Waianae Coast

Today: Sunny. Highs 84 to 91. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 69 to 77. Northeast winds 10 to 15 mph.

Thursday: Sunny. Highs 84 to 91. East winds 10 to 15 mph.

South Shore / Honolulu

Today: Sunny. Highs around 85. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows around 76. Northeast winds around 15 mph.

Thursday: Sunny and breezy. Isolated showers in the morning. Highs around 85. East winds 15 to 20 mph. Chance of rain 20 percent.

East Honolulu

Today: Sunny and breezy. Highs 80 to 86. Northeast winds 10 to 20 mph.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 76. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Thursday: Sunny and breezy. Highs 80 to 86. Northeast winds around 20 mph.

Ewa Plain

Today: Sunny. Highs 83 to 88. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows around 75. Northeast winds 10 to 15 mph.

Thursday: Sunny. Highs around 85. East winds around 15 mph.

North Shore

Today: Sunny. Highs 80 to 86. East winds up to 15 mph shifting to the northeast in the afternoon.

Tonight: Mostly clear. Isolated showers after midnight. Lows 69 to 76. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Breezy. Sunny with isolated showers. Highs 79 to 86. East winds 10 to 20 mph. Chance of rain 20 percent.

Central Oahu

Today: Sunny. Highs 79 to 86. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Isolated showers after midnight. Lows around 71. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 78 to 85. East winds 10 to 20 mph. Chance of rain 20 percent.

Windward Oahu

Today: Mostly sunny with scattered showers. Highs 75 to 85. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 67 to 77. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 85. East winds 15 to 20 mph. Chance of rain 50 percent.

Koolau Leeward

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 73 to 86. Northeast winds 10 to 20 mph. Chance of rain 30 percent.

Tonight: Breezy. Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 76. Northeast winds 15 to 20 mph. Chance of rain 40 percent.

Thursday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 85. East winds 15 to 25 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Moderate trades will gradually build to breezy levels by Thursday as weak troughing around the state dissipates and a new surface high develops north of the state. Expect limited clouds and showers for the next couple of days. Slightly wetter trade wind showers will be possible late Friday into the weekend as winds become slightly stronger.

Discussion

Early this morning, mostly clear skies are prevailing across the state, with the lone exception being a few lingering clouds near Kailua-Kona on the Big Island. The trough aloft that had been lingering near the Big Island for the past few days has now moved east of the area as mid-level ridging builds into the region. Virtually no rainfall has occurred overnight. An overnight ASCAT pass and surface observations from around the islands showed moderate trade winds continuing within the stable environment.
Building surface high pressure north of the state will allow trade winds to gradually strengthen over the next 24 hours, becoming breezy by Thursday then locally strong by the weekend. These locally breezy trades look to continue into early next week.
The ridging aloft will maintain dry and stable conditions for the next couple of days while passing bands of low level clouds and light, infrequent showers embedded within the trade wind flow focus primarily along windward and mauka areas. Friday into early Saturday, a trough aloft will approach the state just as an area of increased low-level moisture arrives from the east. This combination will increase chances of showers for windward and mauka locations. Additional increases in windward and mauka showers will be possible Saturday night and again early next week, though there remains some uncertainty surrounding how much instability will remain in place and also how much dry air will be present in the low levels.

Aviation

Drier air moving in from the northeast will promote statewide VFR. Moderate trades will persist across windward terminals while sea breezes develop within wind-protected leeward spots. Brief MVFR ceilings may occur within better organized showers later today or this evening in or around HTO.
No AIRMETs are in effect.

Marine

A surface ridge extending northeast of the islands will maintain gentle to moderate trade winds today. Trades will strengthen slightly on Thursday to moderate to locally fresh as a surface high begins to build north of the area. Small Craft Advisory (SCA) levels may be reached as early as Thursday night in some of the typical windier waters near Maui and the Big Island. Trades will continue to strengthen further Friday through the weekend as the surface high pressure to the north becomes more well established.
The current medium period northwest swell will linger today, holding surf to near seasonal average for north and west facing shores, before declining tonight through Friday. By late Friday, a medium period north- northwest swell will build and once again help bring surf back to near seasonal averages through the weekend.
The current medium period south swell will keep surf along south facing shores elevated today. A reinforcing long period south swell will help produce surf near seasonal average tonight into early this weekend.
Surf along east facing shores will remain small through Thursday as small wind waves and tiny east swell persist. Choppy surf will increase slightly as trade winds strengthen across the region Friday into the weekend.

Fire weather

Moderate trade winds will gradually strengthen to breezy levels by Thursday. Dry air will keep RH levels near-critical values each afternoon for parts of the state for the next several days. RH values are expected to increase towards the end of the week, however, and winds will remain below critical thresholds. Inversion heights today will range from about 5,000 to 6,000 ft.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov