West Side

Today: Sunny. Isolated showers in the morning. Highs 76 to 83. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 73. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Isolated showers in the morning. Highs 74 to 82. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

South Side

Today: Sunny. Highs 75 to 84. North winds 10 to 15 mph.

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy after midnight. Lows 65 to 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Highs 73 to 83. North winds 10 to 15 mph.

North Shore

Today: Mostly sunny with isolated showers. Highs 66 to 82. East winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 51 to 74. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 81. Northeast winds around 10 mph. Chance of rain 40 percent.

Central Maui

Today: Sunny. Highs 78 to 83. Northeast winds 10 to 15 mph.

Tonight: Partly cloudy with scattered showers in the evening, then mostly cloudy with isolated showers after midnight. Lows around 68. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Mostly sunny. Isolated showers in the morning. Highs 77 to 82. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Today: Partly sunny with isolated showers. Highs around 61 at the visitor center to around 68 at the summit. Light winds becoming northeast around 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 42 to 55. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 60 at the visitor center to around 67 at the summit. Northeast winds around 10 mph. Chance of rain 40 percent.

East Maui

Today: Mostly sunny with isolated showers. Highs 66 to 82. East winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 51 to 74. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 81. Northeast winds around 10 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 71 to 79. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 64. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the morning. Highs 70 to 77. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny with isolated showers. Highs 69 to 84. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 57 to 72. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Sunny. Highs 67 to 82. Northeast winds 10 to 15 mph.

Detailed Forecast

Synopsis

A surface ridge building north of the islands will allow moderate trade winds to return to the islands today. Rainfall will be limited into the weekend due to an upper level ridge over the islands. However low level moisture riding in on the trades will bring more typical windward and mauka showers by the end of the weekend.

Discussion

In the very short term, we are in close contact with the Hawaiian Volcano Observatory with regards to Kilauea's episode 45 eruption which began not long after midnight. An Ashfall Advisory was recently issued for volcanic debris that may be reaching areas to the south to southwest of the volcano.
Otherwise, no significant change to the forecast with the morning package. The PoPs and supporting grids have been nudged to the latest National Blend of Models package.
A low pressure system roughly 700 miles east-northeast of the islands, combined with low about 1000 miles north-northwest of the islands are helping to disrupt the trade wind flow. However the low the east-northeast will continue to weaken today as it moves to the east away from the islands. And the low to the north-northwest will lift to the north. As this happens today, the ridge to the north will strengthen, and moderate trades will filter back over the islands. The global models agree on mid level ridging over the region which will help to maintain a stable airmass, thereby limiting rainfall totals over the next few days.
The global models are in good agreement that moisture from the above mentioned low will get caught up in the trade wind flow over the weekend, and late in the weekend, make its way into the islands. This will help us return to a more typical trade wind weather pattern with some showers over the windward and mauka areas, along with the clouds and showers that form over the Kona slopes during the afternoon.

Aviation

Moderate northeasterly trade winds will focus most showers over windward and mountain areas over the next several days. VFR conditions will prevail with brief MVFR conditions any in showers.
No AIRMETs in effect.
With an eruption of Kilauea underway, increased haze and ash around the southern half of the Big Island is highly likely. SIGMET series Yankee is in place with estimated ash tops at FL250.

Marine

Trade winds will be making a come back today in response to an upper ridge ever so slowly expanding in from west northwest of the islands. The associated surface high far northwest of the offshore waters will travel east, pass north of the local waters and be northeast of the area by early next week. This will produce a tight enough Central Pacific pressure gradient over the islands to maintain moderate to locally fresh trade wind magnitudes the next several days. Trades will persist through the weekend as another high passes north of the state. Brief periods of locally strong winds will be possible this weekend across the windier channels and bays surrounding Maui County and Big Island.
A small, short to medium period northwest swell that peaked yesterday will gradually level out the next few days. A pair of North Pacific gale lows will send a series of small north to northwest swells down into the local waters from Friday night through the first half of next week. These swells will maintain waist to head high surf along north-facing shores into next week.
An overlapping small, short to medium period north northeast swell that peaked yesterday afternoon introduced advisory level surf along many northeast to eastern exposures, as well as elevating surf to above average heights along select Maui and Big Island western shores. This swell has leveled out and fallen below levels that will not produce advisory level surf. Therefore, the High Surf Advisory for east facing shores has been cancelled. An enhanced northeast fetch in the proximity of a vicinity weak low northeast of the islands will push in a secondary swell tomorrow. Moderate to fresh trades will also support near seasonal average east-facing shore wind wave surf.
Small background energy from the west will continue to linger the next few days and fade out this weekend. A small southwest bump from Tasman Sea gale energy that passed across American Samoa's 51209 buoy yesterday is expected to arrive this weekend. No significant south swells are expected through the first half of next week.

HFO Watches/Warnings/Advisories

Ashfall Advisory until 10 AM HST this morning for Big Island South, Big Island Southeast.

Data Courtesy of NOAA.gov