Pacific ENSO Update
2nd Quarter, 2007 Vol. 13 No. 2
Federated States of Micronesia
Pohnpei State: During the 3rd quarter of 2006, the rainfall across most of Pohnpei State was near to above normal. Pingelap, the driest station for the 3rd quarter, still received 91% of it’s average rainfall. Nukuoro and Kapingamarangi were wetter than normal, but the most significant departure from average was at Kapingamarangi. It has been wetter than normal on Kapingamarangi for a very long time (perhaps because of the effects of continually warmer than normal SST on the cloud systems in the area). The 3-month total of 43.30 inches at Kapingamarangi was 193% of the normal for this period, and marks the highest departure from normal rainfall at any recording location in Micronesia for the 3rd Quarter of 2006.
The 3rd quarter rainfall total of 65.88 inches at Palikir was the highest reading in Pohnpei State. It was also the highest value of rainfall recorded during this time period throughout Micronesia and American Samoa. Only the experimental rain gage on top of Nahna Laud (the highest mountain in the interior rainforest highlands of Pohnpei Island) recorded more rainfall – an estimated 76.99 inches from August to October 2006. The rain gages on top of Nahna Laud and at other sites in locations in the remote interior of Pohnpei Island have now been in operation for over 3 years as a joint project between The UOG and the Conservation Society of Pohnpei (CSP).
| Station | Jul. | Aug. | Sep. | 3rd Qtr | |
|---|---|---|---|---|---|
| Pohnpei WSO | Rainfall (inches) | 17.32 | 20.45 | 14.52 | 52.29 |
| % of Normal | 94% | 124% | 90% | 103% | |
| Palikir* | Rainfall (inches) | 24.70 | 22.73 | 18.45 | 65.88 |
| % of Normal | 118% | 121% | 101% | 113% | |
| Nahna Laud * | Rainfall (inches) | 26.96 | 30.03 | 20.00** | 76.99** |
| Nukuoro | Rainfall (inches) | 20.55 | 15.20 | 11.83 | 47.58 |
| % of Normal | 143% | 134% | 108% | 129% | |
| Pingelap | Rainfall (inches) | 18.76 | 13.68 | 9.32 | 41.76 |
| % of Normal | 118% | 92% | 62% | 91% | |
| Mwokilloa* | Rainfall (inches) | 19.99 | 17.39 | 11.89 | 49.27 |
| Kapingamarangi | Rainfall (inches) | 14.72 | 18.72 | 9.79 | 43.30 |
| % of Normal | 142% | 304% | 166% | 193% |
** Estimated
Climate Outlook:
The risk of a damaging tropical storm or typhoon is unlikely at any island in Pohnpei State for the remainder of 2006, and for the first half of 2007. The early stages of developing tropical cyclones may bring some episodes of heavy rain to Pohnpei for the remainder of the year and through January of 2007. Because of El Niño, it is possible that a topical cyclone could form in the Marshall Islands in the three months of November 2006 through January 2007; any such tropical cyclone should pass to the north of all islands in Pohnpei State bringing gusty westerly winds and a chance for a day or two of heavy rainfall.
Dry conditions related to the El Niño that began in the 2nd half of 2006 should not affect Pohnpei too harshly. Most islands from Pohnpei Island eastward into the Marshall Islands could, however, experience a month or two of abnormally dry weather at any time during the period November 2006 through April 2007, after which rainfall amounts should return to near normal. As a precaution, residents of Pohnpei State should make all reasonable repairs and routine maintenance to rain catchments and other drinking water infrastructure. At this time, the dry conditions are not expected to be as bad as those experienced during 1998.
Predicted rainfall for Pohnpei State from November 2006 through October 2007 is as follows:
| Pohnpei Islands and Atolls | Kapingamarangi | |
Nov 2006 - Jan 2007 |
90% | 100% |
Feb - Apr 2007 |
80% | 100% |
May - Jun 2007 |
95% | 100% |
Jul - Oct 2007 |
100% | 95% |
Source: UOG-WERI