Posted by Teo Blašković on February 13, 2019. Watchers.news.
Heavy rains and convection across eastern and northern parts of the island of Kauai, Hawai'i resulted in multiple reports of very heavy rainfall and flooding on April 14 to 15, 2018. In 24-hours to 12:35 HST, April 15, Waipa Garden in Kauai recorded 1 262.1 mm (49.69 inches) of rain, breaking the previous 24-hour record precipitation for the United States of 1 092.2 mm (43.00 inches) registered on July 25/26, 1979 at Alvin, Texas.
Regionally, April 14 – 15, 2018 was marked by several ingredients conducive to very heavy rainfall.
A warm, unstable surface layer and deep moisture prevailed across the region. An upper level low west of the Hawaiian Islands, combined with a subtle mid-level trough nearer to Kauai, acted to further destabilize the atmosphere.
This, combined with the absence of any notable inversion layer in the region, further enabled deep convection as a mode of precipitation. Breezy trade wind flow advected moisture to and through the region, maintaining a supply of warm, moist surface air to fuel convection.
Any national or state record precipitation value is by nature unanticipated. However, heavy rain, with embedded deep, sustained convection, was anticipated and observed across much of Kauai during the 14thand 15th. Flash flood warnings were numerous, and significant to catastrophic flooding was documented across much of the island.
This rainfall record, already familiar to the applied climatology community, was established by the NCEC when originally constituted in 2000.