of the 2010-11 season (February–April). Although risk is reduced east of the International Date Line, all communities should remain alert and prepared.

As of the end of February 2011, eight TCs have occurred in the region covered by the ICU forecast. A total of nine to 12 named TCs were forecast for the southwest Pacific (between 135°E to 120°W) between November 2010 and April 2010. On average, nine tropical cyclones occur each year for the southwest Pacific region, which are grouped into classes ranging from 1 to 5, with 5 being the most dangerous. For this season, activity seen thus far has matched the October 2010 forecast that at least three cyclones would reach at least Category 3, and one system would reach at least Category 4, with mean wind speeds of at least 64 knots or 118 km/h.

Each year, TCs have a significant impact on the southwest Pacific. Projections continue to show an increased risk of TCs for the remainder of the 2010–11 season over the Coral Sea and to the southwest of Fiji, particularly for Papua New Guinea, the Solomon Islands, Vanuatu, and New Caledonia. New Zealand is also at higher risk of experiencing an ex-tropical cyclone interaction, even late in the season. While risk is generally reduced for islands to the east of the International Date Line during La Niña, historical cyclone tracks indicate that TCs can affect parts of southwest French Polynesia, including the Society and Austral Islands, and the Cook Islands during La Niñas. All islands should remain vigilant as La Niña continues to evolve with progression through Austral summer and into autumn. The analogue years used in the 2010–11 forecast indicate the TC season may also extend into May. A total of at least 12 named TCs are expected to occur for the whole season..