Federated States of Micronesia

Kosrae State: For most of 2011, Kosrae has been drier than normal. To date in 2011, only two months (May and August) have had above-normal rainfall and only May exceeded 20 inches. In a typical year, 4 or 5 months exceed 20 inches at the Kosrae Airport. The 3rd Quarter total at the airport of 45.13 inches was 89% of normal. At just under 6° N latitude, Kosrae is not normally affected by La Niña’s reduction of rainfall near the equator, but the extensive tongue of cold SST during the 2010 La Niña may have contributed to dryness in the early part of 2011 when Kapingamarangi, Nukuoro, the western islands of Kiribati, and Nauru all experienced dry conditions. Persistent dryness at Kosrae later in 2011 was not shared by other locations in the region, and may simply be an artifact of the meso-scale nature of tropical rainfall.

Kosrae Rainfall Summary 3rd Quarter 2011

Climate Outlook: For the next several months, persistent trade winds should dominate in Kosrae and throughout eastern Micronesia. This is typically associated with near-normal rainfall in Kosrae. It is worth noting that computer forecast guidance for the rainfall at Kosrae for the final three months of 2011 is evenly divided on the chances of below-average, average, or above-average rainfall. Perhaps counter-intuitively, this forecast distribution does not mean that “near normal” is the best forecast, but rather that there are equal chances for each of the three categories. Based on persistence and similar climatic conditions last year, the PEAC Center will make an educated guess that rainfall will be near normal to slightly below normal during the last two months of 2011 through at least the first quarter of 2012. No adverse tropical cyclone activity is expected for Kosrae State during the remaining months of 2010.

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. Areas prone to wave splash and inundation at high tide are likely to experience more than usual erosive wave action.

Forecast rainfall for Kosrae 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