Weather Forecast

Hawaii County Weather Forecast for October 04, 2021

October 4, 2021, 7:15 AM HST
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Photo Credit: James Grenz

Hilo

Today: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 64 to 72 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 80 percent.

Tuesday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Haze through the day. Highs 83 to 88 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Haze. Lows around 73 near the shore to 51 to 57 near 5000 feet. Light winds. Chance of rain 20 percent.

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Tuesday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Haze through the day. Highs 83 to 88 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Waimea

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Today: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to 55 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

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Today: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to 55 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows 70 to 75 near the shore to around 53 near 5000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Puna

Today: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 64 to 72 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 80 percent.

Tuesday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs 83 to 88 near the shore to 66 to 72 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 75 near the shore to 50 to 56 above 4000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Tuesday: Sunny in the morning then becoming partly sunny. Breezy. Highs 83 to 88 near the shore to 66 to 72 above 4000 feet. Northeast winds up to 20 mph.

Detailed Forecast

Synopsis

Moderate to occasionally breezy trade winds will continue through the first half of the week, with clouds and showers favoring windward and mauka locations. Trade winds are expected to strengthen beginning Wednesday, with windy conditions possible by the end of the week and upcoming weekend.

Discussion

Guidance remains in decent agreement and depicts showery conditions continuing through the first half of the week over the western end of the state due to a combination of an upper trough extending southward into the area and a sufficient amount of moisture moving through. Observations at the gages around the state reflect this, with 24-hr accumulations (through 1 AM HST this morning) ranging from 2 to 4 inches over Kauai and a quarter to half of an inch on Oahu. Although much of these showers will favor the typical windward locations, some will spill over into our dry leeward areas occasionally (best chance overnight/early morning periods). For the eastern end of the state, more of a stable trade wind pattern has limited accumulations, which will continue through much of the week.
Models and ensembles project a tightening pressure gradient by or around midweek, that supports locally strong trades through the upcoming weekend. The aforementioned upper low will continue to lift northeastward and weaken by midweek. This combined with some drier air moving in from the east should limit windward shower coverage into the second half of the week statewide.

Aviation

Moderate to breezy trade winds will persist across the state today. Slight atmospheric instability combined with enhanced moisture is expected to remain across the western end of the island chain this morning. This will result in low clouds and frequent showers across the western half of the state, which will likely keep periods of MVFR low ceilings and reduced visibility in heavier showers over windward sections of these islands. For the remaining islands, expect a more typical trade wind distribution of low clouds and showers concentrated along windward facing coasts and slopes. This may result in brief periods of MVFR conditions this morning.
AIRMET SIERRA is in effect for mountain obscuration along north through east facing sections of Kauai, Oahu and Molokai above 2 thousand feet due to the low clouds and showers.

Marine

High pressure north of the Hawaiian Islands will continue to produce moderate to fresh trade winds over the coastal and offshore waters into Tuesday. Trade winds will likely strengthen from Wednesday into the weekend, as a stronger high builds in north of the region.
Small surf along north facing shores this morning will get a boost from a small, long-period west-northwest swell generated by Typhoon Mindulle. The forerunners of this swell have reached Kauai this morning and will spread to the other islands later tonight. This swell will last through midweek, then diminish thereafter. Small south swells will keep surf from going flat along south facing shores through much of the week. A slightly larger south swell may elevate surf heights from Friday into next weekend. East shore surf will hold fairly steady through Tuesday. Strengthening trades over and upstream of the islands will build surf heights along east facing shores from late Wednesday into next weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov

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