Republic of Palau: Rainfall was abundant throughout the Republic of Palau during the first half of 2009. Six-month rainfall totals of roughly 80 inches at all of the Palau recording sites was 120% of normal. The 86.20 inches of rainfall at the International Airport was the highest value recorded in Palau, and was a bit higher than the 79.53 inches recorded at the Koror WSO. The airport generally receives slightly more rainfall than the WSO in Koror. Likewise, Peleliu is typically drier than the WSO Koror; however, during the first half of 2009, Peleliu recorded slightly more rainfall than the WSO (80.80 inches versus 79.53 inches).

Republic of Palau State Rainfall Summary 2nd Quarter 2009

Climate Outlook: Palau has a complex pattern of monthly rainfall with the highest average rainfall in the months of June and July; the lowest average rainfall in the months of February, March and April; and a secondary minimum in September when the monsoon trough and typhoon tracks pull well to the north. As anticipated in the last PEAC newsletter, the period April to June was wet. During El Niño, the monsoon trough often extends much further to the east than normal. As a result, the rainfall associated with the monsoon trough moves eastward, and dry conditions typically begin to be felt first in Palau in October or November. As the current El Niño is anticipated to be weak to moderate, substantial dryness is not anticipated at this time. Palau could experience two or three episodes of near-gale (25 to 35 mph) westerly winds associated with tropical cyclones passing to the north at any time between mid-August and the end of the year. Because of its southerly location, it is not anticipated that Palau will experience a direct strike by a strong tropical storm or a typhoon.

Forecast rainfall for Palau from July 2009 through June 2010 is as follows:

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

source: UOG-WERI