A broad ridge north of the Hawaiian Islands will dominate our weather for at least the next seven days, with moderate to locally strong easterly trade winds and only subtle day to day wind speed changes. A weak and narrow upper level trough will remain over the region, keeping periods of trade wind showers in the forecast.
Moderate to breezy trades will continue for the next few days. Low cigs and SHRA possible over windward and mauka locations. MVFR conds possible in SHRA, otherwise VFR prevails.
AIRMET Sierra is in effect for mtn obsc for windward locations of Kauai, Oahu, Molokai, Maui and the Big Island.
AIRMET Tango remains in effect for mod low-level turb over and downwind of terrain.
Fresh to strong easterly trades will persist through the first half of the week as the ridge remains north of the state. This will allow the Small Craft Advisory to continue, particularly across the typically windier waters and channels. Expect a gradual downward trend through the second half of the week and next weekend due to a weakness forming in the ridge as a front passes far to the north.
Surf along south facing shores will gradually lower Monday as a medium-period south swell lingers. A fresh long-period south swell will arrive Tuesday, then build to near seasonal average through midweek before slowly easing Thursday. A more significant long-period south-southwest swell is expected due to a storm- force low recently located southeast of New Zealand. Satellite data showed a large fetch of 40 to 50 kt winds generating seas of 35 to just over 40 ft over the weekend, focused toward Hawaii along the 190-degree directional band. Expect surf to begin building locally Friday with 20+ second forerunners, then peak above/around the advisory level next weekend. For the long range, expect a similar trend to persist through the first week of June as the active pattern persists within our swell window down around New Zealand.
Surf along exposed north and west facing shores will lower Monday as a small north-northwest swell eases. Late-season North Pacific activity will continue this week due to a storm-force low currently located around 2000 nautical miles northwest of the state near the Aleutian Islands. Although the bulk of the energy will be focused northeast of the islands, expect long-period forerunners to arrive Tuesday, with this source gradually building down the island chain thereafter. Above-average surf is likely by daybreak Wednesday near the peak before lowering Thursday.
Surf along east facing shores will remain rough through midweek, then gradually lower later in the week as the trades gradually ease.
Small Craft Advisory until 6 AM HST Monday for most Hawaiian Island coastal waters and channels.
Small Craft Advisory until 6 PM HST Tuesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.
