Heavy Rain — Oahu, Hawaii

1996-11-05 to 1996-11-16 · near Oahu, Oahu, Hawaii

Wider weather episode

Record breaking rainfall produced widespread flooding with associated mud and rock slides, road closures, blocked drainage systems, and overwhelmed waste disposal systems. Damage to public and private property and agriculture was substantial. The Waianae Coast was hardest hit with people stranded in their homes for up to a week in some areas with persistent standing water due to the saturated soils.At the beginning of the month, a high amplitude pattern developed with a strong upper level trough over the central Pacific. From the 3rd through 5th, the upper level trough and surface low pressure were located west northwest of Kauai. On the 5th, heavy showers and thunderstorms moved north in convergent low level flow, and produced 12 inches of rain in less than 12 hours over parts of southwest Oahu. On the 7th and 8th, the surface low pressure deepened rapidly and moved north, producing large swell and damaging surf from the 8th through 11th along the north facing shores of all islands.The upper level trough was nearly stationary as the first surface low center moved to the northeast and away from the islands. A second surface low pressure then developed and strengthened west of Kauai, while the upper level trough shifted east and centered over Oahu. From the 12th through 16th, the upper level trough persisted in the vicinity of Oahu. Weak disturbances rotated around the base of the trough bringing more heavy rains to Oahu. Although the highest rain totals occurred on Oahu, rainfall was widespread from Kauai to Molokai during the period.Rainfall totals (in inches) for some locations on Oahu through the first 15 days of the month and their averages for the entire month: First 15 days Average for monthPoamoho 22.4 4.6Palisades 21.4 8.0Waianae 21.3 2.0Kunia 19.2 3.3Waipio 19.2 3.3Lualualei 18.8 2.5Mililani 18.5 4.5Wilson Tunnel 17.8 10.2Waihee Pump 17.2 16.2Hon Intl Arpt 16.1 3.0Aloha Tower 14.9 2.6Maunawili 14.3 7.6Kahuku 11.5 4.6At Honolulu International Airport, rainfall was 18.74 inches for the entire month, establishing a new record for the month of November. The previous record for November was 14.72 inches. The monthly total of 18.74 inches exceeded the total for all of 1995, which was 13.60 inches. One of the highest rainfall reports came from a NWS cooperative observer in Waipahu, where 31.47 inches of rain was recorded for the month.

Source: NOAA Storm Events Database, event_id 5583215. Narrative written by the NWS forecast office that issued the report.