Photo Credit: James Grenz

Hilo

Today: Partly sunny with isolated showers. Highs 79 to 87 near the shore to around 70 at 4000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 62 to 71 near the shore to around 57 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 77 to 86 near the shore to around 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 84 to 90 near the shore to 68 to 73 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 74 near the shore to around 53 near 5000 feet. North winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Friday: Partly sunny with isolated showers. Highs 82 to 88 near the shore to 65 to 70 near 5000 feet. Southwest winds around 10 mph. Chance of rain 20 percent.

Waimea

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs 65 to 86. East winds up to 25 mph increasing to 15 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Isolated showers. Lows 63 to 71 near the shore to 55 to 62 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 65 to 84. East winds 10 to 25 mph. Chance of rain 20 percent.

Kohala

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs 65 to 86. East winds up to 25 mph increasing to 15 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Isolated showers. Lows 63 to 71 near the shore to 55 to 62 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 65 to 84. East winds 10 to 25 mph. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 87 near the shore to around 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Breezy. Lows around 74 near the shore to around 54 near 5000 feet. East winds 10 to 20 mph.

Friday: Partly sunny. Breezy. Isolated showers in the morning. Highs around 86 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny with isolated showers. Highs 79 to 87 near the shore to around 70 at 4000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 62 to 71 near the shore to around 57 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 77 to 86 near the shore to around 68 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Waikoloa

Today: Mostly sunny. Breezy. Highs 84 to 91 near the shore to 67 to 75 above 4000 feet. North winds up to 25 mph with gusts to 45 mph.

Tonight: Partly cloudy. Breezy. Lows around 75 near the shore to 52 to 57 above 4000 feet. East winds 10 to 25 mph.

Friday: Mostly sunny. Breezy. Highs 83 to 90 near the shore to 65 to 73 above 4000 feet. East winds 10 to 25 mph shifting to the north 10 to 15 mph in the afternoon.

Detailed Forecast

Synopsis

Expect gusty trade winds through early Friday as dry and stable air settles over the region. Trades will gradually decrease over the weekend into next week as relatively dry conditions continue.

Discussion

Our airmass continues to slowly dry and stabilize this morning. Shower activity decreased noticeably since yesterday afternoon and rainfall amounts were small overnight compared to the past several days. Satellite loop shows patchy broken high clouds somewhat obscuring the view of lower clouds. However, only sparse windward low cloud cover is noted through the high cloud cover gaps. Relative humidity is trending lower and trade winds remain breezy in many locations. Overnight soundings show an inversion strengthening near 4500 feet. This inversion, while somewhat elevated yesterday afternoon, is expected to lower over the next 24 to 48 hours as upper ridging builds in.
Expect gusty winds for the next few days due to the lowering inversion and a steepened pressure gradient. Models show the areas normally prone to accelerated trades, such as South Point and Leeward Kohala on the Big Island and leeward West Maui, may expect strong wind gusts near wind advisory threshold. This condition will need to be closely monitored over the next day or two. Trade winds look to ease to breezy levels this weekend and hold, along with relatively dry conditions, through early next week.

Aviation

Breezy to strong trades should persist over the next few days. SHRA and low cigs will favor windward and mauka locations. SCT SHRA look to also build up on the Kona slopes of the Big Island during the afternoon hours. MVFR conds will be possible within SHRA but VFR should prevail.
AIRMET Sierra is not in effect but with lowering cigs and SHRA it may be needed tonight for windward locations.
AIRMET Tango for mod low level turb is in effect for areas downwind of island terrain and will likely be needed for the next couple of days due to the strong trades.

Marine

Surface high pressure far northeast of the waters will continue to produce strong to locally near gale trade winds through Friday. A Small Craft Advisory (SCA) has been extended for all Hawaiian waters through Friday. As the high weakens this weekend, trade winds should ease back to fresh to locally strong speeds. The SCA may need to be trimmed by the weekend to just the typical windier areas around Maui County and the Big Island.
Rough and choppy surf will continue over the next few days along east facing shores before gradually easing early next week. Local wind swell may wrap into select north and south facing shores. All other shores look to remain nearly flat today before a background south swell could produce some small surf along south facing shores on Friday. Otherwise, no significant swells are expected for the rest of the week.

Fire weather

Gusty trade winds tonight through Friday could present some fire weather concerns in the normally windier trade wind areas and downslope leeward locations such as West Maui and leeward Kohala on the Big Island. The strongest wind gusts are more likely on Thursday and Friday as the inversion strengthens. Trade winds will gradually decrease this weekend into early next week, but dry leeward conditions will likely persist. Humidity will generally trend downward over the next few days, especially across leeward areas, adding to the fire weather concerns in those areas with gusty winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for all Hawaiian waters,

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Data Courtesy of NOAA.gov