Republic of Palau: Rainfall was abundant throughout Palau during the first half of 2008. During May, Palau was in the path of several tropical disturbances that later became tropical cyclones elsewhere in the basin. The May rainfall at several recording sites was heavy; for example, the reading of 18.39 inches at the WSO was 163% of normal. The 78.35 inches of rainfall (115% of normal) at the International Airport was the highest value recorded in Palau for the first half of 2008. The Airport generally receives slightly more rainfall than the WSO in Koror. In contrast, Peleliu is typically drier than the WSO Koror. For the first half of 2008, Peleliu had about 10 inches less rain than at the WSO.

Republic of Palau State Rainfall Summary 2nd Quarter and 1st Half 2008

Climate Outlook: Palau has a complex pattern of monthly rainfall, with the highest average rainfall in the months of June and July, and the lowest average rainfall in the months of February, March and April. A secondary rainfall minimum occurs in August and September when the monsoon trough and typhoon tracks move well to the north of the islands, causing rainfall amounts in September to be lower than in June and July. This should be the case this year.

As anticipated in the last PEAC newsletter, the period from April to June was wet. During mid-July, the monsoon trough of the western Pacific became established at an abnormally high latitude. This type of pattern is typical during La Niña events. When the monsoon trough moves back southward later in the year (October to December), Palau could experience two or three episodes of near-gale (25 to 35 mph) westerly winds associated with tropical cyclones passing to the north. 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 2008 through June 2009 is as follows:

Note: Palau has a complex mix of rainy and dry months. The wettest months are typically June, July and August. During September, the monsoon trough and tracks of typhoons move far to the north of Palau, lowering the average rainfall in September to below that of both August and October.

source: UOG-WERI