Pacific ENSO Update
4th Quarter, 2006 Vol. 12 No. 4
Monthly Precipitation
State of Hawaii Summary
According to the National Weather Service’s Standardized Precipitation Index (SPI),
3rd quarter rainfall was near average across most of the state. However, moderately dry conditions were recorded along the Koolau range on Oahu, as well as the leeward sides of Maui and Hawaii islands.
On August 7 and 8, heavy showers fueled by the remnant of Tropical Storm Fabio dropped 15.08 inches in 24 hours on Kauai's Mount Waialeale, resulting in flash flooding on Hanalei River and a brief closure of Kuhio Highway at the Hanalei River Bridge. The only significant heavy rain event took place late September 25 through the early morning hours of September 26 when thunderstorms and showers triggered by an upper level low northwest of Kauai dropped 1- to 3-inch totals over portions of the Big Island and 6- to 10-inch totals over the central Koolau Range on Oahu. A USGS gage on Kaluanui Stream in Oahu’s Sacred Falls State Park registered a 4 ft rise in water levels over a 3-hour period. While heavy rains prompted flash flood warnings, no significant damages or injuries were reported.
October marked the beginning of Hawaii’s rainy season (October-April), with several heavy rain and flash flood events around the state. The most significant set of storms occurred during the week of Oct 16-20, when 2 strong systems brought very heavy rain to portions of the Big Island and Maui.
Hawaii Rainfall Summary for Select Stations, 3rd Quarter 2006
| Station | Jul. | Aug. | Sep. | 3rd Qtr | |
|---|---|---|---|---|---|
| Hilo Airport | Rainfall (inches) | 7.83 | 5.69 | 9.52 | 23.04 |
| % of Normal | 73% | 58% | 104% | 78% |
| Honolulu Airport | Rainfall (inches) | 0.08 | 0.11 | 0.66 | 0.85 |
| % of Normal | 16% | 24% | 89% | 50% |
| Kahului Airport | Rainfall (inches) | 0.14 | 0.05 | 0.23 | 0.42 |
| % of Normal | 29% | 9% | 59% | 30% |
| Lihue Airport | Rainfall (inches) | 3.75 | 4.24 | 1.18 | 9.17 |
| % of Normal | 177% | 222% | 44% | 136% |
Additional individual rainfall station information and specific island information for Hawaii can be found in the Monthly Precipitation Summaries which are located online at http://www.prh.noaa.gov/hnl/pages/hydrology.php .
Climate Outlook:
According to the Climate Prediction Center's official 90 day outlook for Hawaii, dynamic and statistical models indicate a tendency toward below normal temperature for Hawaii from NDJ (November-December-January) 2006/07 to JFM (January-Febuary-March) 2007. The models indicate a tendency towards below normal precipitation from DJF (December-January-February) 2007 to FMA (February-March-April) 2007. The ENSO phenomenon is found to play an important role in the climate variability in Hawaii. During the late winter and spring of ENSO events, drier-than-average conditions can be expected in Hawaii.