Federated States of Micronesia

Chuuk State:  Annual rainfall throughout Chuuk State was near normal to slightly above normal during 2011. As with any normal year, there were some months with very little rainfall (e.g., 2.46 inches at Chuuk WSO in February) and some months with large rainfall totals (e.g., 22.64 inches at Chuuk WSO in August. The weather was generally tranquil during 2010, with few extremes of wind or rainfall. Sea level became higher than normal during 2010 because of La Niña, and some minor coastal inundations at high tide were noted in the latter months of the year. Similar to the dry conditions experienced during 2010 in the southeastern atolls of Yap State, the western atolls of Chuuk State (e.g., Polowat) were also quite dry during 2010. The influence of La Niña to replace the normal summer and fall monsoon trough with a weak ridge of high pressure probably contributed to the dry conditions in this region of Micronesia.

Chuuk State Rainfall Summary 4th Quarter 2010

Climate Outlook: During 2011, it is anticipated that the most likely scenario would be for the current La Niña conditions to slowly fade back to ENSO-neutral by June or July. In this scenario, easterly low-level winds should continue to dominate the flow throughout Chuuk State for the next several months. Heavy rainfall should be confined to an east-west band known as the trade-wind trough or Inter-Tropical Convergence Zone (ITCZ). The location of the ITCZ in the spring produces a gradient of rainfall within Chuuk State, with higher amounts to the south of the Chuuk Lagoon area (e.g., Ettal and Lukunoch) and lower amounts to the north (e.g., Fananu and Namonuito Atoll). Rainfall could therefore be heavy across central and southern portions of Chuuk State in the spring (April and May) with above normal rainfall seen across Chuuk Lagoon and in the southern Mortlocks. Thereafter, near normal rainfall is anticipated .

Predictions for Chuuk State from January 2011 through December 2011 are as follows:

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

source: UOG-WERI