Pacific ENSO Update

2nd Quarter, 2008 Vol. 14 No. 2

FSM Flag Federated States of Micronesia

Chuuk State: The 1st Quarter of 2008 brought relatively wet conditions to most of Chuuk State. Three-month rainfall totals ranged from 25 inches to 35 inches across the state, with the lower amounts of 25 to 30 inches occurring across Chuuk Lagoon and in the Northern atolls and 30 to 35 inches occurring in the Mortlocks. Most recording locations in Chuuk State had at least one month in the 1st Quarter with rainfall above 10 inches, with some locations in the Mortlocks receiving 10 or more inches in two out of the three months. To the west, Polowat was much drier with less than 20 inches of rainfall recorded in the 1st Quarter. Polowat and Woleai have both experienced a regional dryness in response to a persistent dry area in the larger pattern of tropical Pacific rainfall distribution. Just as at Woleai, however, abundant rainfall returned to this region in March.

Chuuk State Rainfall Summary 1st Quarter 2008

Station   Jan. Feb. Mar. 1st Qtr Predicted
Chuuk Lagoon
Chuuk WSO
Rainfall (inches)
13.34
8.32
8.36
30.02
25.77
% of Normal
125%
133%
100%
119%
100%
Piis Panew*
Rainfall (inches)
8.95
4.41
9.09
22.45
25.77
% of Normal
N/A
N/A
N/A
89%
100%
Xavier HS*
 Rainfall (inches)
9.05
N/A
N/A
N/A
25.77
% of Normal
N/A
N/A
N/A
N/A
100%
Southern Mortlocks
Lukunoch*
 Rainfall (inches)

10.08

12.87
8.00
30.95
27.70
% of Normal
N/A
N/A
N/A
123%
110%
Ettal*
Rainfall (inches)
7.70
6.78
12.90
27.38
27.70
% of Normal
N/A
N/A
N/A
109%
110%
Ta*
Rainfall (inches)
8.49
9.96
15.64
34.09
27.70
% of Normal
N/A
N/A
N/A
135%
110%
Northern Atolls
Fananu*
Rainfall (inches)
16.86
4.66
7.64
29.16
23.90
% of Normal
N/A
N/A
N/A
116%
95%
Onoun*
 Rainfall (inches)
10.46
8.35
6.66
25.47
23.90
% of Normal
N/A
N/A
N/A
101%
95%
Northern Mortlocks
Losap*
Rainfall (inches)
10.26
9.13
11.43
30.82
25.77
% of Normal
N/A
N/A
N/A
122%
100%
Nama*
Rainfall (inches)
14.33
9.21
10.49
34.03
25.77
% of Normal
N/A
N/A
N/A
135%
100%
Western Atolls
Polowat
Rainfall (inches)
3.90
3.56
12.20
19.66
19.45
% of Normal
N/A
N/A
N/A
96%
95%
Predictions made in 4th Quarter 2007 Pacifc ENSO Update newsletter.
* Long term normal is not established for these sites
** Estimated

Climate Outlook: The threat of a direct strike by a strong tropical storm or typhoon on any of the islands of Chuuk State should be slightly below normal for the remainder of 2008. Because of La Niña-related weather patterns, any tropical cyclones that form near Chuuk throughout most of 2008 will likely be in their disturbance state of development, and should only become tropical storms after passing out of Chuuk State. Some heavy rainfall events (more than 2 inches of rainfall in one day) may occur episodically in association with tropical disturbances in the area. Based on a continuation of La Niña conditions through at least the first half of 2008, rainfall at islands and atolls of the Chuuk Lagoon and on the other atolls of Chuuk State should be above normal for most months of the rest of calendar year 2008.

Forecast rainfall for Chuuk State from May 2008 through April 2009 is as follows:

Inclusive Period
% of Long-Term Average Rainfall /
Forecast Rainfall (inches)
Chuuk Lagoon, and Northern Mortlocks
Polowat
Northern Atolls

Southern
Mortlocks
May - June 2008
 120%
(28.97 inches)
100%
100%
110%
July - September 2008
110%
100%
110%
110%
October - December 2008
110%
100%
120%
100%
January - April 2009
100%
100%
100%
100%
Forecast rainfall quantities represent BEST ESTIMATES given the probabalistic forecast for each particular season and station.

source: UOG-WERI