Federated States of Micronesia

Yap State: Annual rainfall totals for 2008 at all Yap Island locations were generally in the range of 95 to 100 inches, which is approximately 20 to 25 inches below the typical value (120 inches) for a calendar year. The same weather patterns that resulted in tranquil conditions for Guam and other locations throughout Micronesia produced similar tranquil and uneventful weather on Yap during 2008. The 2008 annual rainfall total of 64.56 inches at Woleai was only 51% of normal, making this island one of the driest locations in Micronesia during 2008 (both in actual rainfall total, and with respect to normal). Rainfall amounts were close to normal in the 4th Quarter of 2008, with the 30.30 inches at the Yap WSO coming in at 101% of the long-term average. The 2008 annual total of 106.91 inches (89%) at the Yap WSO was the highest recorded value for all of Yap State for the calendar year of 2008. The 4th Quarter rainfall 2008 (month-for-month) and the 2008 annual rainfall was lower at every location on Yap Island than the rainfall recorded at each location for the 4th Quarter 2007 (month-for-month) and 2007 annual rainfall. Sea-levels have been higher than normal throughout Yap State for the past two years as a response to La Niña conditions in 2007 and its resurgence in late 2008. Astronomically higher tides in recent months have been compounded by high sea-level and strong trade winds to produce notably high water stands across Yap Island. High sea-level with some inundation of low-lying exposed areas has been noted throughout Micronesia in the past few months.

Yap State Rainfall Summary 4th Quarter 2008

Climate Outlook: All of the islands of Yap State should have near normal rainfall for the next three months. The recent resurgence of La Niña should guarantee that most months of 2009 should have normal or above normal rainfall throughout Yap State. Stronger than normal trade winds and sub-surface ocean heating in the western North Pacific will keep sea levels above normal for at least the next three months. Tropical cyclone activity in the western North Pacific is expected to be higher than it was during the quiet years of 2007 and 2008, although the activity should still be displaced farther west than normal. Being on the western side of Micronesia, 2 or 3 tropical cyclones should pass to the north of Yap Island and Ulithi producing gusty westerly winds and rough seas in the island waters, with one such cyclone sometime in the spring months of April to June, and the other two in the fall.

Predicted rainfall for Yap State from January 2009 through December 2009 is as follows:

source: UOG-WERI