Federated States of Micronesia

Pohnpei State: Weather conditions on Pohnpei Island and most of the atolls of Pohnpei State during the 3rd Quarter of 2011 were generally unremarkable. Rainfall was near normal at most locations. Water supplies and stream flow were reported to be adequate. As usual, Palikir topped the list of rainfall totals in Pohnpei State during the 3rd Quarter of 2011 with 57.19 inches (104%). The extreme drought at Kapingamarangi broke in March 2011 when 8.46 inches of rain fell. Since then it has been unusually wet there, with the 3rd Quarter rainfall total nearly double the normal. High surf was recently experienced on Pohnpei Island, likely the result of increased trade wind strength upstream of the island. An unusual occurrence of a waterspout was reported on the afternoon of October 13th.

Pohnpei Rainfall Summary 3rd Quarter 2011

Climate Outlook: With La Niña back in control of the Pacific Basin climate, persistent easterly winds have become established across Micronesia. In this weather pattern, a rather narrow trade-wind Convergence zone forms, and is accompanied by a concentration of rainclouds in an east-west band (i.e., the ITCZ) that is typically located between 4º to 8º N. This is especially true for the months of April and May when Pohnpei Island usually experiences its highest monthly average rainfall. Near normal rainfall is anticipated on Pohnpei Island and the atolls of Pohnpei State for the next several months. The period of April through June 2012 could be very wet on Pohnpei Island and some of the atolls. We are cautiously watching the rainfall at Kapingamarangi which could again fall well below normal as the cold SST of La Niña works back westward along the equator into the longitudes of Pohnpei State.

During La Niña, the sea level typically rises above normal. For the next three to six months, above-normal sea level could exacerbate inundation and coastal erosion during episodes of high surf. Also, brisk easterly winds may develop rough water in the lagoons of atolls, and inside the fringing reef of Pohnpei Island. Areas prone to wave splash at high tide (e.g., the Pohnpei Island airport causeway) may experience more than usual erosive wave action.

No typhoons or tropical storms are anticipated to adversely affect Pohnpei State during for the remainder of 2011 through the first half of 2012.

Forecast rainfall for Pohnpei State from October 2011 through September 2012 is as follows:

Forecast rainfall quantities represent BEST ESTIMATES given the probabalistic forecast for each particular season and station.

source: UOG-WERI