Federated States of Micronesia

Yap State: The month of February was particularly wet in Yap State with almost half of the 1st Quarter rainfall occurring in that month. The 15.07 inches of rain during February at the WSO Yap was over twice (252%) of the normal February rainfall. January rainfall was slightly above normal, while March rainfall (the typical heart of Yap’s dry season) was below normal. Overall, the 1st Quarter rainfall was above normal throughout Yap State, except at Woleai, which was the only Yap State location to report below normal rainfall.

Yap State Rainfall Summary 1st Quarter 2009

Climate Outlook: For the next few months, tropical disturbances and any tropical cyclone activity in the western North Pacific basin will still have the westward bias that has been noted for the past two years. This will allow abundant rainfall to occur throughout Yap State. The westward bias in tropical cyclone formation means that Yap State and the Republic of Palau stand the highest chances of any Micronesia location to be within the circulation of a developing tropical cyclone during the next three months. While a direct hit by a typhoon is not anticipated, there could be one or two episodes of gale-force wind from a tropical cyclone forming within the region, then moving westward toward the Philippines. Later in the year (October through December), there is a normal risk (5-10%) of a damaging tropical cyclone in Yap State or its northern atolls. Based on the gradual shift of the Pacific basin from La Niña to ENSO-neutral conditions, rainfall should be above normal throughout most of Yap State at least through the end of the calendar year.

Predicted rainfall for Yap State from April 2009 through March 2010 is as follows:

source: UOG-WERI