Hilo

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 77 to 84 near the shore to 65 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 30 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 77 to 84 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 68 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 67 to 73 near the shore to 48 to 54 near 5000 feet. Light winds.

Saturday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 81 to 87 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 65 to 83. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 62 to 68 near the shore to 54 to 61 near 3000 feet. Light winds.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 66 to 83. Northeast winds up to 10 mph. Chance of rain 20 percent.

Kohala

Today: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 65 to 83. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 62 to 68 near the shore to 54 to 61 near 3000 feet. Light winds.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 66 to 83. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Big Island

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 83 near the shore to around 65 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 70 near the shore to around 51 near 5000 feet. Light winds.

Saturday: Sunny in the morning then becoming partly sunny. Highs around 82 near the shore to around 66 near 5000 feet. Southeast winds up to 10 mph.

Puna

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 77 to 84 near the shore to 65 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 30 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Saturday: Mostly sunny. Isolated showers in the afternoon. Highs 77 to 84 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Waikoloa

Today: Mostly sunny. Highs 81 to 87 near the shore to 66 to 71 above 4000 feet. Northwest winds up to 10 mph.

Tonight: Mostly clear. Lows around 72 near the shore to 49 to 54 above 4000 feet. Light winds.

Saturday: Sunny. Highs 81 to 87 near the shore to 66 to 73 above 4000 feet. Northwest winds up to 10 mph.

Detailed Forecast

Synopsis

Trade winds will diminish through today giving way to daytime sea breezes and overnight land breezes tonight through the middle of next week. This will lead to clouds and showers over leeward and interior sections each afternoon followed by clearing skies at night.

Discussion

A weakly convergent band of low-level moisture will remain established over the western end of the island through Sunday morning. Moisture will tend to lose organization as the feature weakens through the weekend, but will ultimately be replenished by the approach of a weakening cold front early next week. For the remainder of this morning, light to moderate trades capitalizing on the resident moisture axis will bring occasional showers to windward areas, mainly Oahu and Kauai. By this afternoon, enhanced lee convergence courtesy of the light, and weakening, trades will favor an increase in afternoon showers over leeward/sheltered sections of the same islands.
Two strong extratropical cyclones advancing across the north pacific between now and the middle of next week will effectively wipe out the local pressure gradient across the Hawaiian islands through at least next Tuesday. The emerging land/sea pattern will modulate local weather during this time and will favor mostly clear nights with offshore flow and inland clouds and showers each afternoon. The greatest coverage of showers is expected over leeward and interior sections of Kauai and Oahu coincident with the greater supply of low-level moisture. On Saturday and possibly Sunday, light background flow will back to the NNE in response to a building weak surface ridge to the west impinging on a subtle trough axis modeled to linger in the vicinity of Kauai and Oahu. The most likely consequence of this backing of surface winds will be a tendency for afternoon shower activity to shift to the central and southern leeward zones of Kauai and Oahu. Once the period of deep troughing over the northeast Pacific runs its course, trades will build back into the area bringing a return to typical trade wind weather. The global model consensus maintains that this can be expected during the middle of next week.

Aviation

Light winds will continue through the weekend, which will allow overnight land breezes and daytime sea breezes to form. Relatively dry conditions will prevail over the eastern end of the state, while a few showers could bring some MVFR CIGS/VSBYS to Kauai and Oahu.
AIRMET TANGO will likely be needed later this morning through early Saturday due to moderate to severe turbulence expected over the state between FL200 AND FL400.

Marine

A series of fronts approaching the islands from the north and northwest will cause the trade winds to disappear for a few days through early next week, starting tonight. Each of these fronts entering the offshore waters north of the islands will dissipate before reaching the islands. We already have a stalled front that is dissipating over the northernmost offshore waters tonight and Friday. The next front enters the northern offshore waters Saturday evening and lingers there before dissipating Sunday. The last of these series of fronts eases into the northern offshore waters Monday night where it lingers north of Kauai through Tuesday. Light trades are expected to return Tuesday night and Wednesday.
A north swell is in the process of peaking this early Friday morning. It has been running foot or two above WaveWatch III guidance. Moderate size surf will continue mainly across the north facing shores today, subsiding to small to moderate Saturday. This swell will then be reinforced Saturday night by longer period moderate to large northwest to north swell, where a High Surf Advisory (HSA) is likely along north and west facing shores. This swell will be diminishing Monday, with the surf barely be hanging on to advisory level. A large pulse comes in late Monday night and Tuesday, warranting a High Surf Warning for the north and west facing shores of most islands. This swell will be subsiding gradually Tuesday night through Wednesday.
Along the south facing shore, a small south swell of 12 to 13 seconds will continue into the weekend, before fading. A small boost to the south facing shores is slated for Wednesday of next week as an out-of-season 15 second pulse arrives. Surf along east facing shores will be trending down and becoming flat over the weekend as the trade wind gradually give way to light and variable winds.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov