West Side

Today: Mostly sunny with isolated showers. Highs around 81. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 65 to 73. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 78 to 83. Light winds becoming northeast up to 10 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Mostly sunny with isolated showers. Highs around 86. Light winds. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 66 to 74. Light winds.

Friday: Mostly sunny with isolated showers. Highs around 86. Light winds becoming north around 10 mph in the afternoon. Chance of rain 20 percent.

North Shore

Today: Mostly sunny with isolated showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 70 near the shore to 48 to 53 near 5000 feet. Southeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs around 80 near the shore to around 64 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 87. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 65 to 70. East winds up to 15 mph in the evening becoming light.

Friday: Mostly sunny with isolated showers. Highs 80 to 86. East winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 61 at the visitor center to around 68 at the summit. East winds up to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with isolated showers. Lows around 46 at the visitor center to around 48 at the summit. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 60 at the visitor center to around 69 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 70 near the shore to 48 to 53 near 5000 feet. Southeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs around 80 near the shore to around 64 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny with isolated showers. Highs 72 to 80. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 64. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 72 to 79. Light winds. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny with isolated showers. Highs 71 to 87. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 57 to 72. East winds around 10 mph.

Friday: Mostly sunny with isolated showers. Highs 70 to 87. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Weak winds due to a ridge of high pressure will continue into next week. Stable air and relatively low inversion heights will help keep the state fairly dry through the weekend and into early next week. A front will approach the area in the middle of next week, potentially bringing an increase in rainfall and humidity.

Discussion

Latest satellite images show mostly clear skies over the region. Radar shows very few light showers, mainly over the eastern parts of the Big Island and Maui.
Weak surface ridging extending in from the northeast will remain over the islands through at least early next week. Both upper level and surface troughing will stay well to our north. This will leave us with weak southeast surface winds through Wednesday. It looks like typical northeast to east trade winds will not be back with us for quite a while. This weak southeast flow will allow for sea and land breeze formation and above-normal cloudiness in leeward areas. Showers will be scarce, with stable inversions down in the 5000 to 6000 ft range. There will most likely be a few light showers, favoring the eastern and southeast side of the highest peaks. Vog from the recent eruption of Kilauea will persist over much of the area in coming days, and we continue to carry this in the forecast with the working of haze.
Latest guidance suggests that the approach of an upper level trough next week will come later than earlier runs, so we now expect it to come near the western end of the state towards the middle of next week. It does not appear that it will reach us, but could lead to increased low level moisture after Tuesday. As always, later runs will shed more light on things.

Aviation

Light east to southeast winds will be with us for the foreseeable future. Land and sea breezes will continue to bring interior clouds in the afternoons, with few showers expected. No AIRMETs in effect or expected across Hawaii today.

Marine

A surface ridge, parked just north of the state, will allow for mainly gentle to moderate east to east-southeast flow across the waters through the end of this week. Winds are forecast to ramp up a bit for the typical windy areas around Maui and the Big Island Friday. Waters located in the lee of the islands will be more sheltered, and thus lighter flow with a nocturnally driven land/sea breeze pattern close to the coasts. Similar conditions will prevail through the weekend as a frontal system stalls north and west of the islands.
The current large long-period northwest swell will peak this evening then gradually decline over the next few days. A reinforcing northwest to north-northwest swell generated by a compact low passing north of the islands today should arrive tonight and could help maintain advisory level surf through parts of the day Friday. The current High Surf Advisory is in effect through early Friday morning for select north and west facing shores, but that may need to be extended depending on this reinforcing swell. With offshore buoy readings staying near or just below 10 feet with the current swell, we have held off on issuing a Small Craft Advisory (SCA) for our local waters exposed to the northwest swell.
Over the next few days, models rapidly deepen a low in the north Pacific, roughly 1,500 to 2,000 nm northwest of Kauai. A significant fetch of gale to storm force winds associated with this low will be pointed down the great circle route towards the island chain and will produce XL surf late this weekend. Long-period forerunners should start arriving around mid-day Saturday, then quickly ramp up Saturday evening into the night. The peak of the event currently appears to be Saturday night into Sunday with the potential for giant surf (40 to 50 feet) along north facing shores Saturday night into Sunday out of the 300-320 degree swell direction. Surf heights will easily exceed High Surf Warning thresholds for select north and west facing shores, in addition to a SCA for rough seas.
Surf along east facing shores will remain small through the weekend due to the lighter winds. Select south facing shores could see some westerly wrap from the extra large northwest swell on Sunday.

Fire weather

Even though we will see relative humidity levels fall heading into the weekend, weak winds will preclude reaching critical fire weather conditions for the next few days. Temperature inversion heights near Big Island and Maui will range between 5,000 to 6,000 feet.

HFO Watches/Warnings/Advisories

High Surf Advisory until 4 AM HST Friday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.

Data Courtesy of NOAA.gov