5-7 foot
3-5 foot
0-2 foot
4-6 foot

The recent long-lived run of strong trade winds will be soon ending as a rapidly developing storm-force low replaces the high to the north of the islands on Sunday. The high will support locally strong trade winds today, but winds are expected to become light by Sunday as the high moves east and its associated surface ridge moves over the area. The low will send a front toward the islands from the northwest early next week, which will turn winds to a southerly direction. The front is expected to move through the island chain from Monday night through Tuesday, bringing varying winds and weather.

With winds gradually easing, the existing Small Craft Advisory has been trimmed to include only those zones where winds are most accelerated by island terrain. Winds and seas will fall below criteria in all areas by tonight. The High Surf Advisory for east facing shores is also cancelled this morning as seas are on a downward trend at the windward buoys.

A SCA is likely for waters west of Molokai for strengthening southerly winds on Monday and Monday night.

Although short-period wind waves will be easing, building north-northwest and south swells Sunday and Monday are expected to keep combined seas elevated, but below the SCA criteria of 10 feet. A larger, shorter-period north-northwest swell building on Tuesday will likely lead to SCA in all zones as seas exceed 10 feet once again. The first north-northwest swell will produce surf near the advisory threshold along exposed north facing shores, and the second swell is expected to produce high surf along north facing shores. Advisory-level surf along south facing shores is possible Sunday and Monday, with the swell generated by a distant low in the south Pacific. A small long-period west swell is possible next week, generated by large and slow-moving Super Typhoon Lan in the west Pacific. An even larger long-period northwest swell is possible late in the week as Lan becomes extratropical in the northwest Pacific. south-east swell is also possible over the next several days. The recently updated Oahu Surf Discussion (SRDHFO) has details on the swell sources affecting the islands.

Hawaii Wave Height Model

Tide Predictions

High tide at Kahului was 2.5 foot at 2:00 PM early this afternoon, dropping to a low of 0.7 foot at 2:00 PM early this afternoon, then rising to a high of 1.8 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 06:23 am this morning and will set at 05:57 pm this evening. The Moon is currently 2 days old, and is in a New Moon phase. The next Waxing Crescent will occur at 10:23 PM on Friday, October 27th.

Hawaii Wind Report

Maui Weather

75°/76°
Wind: N at 22 mph
Sunrise: 6:40 AM
Sunset: 5:43 PM
current observations as of 3pm November 20th, 2017

Weather Outlook for Saturday, 21st October 2017

Summary

A change in the weather pattern is in the works. The breezy trade winds will be giving way to light and variable winds on Sunday. Then, a moist southerly wind flow takes over on Monday, ahead of an approaching cold front that is forecast to moved down the island chain between Monday evening and Wednesday. A drier and cooler northerly wind flow will settle over the islands lasting for a few days.

Detailed Discussion

The weakening of the trades has begun, and will continue through today. Winds will still be breezy in some spot, especially around the Big Island and Maui, but not as strong and gusty as in the past few days. The down trend continues through tonight, becoming light and variable on Sunday.

A front approaching the islands from the northwest is responsible for the change in the weather. The winds will turn southerly Sunday night and gain strength on Monday and Monday night, especially for the area west of Maui. It may be windy enough to warrant a Wind Advisory for at least Kauai on Monday. We will see how this transpire. It will be monitored closely as the event nears. The breezy southerly winds is part of the upper level trough aiding the surface front.

The front reaches Kauai early Monday evening, then advances eastward to Maui County toward midnight and early Tuesday morning. The front reaches the Big Island after daybreak Tuesday and exit the Big Island early Wednesday morning, as per GFS solution. The ECMWF is a bit slower in clearing the Big Island, which does not take place until Wednesday afternoon. The front stalls just east of the Big Island, where it will linger through at least Thursday. In its wake, a drier and cooler air mass settles over the area under a light to moderate northeast wind flow.

The unsettled weather will be spreading across the area from the east and south between Sunday afternoon and Monday, beginning with the Big Island. Models are in good agreement with a low level trough and its associated showers reaching the Big Island Sunday afternoon. As the upper trough digs down, it will draw additional moisture from the tropics. The ECMWF and GFS differs on where this moisture will go. The EC points to Kauai and Oahu, while the GFS has it over Maui County. Believe this is something new with the EC, where earlier runs had the moisture over Maui County. What we have in the grids are that of the GFS solution, that is the core of heavy weather to occur over Maui County and the Big Island. Although most of the upper level dynamics will ride north of the islands, there is an outside chance of a thunderstorm. Locally heavy showers are being noted especially for Maui County and the Big Island. More reinforcement and refinement of the forecast is forthcoming, including the discussion of a Flash Flood Watch for part of the island chain.

In the mean time, the dry sloth over Moloka`i, has slid over to Oahu. The northeast to southwest oriented band of clouds and showers has edged to Kauai, but is now showing signs of breaking up. If this continues, the forecast will need to be updated. Spotty trade showers will continue to affect the windward areas of the Big Island, Maui, and Moloka`i this morning. The weather looks drier overall compared to the past few days.

The trades have weaken so much that the Wind Advisory is now canceled.

Central Valley (Kahului, Spreckelsville):

Partly cloudy with isolated showers. Lows around 69. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Leeward West (Lahaina, Ka`anapali):

Breezy. Partly cloudy with isolated showers. Lows 68 to 75. East winds 10 to 20 mph. Chance of rain 20 percent.

Windward West (Wailuku, Waiehu):

Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 61 to 74. Southeast winds 10 to 20 mph. Chance of rain 50 percent.

Windard Haleakala (Hana, Haiku, Makawao):

Mostly cloudy with scattered showers. Lows around 71 at the shore to around 54 at 5000 feet. East winds 10 to 15 mph. Gusts up to 30 mph in the evening. Chance of rain 50 percent.

Leeward Haleakala (Kihei, Wailea, Makena):

Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Lows around 70 at the shore to 54 to 60 upcountry. East winds 10 to 15 mph with gusts to 30 mph decreasing to up to 10 mph after midnight. Chance of rain 20 percent.

Haleakala Summit

Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 46 at the visitor center to around 44 at the summit. Southeast winds 10 to 20 mph. Chance of rain 50 percent.

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