Federated States of Micronesia

Yap State:  The 2004 annual rainfall at most recording locations in Yap State was above normal. The Weather Service Office (WSO) near the Airport on Yap Island had a total of 137.07 inches during 2004, which was 114% of normal. The distribution of rainfall in most of Yap State during 2004 was similar to that on Guam: a wet June, a dry July, a wet August, followed by drier than normal conditions in September, October and December. With Typhoon Nanmadol passing through Yap State in November, the rainfall for that month was much above normal and also much higher than on Guam. At the Yap WSO the rainfall for October, November, and December was 8.27 inches (69%), 17.77 inches (196%), and 4.06 inches (44%) respectively, amounting to 100% of normal for the 3-month period.

At Ulithi, the 2004 annual rainfall total of 133.97 inches was 102% of normal. The rainfall totals at Ulithi for October, November, and December were 10.15 inches (100%), 12.06 inches (156%), and 5.61 inches (73%) respectively, amounting to 109% of normal for the 3-month period. Farther south at Woleai Atoll the 2004 annual rainfall total of 127.44 inches (92%) was lower than at Yap Island and at Ulithi. This rainfall distribution is accounted for by substantial rainfall during the months of April and November when typhoon passages contributed most to heavy rainfall at the northern islands. The rainfall totals at Woleia for October, November, and December were 11.17 inches (82%), 6.85 inches (63%), and 4.51 inches (39%) respectively, amounting to 63% of normal for the 3-month period. The increasing dryness at Woleai during the last three months of 2004 is similar to what has happened on Guam and Palau, and may signal the beginning of a period of moderate reduction in rainfall for the first few months of 2005.

The tropical cyclone threat at Yap during 2005 should be near normal. During most years approximately 2 or 3 tropical cyclones pass close enough to Yap (and/or its outer islands) to cause gales, but there are usually no direct strikes by a typhoon at any Yap location. The threat of a direct strike by a typhoon at Yap Island and at Ulithi is roughly one-half to two-thirds that of Guam and the CNMI. The threat is even less further south at Woleai. Yap has recently undergone a period of unusually high typhoon activity. Three typhoons affected Yap State in a span of one year (Lupit in November 2003, Sudal in April 2004, and Nanmadol in November 2004). While we expect no direct strikes by a typhoon of any island or atoll of Yap State during 2005, residents should always be prepared for the possibility.
Predicted rainfall for Yap State from Feb 2005 through Jan 2006 is as follows: