Hilo

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 81 to 87 near the shore to 69 to 74 at 4000 feet. Northwest winds 10 to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with showers likely. Lows around 69 near the shore to around 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Mostly cloudy. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to 68 to 73 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 86 near the shore to around 74 near 5000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming mostly clear. Isolated showers. Haze. Lows 69 to 74 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Haze through the day. Highs around 85 near the shore to around 73 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 74 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 74 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 85 near the shore to around 75 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Haze through the night. Lows around 69 near the shore to around 55 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Thursday: Breezy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Haze through the day. Highs around 84 near the shore to around 74 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 81 to 87 near the shore to 69 to 74 at 4000 feet. Northwest winds 10 to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with showers likely. Lows around 69 near the shore to around 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Mostly cloudy. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to 68 to 73 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny. Breezy. Highs around 85 near the shore to 70 to 76 above 4000 feet. Southeast winds 10 to 25 mph shifting to the northeast in the afternoon.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 72 near the shore to 52 to 59 above 4000 feet. Northeast winds 10 to 15 mph shifting to the east after midnight. Chance of rain 20 percent.

Thursday: Sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. East winds up to 15 mph shifting to the northeast in the afternoon.

Detailed Forecast

Synopsis

Breezy to locally strong trade winds will strengthen even more toward the end of the week, with windy conditions anticipated over the weekend and early next week. Clouds and showers will tend to favor windward and mauka areas, with a few brief passing showers possible over some leeward locations. A wetter trade wind weather pattern is possible early next week.

Discussion

Trade winds, rather strong this weekend, will prevail through the forecast period, supported by surface high pressure to the distant N and NE. Breezy to locally strong trade winds are expected the next day or two as a 1033 mb high to the distant N moves S. The high will sink further S this weekend, and combined with some decrease in pressure to the S of the islands, the tightened gradient will support windy conditions. A Wind Advisory will likely be required for at least portions of the area, with trade wind speeds remaining elevated into early next week. Longer range guidance supports what one might expect with La Nina conditions; continued breezy to strong trade winds.
Other than sending some wispy high-level cirrus clouds over the Big Island, an E-W oriented trough aloft several hundred miles N of Kauai is not having any apparent influence on island weather. A relative lack of incoming moisture has kept trade winds on the drier side over the last 24 hours or so, and this general pattern is expected to continue into the weekend, with just a few windward showers. Although showers will tend to be focused over windward and mauka areas the next couple of days, the strong trades will tend to carry showers leeward with greater efficiency, particularly at night and early morning.
Global models continue to indicate a surge in moisture approaching the islands from the SE late this weekend, potentially moving over the islands early next week, in tandem with a low aloft. The sources for the moisture are currently along 125W and 140W, with guidance merging these sources as they draw nearer to the islands. Confidence is low in this outcome, but PoP grids were nudged upward a little early next week.

Aviation

Typical trade wind weather will prevail during the next 24 hours with showers mainly focused over windward and mauka areas through the early morning. Brief MVFR conditions will be possible with any heavier showers, but VFR will prevail. Locally breezy trades will ramp up this afternoon, becoming quite strong overnight. AIRMET Tango for lee turbulence will remain in effect through the forecast period due to the strengthening trades.

Marine

High pressure centered far north of the area will maintain moderate to fresh trade winds. The high will strengthen through the day, however, resulting in an increase in the trades over the coastal and offshore waters. A new, stronger high will develop far to the north this weekend which will increase the trades further, with gales in the Alenuihaha Channel possible. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Maui County and the Big Island, and including Maui County windward waters, the Kaiwi Channel, and Oahu leeward waters.
A small, long period west-northwest swell is filling in across the area. The swell should peak today, then lower gradually during the second half of the week and through the weekend. Small, mainly background south swells can be expected through Thursday. A larger, long period south swell is forecast to arrive Thursday night, then peak Friday before slowly declining through the weekend. East-facing shores will continue to be affected by choppy, short period surf. The strengthening of trades later this week will increase surf heights along the east-facing shores.

Fire weather

A Red Flag Warning has been issued for leeward areas of the islands, as the combination of dry fuels, gusty winds and low relative humidity will bring the potential for extreme fire behavior the next couple of days, especially during the afternoon hours.

HFO Watches/Warnings/Advisories

Red Flag Warning from 11 AM this morning to 6 PM HST Thursday for Kauai Leeward, Oahu South Shore, Waianae Coast, Oahu North Shore, Olomana, Central Oahu, Waianae Mountains, Molokai Leeward, Maui Leeward West, Maui Central Valley, Leeward Haleakala, Kona, Kohala, Big Island Interior.
Small Craft Advisory until 6 PM HST Saturday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov