Pacific ENSO Update

1st Quarter, 2009 Vol. 15 No. 1

Palau Flag Republic of the Marshall Islands: During 2008, the rainfall in the central and southern atolls of the RMI was slightly lower than normal rainfall. The 115.17 inches at the WSO Majuro was 88% of its long-term average. The 2008 annual rainfall totals at some of the atolls in the northern RMI were among the lowest values at any of the USAPI. The less than 50 inches of annual rainfall at Wotje represented only half of the normal annual rainfall expected at this location. The RMI was hit hard by the phenomenal surf event of early December 2008. High surf sent white water surging across the beachfront and into homes and crops. The College of the Marshall Islands in Majuro was particularly hard hit, reporting $760,000 in damage. The causeway connecting Ebeye with Gugeegue was washed out. Japanese structures built on Rui Namur during the WWII were undermined by run-up from waves that may have exceeded 20 feet in height. At the time of this writing, U.S. government officials from FEMA and USAID are assessing the damage caused by this event. The PEAC Center will author a meteorological summary of this unusual event.

Republic of the Marshall Islands Rainfall Summary 4th Quarter 2008

Station   Oct. Nov. Dec. 4th Qtr
Annual
RMI Central Atolls (6°N - 8°N)
Majuro WSO
Rainfall (inches)
12.18
14.27
11.80
38.25
115.17
% of Normal
88%
111%
100%
99%
88%
Laura*
Rainfall (inches)
8.26
9.26
N/A
N/A
N/A
% of Normal
N/A
N/A
N/A
N/A
N/A
Arno*
Rainfall (inches)
N/A
N/A
N/A
N/A
N/A
% of Normal
N/A
N/A
N/A
N/A
N/A
Alinglaplap*
Rainfall (inches)
11.86
11.26
15.56
38.68
108.97
% of Normal
N/A
N/A
N/A
112%
93%
RMI Southern Atolls (South of 6 °N)
Jaluit*
Rainfall (inches)
7.56
10.28
2.55
20.39
94.05
% of Normal
N/A
N/A
N/A
53%
72%
RMI Northern Atolls (North of 8°N)
Kwajalein
Rainfall (inches)
11.89
5.85
7.45
25.19
85.22
% of Normal
100%
55%
92%
82%
83%
Wotje*
Rainfall (inches)
6.17
4.31
2.71
13.19
47.93
% of Normal
55%
43%
35%
45%
49%
* Long term normal is not established for these sites
** Estimated

Climate Outlook: With the resurgence of La Niña in the Pacific basin, the trade wind trough sharpens across Micronesia; this also sharpens the rainfall gradient across the RMI. In this pattern, rain bands just graze Majuro at its northern extent, keeping the more southerly atolls (Mili) in abundant rain. Atolls to the north of Majuro (Kwajalein and Wotje) are now entering their normal dry season, and rainfall on some of these northern atolls may be meager for a few months. Low rainfall in the next two or three months might impact potable water supplies on some atolls in the northern RMI, such as Utirik and Wotje. Residents of the northern RMI are thus urged to participate in voluntary water conservation measures. Near normal rain should return to all atolls by mid-year and continue for the rest of the calendar year.

Forecast rainfall for the RMI from January 2009 through December 2009 is as follows:

Inclusive Period
% of Long-Term Average Rainfall /
Forecast Rainfall (inches)
S. of 6° N
6° N to 8° N
N. of 8° N 
January - March 2009
(Dry Season)
110%
(25.72 inches)
95%
(22.21 inches)
85%
(10.77 inches)
April - June 2009
(Onset of Rains)
100%
95%
95%
July - September 2009
(Rainy Season)
100%
100%
100%
October - December 2009
(Start of Dry Season)

100%
100%
100%
Forecast rainfall quantities represent BEST ESTIMATES given the probabalistic forecast for each particular season and station.

source: UOG-WERI