UPDATED: Thursday, 5:20 a.m.
Although a flash flood warning for Oahu expired Wednesday night, a flash flood watch remains in effect for most islands through tonight.
A kona low west of the state will continue to produce periodic bands of heavy rain and thunderstorms across portions of the island chain through tonight, according to the National Weather Service.
All islands, except for Hawaii island, are under a flash flood watch through late tonight.
A flash flood watch will be in effect for all islands through Thursday afternoon.
A small craft advisory for the windward waters of Maui County and the waters surrounding Hawaii island, including the Alenuihaha Channel, will be in effect until 6 a.m. Thursday.
Southeast winds of 20 to 25 knots and seas seven to 10 feet are expected. A small craft advisory means conditions will be hazardous to small craft.
A persistent kona low sitting west of Kauai will begin weakening Thursday, according to the National Weather Service. A convergence band, or a band of clouds that causes heavy rain, will be present through the weekend, but trade winds are expected to be back over all the islands by Sunday.
Flash floods and thunderstorms are still possible tonight, mainly on Oahu and Kauai.
For Thursday, there is a 90% chance of rain on Niihau; a 90% chance throughout Kauai; an 80% chance throughout Oahu except for the windward side — Kailua, Waimanalo and Kaneohe —where there is a 70% chance of rain; a 70-80% on Lanai; a 50% chance on Kahoolawe; a 50-70% chance on Maui; and a 50% of rain throughout Hawaii island except for the summits of Mauna Kea and Mauna Loa about 8,000 feet elevation, where there is a 40% chance of rain until the evening, when there is a 20% chance of rain.
The National Weather Service issued a flash flood warning for Oahu until 6:45 p.m. today.
“At 3:52 p.m., the Waikane Stream gauge reported a rapid rise in water level. This indicates that the stream is expected to overflow onto Kamehameha Highway in Waikane shortly. Radar data also showed heavy rainfall continuing over Oahu from Mililani to Haleiwa,” forecasters said.
Heavy rain can cause flooding in drainages, streams, rivers, roads, properties, and other low-lying areas, they said. Landslides are also possible in steep terrain.
Flooding could occur in Honolulu, Waimanalo, Haleiwa, Wahiawa, Schofield Barracks, Hawaii Kai, Ahuimanu, Punaluu, Wheeler Field, Waikele, Kahuku and Kalihi, they said.
Kauai, meanwhile, is under a flood advisory until 6:30 p.m. and the entire state is under a flash flood watch until Thursday afternoon.
“A kona low west of the state will continue to produce bands of heavy rain and thunderstorms across portions of the island chain through Thursday,” the weather service said. “While all islands could experience flooding rainfall, the greatest risk for flooding will be on Kauai and Oahu where soils remain saturated due to recent heavy rain. Heavy rain will likely affect urban and leeward locations, as well as lower elevations, which are more vulnerable to flooding impacts.”
The severe thunderstorm warning for the island of Kauai has expired.
The severe thunderstorm warning for the island of Kauai has been extended through noon today.
The severe thunderstorm warning for the island of Kauai has been extended to 11:30 a.m.
A severe thunderstorm warning has been posted for the island of Kauai through 11:15 a.m.
At 10:47 a.m., a line of severe thunderstorms was detected 11 miles southwest of Kohala moving northwest at 40 mph. The thunderstorms are expected to reach Barking Sands by 11 a.m. and mover across south and west Kauai, the National Weather Service said.
People on Kauai can expect gusts of 60 mph and damage to roofs, siding and trees.
A new severe thunderstorm watch has been posted for the island of Kauai as a flash flood watch remains in effect for the entire state.
The severe thunderstorm watch, which is in effect through 2 p.m. today, means conditions are favorable for severe thunderstorms in and around the watch area, according to the National Weather Service. Severe thunderstorms can produce damaging winds of 58 mph or greater or destructive hail the size of quarters or larger.
The flash flood watch for all islands is in effect through Thursday afternoon as the Kona low generates bands of heavy rain and thunderstorms across portions of the island chain, forecasters said. Kauai and Oahu have the greatest risk of flooding, where soils remain saturated due to heavy rain this week.
Heavy rain will likely soak urban and leeward locations as well as lower elevations, the NWS said.
A wet and unsettled weather pattern will continue through Thursday as a Kona low lingers several hundred miles west of Kauai, the NWS said. The main threat to the islands remains heavy rain and flooding over already saturated ground, though the potential for severe weather continues today across the western end of the state.
Forecasters expect the Kona low to slowly weaken and drift northward on Friday, stabilizing the atmosphere and easing rain throughout the state. Tradewinds will return, albeit gradually, over the weekend.