1-3 foot
0-2 foot
1-3 foot
2-4 foot

High pressure north of the islands will maintain strong trade winds through at least Friday. A Small Craft Advisory is in effect for all coastal zones through Friday afternoon, but will likely need to be extended through Saturday due to the persisting strong trade winds. A slight decrease in trade winds is expected on Sunday, but breezy trade winds are expected for the foreseeable future.

The elevated trade winds will produce choppy surf along east facing shores, with wave heights increasing through the day today as the winds strengthen. Surf is expected to hold steady through the rest of the week due to the persistent strong trade winds. Small southeast and south swells will maintain small background surf along south facing shores through the week. Small, short-lived west and northwest swells are expected to arrive today, providing a very small bump along exposed north and west facing shores. However, Kauai will help block most of the west swell energy from the other islands.

Hawaii Wave Height Model

Tide Predictions

High tide at Kahului was 1.38 foot at 2:00 PM early this afternoon, dropping to a low of 0.42 foot at 2:00 PM early this afternoon, then rising to a high of 2.16 foot at 2:00 PM early this afternoon.

The sunrise was at 05:59 am this morning and will set at 07:04 pm this evening. The Moon is currently 19 days old, and is in a Waning Gibbous phase. The next Last Quarter will occur at 6:19 PM on Saturday, August 4th.

Hawaii Wind Report

Maui Weather

°/°
Wind: n/a at 0 mph
Sunrise:
Sunset:
current observations as of 8am August 20th, 2018

Weather Outlook for Wednesday, 1st August 2018

Summary

High pressure north of the state will keep breezy trade winds in place through at least Friday. A fairly typical trade wind shower regime is then expected through Friday, with showers favoring windward and mauka areas. An upper level trough is expected to bring an increase in shower coverage and intensity late Friday through the weekend, with shower activity expected to be most prevalent in windward areas. A drier and more stable trade wind pattern is then forecast to overspread the state late Sunday through early next week.

Detailed Discussion

Currently at the surface, a 1031 mb high is centered around 1200 miles north-northeast of Honolulu, with a new strengthening 1033 mb high building around 1250 miles north of Kauai. This is resulting in breezy conditions across the island chain early this morning. Meanwhile, the remnant trough of former tropical cyclone Gilma is located around 300 miles south-southeast of South Point. Aloft, the state remains in the transition zone between an upper level ridge southwest of the islands and an upper level trough to the northeast. Infrared satellite imagery shows mostly cloudy skies across the western islands, with partly to mostly cloudy skies over the eastern end of the state. Radar imagery shows scattered showers moving into windward areas, with a few showers spilling leeward from time to time. Main short term concern revolves around rain chances over the next few days.

The area of high pressure north-northeast of the state will become absorbed into the strengthen high north of Kauai today. This new high will then strengthen and lift northward further away from the island chain tonight through the weekend, then will weaken well north of the area early next week. Meanwhile, the weak trough associated with the remnants of former tropical cyclone Gilma will pass by to the south of the Big Island today. As a result, we expect a further tightening of the pressure gradient today and tonight, with breezy conditions expected to continue through at least Friday, and possibly right through the weekend.

As for sensible weather details, a fairly typical trade wind shower pattern is expected over the next few days. This should result in mainly windward showers and a few leeward spillovers, particularly during the overnight and early morning hours. Due to weak instability lingering over the island chain, an isolated thunderstorm or two will be possible each afternoon across the leeward Big Island slopes each afternoon through Friday.

The forecast becomes more interesting late Friday through the weekend. Both the GFS and ECMWF show a digging upper level trough over the western end of the state on Friday, closing off into a low Friday night, then retrograding west of the islands Saturday through early next week. In response, deep layer moisture will increase beginning on Friday across the eastern islands, then spread northwestward over the remainder of the state Friday night and Saturday, before exiting from southeast to northwest Saturday night and Sunday. The GFS remains the most aggressive with the deep moisture return, while the ECMWF shows the deepest moisture remaining to the south and west of the state. We will continue to follow a middle of the road solution until the models converge. As a result, we will advertise a wet trade wind pattern developing late Friday over the Big Island, transitioning up the island chain Friday night, holding in place Saturday, then drying out and returning to more of a typical trade wind shower regime from southeast to northwest Saturday night and Sunday. Given the instability over the islands, some of the showers could be heavy and we will keep a mention of locally heavy rain in place across windward areas Friday night and Saturday when the deepest moisture and strongest forcing for ascent most closely align.

Sunday night through next Tuesday the models are in good agreement showing precipitable water values dropping back to near or below normal levels for this time of year. As a result, we should see a drier than normal trade wind pattern return across the island chain. In addition, the latest forecast from the National Hurricane Center in Miami shows tropical cyclone Hector reaching 140W as a Hurricane Sunday evening, so we will be monitoring this system closely as it tracks westward toward the Central Pacific.

Central Valley (Kahului, Spreckelsville):

Partly cloudy. Breezy. Lows 72 to 78. Northeast winds 15 to 25 mph.

Leeward West (Lahaina, Ka`anapali):

Windy. Partly cloudy with isolated showers. Lows 73 to 79. Northeast winds 25 to 30 mph. Chance of rain 20 percent.

Windward West (Wailuku, Waiehu):

Windy. Mostly cloudy with scattered showers. Lows 65 to 77. East winds 20 to 30 mph with gusts to 55 mph. Chance of rain 50 percent.

Windard Haleakala (Hana, Haiku, Makawao):

Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows around 75 at the shore to around 59 at 5000 feet. East winds 15 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Leeward Haleakala (Kihei, Wailea, Makena):

Partly cloudy. Breezy. Lows around 75 at the shore to 59 to 64 upcountry. East winds 10 to 20 mph.

Haleakala Summit

Windy. Partly cloudy with scattered showers. Lows around 51 at the visitor center to around 47 at the summit. East winds 20 to 30 mph. Chance of rain 50 percent.