SynopsisA ridge to the north will produce breezy trade winds. Remnants of a front will keep the weather rainy through tomorrow, especially over Oahu this evening and Kauai later tonight. It will turn drier early next week as the frontal remnants dissipate. The trade winds will subside next week as the ridge weakens.
DiscussionAn east to west surface ridge 800 miles north of Oahu continues to produce breezy trade winds over the main Hawaiian islands. An east northeast to west southwest band of showers, the remnant of an old front, remains centered over Oahu this afternoon. The shower band is parallel to the trade-wind flow so it is likely to remain lined up over Oahu this evening and keep the windward side of that island quite rainy. The clouds will be tall enough and the winds strong enough for scattered showers to spread leeward. It will be less rainy over the other main Hawaiian islands this evening, but the trades will carry showers over windward areas of all the islands. The shower band will shift northwest over Kauai later tonight. Rainfall will decrease over Oahu and increase over Kauai. A new band of showers will move over the Big Island and increase windward showers there.
The surface ridge will maintain trade winds over the islands through at least the middle of next week. Wind speeds will subside early next week as the pressure gradient south of the ridge slackens. Rainfall will also decrease early next week as the atmosphere becomes drier and more stable.
AviationThe remnant of an old front will remain centered over Oahu this evening producing extensive MVFR cond. Airmet sierra for mtn obsc will likely remain in effect for Oahu this evening. The frontal remnant may bring mtn obsc to Kauai later tonight.
The strong trade winds will likely produce turb in the lee of the mountains. Airmet tango continues for moderate turb S thru W of the mountains of all islands.
MarineA ridge north of the area will produce locally strong trade winds over the coastal waters through the weekend. A small craft advisory, SCA, is up for most coastal waters and the SCA may need to be extended through the weekend for some areas. The strong trades will produce rough surf along east facing shores.
A moderate northwest swell will persist through Friday. A bigger northwest swell is expected to arrive Friday night, peak Saturday saturday night, then slowly subside early next week. This swell will produce surf well above the advisory level. Surf will remain small along south facing shores.
HFO Watches/Warnings/AdvisoriesSmall craft advisory until 6 pm HST Friday for Kauai northwest waters, Kauai windward waters, Kauai leeward waters, Kauai channel, Oahu windward waters, Oahu leeward waters, Kaiwi Channel, Maui county windward waters, Maalaea Bay, Pailolo channel, Alenuihaha channel, Big Island leeward waters, Big Island southeast waters.