A plume of shallow moisture lingering in a light to moderate trade wind flow will maintain increased cloud cover through the morning, while wet conditions persist over mainly windward Big Island. An approaching disturbance aloft may trigger a few heavy showers this afternoon and tonight, mainly over Kauai and Oahu. The tail end of a front will move down the island chain late Sunday through Monday, bringing breezy northeasterly trades and drier air in its wake. Breezy easterly trades will bring periods of windward and mauka showers through the rest of the week.
A trough to the west and ridge to the east will maintain easterly trade winds into the afternoon. Light showers and clouds will focus primarily over windward and mountain areas this morning. There is also the chance for some pop up afternoon showers today, especially over the Big Island, as low level moisture associated with the trough lingers.
Most high res models bring some deeper moisture over Kauai, and possibly Oahu, later this afternoon into tonight, along with veering light winds out of the southeast. This would mean more showers and low ceilings/reduced visibility over Kauai and Oahu tonight, with the greatest potential for Kauai.
AIRMET Sierra for mountain obscuration is in effect for windward areas of most islands this morning, though conditions are expected to improve for Maui, Molokai, and possibly the Big Island by the afternoon.
Issued at 346 AM HST Sat Oct 31 2026
High pressure to the north will bring moderate to fresh trades to the region today. Northeast winds are forecast to strengthen behind a trough dropping south across the islands on Sunday, which may require a Small Craft Advisory for all coastal waters. An incoming north-northwest swell combined with strengthening trades will push seas in excess of 10 feet for exposed waters. Moderate to fresh northeast trades remain in place through much of the week as high pressure sits north of Hawaii.
The current small, short period north-northeast swell will maintain small surf along north- and east-facing shores today. The forerunners from a moderate, long-period northwest swell are expected to arrive this afternoon/evening, with the swell building quickly overnight. By Sunday, advisory level surf is expected for north and west facing shores, which is expected to continue into Monday. The swell is may shift slightly more northerly briefly build further on Monday before dropping on Tuesday. Depending on the exact direction, a Marine Weather Statement may eventually need to be issued due to the potential for harbor surges at Kahului and Hilo during that time. Another advisory level northwest swell is possible Thursday into Friday.
The current moderate, medium period south swell will gradually decline through the weekend. Surf above seasonal average returns to seasonal average on Sunday as the south swell energy fades. During the first half of next week, south shore surf will return to below seasonal averages.
East-facing shores will see an increase in trade wind swell as northeast winds return on Sunday. Surf along east-facing shores will increase through Monday night and conditions will be choppy as trades sustain through much of the week.
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