There isn’t going to be much action today along any shore, but a very small northwest swell may offer tiny knee to waist-high surf along the winter shores. Tiny windswell won’t add much to the mix, so don’t really expect anything decent. South shores also won’t offer much although a few waist-high sets may limp into select summer breaks if you are patient enough. There will be little to no surf along the south shores after this southerly energy fades, leaving us with flat conditions through the rest of the forecast period. We may see a small northwest swell arriving around Wednesday. Currently, a broad but unimpressive low can be found southeast of Kamchatka but it is already fading. Minor swell is being aimed in our direction but the extreme distance it must travel to our shores will greatly decrease its energy. This swell would arrive around the middle of the week, most likely only reaching tiny to small levels. No other sources are forecast in the North Pacific through the period. A minor low heading up the Tasman Sea won’t really send anything that would reach our shores, but a secondary low is predicted to develop Sunday following a similar track, and then strengthening as it passes north of New Zealand early this week. This may result in a small to moderate swell arriving next Saturday. Long-range forecast models continue to predict a strong storm southeast of New Zealand Tuesday which may whip up a larger south-southwest to south swell that would arrive around next Monday. It’s too early for confidence, so check back for details later in the week.
Today’s Surf Summary
North and northwest facing shores may be around 1-3 foot today, but don’t expect much action. Upper West shores will stay flat at 0-2 foot. South facing shores will be mostly flat at 0-2 foot but select breaks could see an occasional slightly higher set. Windswell along the east and northeast facing shores will stay tiny at only 1-3 foot. Not a good day to surf.
Wind and Tide Information
High tide at Kahului was 1.5 foot at 1:18 AM late last night, dropping to a low of 0.4 foot at 7:12 AM this morning, then rising to a high of 2.3 foot at 1:55 PM early this afternoon, before once again dropping to a low of 0.6 foot at 8:16 PM early this evening
The sunrise was at 06:13 am this morning and will set at 06:24 pm this evening. The Moon is currently 26 days old, and is in a Waning Crescent phase. The next New Moon will occur at 6:13 AM on Wednesday, September 24th.
Light easterly tradewinds will continue around 5-15 mph today but are expected to slowly increase over the next several days, peaking around moderately breezy levels around the middle of next week.
Sunset: 6:21 PM
Weather Outlook for Saturday
Light winds will maintain a pattern of local nighttime land and afternoon sea breeze circulations across the aloha state through this weekend. In this regime, expect mostly clear nights and mornings, with cloud builds and isolated showers developing over leeward and interior sections each afternoon. A return of light to moderate trades is expected early next week, with brief passing showers favoring windward and mauka areas through mid-week. The trade winds may become wetter from Thursday into next weekend as moisture associated with a weakening front pushes down over the islands.
A weak north to south oriented surface trough remains in the vicinity of Oahu early this morning. The weak winds west of this feature are from the northeast, and from the southeast to the east of the trough axis. Elsewhere, a weak surface front located about 540 miles north of Lihue is also disrupting the pressure gradient across the region. As a result, the background low-level flow across the islands remains very weak. This is allowing alternating local nighttime land breeze and afternoon sea breeze circulations to dominate the weather pattern across each of the individual islands.
Elsewhere, weak tropical disturbances are evident in satellite imagery south and southeast of the Big Island. Although these features are not having a significant impact on our local winds, these systems are providing a source of deep tropical moisture that has been advecting up over parts the Big Island since Friday. The outer fringes of this moisture continue to stream up over parts of the Big Island this morning. As a result, the early morning sounding from Hilo shows a very moist and relatively unstable air mass remains in place. The southeastern and windward sections of the Big Island and adjacent coastal waters will continue to have a more active shower pattern at least through tonight due to the passage of these tropical disturbances to the south of the area.
Aloft, a weak mid-level trough passing north of the islands will eventually be replaced by mid-level ridging starting some time on Sunday. The surface front north of the islands will move slowly southward today, but will stall north of the area sometime on Sunday. As a result, the pressure gradient over the islands will remain weak through this weekend. This will maintain the alternating local land and sea breeze circulation pattern through Sunday. Therefore, expect generally clear skies each night and morning, followed by cloud build ups and isolated showers developing by late morning and lingering into the early evening hours. The afternoon convection could also feature some brief heavy downpours again today, but these may be a little less likely on Sunday as a slightly more stable weather pattern begins to develop.
A moderately strong surface high passing far north of the islands will increase the pressure gradient over the area early next week. This will allow the low-level trade wind flow to gradually return starting Monday. Light to moderate trade winds will likely persist through the remainder of the week. The forecast models show a new front moving down toward the area around Thursday. This feature appears to be dropping down toward the island chain as an east to west oriented band of clouds and showers. As a result, it appears this feature will impact the islands from Thursday into Friday. Most of the moisture will likely be focused over windward sections of the state, and it will possibly linger into next weekend. The slightly stronger low-level trade wind flow may transport a few of these showers over to leeward areas on the smaller islands, especially nights and mornings.
Note that the light winds will allow vog and smoke from the Big Island’s active volcano/lava flows to pool near the surface over parts of the Big Island during the overnight and early morning hours this weekend, before clearing by mid-morning. Stronger winds next week will likely prevent a strong ground-based inversion from developing, and the pooling of particulates near the surface should be less pronounced.
Local sea surface temperatures /ssts’ are anomalously warm for mid-september, which is contributing to the ongoing muggy conditions. Surface dew points remain in the upper 60’s to lower 70’s this morning. The ssts are not expected to change significantly in the near future. With the return of the trade winds next week, air temperatures may cool slightly. However, the dew points will likely remain relatively high due to the addition of moisture from the adjacent warm ocean waters.
Central Valley (Kahului, Spreckelsville):
Partly cloudy. Lows 66 to 72. Northeast winds around 10 mph.
Leeward West (Lahaina, Ka`anapali):
Mostly clear. Isolated showers in the evening. Lows 68 to 75. Light winds. Chance of rain 20 percent.
Windward West (Wailuku, Waiehu):
Partly cloudy with isolated showers. Lows 62 to 74. Light winds. Chance of rain 20 percent.
Windard Haleakala (Hana, Haiku, Makawao):
Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 72 at the shore to around 57 at 5000 feet. Southeast winds around 10 mph. Chance of rain 50 percent.
Leeward Haleakala (Kihei, Wailea, Makena):
Mostly clear. Isolated showers early in the evening. Lows around 70 at the shore to around 58 at 5000 feet. Light winds. Chance of rain 20 percent.
Mostly clear. Isolated showers early in the evening. Lows around 55 at 7000 feet to around 49 at the summit. Light winds. Chance of rain 20 percent.
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