The National Weather Service has extended the High Surf Advisory for Maui’s east facing shores through 6pm tonight. There could still be large and rough sets along our windward shores today, at least through the afternoon hours. This windswell will be slow to fade and may hover just under advisory levels through Friday but is expected to increase again over the weekend to levels near or just at advisory levels again. The current northwest swell along our north shores has peaked and is on the way down and will fade quickly through the day and into Thursday. Minor background swell may still hang around Thursday into Friday. Our next chance for surf won’t come until Saturday as swell produced by a Kamchatka low reaches the islands. The source was too far away to amount to much surf locally, probably peaking at upper-end small levels early Saturday. Looking into the long-range models, a low is forecast to develop near the dateline Friday before rapidly pushing north-northwest toward the Aleutian Islands over the weekend. Another fetch is also modeled to form just behind the first low which is predicted to take better aim toward our islands. At this time, it isn’t looking too promising, but there is a chance that we could see advisory level surf arriving around Monday if we’re lucky. Keep those fingers crossed and check back for updates.
Windswell along our east and northeast facing shores should hold around 5-8 foot through most of the day today, but we should see a slight drop later in the afternoon hours. North and northwest facing shores have a fading northwest swell around 4-7 foot at the better breaks while lesser breaks pull in half that size. Upper West shores may not see much action at 1-4 foot, but select breaks could see slightly higher sets. South facing shores have no swell to mention and will stay near flat at 0-2 foot.
Wind and Tide Information
High tide at Kahului was 2.7 foot at 1:28 AM late last night, dropping to a low of 0.84 foot at 8:02 AM this morning, then rising to a high of 1.33 foot at 12:08 PM just after noon, before once again dropping to a low of -0.58 foot at 6:39 PM early this evening. The sunrise was at 07:03 am this morning and will set at 06:03 pm this evening. The Moon is in a waning crescent phase and will reach New Moon this Friday.
Weather Outlook for Wednesday
Locally breezy and gusty trade winds will gradually weaken through Thursday, and windward showers will briefly carry over to leeward sections of the smaller islands at times. Trades will weaken further on Friday and shift southeasterly on Saturday, leading to a land and sea breeze regime. Afternoon land breezes will promote interior clouds and chances of showers, and an upper low moving over the eastern end of the state will bring the potential for unsettled weather.
The current breezy trade winds across the Hawaiian islands are driven by a 1036 mb high far to the northeast near 40°N 150°W. These winds are expected to slowly weaken over the next couple of days as the high moves further away to the east and the pressure gradient over the islands relaxes. The gradient between buoys 51101 and 51003 continues to drop this evening. The high will strengthen to 1041 mb and settle near 40°N 140°W on Wednesday night as an advancing front moves to within 450 miles northwest of Kauai. This will cause the pressure gradient and the resulting winds over the islands to decline.
Radar and satellite this evening shows numerous low-topped clouds and showers associated with a moisture band running the length of the island chain. This band will likely stay over us through Wednesday morning, then dissipate somewhat during the afternoon. Rainfall will be focused over windward slopes, but the breezy winds will carry many of these showers leeward sections of the smaller islands. An upper low presently 500 miles southeast of the Big Island will cause the inversion to be somewhat weak, which will help leeward sides get more of the rain.
Our weather pattern doesn’t change much Wednesday night into Thursday. The mentioned band will move off the island chain, but moisture coming in from upstream will focus more on windward Kauai, Maui and Big Island.
Winds will diminish on Friday and Saturday, with an unsettled land and sea breeze regime possible for portions of the state. The upper low currently east southeast of the state will drift back over the islands Thursday night or Friday and merge with a broad upper trough moving in from the northwest. These features will erode the low level ridge, causing trades to weaken on Friday and shift southeasterly on Saturday. The result will be a land and sea breeze regime, featuring spotty afternoon interior convection. The atmosphere will become unstable, but the amount of available moisture is still in question. Forecast models hold the bulk of the deep moisture off to the east of the islands, but we feel that there will be enough instability to warrant a slight chance of thunderstorms for Big Island slopes on Friday afternoon. The upper low may linger into Saturday, but the current, low-confidence forecast calls for an increasingly stable convective pattern for the weekend.
Early next week a front or shear line is expected to move over the islands from the northwest. A surface high moving east behind this feature will bring a return of trade winds.
Central Valley (Kahului, Spreckelsville):
Sunny. Isolated showers in the morning. Highs 77 to 82. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Leeward West (Lahaina, Ka`anapali):
Sunny with isolated showers. Highs 75 to 82. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
HIGH SURF ADVISORY IN EFFECT UNTIL 6 PM HST WEDNESDAY. Mostly cloudy with occasional showers. Lows 49 to 70. Northeast winds 10 to 20 mph with gusts to 35 mph. Chance of rain 90 percent.
Windard Haleakala (Hana, Haiku, Makawao):
HIGH SURF ADVISORY IN EFFECT UNTIL 6 PM HST WEDNESDAY. Mostly cloudy with occasional showers. Lows 64 to 69 at the shore to around 47 at 5000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Sunny. Isolated showers in the afternoon. Highs around 81 at the shore to around 65 at 5000 feet. East winds 10 to 15 mph with gusts to 35 mph. Chance of rain 20 percent.
Sunny with isolated showers. Highs around 64 at 7000 feet to around 57 at the summit. East winds 15 to 20 mph. Chance of rain 20 percent.