Honolulu residents should prepare for wet and unpredictable weather, as a cold front currently near the Kauai Channel is expected to move toward Oahu at dawn, slowing down before reaching Molokai between today and Thursday. According to the National Weather Service (NWS) - Honolulu, this slow-moving front is forecast to bring moisture to the area, with an upper disturbance following it, keeping rain chances elevated through the weekend. As the trade winds return, they are expected to direct rainfall toward the windward and mauka regions through early next week.
The NWS outlook indicates that a shower-filled front will move eastward this morning and is expected to stall between Oahu and Molokai later today. The main moisture is likely to remain to the north, but low-level moisture streaming over the state will continue to support elevated chances of precipitation. On Kauai, west-northwest winds are expected to bring light post-frontal rain, mainly over the west to north-facing areas. A similar pattern is forecast for Oahu as the front stalls. Northeast to east trade winds are expected to return statewide starting Thursday.
Aviation conditions are expected to become marginal visual flight rules (MVFR) as the front moves eastward, bringing showers and mountain obstructions to Oahu for much of the day. The AIRMET Sierra for mountain restrictions on Kauai will expire at sunrise and will be replaced by similar conditions over Oahu as the front advances.
For coastal residents and mariners, a strong west-northwest swell is producing high surf along northern and western shorelines, with a High Surf Warning in effect for most areas until Thursday evening. Waves may reach up to 40 feet in exposed locations. These swells, along with varying wave periods, are expected to gradually decrease into the weekend. Surf conditions are forecast to drop below High Surf Warning levels by Thursday night and further decline below advisory criteria by Saturday. A smaller northwest swell is expected to arrive on Sunday.
The Small Craft Advisory remains in effect for most Hawaiian coastal waters (except Maalaea Bay) through Thursday, with combined seas reaching or exceeding 10 feet. The cold front moving eastward at 10 to 15 knots over the Kauai Channel is expected to bring increased cloud cover and showers to the waters around Kauai and Oahu. As the front dissipates, high pressure from the north will build, resulting in moderate to strong trade winds across the state by the weekend.
The fire weather forecast indicates no critical conditions through the week, due to the moisture and rain chances associated with the stagnant front. NWS - Honolulu ensures no heightened fire-related alerts are anticipated in the coming days.
Lastly, for those heading to the beaches or navigating the waters, the High Surf Warning is in effect until 6 p.m. HST Thursday for regions from Niihau to the Big Island South. The Small Craft Advisory is also in effect for all Hawaiian waters, except Maalaea Bay, until 6 p.m. HST Thursday.
