Hilo

Tonight: Cloudy with occasional showers. Lows around 69 near the shore to around 54 at 4000 feet. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 80 percent.

Friday: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then occasional showers after midnight. Lows around 69 near the shore to around 54 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 80 percent.

Kona

Tonight: Partly cloudy. Lows 72 to 77 near the shore to around 55 near 5000 feet. Light winds.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday Night: Mostly clear. Lows 72 to 77 near the shore to around 55 near 5000 feet. Light winds.

Waimea

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 69 near the shore to 57 to 62 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Friday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 76 to 81 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows around 69 near the shore to 57 to 62 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Kohala

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 69 near the shore to 57 to 62 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Friday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 76 to 81 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows around 69 near the shore to 57 to 62 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Lows 68 to 74 near the shore to around 53 near 5000 feet. Northeast winds 10 to 20 mph.

Friday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 86 near the shore to around 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Friday Night: Mostly clear. Lows 68 to 74 near the shore to around 53 near 5000 feet. Northeast winds 10 to 15 mph.

Puna

Tonight: Cloudy with occasional showers. Lows around 69 near the shore to around 54 at 4000 feet. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 80 percent.

Friday: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 82 to 88 near the shore to around 73 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Breezy. Numerous showers in the evening, then occasional showers after midnight. Lows around 69 near the shore to around 54 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 80 percent.

Waikoloa

Tonight: Partly cloudy. Breezy. Lows 72 to 77 near the shore to 51 to 58 above 4000 feet. Northeast winds up to 20 mph shifting to the southeast after midnight.

Friday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 83 to 88 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Friday Night: Mostly clear. Lows 72 to 77 near the shore to 51 to 58 above 4000 feet. East winds up to 15 mph.

Detailed Forecast

Synopsis

Breezy trade winds will persist through Friday, with showers favoring windward and mauka locations. The Central Pacific Hurricane Center is closely monitoring Tropical Storm Hone far east-southeast of the state currently tracking westward. Hone is expected to pass south of, or possibly near to the Big Island this weekend, bringing the potential for flooding rain and damaging winds.

Discussion

Short-term forecast remains on track with breezy trade wind conditions continuing through Friday due to a strong high pressure system well north of the state. Showers will predominantly affect windward and mauka areas, with some occasionally reaching leeward sections. A mid-level trough moving from east to west across the state this evening, combined with increasing low-level moisture, will likely enhance shower coverage tonight through Friday. This trough may also weaken or lift the strong subsidence inversion, increasing rainfall chances over leeward areas, particularly during the overnight and early morning hours.
A break in the typical summertime tradewind pattern comes this weekend…
The Central Pacific Hurricane Center forecast shows Tropical Storm Hone strengthening to become a strong tropical storm over the weekend as it passes south of the Big Island. Forecast confidence is increasing that Hone will impact our local weather conditions, regardless of its exact development and track over the next several days.
On the current forecast track for Hone, winds will strengthen through the weekend across the state as the pressure gradient increases. The strongest gusts, which could become locally damaging, given this storm track would typically be expected around South Point/Ka Lae, as well as downslope from Mauna Kea, Mauna Loa, the Kohala Mountains, and the Humuula Saddle. CPHC has issued a Tropical Storm Watch effective at 5 pm HST this evening for the Big Island as Hone approaches.
Drier air is expected to move across the western end of the state ahead of Hone on Saturday, so it should be a dry and windy day for those areas. Then increased moisture, with PW likely over 2 inches, will move in from the east sometime late Saturday into Sunday, increasing the potential for heavy rainfall across windward and southeast areas of the Big Island. Then heavy shower coverage may expand northward to cover more of the state by Sunday. Given the potential for prolonged heavy rainfall, localized flash flooding could occur if the rain becomes concentrated. A Flood Watch has been issued for the Big Island and is in effect from Saturday afternoon through Monday. We will continue to monitor the trend and might need to expand the Flood Watch to other areas as Hone passes by.
If Hone follows more closely to the right side of the forecast track cone from CPHC, there would be greater impacts felt across portions of Hawaii…with an increased potential for damaging winds and flash flooding, mainly for the eastern end of the state.
For further details on Hone's development, refer to the latest forecast issued by the Central Pacific Hurricane Center at hurricanes.gov.
Note that public and marine forecasts from WFO Honolulu will be updated on a modified schedule, in conjunction with the latest CPHC forecast issued at 5 am/pm and 11 am/pm HST.

Aviation

Breezy to locally windy trade winds will remain in place and could strengthen slightly tomorrow. An increase in moisture and elevated inversion heights tonight through tomorrow morning could boost shower activity and bring more widespread MVFR with isolated IFR ceilings and visibility for windward and mountain areas. A few of those showers could spill over into leeward areas. Shower coverage and intensity will favor the night time and early morning hours. Drier air is then expected to fill in later tomorrow night.
AIRMET Tango is in effect for moderate low level turbulence downwind of the terrain of all islands. This AIRMET will likely remain at least through tomorrow as the breezy trade winds persist. AIRMET Sierra for mountain obscuration is in effect for Maui, Molokai, and Oahu and could be expanded tonight as clouds and showers increase along windward and mountain areas.
Uncertainty in the forecast increases after tomorrow night. Tropical Storm Hone far southeast of the Big Island could strengthen over the weekend and pass just south of the Big Island as it moves west. Aviation interests should continue to monitor the storm and view the latest forecasts issued by the Central Pacific Hurricane Center as it develops over the next few days.

Marine

Fresh to strong trades will prevail through Friday, then ramp up to strong to gale force levels this weekend. A Small Craft Advisory (SCA) remains in effect for the typically windy waters east of Oahu through early Saturday. Winds from Saturday afternoon into early next week will be influenced by Tropical Storm Hone as it nears the islands from the southeast. Based on the latest advisory from the Central Pacific Hurricane Center for Tropical Storm Hone, a Tropical Storm Watch has been issued for Big Island coastal waters. In addition, rain bands from Tropical Storm Hone will also result in occasional heavy rain, low visibility, and the possibility of thunderstorms from Saturday afternoon through late Sunday night. Marine interests should continue to monitor for any future updates and adjustments to watches or warnings over the next several days.
The current small northwest swell will slowly decline through Friday. Surf along north facing shores will then return to typical summertime flat levels over the weekend through the middle of next week, aside from some trade wind swell wrap.
Surf along south facing shores will remain small and below the summertime average through Friday. Meanwhile, surf along east facing shores will remain near seasonal levels through Friday, then rise above normal this weekend as winds strengthen over and upstream of the islands. As Tropical Storm Hone approaches and passes near the islands this weekend into early next week, surf along south and east facing shores will increase, possibly reaching advisory levels over some east facing shores.

Fire weather

Drier air is expected to filter in across the western end of the state on Saturday. This drier airmass will arrive on the far periphery of Hone in conjunction with increasing easterly winds, effectively raising the fire weather threat, particularly for downslope and leeward areas of the smaller islands. The threat might decrease once the moisture from Hone begins spreading up the island chain later in the weekend.

HFO Watches/Warnings/Advisories

Tropical Storm Watch for Big Island,
Flood Watch from Saturday afternoon through Monday evening for Big Island,
Tropical Storm Watch for Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 AM HST Saturday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov