A powerful Kona storm is expected to affect the state this week and into the weekend, bringing several potential hazards to the islands. The combination of deep tropical moisture, strong winds, and increasing instability could produce periods of heavy rainfall with significant flash flooding, damaging winds, and strong to severe thunderstorms from Tuesday through at least Saturday. Flooding concerns may begin as early as Tuesday and Tuesday night over Kauai and Oahu as deep moisture spreads into the western end of the state, then expands eastward across the island chain later in the week. The potential for strong to severe thunderstorms is expected to increase late in the week and into the weekend.
Issued at 903 PM HST Mon Mar 9 2026 Rainfall and thunderstorm chances will quickly ramp up overnight through Tuesday across the western end of the state, particularly over Kauai tonight, as a powerful Kona low evolves and draws closer. This activity will lead to MVFR conditions, with LIFR conditions expected in the heavier showers and storms that move through.
Light to moderate southeast winds will gradually veer southerly and increase over the western end of the state through the day Tuesday. Any storms that develop and move through will be capable of producing damaging winds. These impacts will gradually advance eastward down the island chain by midweek.
AIRMET ZULU is in effect for light icing for Kauai and Oahu. AIRMET SIERRA for mountain obscuration will likely be needed overnight through Tuesday, especially for Kauai and Oahu. Additionally, AIRMET TANGO for turbulence may also become necessary.
Issued at 903 PM HST Mon Mar 9 2026
A powerful Kona storm is expected to bring heavy rain, thunderstorms, and rough seas to the islands and adjacent waters Tuesday into the weekend. Winds will veer southerly and increase to fresh to locally strong speeds Tuesday through late this week as the Kona storm approaches. A Small Craft Advisory (SCA) will go into effect for waters north and west of Kauai beginning early Tuesday morning, when winds will begin to increase. Later this week, possibly as early as Thursday night, winds will approach, or possibly reach, gale force for portions of the area. These strong winds will slowly creep eastward with the front heading into the weekend.
A series of small, medium- to long-period west-northwest swells returning tonight will bring small surf to north and west facing shores through the rest of the week. The first of these will peak on Tuesday, resulting in a slight bump in surf along north and west- facing shores. Another small, medium-period north swell is also possible late this week.
Choppy surf along east-facing shores will gradually trend downward, falling below seasonal levels by mid-week as winds veer southerly. Surf along south-facing shores will remain small, though will become rough and choppy as southerly winds increase. A series of small, long-period south swells will also impact south-facing shores through late this week.
Flood Watch from 6 AM HST Tuesday through Saturday afternoon for Kauai East-Kauai Mountains-Kauai North-Kauai South-Kauai Southwest-Niihau.
Flood Watch from Tuesday evening through Saturday afternoon for Central Oahu-East Honolulu-Ewa Plain-Honolulu Metro-Koolau Leeward-Koolau Windward-Oahu North Shore-Olomana-Waianae Coast- Waianae Mountains.
Flood Watch from Wednesday morning through Saturday afternoon for Haleakala Summit-Kahoolawe-Kipahulu-Lanai Leeward-Lanai Mauka-Lanai South-Lanai Windward-Maui Central Valley North-Maui Central Valley South-Maui Leeward West-Maui Windward West- Molokai Leeward South-Molokai North-Molokai Southeast-Molokai West-Molokai Windward-South Haleakala-South Maui/Upcountry- Windward Haleakala.
Small Craft Advisory from 6 AM Tuesday to 6 AM HST Wednesday for Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters.
