textproduct: Honolulu

SYNOPSIS

Strong high pressure north of the Hawaiian Islands will maintain breezy to locally windy trades supporting windward and mauka showers. As the high begins to drift farther east, trades will ease to moderate to breezy levels, persisting through the rest of the week. Some models are hinting at unsettled weather returning to the islands by the weekend, but strengthening trades with periods of windward and mauka showers is looking like the more likely outcome for the weekend into early next week.

DISCUSSION

With strong high pressure positioned to the northeast of the island chain and a trough of low pressure well to the west, breezy to locally windy trade winds will persist through the afternoon. As the high gradually drifts farther east, the pressure gradient will relax slightly, allowing trades to ease to moderate to breezy levels this evening through Friday. This will allow a more typical trade wind pattern to persist through the end of the standard work week, bringing periods of enhanced showers and increased clouds to windward and mauka locations. Radar and satellite imagery show isolated showers moving into windward and mauka areas this afternoon, with deeper moisture expected to remain focused near the Big Island through this evening. This moisture is expected to remain deep enough to support wintry precipitation at the Big Island summits. Temperatures at the summits, which are slightly above freezing this afternoon, are expected to drop below freezing again this evening, favoring additional snowfall accumulations and the potential for freezing fog. A Winter Weather Advisory has been extended through early Thursday morning to account for these potential continued impacts.

Looking ahead to the weekend and early next week, models continue to advertise a low developing west of the state that eventually becomes absorbed by a larger system to the northwest. There's some deep moisture tied to this setup, but for now, guidance keeps most of it west of the islands. Instead, the more likely outcome is strengthening trade winds across the state, along with a few rounds of enhanced moisture from decayed fronts drifting in from the east, bringing increased shower activity.

AVIATION

Breezy trades continue across most of the island chain, with wind speeds expected to gradually decrease over the next couple of days. Light windward showers are also expected under this pattern, especially for Maui and the Big Island, which may lead to localized MVFR conditions.

AIRMET Sierra remains in effect for mtn obsc above 030 for N thru SE sections of Maui and the Big Island through today.

AIRMET Tango remains in effect for mod turb below 070 for leeward sides of the islands.

MARINE

Strong high pressure far north of the state will continue to produce rough marine conditions across the state through next week as another strong high builds far north of the state Friday into the weekend. The current strong to near gale force trade winds will ease slightly by Thursday before picking back up over the weekend. Widespread strong to near gale force trades are expected by Sunday with some of the windier channels such as Alenuihaha Channel approaching gale force. Small Craft Advisory is in effect across all waters due to the strong trade winds with seas in excess of 10 feet for exposed coastal waters.

Strong trade winds will continue to bring advisory level surf to east facing shores through tonight. Latest nearshore buoy observations just started to show a downward trend in wave heights and we should see a gradual downward trend tonight. Surf is expected to fall just below advisory levels by Thursday, but will remain rough and elevated for the foreseeable future. Trades are expected to restrengthen over the weekend into early next week, which will produce another round of advisory level surf and possibly warning level surf along east facing shores of Oahu and Kauai.

Small to medium northwest swells will continue through the weekend with smaller surf expected during the first half of next week. Currently we have a small northwest swell that filled in during the day today and will be followed by a slightly larger northwest swells Thursday and Friday. Small along south facing shores will continue to remain small with some background windswell for select exposures.

Thunderstorms remain a possibility in the offshore waters to the southwest and west of the Hawaiian coastal waters, due to an upper level trough in the area. While this upper level feature is expected to weaken over the next couple of days, a new developing mid to upper level trough moving in from the northwest will maintain the possibility for thunderstorms through the weekend.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Advisory until 6 AM HST Thursday for Olomana-Kahoolawe- Maui Windward West-Kauai East-East Honolulu-Koolau Windward- Molokai Windward-Molokai Southeast-Windward Haleakala-Kipahulu- South Haleakala-Big Island Southeast-Big Island East-Big Island North.

Winter Weather Advisory until 6 AM HST Thursday for Big Island Summits.

Small Craft Advisory until 6 PM HST Thursday for all Hawaiian waters-