West Side

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 77 to 85. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 71 to 77. East winds 15 to 25 mph. Chance of rain 40 percent.

Friday: Breezy. Partly sunny with isolated showers. Highs 77 to 85. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

South Side

Today: Mostly sunny. Breezy. Highs around 85. Northeast winds 10 to 20 mph.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 72 to 79. Northeast winds 15 to 25 mph. Chance of rain 40 percent.

Friday: Partly sunny. Breezy. Isolated showers in the morning. Highs around 85. Northeast winds 15 to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

North Shore

Today: Breezy. Mostly cloudy with numerous showers. Highs around 81 near the shore to around 65 near 5000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 70 to 75 near the shore to around 57 near 5000 feet. East winds 15 to 25 mph. Chance of rain 70 percent.

Friday: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 66 to 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Central Maui

Today: Mostly sunny. Breezy. Scattered showers in the morning. Highs 80 to 85. East winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 73. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Friday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 85. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Upcountry

Today: Windy. Partly sunny with scattered showers. Highs around 61 at the visitor center to around 71 at the summit. East winds 10 to 30 mph decreasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 52 at the visitor center to around 47 at the summit. East winds 15 to 25 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 64 to 81. East winds 10 to 25 mph. Chance of rain 50 percent.

East Maui

Today: Breezy. Mostly cloudy with numerous showers. Highs around 81 near the shore to around 65 near 5000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 70 to 75 near the shore to around 57 near 5000 feet. East winds 15 to 25 mph. Chance of rain 70 percent.

Friday: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 66 to 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Lanai City

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 72 to 80. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Windy. Lows 67 to 73. Northeast winds 15 to 30 mph.

Friday: Partly sunny in the morning then becoming mostly sunny. Windy. Highs 76 to 82. Northeast winds 20 to 30 mph with gusts to 50 mph.

Kaunakakai

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 70 to 87. Northeast winds 20 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 76. Northeast winds 20 to 25 mph. Chance of rain 50 percent.

Friday: Breezy. Mostly sunny with isolated showers. Highs 75 to 87. Northeast winds 15 to 25 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy trade winds will persist for the next several days. Trades winds will increase in strength tonight into Saturday due to a tropical disturbance passing well to the south of the area and a strong high building in from the northwest. Enhanced trade wind showers are also anticipated for windward areas tonight into the weekend as tropical moisture surges in from the south. Isolated thunderstorms will also be possible for Big Island tonight and Friday. A drier airmass and more stable conditions will return Sunday into next week with limited showers focusing mainly along windward and mauka areas.

Discussion

Latest surface analysis shows a ridge of high pressure north of the state is driving breezy trades across the island chain today and a pair of troughs southeast of the Big Island. The Wind Advisory for the Kohala District of Big Island has been cancelled as winds have eased below advisory levels.
Radar imagery show numerous light to moderate showers moving east to west across the state. Rainfall totals for the past 12 hours show most windward areas received between 0.3 to over 1.0 inch, including some central areas of Oahu. Satellite imagery shows a broad area of thinning low level clouds just upstream of the state indicating shower coverage should trend down during the day today.
Starting tonight, another area of enhanced low level clouds associated with a trough southeast of Big Island will draw deep tropical moisture and precipitable water values near 2.50 inches from the south later this afternoon. This will increase the chance of showers for windward Big Island before spreading to Maui County tonight into Friday. Isolated chance of thunderstorms capable of producing heavy downpours also cannot be ruled out for Big Island tonight through Friday as this area of moisture erodes the inversion heights, allowing for some terrain induced convection to occur. These showers are expected to be brief and move quickly within the breezy trade wind flow so not anticipating issuing a Flood Watch at this time. ASCAT imagery overnight showed a large fetch of strong northeast winds ahead of this trough that will reach the eastern half of state tonight, strengthening winds to advisory levels due to terrain enhancements near peaks and points, as well as along and downslope of ridges. Thus a Wind Advisory for select areas of Maui County and the Big Island may need to be issued later this afternoon if this area remains intact.
NHC continues to monitor the high likelihood of a developing tropical cyclone withing the next day or so well southeast of the state. This area will follow close behind the first trough, Friday into Saturday as a ridge of high pressure builds in from the northwest, tightening the pressure gradient across the state. This could translate to trade winds strengthening across the state, maintaining or expanding advisory level winds for select areas across the island chain.
After the system passes west of the state Saturday into Sunday, a much drier airmass and lower inversion heights will filter in from the east into next week. Winds will ease to more typical breezy levels. The drier airmass and lower inversion heights will also limit shower coverage to mainly windward and mauka areas.

Aviation

Breezy trades expected for next few days. Low cigs and SHRA will continue over windward and mauka locations with some spillover into leeward areas at times. MVFR conds in SHRA, otherwise VFR prevails.
AIRMET Sierra is in effect for mtn obsc for windward portions of all island except Lanai. Conds should improve in the mid morning hours.
AIRMET Tango remains in effect for mod turb lee of terrain and should remain in effect for next few days.

Marine

Fresh to strong trade winds with periods of near gales will remain in place throughout the week as a broad area of high pressure remains in place north of the state. Small Craft Advisory (SCA) is in effect for all Hawaiian Waters and the SCA conditions will likely persist across the state through the weekend due to a combination of winds and seas. Additionally this weekend, a tropical cyclone could pass far south of the state. According to National Hurricane Center, there is a high chance of formation during the next 48 hours. Latest satellite imagery is starting to show better organization during the past 6 hours.
Surf along north and west-facing shores will quickly build this morning as a new long-period north-northwest swell arrives. Buoy readings at buoy 51001 has ranged from 7 to 9 ft and 16 to 19 seconds over the past several hours. Long-period energy is starting to arrive at the Waimea buoy this morning and we should see surf quickly rising throughout the morning hours across north and west facing shores. High Surf Advisory is in effect for most north and west facing shores of the smaller islands through tonight. This swell is expected to peak during the day today then fade over the next few days. Surf will likely be at borderline High Surf Advisory thresholds on Friday as the north-northwest swell declines. A wide fetch of gales seen on the ASCAT pass overnight near 40N180W, should send reinforcing medium period energy out of the north-northwest late Saturday into Sunday. Surf could approach advisory thresholds during its peak early Sunday morning. Another large northwest to north-northwest swell is possible towards the middle of next week.
A compact fetch of gales passing east of New Zealand last week Friday should produce some waves slightly above average around Friday into Saturday along south facing shores. Surf along east- facing shores will stay elevated and choppy through much of the week due to the strong trades. Select northeast exposures should see long-period energy from the large north-northwest swell today into tonight.

Fire weather

Persistent rainfall will likely limit the widespread availability of receptive fuels. Breezy and gusty winds will continue during the next several days, generating moderate fire weather conditions. Isolated thunderstorms will be possible for Big Island tonight through Friday. The inversion near Big Island will range from 8000 to 10000 ft through Friday.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Friday for Kauai North, Kauai Southwest, Maui Central Valley North, Maui Windward West, Molokai North, Molokai West, Molokai Windward, Niihau, Oahu North Shore, Waianae Coast, Windward Haleakala.
Small Craft Advisory until 6 AM HST Saturday for Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters, Big Island Windward Waters, Kaiwi Channel, Kauai Channel, Kauai Leeward Waters, Kauai Northwest Waters, Kauai Windward Waters, Maalaea Bay, Maui County Leeward Waters, Maui County Windward Waters, Oahu Leeward Waters, Oahu Windward Waters, Pailolo Channel.

Data Courtesy of NOAA.gov