The fun-sized late season north-northwest swell will continue along our north and northwest facing shores today offering some much needed surf to our wave starved breaks. Wave heights should be around head-high to slightly overhead at the better breaks with an occasional larger set or two from time to time. Get what you can while it’s here as there won’t be anything more than background swell through the rest of the period, aside from a minor west-northwest to northwest bump arriving around Wednesday. Our south shores will stay relatively flat but a small southwest swell is rolling through the island chain and may appear at some exposed breaks along the south shores.
The current north-northwest swell was produced by a fairly broad but unimpressive low spinning far northwest to north-northwest of Hawai`i several days ago. Another low well east of Japan may be able to provide us with another minor west-northwest swell around Wednesday, but the odds are quite low. Other than that, background swell will be held to a minimum throughout the rest of the forecast period. Thankfully the South Pacific is set to provide us with a long run of south swells through the period and beyond. The first of these swells is already on the way, produced by a strong low pushing up from the ice shelf while aiming an excellent fetch in our direction over several days. This low is still going strong but it will head out of our swell window later today. However, another low is forming along the southwest flank of this low and will spawn a secondary fetch also aimed very well in our direction. Yet another stronger low is modeled to form Monday but this one will be aimed more toward the Americas. And yes, yet another similar low is modeled to develop Tuesday! The combination of all of this activity will lead to an extended period of above advisory level back-to-back south to south-southeast swells beginning Thursday, again Saturday, late Sunday and again Tuesday. We can expect near or above advisory level surf for over a week! This should be a great way to really kick the upcoming summer season into gear. Keep in mind that it may take a couple of days to really move the sandbars into place. More details to come as these swells are still forming.
North and northwest facing shores should see surf around 4-7 foot along the better exposed areas, possibly a bit higher at the best breaks. Upper West shores should see smaller surf around 2-4 foot and could potentially be higher at the better breaks if you know where to look. Select south facing shores should pull in small to moderate surf around 1-4 foot out of the southwest but Kaho`olawe will block much of this energy. East and northeast facing shores will only be around 1-3 foot with only a minor short-period east-northeast windswell to mention.
Wind and Tide InformationHigh tide at Kahului was 1.23 foot at 3:42 AM late last night, dropping to a low of -0.3 foot at 10:05 AM this morning, then rising to a high of 2.29 foot at 5:30 PM late this afternoon, before once again dropping to a low of 0.78 foot at 12:05 AM just after midnight. The sunrise was at 05:47 am this morning and will set at 06:56 pm this evening. The Moon is in a waxing crescent phase and will reach First Quarter Friday.
The northeasterly tradewinds should be around 10-20 mph today with speeds around 25 mph in some areas. The winds are likely to shift to a more east-northeasterly to easterly direction beginning overnight and may rise to stronger levels throughout the upcoming week.
Sunset: 5:45 PM
Weather Outlook for Sunday
Moderate to fresh trade winds will prevail for the next week, except for a period around Monday when trades will be light. Windward areas will be rather wet in some areas through Monday, as an area of enhanced moisture near Maui county moves west to O`ahu and Kaua`i. The increased moisture will move west of the islands on Tuesday, and a more typical trade wind weather pattern will develop, with clouds and brief showers favoring windward slopes and coasts during nights and mornings.
All of the Maui county stream gages have risen in the last 24 hours in response to constant rain over the area. A flood advisory was issued this evening in response to the continuing rain over windward Maui, and we are continuing to monitor stream gages and rainfall amounts in the area.
The rain falling over windward O`ahu, to the Big Island is associated with the stalled and dissipating front. The bulk of the rain has been falling over windward Maui and Moloka`i, which appears to match up well with the GFS low level moisture associated with a low level trough in the 850-700 layer. The GFS keeps this trough/moisture nearly stationary overnight, and has it starting to lift back to the north Sunday afternoon, clearing the Hawaiian islands Monday night.
High pressure to the northwest of the islands is expected to move to the east over the next couple of days, allowing trade winds to remain established over the islands through most of next week.
As the above mentioned moisture lifts north, look for drier easterly trade wind weather to settle in over the islands for Tuesday onward. The biggest divergence in the models comes late next weekend with the ECMWF developing a closed low aloft northwest of the islands, which could bring unsettled weather.
Central Valley (Kahului, Spreckelsville):
Mostly sunny with isolated showers. Windy. Highs 82 to 88. Northeast winds 15 to 20 mph increasing to 20 to 30 mph in the late morning and afternoon. Chance of rain 20 percent.
Leeward West (Lahaina, Ka`anapali):
Mostly sunny with isolated showers. Breezy. Highs 78 to 86. Northeast winds 10 to 25 mph. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
Frequent showers in the morning, then showers likely in the afternoon. Highs 64 to 83. Northeast winds 10 to 20 mph with gusts to 35 mph. Chance of rain near 100 percent.
Windard Haleakala (Hana, Haiku, Makawao):
Frequent showers. Highs around 80 at the shore to around 67 at 5000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Mostly sunny in the morning then becoming partly sunny. Highs around 87 at the shore to around 70 at 5000 feet. East winds 10 to 15 mph with higher gusts.
Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 65 at 7000 feet to around 60 at the summit. East winds 10 to 20 mph. Chance of rain 20 percent.