Moderate trade winds will focus showers over windward and mauka areas through today. A band of enhanced moisture (the remnants of an old dissipated front) will move across the state through Friday, bringing an increase in rainfall and stronger trade winds. Drier trades return Saturday. Winds will turn southeast Sunday, followed by a potential increase in showers Sunday through Monday night. After that, a return to drier trades is likely.
A moderate to locally breezy easterly trade wind regime will continue today. Embedded trade wind showers will primarily affect windward and mauka areas. A moisture band will move down the island chain from the north tonight, potentially enhancing showers. Expect VFR outside of showers, where MVFR is likely.
No AIRMETs in effect. AIRMET Sierra for mountain obscurations is possible later today if showers/clouds increase as expected.
Moderate to locally strong easterly trade winds will continue through Friday as high pressure builds north of the islands. The Small Craft Advisory continues through this afternoon for the typically windy waters around Maui County and the Big Island. Model trends indicate winds weakening and veering from the east to southeast direction this weekend, as an area of low pressure develops northwest of the state. The latest forecast guidance shows breezy to strong easterly trade winds building swiftly into Hawaiian Waters from Sunday into early next week.
A medium-period north-northwest (340-350 degree) swell continues to lower and shift from a more northerly (350-360 degree) direction. Another moderate, medium-period north-northeast (360-020 degree) swell will build into Hawaiian waters by early Friday morning, producing moderate surges into north facing harbors, as well as boosting surf heights along north facing shores to near advisory levels. The latest north swell model guidance may be running 2 to 3 feet too low as compared to the long upstream generating fetch area. In any case, we boosted the swell heights 2 feet above model guidance for this next long duration Friday through Monday north-northeast swell that will peak from late Friday into Saturday, then diminish into Monday. The next long period, small northwest (310-320 degree) swell will build into Hawaiian waters by next Tuesday and then slowly decrease through the end of next week.
Choppy east shore surf will continue into Friday, before decreasing this weekend as wind speeds begin to weaken shift out of the east-southeasterly direction. Stronger easterly trade winds starting on Sunday will build rough surf along east facing shores into early next week. Surf along south facing shores will remain tiny to small through the forecast period.
Peak astronomical monthly tides may produce minor coastal flooding through early next week, and may be enhanced along north facing shores later this week due to the next north swell. A Coastal Flood Statement has been issued to highlight this flooding potential through Friday night.
A building north-northeast swell over the next several days will also produce moderate surges for north facing harbors, especially for Kahului and Hilo. A Marine Weather Statement was issued this morning for maritime interests to watch for these impending harbor surges.
Small Craft Advisory from 6 PM this evening to 6 AM HST Saturday for Maalaea Bay.
Small Craft Advisory until 6 AM HST Saturday for Pailolo Channel- Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
