The current swell has started to shift to the north at buoy 51101 over the last couple of hours, but remains out of the north-northwest at buoy 51001. Wave heights will be mostly in the waist- to head-high range, potentially higher from time to time at the better exposed breaks. As the swell shifts to the north and then north-northeast, we could see surf rise to near advisory levels on some east facing shores late Saturday or overnight into Sunday. With the northerly switch just starting to show at one of the buoys, there is no advisory posted at this time, but the NWS will monitor the swell to see if one will be warranted.
A large low pressure system far to the west of the state produced a west-northwest swell, which is forecast to start arriving Saturday night, peaking Sunday night, and then gradually subsiding through Tuesday. The grids reflect swell a few feet above the Wave Watch III guidance, which also would suggest a High Surf Advisory would be likely for exposed north and west facing shower of some of the smaller islands with this swell. Due to the expected westerly component, island shadowing will be a factor into which islands will be impacted. West facing shores of the Big Island will likely see advisory level surf, but if the swell comes in as expected, surf could reach warning levels Sunday night into Monday night.
A second, reinforcing west-northwest swell is forecast to arrive Tuesday night and peak Wednesday, almost certainly peaking well below advisory levels.
A series of small long period south swells will continue to produce small surf along the south facing shores. An increase in trade winds over the next few days will also produce choppy surf along east facing shores. Trade winds are forecast to increase into the weekend, and winds have been bumped up a bit in the typically windier locations. The west-northwest swell combined with the wind waves from the increasing trades could produce near seas in excess of 10 feet Sunday and Monday.
High tide at Kahului was 1.3 foot at 4:27 AM early this morning, dropping to a low of 0.2 foot at 11:22 AM shortly before noon, then rising to a high of 1.5 foot at 7:02 PM early this evening.
The sunrise was at 06:29 am this morning and will set at 06:37 pm this evening. The Moon is currently 20 days old, and is in a Last Quarter phase. The next Waning Crescent will occur at 2:59 AM on Tuesday, March 28th.
Sunset: 6:38 PM
Weather Outlook for Saturday
Clouds and showers associated with a weakening front will push southward across the Big Island today. North and northeast facing slopes will see most of the shower activity, but no heavy rainfall is expected. A fairly dry trade wind weather pattern is then expected tonight through late next week, with clouds and showers limited primarily to windward and mauka areas.
Satellite loop shows a ragged band of broken to overcast low clouds extending northeast to southwest across east Maui and the Big Island. This cloud band, marking a weak cold front, continues drifting southeastward slowly and is expected to pass east of the state tonight. Radar shows very little associated precipitation. Stable low cloud cover has increased north of the front, affecting north and east facing shores and slopes of Kauai.
The upper trough supporting the front has already passed east of the state, allowing mid and upper level ridging to move in from the west. Models show ridging aloft will become firmly established over the weekend. Latest soundings show a stable airmass, with positive lifted index values and PW from 1.6 inches at Hilo, beneath of band of low clouds, to just over an inch at Lihue, north of the cloud band. We expect rainfall amounts will remain light as the front passes over the Big island.
Models show high pressure will build north of the islands over the next few days. This will kick start a return to a trade wind weather pattern which will likely last through the next week. Frontal clouds will linger across east Maui and the Big Island today, then a clearing and drying trend is expected. Clouds and showers will begin to favor windward and mauka areas of these islands as the trade wind pattern sets in. This process has already begun for islands farther to the west.
Central Valley (Kahului, Spreckelsville):
Partly cloudy. Breezy. Lows 62 to 67. Northeast winds 10 to 20 mph.
Leeward West (Lahaina, Ka`anapali):
Mostly clear. Breezy. Isolated showers after midnight. Lows 63 to 69. Northeast winds 15 to 20 mph. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 55 to 67. Northeast winds 10 to 20 mph. Chance of rain 30 percent.
Windard Haleakala (Hana, Haiku, Makawao):
Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 66 at the shore to around 49 at 5000 feet. East winds 10 to 15 mph with gusts to 30 mph. Chance of rain 30 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Mostly clear. Lows around 65 at the shore to around 52 upcountry. East winds 10 to 15 mph. Gusts up to 30 mph early in the evening.
Mostly clear. Breezy. Lows around 49. Northeast winds 15 to 20 mph.