Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 61 to 69 near the shore to 51 to 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 66 near 5000 feet. Northeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 67 to 72 near the shore to 45 to 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Saturday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 66 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 62 to 83. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 59 to 64 near the shore to 51 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 63 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 62 to 83. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 59 to 64 near the shore to 51 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 63 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 70 near the shore to around 49 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Breezy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 61 to 69 near the shore to 51 to 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs 79 to 86 near the shore to 63 to 69 above 4000 feet. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows 65 to 72 near the shore to 45 to 53 above 4000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Sunny and breezy. Highs 78 to 86 near the shore to 64 to 70 above 4000 feet. Northeast winds 10 to 25 mph.

Detailed Forecast

Synopsis

Trade winds will continue to increase and become gusty through the weekend. Showers will favor windward slopes and, aside from afternoon showers over the Kona slopes of the Big Island, leeward areas should see little rainfall. Increasing moisture could enhance shower coverage early next week as an upper disturbance moves into the area.

Discussion

Trade winds continue to strengthen this morning. A high located far north northwest of the state is driving the resurgent trade winds. Upper ridging has increased airmass stability. A diffuse pocket of moisture moving along the trade wind flow has passed west of the islands, resulting in noticeably drier conditions this morning. However, isolated showers persist along windward slopes of all islands within decreased cloud cover.
Trade winds will ramp up today and will be breezy and gusty through the weekend as the high moves north of the state. Upper ridging will maintain somewhat stable conditions, but it should not be strong enough to produce a firm low level inversion. As a result, the gusty trades may fall short of Wind Advisory strength, and a few showers will likely be carried over to leeward areas from Maui to Kauai at times.
Trade winds will decrease and shower chances may increase during the first half of next week. Trades will ease as the high is weakened and displaced eastward by a front. The upper ridge will be eroded by a deepening upper trough, leading to some instability. The initial result will be thickening high clouds on Monday and, as the upper trough moves overhead on Tuesday, deeper low level moisture being drawn up from the south could increase shower activity.

Aviation

With robust high pressure centered far north of the islands, trade winds will be breezy to locally strong. Showers, with accompanying MVFR ceilings and visibilities, will mainly affect windward and mauka sections, though occasionally spreading leeward with the gusty trades.
An AIRMET for low level turbulence to the lee of the islands remains posted and will likely be extended at least through tonight. Another AIRMET has been issued for TEMPO mountain obscuration from Oahu to the Big Island as showery low clouds move over the isles riding on the trades.

Marine

A surface high pressure system centered far north of the islands will continue moving slowly east. This will produce locally strong trade winds through this afternoon. Therefore, a Small Craft Advisory (SCA) remains in effect for the typically windier waters adjacent to the islands of Maui County and the Big Island. By tonight, the surface high will build, which will cause additional strengthening of the trade winds. with winds possibly peaking near gale force this weekend in the windier channels. In addition, combined seas will become elevated and rough over areas exposed to the strong trades and a building northwest swell. Therefore, the SCA has been expanded to include all remaining Hawaiian waters from this evening through Saturday night. The surface high will eventually weaken northeast of the islands early next week, which will cause the trade winds to gradually ease from late Sunday night and Monday through Tuesday.
Forerunners from the new long-period northwest swell are expected to arrive later this morning. Surf produced by this swell will build through this evening, and then will likely peak later tonight and early Saturday. Surf is expected to reach the High Surf Advisory criteria along exposed north and west facing shores of the smaller islands when it peaks. This swell will then gradually lower from late Saturday night through early next week. Small background northwest swells will continue to produce small surf along most north and west facing shores during the middle of next week.
The strengthening trade winds will cause surf to build along east facing shores, and it will become elevated and rough this weekend. By early next week, the weakening trade winds will cause the surf to gradually lower along east facing shores. Background south swell energy will maintain small. near seasonal surf heights along most south facing shores. Note that the trade wind wrap may produce slightly elevated surf along some shorelines with an east exposure this weekend, such as along the coast of the southeast Big Island.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory from 6 PM this evening to 6 AM HST Sunday 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, Big Island Windward Waters.

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Data Courtesy of NOAA.gov