Pacific ENSO Update

3rd Quarter, 2005 Vol. 11 No. 3

RMI Flag Republic of the Marshall Islands (RMI): The northern atolls of the RMI (Kwajalein, Utirik and Wotje) were among the driest of locations in Micronesia during the first half of 2005; only some of the locations in the CNMI were drier. Islands further south had more rainfall, which was closer to the normal amount expected. Kwajalein has been particularly dry with four of the first 6 months of 2005 seeing less than 50% of normal rainfall.The most rainfall recorded in the RMI during the half of 2005 was at Mili with 57.29 inches (102%).

RMI Rainfall Summary 2nd Quarter 2005
Station   Apr. May Jun. Total 6-month
Majuro WSO Rainfall (inches) 13.85 6.84 8.02 28.71 53.53
% of Normal 123% 59% 72% 85% 95%
Laura* Rainfall (inches) N/A 7.70 8.99 N/A N/A
Arno* Rainfall (inches) 6.24 5.83 8.42 20.49 46.63
Alinglaplap* Rainfall (inches) 5.35 N/A 6.37 11.72 N/A
Mili* Rainfall (inches) 10.88 12.61 9.05 32.54 57.29
Kwajalein Rainfall (inches) 3.12 2.68 6.49 12.29 26.95
% of Normal 41% 27% 67% 45% 69%

Utirik

Rainfall (inches) 4.31 2.76 2.18 9.25 17.26
% of Normal 67% 33% 27% 40% 52%

Wotje

Rainfall (inches) 4.38 2.13 3.73 10.24 15.76
% of Normal 61% 22% 41% 41% 46%

Climate Outlook:

In the year following an El Niņo event, the islands in the western and northern portions of Micronesia are typically dry. This was true for Palau, Yap, Guam and the CNMI, and it was also true for the northern islands of the RMI. At 69%, 52%, and 46% of normal for the first six months of 2005, Kwajalein, Utirik, and Wotje, respectively, were among the driest of the islands. With tropical cyclones forming well to the west of normal, and the southwest winds of the Asian monsoon also staying west of normal, the RMI has a very low risk of a typhoon through the rest of 2005 and early 2006. Usually the RMI is wettest in the latter half of the year, as the monsoon works its way east, and tropical disturbances that later move west and become tropical cyclones affect the RMI. The remainder of 2005 should be very tranquil, and it is unlikely that any extreme rain events will take place.

Based on the continuation of ENSO Neutral conditions for the remainder of 2005 and early 2006, rainfall should continue to average below normal in the northern islands for the foreseeable future, and be near normal in the central and southern islands with only moderate month-to-month variation.

Predicted rainfall for the RMI from September 2005 through August 2006 is as follows:

Inclusive Period
% of Long-Term Average
S. of 6°N
 6°N to 8°N
N. of 8°N 
Sep - Dec 2005
100%
95%
90%
Jan 2006 – Apr 2006
100%
95%
85%
May – Aug 2006
95%
100%
90%

source: UOG-WERI