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Pacific ENSO Update

4th Quarter, 2011 Vol. 17 No. 4


Guam and CNMI text Guam/CNMI: Throughout Guam and the CNMI, the rainfall during the 3rd Quarter of 2011 was mostly above normal, with many locations throughout these islands experiencing 130% to 150% of average rainfall. For the first time in several years, monsoonal southwesterly winds persisted for many days, accompanied by some heavy showers and thunderstorms. Some of the basin’s tropical cyclones formed to the north and west of Guam, helping to maintain the unsettled southwesterly airstream. The only reported below-normal 3rd Quarter rainfall occurred at the Saipan International Airport, where the 3-month total of 30.85 inches was 90% of normal. The reading of 58.03 inches (154%) at the mid-Guam location of Sinajaña was the highest 3rd Quarter total recorded throughout Guam and the CNMI. A round of thunderstorms during the early morning hours of 2 September dumped 5 to 7 inches of rain across Guam in only a few hours. Minor street flooding inconvenienced morning commuters. This was the heaviest 24-hour total experienced since typhoon Chaba dumped 7 to 9 inches across Guam during the night of 22 August 2004.

On the afternoon of Friday 15 October 2011 a fisherman was killed by a lightning strike. Edward Cruz San Nicolas was electrocuted while fishing off the reef near Paseo De Susana in Hagåtña. According to Pacific Daily News files, the last time a person on Guam was killed by a lightning strike was 2003, when a tourist was killed while swimming in Tumon. During another thunderstorm in the early morning hours of 27 October, lightning temporarily knocked-out the Guam police radio system, and police were forced to use their personal cell phones to communicate until about 10 a.m.

Guam and CNMI Rainfall Summary 3rd Quarter 2011

Station   Jul. Aug. Sep. 3rd Qtr
Predicted
Guam
Guam Intl. Airport (WFO)
Rainfall (inches)
20.54
15.00
16.37
51.91
45.30
% of Normal
195%
109%
121%
138%
120%
Anderson AFB
Rainfall (inches)
9.50
12.41
17.71
39.62
45.19
% of Normal
87%
92%
118%
105%
120%
Dedado (Ypapao)
Rainfall (inches)
16.44
15.68
17.42
49.54
47.94
% of Normal
140%
107%
116%
124%
120%
Ugum Watershed
Rainfall (inches)
16.26
19.05
19.99
55.30
45.30
% of Normal
154%
139%
148%
146%
120%
Sinajaña
Rainfall (inches)
17.97
18.11
21.95
58.03
45.30
% of Normal
171%
132%
163%
154%
120%
Commonwealth of the Northern Mariana Islands
Saipan Intl. Airport
Rainfall (inches)
11.20
12.26
7.39
30.85
40.92
% of Normal
138%
98%
55&
90%
120%
Capitol Hill
Rainfall (inches)
12.57
16.49
17.26
46.32
47.69
% of Normal
140%
132%
128%
132%
120%
Tinian Airport
Rainfall (inches)
10.32
13.94
12.42
36.68
47.69
% of Normal
115%
112%
92%
105%
120%
Rota Airport
Rainfall (inches)
10.20
17.64
18.94
46.78
44.40
% of Normal
113%
134%
142%
126%
120%
Predictions made in 2nd Quarter 2011 Pacifc ENSO Update newsletter.

Climate Outlook: The rainy season has nearly run its course on Guam and across the CNMI. With the return of La Niña, the rainfall should average near or slightly above normal for the next few months as trade winds increase, and rainfall amounts begin to decrease. La Niña has ushered in substantial low-level easterly wind anomalies to the low latitudes, which effectively prevents the formation of tropical cyclones across most of Micronesia. The PEAC Center is cautiously optimistic that no tropical cyclones will adversely impact Guam or the CNMI for the remainder of the year. There may be one or two more cyclones that form to the south of the islands, but pass safely to the west before intensifying to a typhoon or tropical storm. The chances for extremes of rainfall (4 or more inches of rain in 24 hours) are similarly reduced. The rainfall distribution for the upcoming year should be similar to that of the year just past: a continuation of mostly near-normal to wetter-than-normal conditions.

Predicted rainfall for Guam and the Mariana Islands from October 2011 through September 2012 is as follows:

Inclusive Period

% of Long-Term Average Rainfall /
Forecast Rainfall (inches)
Guam/Rota
Saipan/Tinian
October – December 2011
(End of Rainy Season)
120%
(30.76 inches)
110%
(24.27 inches)
January – March 2012
(Onset of Next Dry Season)
110%
115%
April – June 2012
(2nd Half of Next Dry Season)
100%
100%
July– September 2012
(Next Rainy Season)
120%
110%

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

source: UOG-WERI



Pacific ENSO Applications Climate (PEAC) Center
c/o NOAA NWS - Weather Forecast Office Honolulu
2525 Correa Road, suite 250
Honolulu, HI 96822
(808) 956-2324

Web Master's email: peac@noaa.gov
Page Last Modified: December 10 2011 01:44:32 GMT

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