10-15+ foot
5-8+ foot
2-4+ foot
8-12+ foot

Satellite imagery showed a cloud band associated with a an old frontal boundary dropping south over the area this morning bringing moderate to heavy showers and a surge of strong north- northeast winds. Recent ASCAT pass and offshore buoy observations confirmed this showing pockets of 25 to 30 kt winds trailing this boundary earlier. This boundary marks the leading edge of a large fetch of strong to gale force northeast winds that has setup across the northeast Pacific between low pressure several hundred nautical miles northeast of the islands and strong high pressure centered far north of the state.

Seas have already responded at the exposed nearshore buoys and are near 15 ft this morning, which is already a few feet above predicted levels. A combination of the increasing winds and building seas will translate to small craft advisory conditions across exposed waters today. Expect this trend to continue through the rest of the week. Additional marine zones, such as Maalaea Bay, leeward Big Island waters and waters around South Point, will need to be included in the advisory as the winds transition to northeast and increase later today and tonight.

Surf along exposed north and east facing shores will remain large and rough into the second half of the week due to the new northeast swell and gusty winds trailing this boundary in place this morning. Warning-level surf will result for east facing shores with advisory levels continuing for north facing exposures. This will be a long-duration event that will likely continue through the second half of the week. At this point, a peak appears likely today, then slowly lowering to advisory levels for east facing shores by Friday.

Impacts associated with this large northeast swell will include significant beach erosion along exposed coasts due to the long duration of the event. A combination of the large northeast swell and fresh to strong onshore winds will likely correspond to overwash along vulnerable coastal sections of the islands around the high tide cycles each day through Friday.

Surf along west facing shores will remain small through the week with mainly small long-period northwest swells expected through Friday. A moderate west-northwest swell will be possible over the upcoming weekend that may bring surf up to around advisory levels by Sunday for north and west facing shores.

Forecast confidence quickly lowers over the upcoming weekend due to significant model differences. All depict another area of low pressure developing nearby/over the islands, but the positions of this feature has varied significantly from cycle to cycle.

Hawaii Wave Height Model

Tide Predictions

The sunrise was at 06:55 am this morning and will set at 06:24 pm this evening. The Moon is currently 8 days old, and is in a Quarter phase. The next Waxing Gibbous will occur at 3:53 PM on Tuesday, February 19th.

Maui Weather

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Wind: n/a at 0 mph
Sunrise:
Sunset:
current observations as of 10am May 20th, 2019

Weather Outlook for Wednesday, 13th February 2019

Summary

A weak cold front will continue to move through the Hawaiian Islands this morning spreading showers across the state today. Colder temperatures with breezy to windy trade winds will move in behind the front. A kona low will develop over the state on Thursday with unsettled wet weather forecast to continue through Sunday. The kona low drifts towards the northwest away from the islands next week with unsettled weather lingering over the island chain through the first half of next week.

Detailed Discussion

A weak cold front is passing through Oahu and Maui Counties this morning producing cloudy skies, numerous showers and isolated thunderstorms along the frontal band. Colder air, additional showers, and breezy to windy trade winds will ride in behind the front as it passes through the islands today. A sharp upper level trough will enhance clouds and showers behind the front, strong trade winds will lift these unstable showers over windward and mountain areas trough this evening with scattered showers drifting into leeward sections.

Temperatures will drop statewide through Thursday as our winter weather pattern continues. Falling temperatures over the summits of Haleakalā on Maui, and the Big Island summits of Maunakea and Maunaloa will cause snow showers and periods of freezing rain to impact road conditions. A winter storm warning is in effect for all three summits today and tomorrow. Warmer temperatures are forecast on Thursday night over Haleakalā with snow transitioning to rain showers overnight. Snow showers and icy conditions will continue over the highest peaks on the Big Island through Friday. Avoid traveling to the summits during this period as icy roads and low visibilities will produce treacherous driving conditions.

Cold air at the base of this upper trough will interact with a warmer ridge to the northwest causing a kona low to form over the islands on Thursday. Instability and lift associated with this low will produce scattered to frequent showers across all islands in a breezy to windy trade wind surface pattern. These strong trade winds will focus the highest shower activity along windward and mountain areas. However, the unstable environment and strong winds will carry some of these showers into leeward areas. Isolated thunderstorms are also forecast across the state with this system.

The kona low will produce a surface low over the eastern half of the state by Friday night interrupting the trade wind flow across Maui and Hawaii Counties later this weekend. Wind directions over the Big Island and Maui will become more variable, trending towards a more southerly direction on Sunday as the low begins to drift west. Unstable shower activity will continue over all islands through the weekend with the potential for locally heavy showers developing across the state.

Over the past 24 hours our medium range model guidance has struggled with the track of this low. The latest 06Z model run shows better agreement in a slow northwest track away from the state on Monday. Our forecast confidence for wet weather this weekend is improving however the locally heavy rainfall impacts remain less certain at this time.

Central Valley (Kahului, Spreckelsville):

HIGH SURF ADVISORY IN EFFECT UNTIL 6 PM HST THURSDAY. Mostly cloudy. Breezy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs 73 to 78. Northeast winds 10 to 15 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Leeward West (Lahaina, Ka`anapali):

Breezy. Mostly cloudy with scattered showers. Lows 60 to 67. Northeast winds 15 to 25 mph with gusts to 45 mph. Chance of rain 40 percent.

Windward West (Wailuku, Waiehu):

HIGH SURF WARNING IN EFFECT UNTIL 6 PM HST THURSDAY. Breezy. Cloudy with frequent showers and isolated thunderstorms. Highs 56 to 76. Northeast winds 10 to 25 mph. Chance of rain 90 percent.

Windard Haleakala (Hana, Haiku, Makawao):

HIGH SURF WARNING IN EFFECT UNTIL 6 PM HST THURSDAY. Cloudy and breezy. Frequent showers early in the morning, then frequent showers and isolated thunderstorms in the late morning and afternoon. Highs around 75 at the shore to around 56 at 5000 feet. North winds 10 to 20 mph. Chance of rain 90 percent.

Leeward Haleakala (Kihei, Wailea, Makena):

Breezy. Mostly cloudy with isolated showers. Lows around 63 at the shore to 46 to 52 upcountry. North winds 10 to 20 mph shifting to the northeast up to 20 mph after midnight. Chance of rain 20 percent.

Haleakala Summit

WINTER STORM WARNING IN EFFECT UNTIL 6 PM HST THURSDAY. Mostly cloudy. Breezy. Frequent snow showers and periods of light freezing rain in the morning. Scattered rain showers and isolated thunderstorms in the late morning and afternoon. Scattered snow showers in the afternoon. Snow accumulation around 1 inch. Highs around 42 at the visitor center to around 45 at the summit. North winds 10 to 20 mph. Chance of precipitation 90 percent.