Hawaii

Hawaii: The winter wet season of 2005-2006 started off extremely dry across Hawaii as a strong jet stream persisted across the north Pacific, keeping all significant rain makers well to our north. December 2005 was the driest December on record for Lihue, with only 0.08 inches (normal is 4.8 inches). Even normally wet Mt Waialeale on Kauai received only 1.67 inches (normal is over 45 inches). This pattern broke down in early February as the jet stream across the Pacific weakened, likely in concert with a developing weak La Nina pattern, and allowed storm systems to move much farther south. Normally during March, Hawaii will see several strong trade wind events and shear line passages with considerable rainfall over the windward, or north- and east-facing, slopes of the islands. Instead, March 2006 brought only 5 days of low level winds from a trade direction with the remainder being from the southeast through southwest due to the persistent pattern of low pressure to our west. It was not a single low that persisted for nearly 7 weeks, but rather a series. Several stations (Waimanalo, Pahala, Moloaa) broke their March record and Lihue had its wettest month ever.

This unprecented wet period created severe flooding throughout the state and devastating property damage throughout the month. The Honolulu Forecast Office issued 111 flash flood warnings from Feb 19th-Apr 2nd; typically only 2-3 are issued during this time period. In addition there were landslides, heavy winds and tornados. The repeated heavy rainfall stressed many of the reservoirs throughout the state. On March 14th, Ka Loko Dam on Kauai failed. The wall of water swept away homes and structures and resulted in 3 confirmed deaths and 4 persons missing. Our condolences go out to the families and friends affected by this tragedy.

This information was taken from the NOAA NWS Unprecedented Extended Wet Period across Hawaii event summary. For more detailed information and the full event summary go to http://www.prh.noaa.gov/hnl/pages/events/weeksrain/weeksrainsummary.php . 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 forecast for Hawaii, dynamical and statistical tools predict a tendency towards below normal temperatures from JJA (June-July-August) 2006 to ASO (August-September-October) 2006. Dynamical and statistical tools also indicate a tendency towards above median precipitation from MJJ 2006. For the MJJ all four Hawaii stations ( Hilo , Kahului, Honolulu and Lihue) have a 40% chance of having above normal rainfall. Honolulu and Lihue have a 40% chance of having above normal rainfall for JJA and ASO; Kahului and Hilo have an equal chance of below normal rainfall, near normal rainfall and above normal rainfall for JJA and ASO.