Pacific ENSO Update

4th Quarter, 2004 Vol. 10 No. 4

RMI Flag Republic of the Marshall Islands (RMI): The month-to-month variability of rainfall recorded at most stations in the RMI over the past 5 months was the same pattern seen at Guam (Fig. 1), and at many other islands in Micronesia: June was wet; July was dry; August was very wet; September and October were both dry. The total rainfall for the 5-month period June through October 2004 varied from slightly above normal at Kwajalein (due to a very wet August) to moderately drier than normal at Majuro (due mostly to very dry conditions in September and October). August was the wettest of the past five months at all reporting sites in the RMI. Islands with over 20 inches of rainfall during August 2004 include: Kwajalein, Arno, and Alinglapap (all in the north). During June, July, August, September, and October, the Weather Service Office (WSO) at Majuro measured 12.29 inches (106%), 9.09 inches (70%), 13.53 inches (117%), 4.27 inches (34%), and 7.26 inches (52%) respectively. This amounted to a total of 46.44 inches (74%) for the 5-month period. At Kwajalein and nearby Ebeye in the northern atolls of the RMI, the rainfall for June, July, August, September, and October was 6.92 inches (72%), 7.20 inches (69%), 23.61 inches (233%), 8.40 inches (71%), and 9.74 inches (82%), respectively. This amounted to a total of 55.87 inches (104%) for the 5-month period. At Utrick, in the northern atolls, the June, July, August, September, and October rainfall was 7.05 inches (86%), 10.73 inches (121%), 12.01 inches (140%), 6.53 inches (65%) and 9.36 inches (92%), respectively. This amounted to a total of 45.68 inches (100%) for the 5-month period. At Jaluit in the southern portion of the RMI, the rainfall for July, August, September, and October was 8.20 inches (63%), 14.64 inches (127%), 9.51 inches (77%), and 6.44 inches (47%), respectively. This amounted to a total rainfall of 38.79 inches (76%) for the 4-month period.

El Niño conditions bring an enhanced threat of a tropical cyclone to the central and northern Marshall Islands. It is possible, during the next 3 months (November, December 2004, and January 2005) for a tropical storm to form within the RMI, or move westward across the International Date Line into the RMI.

Predicted rainfall for the RMI from Nov 2004 through Oct 2005 is as follows:

Inclusive Period
% of Long-Term Average
S. of 6°N
6°N to 8°N
N. of 8°N 
Nov - Dec 2004 110%
90% 80%
Jan - Mar 2005 100%
85% 75%
Apr - Oct 2005 100%
95%
90%
source: UOG-WERI