A flood watch has been issued for all Hawaiian Islands from Wednesday morning through Friday afternoon as forecasters warn that significant flooding may develop. Roads in several areas may close, and landslides are possible in steep terrain if the expected rain bands intensify.
The National Weather Service said the watch comes as a hydrologic outlook points to heavy rain and potential flooding late Tuesday into next weekend. The agency said a significant pattern change is expected to begin Tuesday, when an upper-level disturbance and a surface low pressure system evolve northwest of the islands and draw deep tropical moisture northward over the state. That setup could bring an extended period of moderate to breezy southerly winds and increase the chance of widespread rainfall and renewed flooding concerns.
Forecasters said instability may increase as early as Tuesday night, with enhanced showers possibly reaching Kauai by late Tuesday night. There is also a slight chance of thunderstorms on Hawaii island Tuesday afternoon. Cole Evans said the rains are expected to fall daily from Tuesday into the first half of the weekend.
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The flood watch matters now because the weather is expected to turn after back-to-back Kona-low storms last month, adding more rain to communities still dealing with the aftermath. The forecast points to a developing pattern that could repeatedly soak the state rather than deliver a single quick round of showers, which is why officials are warning of flooding on roads and in low-lying areas.
The tension in the forecast is that the rain may not arrive as one clean event. The weather service said the same system that can produce widespread rainfall could also bring flash flooding across all islands, especially where steep terrain and saturated ground leave little room for runoff. Residents near streams, rivers, gulches, valleys, ravines and other flood-prone areas are being told to stay especially alert and be ready to move to higher ground if flash flooding develops.
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The weather service is urging people to clear gutters, storm drains, culverts and other drainage areas of debris, move valuable items out of low-lying or flood-prone areas, and check pumps, generators and emergency equipment. It also recommends taking stock of food, water, medications, flashlights and backup power sources, and reviewing family emergency plans while checking on neighbors and relatives who live in vulnerable spots. That advice points to the likely answer to the question at the center of the forecast: yes, this is a multi-day flood threat, and the risk is broad enough that preparations need to be made before the heaviest rain arrives.
For readers following the broader rain pattern, it is another reminder of how quickly a wet forecast can spread beyond one region; a similar flood watch was posted for Central Florida as heavy rain threatened that area, too, in a separate weather event. In Hawaii, the watch runs through Friday afternoon, but the heavier concern lasts beyond it, with the weather service expecting the threat of flooding to stretch from late Tuesday through next weekend.
