American Samoa:  The average rainfall at American Samoa typically begins to decrease during May and June as the dry season gets underway. However, these two months were substantially wetter than normal this year, and both A‘asufou and Pago Pago ended the first half of the year with an abundance of rainfall. The 2008 first half total rainfall of 81.87 inches at Pago Pago was 124% of its normal value (17.03 inches above normal). In terms of percent of normal, this was among the highest rainfall at any of the USAPI stations for the first half of 2008.— WSO Pago Pago

American Samoa Rainfall Summary 2nd Quarter and 1st Half 2008

Climate Outlook: American Samoa is now within the heart of its dry season (May through November). Nearly all nclimate models favor near normal to slightly above normal rainfall over the next few months, and there has certainly been abundant rainfall to-date as the dry season commences. With ENSO-neutral conditions expected to continue through the Northern Hemisphere fall months (Southern Hemisphere spring months), American Samoa should receive normal to above normal rainfall through December 2008. However, rainfall amounts may vary greatly from month to month depending on the establishment of the South Pacific Convergence Zone (SPCZ) and the continued establishment and placement of the monsoonal trough originating out of Australia.

The PEAC Center remains cautiously optimistic that the focus of South Pacific tropical cyclone activity will remain west of the International Date Line from northeastern Australia eastward to Fiji in the upcoming 2008-09 cyclone season, and that the risk of a damaging impact by a hurricane or strong tropical storm in American Samoa will be near normal (roughly 10% probability).

Forecast rainfall for American Samoa from July 2008 through June 2009 is as follows:

source: UOG-WERI