Pacific ENSO Update

3rd Quarter, 2007 Vol. 13 No. 3

Palau Flag Republic of the Marshall Islands: A welcome return of abundant rainfall occurred in April for most of the RMI. Rainfall in April at some atolls was greater than in the previous 3 months combined! During the first half of 2007, there was a sharp north-south gradient of rainfall in the RMI with islands to the south (such as Mili) receiving abundant rainfall, and islands to the north (such as Kwajalein and Utirik) undergoing extremely dry conditions.

Republic of the Marshall Islands Rainfall Summary 2nd Quarter 2007

Station   Apr. May June 2nd Qtr
Predicted (2nd Qtr)
First Half 2007
Majuro WSO Rainfall (inches)
11.26
9.54
6.67
27.47
32.22
38.68
% of Normal
110%
85%
58%
83%
95%
69%
Laura* Rainfall (inches)
6.31
13.01
3.66
22.98
32.22
35.93
Alinglaplap* Rainfall (inches)
8.92
10.58
10.61
30.11
32.22
47.49
Mili* Rainfall (inches)
16.88
13.23
8.00
38.11
33.92
61.51
Kwajalein Rainfall (inches)
11.06
5.57
5.00
21.63
22.59
27.22
% of Normal
146%
56%
52%
80%
90%
70%

Utirik*

Rainfall (inches)
5.68
0.46
3.42
9.56
22.59
14.53

Arno*

Rainfall (inches)
10.13
10.79
8.04
28.96
32.22
41.43

Wotje*

Rainfall (inches)
5.40
2.06
2.77
10.23
22.59
12.32
Predicted rainfall refers to forecast made in 1st Quarter 2007 PEAC Newsletter.
* Long term normal is not established for these sites
** Estimated

Climate Outlook: Welcome rains came to the northern RMI in April, after a tense 3-month period of very dry conditions that became a water emergency in the northern islands. Near normal rainfall is now anticipated for most of the atolls of the RMI for the rest of 2007. Residents of the northern RMI, though not in any immediate threat of extreme dry conditions, are urged to take every measure possible to ensure adequate water supplies should dry conditions return in the next dry season (January through April 2008). Near normal summer rains should be experienced on all islands.

Tropical cyclone activity is expected to be below normal throughout the entire western North Pacific basin during 2007, and especially in the eastern portion of the basin. No tropical cyclones are anticipated in the RMI through the rest of 2007. It is possible that during the period August through October, a remnant of 2 or 3 eastern or central Pacific tropical cyclones may enter the western North Pacific somewhere between Kwajalein and Wake Island. The chance for a tropical storm to threaten Wake Island is a plausible scenario, but the chance for a tropical storm at any other island of the RMI is remote for the foreseeable future. This level of risk is below normal.

Forecast rainfall for the RMI from August 2007 through July 2008 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 
Aug - Oct 2007
100%
(37.78 inches)
95%
(35.89 inches)
90%
(30.47 inches)
Nov 2007 - Jan 2008
100%
100%
100%
Feb - April 2008
100%
95%
85%
May - July 2008
100%
100%
90%
Forecast rainfall quantities represent BEST ESTIMATES given the probabalistic forecast for each particular season and station.

source: UOG-WERI