An easterly wave passing on an easterly track, just south of the Hawaiian Islands, will combine forces with a weak upper low to the west of the state. Expect enhanced clouds and showers into Saturday morning favoring Maui and Hawaii Counties. Easterly trade wind speeds will also increase slightly through the weekend. A second tropical disturbance passes farther south of the state early next week. This system will likely boost trade wind speeds as it will likely track too far south for any rainfall impacts. The next best chance for increasing statewide shower trends may develop by next week Thursday.
Breezy to strong trade winds will persist across the islands through the period. Pockets of higher moisture riding in on the trades will maintain lower ceilings and frequent windward showers. PHTO will experience the most MVFR and occasional IFR conditions.
AIRMET Sierra is in effect for mountain obscuration across windward Big Island and windward Maui. Sierra may expand further west into Oahu this morning.
AIRMET Tango remains in effect for moderate turbulence within the lee of higher terrain the next few days.
Fresh to strong trade winds with periods of near gales in the channels will prevail through the weekend as high pressure persists north of the state. A Small Craft Advisory (SCA) remains in place for all Hawaiian Waters due to a combination of winds and elevated seas through Saturday night. The SCA will likely remain in place through at least Sunday night as a disturbance or tropical cyclone passing a couple hundred miles to the south keeps the local pressure gradient tight. Winds are expected to ease slightly late Monday and Tuesday as the ridge to our north erodes and the potential tropical cyclone moves away to the southwest. The SCA will likely be trimmed back to the typical windy waters around Big Island and Maui at that time. Trade winds are expected to strengthen again on Wednesday.
A north-northwest swell will continue a slow decline through Saturday, and surf along exposed north and west facing shores should drop below High Surf Advisory thresholds this afternoon or evening. A reinforcing medium period energy out of the north- northwest (330 to 340 degree) should arrive late Saturday into Sunday. Surf could approach advisory thresholds during its peak early Sunday morning. Another large northwest to north-northwest swell is Wednesday or Thursday.
A small south-southwest swell should produce south shore surf slightly above seasonal average through Saturday. A tiny pulse from the south-southeast may maintain surf near seasonal average Sunday and Monday, followed by background level surf through the remainder of the week.
Rough surf along east-facing shores will hold around seasonal average into Monday due to the strong trades. Select northeast exposures should see long-period energy from the large north- northwest swell into tonight.
High Surf Advisory until 6 PM HST this evening for Kauai North- Kauai Southwest-Maui Central Valley North-Maui Windward West- Molokai North-Molokai West-Molokai Windward-Niihau-Oahu North Shore-Waianae Coast-Windward Haleakala.
Small Craft Advisory until 6 AM HST Sunday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters- Maalaea Bay-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel.
