First Alert: Periods of heavy rain especially for Hawaii Island and Maui

HONOLULU (HawaiiNewsNow) – It is a First Alert Weather Day windward Kauai, windward Oahu and windward Molokai as we track a front on Wednesday.
The HNN First Alert Weather team has declared that Wednesday will be a First Alert Weather Day for windward Oahu, Kauai and all of Molokai.
Offshore thunderstorms continue just to the north of Kauai and Oahu, and some could move onshore late Tuesday night.
A flash flood warning is in effect for the island of Kauai until 12:15 a.m.
Radar indicated heavy rain over central and eastern portions of Kauai. The Hanalei River stream gage jumped to near 6 feet in the last hour. This typically results in closure of Kuhio Highway near the Hanalei River bridge due to flooding.
Rain was falling at a rate of up to 3 inches per hour. With runoff on Hanalei River, it has been a concern into the night.
A weak cold front is expected to move across the state and dissipate on Wednesday, leading to an increased chance for rainfall. Rainfall and clouds will be focused over windward regions.
High pressure is also expected to build in quickly behind the dissipating front on Wednesday, leading to breezy trade winds out of the northeast.
Wet trade winds will continue throughout the rest of this week and into the weekend. These trades will also be gusty, with some sustained winds reaching 20 miles per hour and above. Wind gusts could potentially reach 30 miles per hour.
The front should reach the western end of the state through the day Wednesday, then stall near/over the eastern end late Wednesday through Thursday. Despite some drier air following the front over the western end of the state, shallow moisture combined with the gusty northeast winds will likely keep the rain chances in the forecast for windward areas.
A moderate-sized NNW swell will gradually subside through Wednesday but continue to produce high surf today. A relatively short period NNW swell is expected Thursday, peaking below High Surf Advisory heights. A longer period NW swell is expected Friday and Saturday, potentially reaching advisory levels, with an even larger swell possible Sunday and Monday. Short-period wind waves will increase from the NE as high pressure builds far N of the islands after mid-week.
Moisture ahead of the front being brought in by the strengthening trades will maintain the chance of showers across mainly windward areas tomorrow. Breezy trades will continue through the rest of the week and into the weekend as high pressure remains anchored to the northwest and batches of moisture filter in on the trades. Models show an upper low digging over and southeast of the Big Island late this week and into the weekend, which could help to enhance trade wind showers.
Wishing you blue skies and much aloha.
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