Guam/CNMI:  Rainfall on Guam during the first quarter of 2005 was near normal to slightly drier than normal at most locations. At the University of Guam on Guam's central east coast, the total rainfall of 8.21 inches for January, February, and March was drier overall than at the central interior station (GIA at 9.19 inches) and at northern station (Anderson Air Force Base at 14.29 inches).

Each of the first three tropical cyclones of 2005 passed close enough to Guam to influence the weather. Tropical Storm Kulap passed about 100 miles east of Guam producing some high surf on the east side of the island, the tropical disturbance that became Typhoon Roke passed south of Guam giving some much-needed dry season rainfall, and the disturbance that became Typhoon Sonca passed to the south depositing some much-needed dry season rainfall. Wildfires in Guam's grasslands have been occurring regularly throughout the current dry season, but have not been excessive. During the first quarter, trade winds were unusually strong and hazardous surf was experienced on many days.

In the heart of its dry season, most of CNMI's rainfall stations during the first quarter of 2005 reported less rainfall than on Guam--both in inches and as a percent of normal. Saipan International Airport and Capital Hill were at 93% of normal and 72% of normal respectively, Rota was also drier at 64% of normal. The rainfall recorded at Tinian during the first quarter of 2005 was the lowest amount at any recording station in Micronesia at 5.53 inches (58% of normal).

Eruptions of Anatahan volcano, located about 90 miles north of Saipan and 200 miles north of Guam, have sent episodes of hazy volcanic smog (vog), fumes and volcanic ash southward to Guam and the islands of the CNMI. More information on these events and current volcanic activity is available through USGS and the Hawaii Volcano Observatory website.

Climate Outlook:

With the demise of weak El Niño conditions in 2005, the threat of a typhoon for Guam and the CNMI during the upcoming year is near normal. During an average year, three or four tropical storms and one or two typhoons pass within 200 miles of any location. The odds of typhoon force winds (or greater) at any given location on Guam or in the CNMI during any given year (status of ENSO not considered) are approximately 1 in 7. During El Nino years, the odds of typhoon force winds on Guam or in the CNMI rise to about 1 in 3. During non-El Nino years the odds fall back to around 1 in 10. 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.

Based on the gradual demise of weak El Niño conditions during 2005, conditions are anticipated to be drier than normal for Guam and the CNMI through the upcoming dry season and into the onset of the summer rainy season. Predicted rainfall for the Mariana Islands from Jun 2005 through May 2006 is as follows: