Moderate to locally breezy trades will prevail through the next several days, resulting in periods of shower activity across windward and mauka locations. An upper-level trough and developing low will slowly move eastward and become stationary northeast of the islands, enhancing clouds and shower activity. By the weekend, the upper-level trough is expected to dislodge and meander northeastward away from the state, however, periods of showers are expected to continue.
Moderate to locally breezy trades will continue courtesy of the broad surface high just north of the Hawaiian Islands. Aloft, an upper-level low and escorting upper-level trough moving eastward across the Central Pacific will become stationary just northeast of the islands later today. This will enhance clouds and shower activity across the state, namely favoring windward slopes of all islands, with some possible shower activity drifting into leeward areas briefly. However, by this weekend, the upper-level trough and associated low will finally dislodge and exit the region, though periods of showers will likely continue.
Trades will remain the dominant feature through the next several days, where showers focus across windward and mauka areas, with only slight variations in the day to day weather pattern across the state. Model guidance portrays a shallow cold front and another upper-level trough approaching the islands from the northwest early next week. Future forecasts will monitor the evolution of this system as the week progresses and revise as necessary.
Moderate easterly trade winds will continue with an upper level trough producing periods of MVFR conditions in passing showers mainly over windward mountain areas, and favoring the overnight to early morning hours. Terrain sheltered leeward areas along the western island slopes may see afternoon showers as sea breezes converge with trade winds each day.
No AIRMETs in effect. However, AIRMET Sierra may be needed later today for mountain obscurations mainly over north and east slopes of island mountains.
Moderate to fresh east-northeast trades will continue today as a weak trough shifts to the west and a ridge builds north of the state. A Small Craft Advisory (SCA) has been issued for the typical windier waters surrounding Maui County and the Big Island. The SCA is likely to be extended through at least Friday before a trough approaches from the northwest this weekend, which will lead to a period of more relaxed trade winds.
Surf along north and west facing shores will get a small reinforcing bump today. An upward trend is then expected during the second half of the week as another northwest swell arrives overnight from a storm-force low that tracked into the Bering Sea this past weekend. 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 near advisory levels along 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 this weekend from recent activity east of New Zealand, providing a small increase in surf.
Surf along east-facing shores will remain small and choppy through midweek, with a slight rise possible Thursday and Friday as trades strengthen.
Small Craft Advisory until 6 AM HST Thursday for Kahoolawe.
Small Craft Advisory until 6 AM HST Thursday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
