Hilo

Today: Partly sunny. Breezy. Numerous showers 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 up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 69 near the shore to around 55 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 86 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 70 percent.

Kona

Today: 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. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Haze through the night. Lows 69 to 74 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Haze through the day. Highs around 86 near the shore to around 73 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Windy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 55 to 62 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Friday: Windy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain 50 percent.

Kohala

Today: Windy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 30 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 55 to 62 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Friday: Windy. Partly sunny with scattered showers. Highs around 82 near the shore to 73 to 80 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. 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 74 near 5000 feet. East winds up to 25 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 54 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Friday: Windy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs around 85 near the shore to around 74 near 5000 feet. East winds 10 to 30 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Breezy. Numerous showers 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 up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 69 near the shore to around 55 at 4000 feet. North winds up to 15 mph. Chance of rain 70 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 86 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 70 percent.

Waikoloa

Today: Sunny and breezy. Highs around 85 near the shore to 69 to 75 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Mostly clear. Breezy. Lows around 72 near the shore to 51 to 58 above 4000 feet. Southeast winds up to 20 mph.

Friday: Sunny and windy. Highs around 85 near the shore to 69 to 75 above 4000 feet. Northeast winds up to 30 mph.

Detailed Forecast

Synopsis

Trade winds for days as a strong high pressure system far north of the islands keeps breezy to locally strong trade winds in forecast today. High pressure will build over the region on Friday, strengthening trade winds into the breezy to windy range from Friday into early next week. Long range guidance continues to show wet weather trends from Saturday night through Tuesday as a low level disturbance passes through the island chain with an unstable upper level low lingering just north of the state.

Discussion

Looking into the satellite imagery this morning we see a few bands of showers drifting into windward sections of each island. In the upper levels, using the water vapor imagery channel, we see a narrow upper trough (TUTT) just north of the islands with a few embedded upper lows. A few high level cirrus clouds are drifting over the islands this morning due to a subtropical jet stream. These scattered high clouds will continue to drift over the islands into the weekend, enhancing sunrise and sunset colors.
The weather story for the next seven days is Blasting Trade Winds lasting into early next week. A strong 1032 MB high center far north of the state will slowly drift south into the weekend. Breezy to locally strong trade winds today will increase in strength on Friday and Saturday, producing windy conditions across the region. A wind advisory may be needed over windier island locations during this time period. Weather models agree on this extended breezy to windy weather pattern lasting into early next week.
Passing showers will prevail through Saturday, favoring windward and mountain sections, as an upper level low approaches the islands from the east. In the short term, the trade wind temperature inversion will weaken enough for periods of passing showers lasting through Saturday afternoon. An upper low will drift by just north of the state on Sunday and Monday and a passing low level (700 MB) trough will keep wet weather trends in the forecast. Moisture levels will rise over the next few days with Precipitable Water (PW) rising into the 1.0 to 1.5 inch range on Saturday and Sunday. PW levels will then rise into the 1.5 to 2.0 inch range from Sunday night into Tuesday. Expect increasing cloud and shower trends during this time period. Higher cloud coverage and numerous shower trends will favor windward and mountain areas with more scattered showers spreading into leeward locations. Some of these developing showers may become locally heavy at times.

Aviation

High pressure north of the state will continue generate breezy trades across the islands for the forecast period. Thus, scattered showers will be concentrated mainly along the windward coasts and slopes. Expect brief periods of MVFR ceilings and visibility with this activity. Elsewhere, VFR conditions and partly cloudy skies prevail.
AIRMET TANGO remains in effect for tempo moderate turbulence below 8000 feet over and immediately south through west of all mountains.

Marine

High pressure north of the state and an active ITCZ to the south, will keep elevated trade winds in place through the middle of next week. The trades will ramp up in the near term, peaking Friday night through Sunday, before easing slightly during the first half of next week. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Maui and the Big Island, as well as some additional waters around Maui County and Oahu. The SCA will likely need to be expanded to include all waters Friday night through Sunday due to winds and seas, with Gale Force conditions not out of the question for some of the typically windy areas around Maui and the Big Island. Although the trades are expected to ease slightly early next week, seas will likely remain at SCA levels across most waters through Monday and possibly beyond.
With trade winds strengthening, very rough east shore surf can be expected through early next week. Surf should rise to above normal levels by Friday and potentially reach High Surf Advisory (HSA) levels over the weekend into early next week. The very rough east shore surf will decline Tuesday through the middle of next week, but will likely remain above normal levels. The current west-northwest swell will decline today and fade on Friday. No other significant northwest swells are expected through the middle of next week. A long period south swell will arrive tonight, build on Friday, then peak during the weekend. This swell as observed by the PacIOOS American Samoa Buoy registered fairly consistent around 6 ft/17 seconds for a roughly 24-30 hour period Tuesday night into Wednesday evening. Although, the bulk of this swell energy will pass east of Hawaii, advisory level surf remains a possibility Saturday into Sunday as this swell peaks locally. South shore surf will lower early next week, but a reinforcing south swell will likely keep south shore surf above normal levels through the middle of next week.

Fire weather

Breezy trade winds and low humidity levels will exceed Red Flag Warning (RFW) thresholds for leeward areas of the Hawaiian Islands through Friday afternoon. The RFW was extended into Friday, due to the continued potential for extreme fire behavior over leeward sections of each island. Wind speeds will continue to strengthen from Friday into the weekend. Moisture levels are forecast rise later this weekend, decreasing the potential for extreme fire behavior on Saturday and Sunday. Changing humidity levels will determine how long the RFW gets extended in time.

HFO Watches/Warnings/Advisories

Red Flag Warning until 6 PM HST Friday 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 Sunday 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