Climate Outlook:

The tropical cyclone distribution in the western North Pacific basin through August 2005 is typical for a year after an El Niño. The numbers have been below normal and the formation region has been west and north of normal. During the months of September through December 2005, the formation region of tropical cyclones is expected to expand into the Caroline Islands, resulting in a near normal threat of a typhoon for Guam and the CNMI during the remaining months of the year. Thus, two or three tropical storms and one or two typhoons should pass within 200 miles of any Guam and CNMI location. The months of greatest threat will be October and November. The odds of typhoon force winds (or greater) at any location on Guam or in the CNMI during any given year (status of ENSO not considered) are approximately one in seven. During El Nino years, the odds of typhoon force winds on Guam or on any individual island in the CNMI rise to about one in three. During non-El Nino years the odds fall back to around one in ten. Dangerous surf from a typhoon does not require that the typhoon pass close to any location, so it is certain that at least one episode of dangerous typhoon-generated waves will occur. Every year several lives are lost due to hazardous surf. Rainfall is anticipated to be near normal for Guam and the CNMI through the the summer rainy season, and then be slightly drier than normal in the next dry season.

Predicted rainfall for the Mariana Islands from September 2005 through August 2006 is as follows: