Light to moderate trade winds will produce modest showers over most windward areas into early Saturday, while lingering moisture produces wetter conditions on windward Big Island. A disturbance aloft may trigger isolated heavy showers over the state late Saturday. 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. Then 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 tonight through early tomorrow morning, with significant differences in model solutions beginning tomorrow mid morning. Light showers and clouds will focus over primarily windward and mountain areas tonight and tomorrow morning, although conditions are expected to gradually improve tonight. The exception will be windward Big Island, where increased moisture will linger through the forecast period, keeping lower ceilings and reduced visibility in place. Tomorrow and tomorrow evening's conditions will depend on the progression of the trough to the west. Half of our model solutions depict this feature bringing deeper moisture over Kauai and moving down to Oahu through late Saturday night, along with veering winds to the southeast. This solution would mean more showers and low ceilings/reduced visibility over Oahu and Kauai Saturday evening. The other half of our models show drier conditions with light easterly winds. There is also the chance for some pop up afternoon showers tomorrow as low level moisture associated with the trough lingers.
AIRMET Sierra for mountain obscuration remains in effect abv 020 for windward areas of the Big Island and could linger through the evening as moisture remains anchored.
High pressure to the north will bring moderate to fresh trades to the region into the weekend. As the trades build, a Small Craft Advisory will likely be needed for the typical windier waters, and an incoming north-northwest swell will bring seas in excess of 10 feet to exposed waters.
The current small, short period north-northeast swell will maintain small surf along north-facing shores into Saturday. A larger, long-period northwest swell is expected to arrive late Saturday and will bring advisory level surf to north and west facing shores exposed to the swell Sunday into Monday. The swell is expected to shift slightly more northerly and may briefly build further on Monday before dropping 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.
The current small, medium period south swell will gradually decline through the weekend. During the first half of next week, south shore surf will return to below seasonal averages. East- facing shores will continue to be boosted due to the wrap from the north and southerly swells. As the larger north swell builds in Sunday night and Monday, the wrap from that will have the potential for advisory level surf during that time.
None.
