Photo Credit: James Grenz

Hilo

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68 near the shore to around 54 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs around 83 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 69 to 74 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with numerous showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Tonight: Windy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

Sunday: Windy. Mostly sunny with scattered showers. Highs around 82 near the shore to 70 to 80 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with numerous showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Tonight: Windy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

Sunday: Windy. Mostly sunny with scattered showers. Highs around 82 near the shore to 70 to 80 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

South Big Island

Today: Windy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds 10 to 30 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 70 near the shore to around 53 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Sunday: Windy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 30 mph increasing to 10 to 30 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68 near the shore to around 54 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs around 83 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Windy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 20 percent.

Tonight: Windy. Partly cloudy with isolated showers. Lows around 72 near the shore to 51 to 58 above 4000 feet. East winds up to 30 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Windy. Isolated showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Trade winds will remain at breezy to locally windy levels through early next week, peaking this weekend. The trades are expected to ease slightly during the middle to latter part of next week. Little change in the overall weather pattern is expected during the next 7 days, with bands of clouds and showers moving through the islands at times. Showers will favor windward and mauka areas, particularly at night and during the early morning hours, with a few showers occasionally reaching leeward communities due to the strength of the trades.

Discussion

Currently at the surface, a 1028 mb high is centered around 850 miles north-northeast of Honolulu, and is driving breezy trade winds across the island chain early this morning. Infrared satellite imagery shows partly to mostly cloudy conditions across the state, with cloud coverage the highest in windward and mauka areas as well as leeward sections of the Big Island. Radar imagery shows scattered to numerous showers moving into windward areas, with some of these showers reaching leeward communities at times. Main short term focus revolves around rain chances during the next few days.
High pressure will remain nearly stationary to the north of the islands through Tuesday, keeping breezy trade winds in place across the island chain. The trade winds will peak at locally windy levels this weekend as a drier more stable airmass builds in and lowers inversion heights to around 5-6 kft. This should allow the terrain to be particularly effective at accelerating the winds through the islands. A a result, a Wind Advisory has been issued for portions of the Big Island, Maui, Lanai and Kahoolawe from 10 am this morning through 6 pm Sunday. The trades are expected to ease back to moderate and locally breezy levels Wednesday through late next week as the high to the distant north weakens slightly.
As for the remaining weather details, typical trade wind weather is expected to continue during the next 7 days, with the exception of this weekend, when a drier more stable airmass should reduce shower coverage statewide. Overall, bands of clouds and showers will periodically move through the islands throughout the forecast period, with showers favoring windward slopes and coasts, particularly at night and during the early morning hours. A few showers will reach leeward areas at times as well due to the strength of the trades.

Aviation

Breezy to locally strong trade winds will continue through the weekend. As a result, AIRMET Tango will remain posted for low level turbulence over and downwind of the terrain of all islands.
Low clouds and showers will continue to favor windward and mauka areas, with a few showers spilling over into leeward areas due to the strong trades. Expect mainly VFR conditions across the area, with periods of MVFR cigs and vsbys under SHRA. AIRMET Sierra for mountain obscuration over windward sections of Oahu and the Big Island will remain posted through the morning hours.

Marine

Small Craft Advisory level easterly trade winds (20-30 kt) and associated rough seas are expected to continue through early next week. Seas will reach the 8 to 12 ft range this weekend due to a combination of a solid long-period south-southeast swell and the short-period wind generated seas out of the east. Winds are forecast to increase to near-Gale speeds today, mainly over the Alenuihaha Channel. Latest ASCAT shows a solid area of strong winds in this zone, thus will continue the Gale Watch, but this may need to be upgraded to a Gale Warning later today.
Near shore buoys are already seeing an increasing in south swell energy as the new south (170 degree) swell fills in. This swell will continue to build today, peak tonight and hold through Sunday. A High Surf Advisory has been issued for south facing shores as surf builds to advisory levels (10 ft) today. A second pulse is expected to arrive Monday, keeping surf well above average through the first half of next week. Surf will return to the summertime average late next week with more typical background southerly energy moving through.
Surf along east facing shores will trend up and remain rough through early next week due to the strong to near gale force trades trades.
Surf along north and west facing shores will remain near the summertime average through today, then slightly rise Sunday into next week as a small northwest swell arrives.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Wind Advisory from 10 AM this morning to 6 PM HST Sunday for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island North.
Small Craft Advisory until 6 PM HST Monday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 8 PM HST this evening for Alenuihaha Channel.
Gale Watch from this evening through late Sunday night for Alenuihaha Channel.

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Data Courtesy of NOAA.gov