(BIVN) – The National Weather Service has issued a Flood Watch for the entire island of Hawaiʻi, where flash flooding caused by excessive rainfall will be possible through Saturday morning.
“An upper level low and associated surface boundary will provide conditions favorable for heavy rain through tonight,” the forecasters wrote Friday afternoon. “Heavy rain has been observed on Oahu and Molokai, and this feature is moving toward Big Island tonight.”
At the time the Flood Watch was issued for Hawaiʻi island, the entire island of Oʻahu was under a Flash Flood Warning.
UPDATE – (5 p.m.) – From a National Weather Service forecast discussion posted at 3:22 p.m. HST:
An upper level low centered near Kauai was moving slowly southeast this afternoon. This low is expected to gradually weaken and move east and then northeast tonight. The cold air aloft associated with this low will help provide unstable conditions through tonight, and therefore we have extended the flood watch for Oahu and Maui County, and added Big Island. Kauai seems to be too far west now to have a significant threat of flooding, so they were removed from the watch. Where the watch remains, it goes through 6 AM HST Saturday.
As the low moves away from the islands Saturday into Sunday, the atmosphere will become more stable, and even though lots of low level moisture will remain with us through Tuesday, the chance of flooding will decrease. Trade winds will return Sunday after another day of southeast winds Saturday. Once the trades return, they are expected to remain over the state through the end of next week. Initially, the increased moisture from this current system will bring wet trades Sunday through Tuesday. After Tuesday, more typical trade wind showers should be with us through the end of the week.
