5-8 foot
4-6 foot
0-2 foot
5-8+ foot

Fresh to strong trades associated with 1034 mb high pressure building southward over the central Pacific following a dissipating frontal boundary that has moved into the area will translate to rough boating conditions across the Hawaiian waters through Thursday. A mix of wind seas, a small west-northwest (300 deg) swell and a, relatively short-period, north-northeast (000-020 deg) swell has already translated to advisory-level (10 ft) seas at most exposed nearshore PacIOOS buoys. Observations at these buoys are running around 1-2 ft higher than predicted. The local winds and seas should trend down temporarily Friday into the upcoming weekend as another front approaches.

For surf, guidance supports the current active trend over the northeast Pacific continuing due to a persistent blocking pattern that remains established across the central Pacific. This pattern will continue to feature storm tracks setting up over the Gulf of Alaska from northwest to southeast, that will drive overlapping north-northeast swells toward the islands through the rest of the weekend and next week.

The current north-northeast (000-020 deg) swell is forecast to peak today, then slowly ease through the second half of the week. This source combined with the locally strong trade winds will support rough beach conditions along east facing shores. The high surf advisory remains in effect for these beaches through early Thursday morning. A reinforcing north-northeast (010-020 deg) swell is expected Friday through the upcoming weekend, that will continue to generate advisory-level surf along east facing beaches into the weekend.

Surf along north facing shores exposed to north-northeast swells will remain up through the upcoming weekend, but should remain below advisory levels each day through Saturday. Although confidence remains low at this time, more significant northerly swells will be possible Sunday into Monday and again by midweek.

Surf along south and west facing shores will remain small with mainly long-period south-southwest swells expected.

Hawaii Wave Height Model

Tide Predictions

High tide at Kahului was 2.1 foot at 2:00 PM early this afternoon, dropping to a low of 0.8 foot at 2:00 PM early this afternoon, then rising to a high of 1.9 foot at 2:00 PM early this afternoon, before once again dropping to a low of 0.0 foot at 2:00 PM early this afternoon

The sunrise was at 06:35 am this morning and will set at 05:45 pm this evening. The Moon is currently 27 days old, and is in a Waning Crescent phase. The next New Moon will occur at 11:42 AM on Saturday, November 18th.

Hawaii Wind Report

Maui Weather

73°/75°
Wind: NE at 15 mph
Sunrise: 7:05 AM
Sunset: 6:06 PM
current observations as of 11pm January 15th, 2018

Weather Outlook for Wednesday, 15th November 2017

Summary

High pressure far to the north of Hawaii will produce locally windy trades through mid-week. A weak frontal boundary pushing down across the islands will continue to bring wet weather to parts of the state today. Most of the rainfall will be focused along windward facing slopes, but brief showers may spread to some leeward sections of the smaller islands. Drier weather conditions are expected from Thursday through Friday, with brief trade showers mainly over windward and mauka area. The trades will weaken later this week as a surface low develops far north of the region.

Detailed Discussion

A 1034 mb surface high centered near 38N 161W, or about 1150 miles north of Honolulu, has been moving slowly southward early this morning. This feature continues to push a diffuse frontal boundary down across Maui County toward the northern Big Island early this morning. The pressure gradient is becoming tighter across the state. This is producing locally breezy northeasterly trade winds across most areas, especially north of the weak frontal boundary. Low clouds and showers associated with the boundary are currently spreading down across the central islands, especially along the windward facing slopes and beaches. Low clouds and showers are also lingering over windward and mauka sections of Kauai and Oahu, while the clouds and showers are now approaching the windward Big Island. In addition, brief showers are being transported over to some leeward sections of the smaller islands from Kauai to Maui.

Aloft, a mid-tropospheric trough extends northeast from the islands. The presence of this feature and the weak frontal boundary has caused the low-level inversion to be elevated, or non-existent. This instability combined with moisture along and ahead of the boundary will maintain wet conditions today across most of the state today, especially over windward and mauka sections. The tightening pressure gradient will also produce locally windy trade winds across the islands, especially after mid-morning.

After the remnant front passes through, the airmass is expected to become relatively dry, with fewer showers expected for the smaller islands starting later tonight or Thursday. In addition, the strong trades and drier air (background dewpoints are expected to drop to the lower 60s) will make it feel rather cool and “fall-like” by Hawaii standards. The surface high will likely begin to weaken as it shifts to a position far northwest of the region toward the end of the work week. Therefore, we expect the trades to weaken slightly from late Thursday through Friday.

Unfortunately, the global forecast models continue to have divergent solutions for the large-scale weather pattern over the Central Pacific Ocean this weekend. This means that we are uncertain about the type of sensible weather conditions we might experience in Hawaii from this weekend into early next week.

The ECMWF model remains the outlier, since it has been rather consistent in developing a surface low far north of the region on Thursday. The latest model output indicates this low will move rapidly toward the south, and will stall north of islands near Latitude 30N by late Saturday. Assuming this scenario verifies, it appears that a front may move down across the islands some time this weekend. This would be followed by a period of northwest to north winds. Wetter weather conditions might also develop, with rainfall amounts possibly becoming locally heavy over some areas.

In contrast, the GFS model appears to keep the surface low much farther northeast away from the islands. This scenario would likely cause north to northeast low-level flow to develop over the islands starting some time this weekend. Our confidence in the weekend forecast and beyond will remain rather low until we see more definitive model solutions. At the moment, the forecast beyond Friday essentially follows a blend of climatology and multi-model output. We expect adjustments will be needed for the forecast this weekend and early next week as the synoptic pattern becomes more clear.

Central Valley (Kahului, Spreckelsville):

Mostly clear. Breezy. Isolated showers after midnight. Lows 62 to 68. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Leeward West (Lahaina, Ka`anapali):

Breezy. Mostly clear with scattered showers. Lows around 68. Northeast winds 15 to 20 mph. Chance of rain 30 percent.

Windward West (Wailuku, Waiehu):

HIGH SURF ADVISORY IN EFFECT UNTIL 6 AM HST THURSDAY. Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 62 to 79. Northeast winds 15 to 25 mph. Gusts up to 40 mph in the late morning and afternoon. Chance of rain 70 percent.

Windard Haleakala (Hana, Haiku, Makawao):

HIGH SURF ADVISORY IN EFFECT UNTIL 6 AM HST THURSDAY. Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 76 at the shore to around 60 at 5000 feet. East winds 10 to 15 mph with gusts to 35 mph. Chance of rain 70 percent.

Leeward Haleakala (Kihei, Wailea, Makena):

Mostly clear. Lows around 68 at the shore to 54 to 59 upcountry. Northeast winds 10 to 15 mph.

Haleakala Summit

Mostly clear with isolated showers. Lows around 49 at the visitor center to around 47 at the summit. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

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