An upper trough will slide from north of the state to the east through Wednesday before settling northeast of the area. Moderate to fresh trade winds will continue to funnel in clouds and showers that will be enhanced by the upper trough over the next several days.
An upper trough north of Hawaii will dive southeastward through tonight. The trough will form a cutoff low and become stationary around 600 miles northeast of Hawaii through Friday night before shifting away this weekend. Meanwhile, moderate to fresh trade winds continue at the surface. Current visible satellite and radar show scattered low clouds and showers over windward Big Island, with isolated shower coverage and partly cloudy skies across the rest of the state. 12Z soundings show elevated inversions around 10-11 kft.
For the rest of today, expect some build up of leeward clouds, especially Big Island. Some instability generated by the cold pool aloft will enhance showers and bring a slight chance of thunderstorms on the Big Island. Some enhanced showers may carry in on the trade winds impacting other islands this afternoon into Wednesday. Windward showers will see the highest shower activity during the overnight to early morning hours.
The upper low northeast of the islands will keep inversion and cloud heights elevated, allowing periods of showers to continue through the second half of the week. Only subtle day to day changes in island weather patterns are expected. This wet trade wind pattern may linger into the first half of next week as a shallow cold front and upper level trough approach the islands from the northwest.
Locally breezy trades continue through the period. Shower activity and isolated MVFR focus windward and mauka during this time. AIRMET Tango for lee turb may be needed as early as Wednesday afternoon as trades strengthen.
No AIRMETs in effect.
Moderate to fresh east-northeast trades will continue today before strengthening late tonight into tomorrow as a weak trough shifts to the west and a ridge builds north of the state. This will likely correspond to Small Craft Advisory winds across the typically windier waters surrounding Maui County and the Big Island beginning tonight or Wednesday.
Offshore buoys show that the newly arriving northwest swell is below 1 ft as of this morning. Therefore, surf along north and west facing shores will remain small today before a bump is possible later tonight as the peak of the swell continues to approach. An upward trend is expected during the second half of the week as another northwest swell arrives as early as Wednesday night. Looking further ahead, a storm-force low east of Japan will send a moderate, longer- period northwest swell toward the islands for Friday and Saturday, with surf heights potentially approaching advisory levels along exposed north and west facing shores.
Surf along south-facing shores will remain small through much of the week, with mainly background south to southwest swell expected. Another south-southwest pulse may arrive by this weekend from recent activity within our swell window east of New Zealand, providing a small increase in surf.
Surf along east-facing shores will remain relatively small and choppy through midweek, with a slight rise possible Thursday and Friday as trades strengthen.
None.
