Hawaii Weather Alert: Heavy Rain, Flooding Concerns Persist Across State as Trough Shifts

HONOLULU (Hawaii News Now) — A significant weather system continues to impact the Hawaiian Islands, bringing heavy rainfall, thunderstorms, and localized flooding concerns. A surface trough shifting over the eastern half of the state has triggered a First Alert Weather Day, with moderate to heavy showers expected to persist through the night.

Current Weather Conditions and Flooding Threats

The trough axis has shifted eastward, bringing heavy rain and thunderstorms across Maui County and parts of Hawaii Island, including the Hamakua coast. The airmass overhead is holding double its usual moisture, creating a high capacity for producing heavier rain at times and a more humid airmass overhead overall. While the upper-level jet and dynamics of this broad trough haven’t been as significant as earlier weather model runs originally predicted, the moist and somewhat unstable airmass still poses a threat for minor flooding and ponding.

School Closures and Road Flooding on Molokai

The impacts of the heavy rainfall have already led to significant disruptions. All schools on Molokai were closed Wednesday due to flooded roads. The threat for minor flooding and ponding will continue through tonight as the surface trough shifts, with moderate to heavier showers and isolated thunderstorms expected along the affected track. Lighter showers are expected over the western end of the state, focused over windward and mauka areas.

Rainfall Totals Vary Significantly Across the Islands

The rainfall totals have been overall beneficial, though highly uneven. Molokai received the most rain, while Kauai received the least. Heavy pockets have been reported over the mountains, though some neighborhoods saw drizzle rather than heavy rain, keeping totals under what the original weather models were projecting. Hawaii Island has seen a trace to about 3 inches of rain, but not everyone in the island chain experienced the downpours. The rain has been particularly limited on Kauai.

Flood Watch Remains Active for Most of Hawaii

A Flood Watch remains in effect for Oahu, Molokai, Lanai, Maui, Kahoolawe, and Hawaii Island through early Thursday as the trough brings moist air over the state from the south. Kauai is no longer under a watch. The First Alert Weather Team will closely monitor conditions and alert residents to any changes as the unstable airmass continues to pass over the state.

Improvement Expected Thursday or Friday, Halloween Forecast

Conditions are expected to improve Thursday or Friday, with trade winds returning this weekend, though spotty heavy showers could linger. A brief period of trade winds is expected to return Friday night into Saturday, with breezy northeast winds developing Sunday as a shallow front moves near or over the state. Looking ahead to Halloween, trick or treating weather could be a little wet, but mainly for windward and mauka neighborhoods. Residents should stay prepared for changing conditions.

Weekend Outlook and Trade Winds Return

As the broad trough shifts out of the area, more typical trade wind weather patterns are expected to establish. The return of these breezy northeast winds will help stabilize the atmosphere and reduce the widespread threat of heavy flooding, though localized showers may still occur in typical windward and mountain areas.

Your First Alert Weather Team will closely monitor conditions and First Alert you to any changes. Stay tuned to the latest forecasts for updates on the ongoing weather situation across the Hawaiian Islands.

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