UPDATE: Weekend Flash Flood Advisory for Big Island
Saturday, April 7, 2018, 1:47 p.m.: The National Weather Service in Honolulu has issued a Flood Advisory for Hawai‘i County until 4:45 p.m.
At 1:41 p.m., radar and rain gages indicated heavy showers and thunderstorms over interior portions of the Big Island along the upper slopes of Mauna Kea and Mauna Loa, in the saddle and the Kohala Mountains.
Rain rates in excess of 2 inches per hour are occurring with the heaviest showers.
Be aware of rapid rises in streams and dry gulches across the Kohala and Kona Districts and in Hāmākua.
Locations in the advisory include but are not limited to Kailua-Kona, Pa‘auilo, Waipio Valley, Kukuihaele, Hawi, Honaunau, Kamuela, Kahalu‘u-Keauhou, Honokaa, Kealakekua, Ookala and Kapa‘au.
Stay away from streams, drainage ditches and low lying areas prone to flooding.
Rainfall and runoff will also cause hazardous driving conditions due to ponding, reduced visibility and poor braking action.
Do not cross fast flowing or rising water in your vehicle, or on foot. Turn around, don’t drown.
This advisory may need to be extended beyond 4:45 p.m.if heavy rain persists.
Friday, April 6, 2018, 3:28 p.m.: The National Weather Service in Honolulu has issued a flash flood watch for all Hawaiian Islands for Saturday and Sunday, April 7 and 8, 2018.
An upper level disturbance will approach Hawai‘i from the northwest on Saturday and drag a band of deep, layered moisture over the islands.
The upper level disturbance will interact with an old front resulting in periods of heavy rainfall and a slight chance of thunderstorms through Sunday. Flash flooding may result.
High moisture levels, in combination with the unstable atmosphere provided by the trough, may provide persistent moderate to heavy rains over the state this weekend.
Showers and thunderstorms are expected to increase and intensify through the day Saturday and continue through 6 p.m. Sunday.
The Flash Flood Watch for the Big Island. Kaho‘olawe, Kaua‘i, Lana‘i, Maui, Moloka‘i,
Ni‘ihau and O‘ahu begins Saturday morning and extends through Sunday afternoon.
A Flash Flood Watch means that conditions may develop that lead to flash flooding.
Flash flooding is a VERY DANGEROUS SITUATION.