Moderate to breezy trades today will continue to weaken through Thursday, allowing winds to decrease to moderate levels for the remainder of the week. Passing showers will be carried in on the trade wind flow at times, mainly over windward and mauka areas. While details remain very uncertain, a wet pattern is expected to develop towards the middle of next week.
This morning's satellite imagery shows scattered cumulus clouds across the state with some passing showers riding in with moderate to locally breezy trades. As the 1028 mb high continues to weaken and drift eastward over the next few days, the trades will weaken to moderate speeds by Thursday. Generally fair trade wind weather is expected Thursday and Friday, but some scattered showers riding in with the trade winds will be capable of producing some moderate showers mainly during the overnight and morning hours.
Over the weekend, generally a drier weather pattern is expected over the smaller islands. A weak trough currently southeast of the Big Island is expected to drift further northward, but the northward extent remains uncertain. Depending on how far north the moisture gets, we could possibly see some heavier showers develop over windward Big Island this weekend.
Beyond the weekend, the forecast remain very uncertain. While confidence remains high on a wetter pattern developing around Tuesday or Wednesday of next week, the potential impacts remain very uncertain. Majority of the global models and its ensemble members show some type of low pressure system developing around 15N180W this weekend then drifting eastward and approaching the state next week. While the GFS ensembles are showing deep tropical moisture moving over the state by late Monday, the EC and Canadian ensemble members are showing a later arrival of the deep moisture (closer to the middle of next). Please stay tuned to the forecast as we get more information on the potential high impact event next week with the main concern being flash flooding.
Trades will be a bit lighter than the past few days as a surface high north of the state weakens and slides east. Isolated showers are possible for windward locales, but overall expecting VFR conditions to prevail.
No AIRMETs currently in effect.
High pressure north of Hawaii is weakening and moving east as a low pressure system moves in from the northwest. Moderate to locally strong trades will hold through today. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Big Island and Maui County. Winds will weaken as the low draws closer, and then light to moderate trades will continue through the weekend, and probably into the middle of next week. A potential tropical system west of the state is complicating the wind forecast for next week, and confidence is low at this point.
Tiny surf along north-facing shores will persist through today. A small northwest swell will arrive Thursday giving a small bump Thursday afternoon and Friday. This will then be followed by a slightly larger medium-period north-northwest swell this weekend. A potential storm-force low in the process of developing north of Japan could send a larger long period west-northwest swell early next week. This swell is still uncertain and will depend on the evolution of the developing low.
South shores will remain small before a series of moderate, south- southwesterly swells boost surf heights near to above seasonal average this weekend into early next week.
Rough trade wind swell will gradually decline later today as trade winds decrease, leading to a slight reduction in surf through the remainder of the week. A small, medium-period east swell is possible Thursday into the weekend that will help keep surf elevated for east-facing shores.
Small Craft Advisory until 6 PM HST this evening for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.
