Pacific ENSO Update
3rd Quarter, 2005 Vol. 11 No. 3
Federated States of Micronesia
Pohnpei State: Apart from an extremely dry February, the rainfall at most Pohnpei locations was abundant during the first half of 2005, with an extreme event of 11 inches of rain in 24 hours occurring at the WSO Pohnpei on the 30 th of April. The rainfall total for the first half of 2005 at the Pohnpei WSO (on the north side of Pohnpei Island ) was 104.83 inches. This value exceeded only by the 105.84 inches recorded at Kosrae SAWRS during the same time period. The experimental UOG/CSP rain gage network in the mountainous interior of Pohnpei island indicated that the top of Nahna Laud (Pohnpei Island's highest mountain) received a whopping 182 inches in the first half of 2005, with 57.40 inches in the month of May. Elsewhere on Pohnpei Islan , the rainfall totals during the first half of 2005 were similar to those at the WSO. The 6-month total at Palikir (on the northwest side of the island) was 101.21 inches. On the atolls of Pohnpei State, the rainfall pattern in the first quarter of 2005 was similar to that at the WSO on Pohnpei island.
Pohnpei Rainfall Summary 2nd Quarter 2005| Station | Apr. | May | Jun. | Total | 6-month | |
|---|---|---|---|---|---|---|
| Pohnpei WSO | Rainfall (inches) | 26.11 | 23.95 | 15.64 | 65.70 | 104.83 |
| % of Normal | 154% | 123% | 91% | 125% | 116% | |
| Palikir* | Rainfall (inches) | 22.86 | 22.14 | 16.38 | 61.38 | 101.21 |
| % of Normal | 139% | 116% | 96% | 116% | 112% | |
| Song Kroun* | Rainfall (inches) | 28.98 | 26.16 | N/A | N/A | N/A |
| Nukuoro | Rainfall (inches) | 21.93 | 12.25 | 16.37 | 50.55 | 88.10 |
| % of Normal | 146% | 83% | 134% | 121% | 113% | |
| Pingelap | Rainfall (inches) | 15.68 | 19.89 | 19.52 | 55.09 | 99.27 |
| % of Normal | 91% | 117% | 120% | 109% | 111% | |
| Mwokilloa* | Rainfall (inches) | 10.26 | 18.86 | 16.92 | 46.04 | 82.95 |
| Kapingamarangi | Rainfall (inches) | 14.64 | 13.44 | 10.54 | 38.62 | 70.04 |
| % of Normal | 108% | 130% | 145% | 124% | 106% |
Climate Outlook:
During 2005, the tropical cyclones of the western North Pacific have been forming to the west and north of normal. The region of formation is expected to expand eastward into the Caroline Islands by October. It is expected at this time that Pohnpei will only experience rain from tropical disturbances, some of which may later become tropical storms and typhoons after they have moved to the west and northwest away from Pohnpei. Thus, a direct strike by a tropical storm or a typhoon is unlikely at any island in Pohnpei State for the remainder of 2005 and into the spring of 2006.
Based on the continuation of ENSO Neutral conditions for the remainder of 2005 and early 2006, rainfall at Pohnpei Island and at Pohnpei's atolls should be near normal for the next 3 to 6 months, and then potentially wetter than normal on Pohnpei Island and atolls to the east and west when the trade-wind trough becomes established in the region by April 2006. Kapingamarangi has been wetter than normal for a long time, but the rainfall on this island should return to normal for the duration of this forecast period.
Predicted rainfall for Pohnpei State from September 2005 through August 2006 is as follows:
| Pohnpei Islands and Atolls |
Kapingamarangi |
|
Sep – Dec 2005 |
100% |
95% |
Jan 2006 – Mar 2006 |
95% |
100% |
Apr – Jun 2006 |
110% |
95% |
Jul – Aug 2006 |
100% |
90% |
Source: UOG-WERI