Republic of Palau: During the first half of 2006, the rainfall throughout most of Palau was near normal. January and June were particularly wet with monthly rainfall exceeding 20 inches at some locations (26.45 inches at the Airport, and 21.43 inches at the WSO, Koror). The driest month of the year (so far) was February with less than 10 inches at many locations. The highest monthly rainfall totals at recording locations in Palau most often to occur at the International Airport. The lowest monthly rainfall totals are often seen at Peleliu. 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. The annual migration of the monsoon trough across Palau and the paths taken by tropical cyclones in response to the position of the monsoon trough govern the behavior of the mean monthly rainfall on Palau.

Because of the westward shift in tropical cyclone formation during the first half of 2006, Palau was in the path of some of the few tropical disturbances that moved from western Micronesia towards the Philippines. One of these disturbances became the first numbered tropical cyclone of 2006 (TC 01W), which passed well south of Palau in early March. When Tropical Storm Ewiniar passed close to Yap on the 1st of July, it also affected Palau with gusty westerly winds and heavy rain showers. Peak gusts reached 37 knots at the WSO, Koror,and 46 knots at the International Aiport. Minimum sea level pressure fell ot 1006.8 mb at the WSO Koror. Peak 24-hour rainfall from this tropical cyclone was 1.88 inches. A direct strike by a typhoon is not expected to occur on any island in the Republic of Palau during 2006, however, the tendency so far this year for some of the basin’s tropical cyclones to pass close enough to Palau to cause gusty west and southwest winds and some heavy showers should continue for the remainder of the year into January of 2007.

Climate Outlook:

In general, most tropical storms and typhoons that move past Palau stay well to the north, but westerly gales, heavy rain showers, and rough seas are often experienced as they move by. During the remainder of 2006, there should be several episodes of heavy rainfall and 2 or 3 occurrences of gusty westerly winds and rough seas from tropical cyclones passing to the north.

Rainfall throughout Palau is anticipated to be near normal for most months of the year, with some large month-to-month variations attributed to the episodic nature of rainfall associated with tropical cyclones passing to the north, and other short-term enhancements related to the behavior of the monsoon trough.

Predicted rainfall for Palau from July 2006 through June 2007 is as follows