Hilo

Today: Mostly cloudy. Showers in the morning, then showers likely in the afternoon. Locally heavy rainfall possible. Highs 76 to 82 near the shore to 63 to 68 at 4000 feet. East winds around 10 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 53 to 58 at 4000 feet. Northeast winds around 10 mph shifting to the north after midnight. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 75 to 82 near the shore to 63 to 70 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows 69 to 74 near the shore to 47 to 56 near 5000 feet. Light winds.

Friday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Partly sunny with scattered showers. Highs 64 to 83. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 67 near the shore to 53 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 64 to 83. East winds up to 10 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny with scattered showers. Highs 64 to 83. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 67 near the shore to 53 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 64 to 83. East winds up to 10 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to around 67 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows around 71 near the shore to around 51 near 5000 feet. Northeast winds 10 to 20 mph.

Friday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Showers in the morning, then showers likely in the afternoon. Locally heavy rainfall possible. Highs 76 to 82 near the shore to 63 to 68 at 4000 feet. East winds around 10 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 53 to 58 at 4000 feet. Northeast winds around 10 mph shifting to the north after midnight. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 75 to 82 near the shore to 63 to 70 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to 67 to 72 above 4000 feet. North winds around 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 69 to 74 near the shore to 48 to 55 above 4000 feet. East winds around 10 mph.

Friday: Mostly sunny. Highs 80 to 86 near the shore to 65 to 70 above 4000 feet. Northeast winds around 10 mph in the morning becoming light.

Detailed Forecast

Synopsis

Expect moderate trade winds to spread across the islands today, then gradually decline Friday into Saturday. An increase in moisture over the eastern end of the state today will boost rainfall there, particularly over windward Big Island and east Maui. The remainder of the state will remain on the drier side with some scattered showers through the end of the week. Breezy trade winds will likely return Sunday into early next week.

Discussion

No changes to the short term forecast this morning, with the forecast seemingly on track. Precipitable water has increased over the southern end of the state as expected, with some heavier showers moving onshore of the Big Island shortly afternoon midnight. Still expecting some locally heavy showers today on the east side of the Big Island, and showers will be more likely over east Maui and the Big Island today with that surge of moisture moving in. The rest of the state will see some scattered showers focused over the windward sides in the trade wind flow.
The drier weather will return statewide tomorrow, leading to scattered showers over the typical windward and mauka areas. The ridge to the north of the islands will be nudged towards the islands Friday and Saturday so look for trade winds to be in the light to moderate range.
Heading into Sunday, an upper level trough moves over the islands and forms a cut off low over the southern end of the state. This is expected to increase winds over Haleakala, Mauna Kea and Mauna Loa with warning level winds quite possible. The ECMWF is stronger than the GFS solution at this time for Sunday night and into Monday, but both models bring warning level winds to the summits.
Meanwhile at the surface, a cold front north of the islands is expected to dissipate and lift north on Sunday, which will allow the ridge to build back north. The result will be increasing trade winds as we head into the new week. At the same time, remnant moisture from the front will get caught up in the trade wind flow which could boost shower activity. Another front approaching the islands from the northwest during the second half of the week could bring even more wet weather. Still plenty of time to see how the models evolve in the handling of that situation.

Aviation

Light to moderate trade winds will persist through this Thanksgiving Day as high pressure remains nearly stationary far northeast of the state. Most locales will remain VFR. However, an area of showers with accompanying MVFR conditions has been affecting portions of windward Big Island this early morning. Some of this moisture may eventually move over windward sections of Maui as well.
An AIRMET for mountain obscuration has been posted for windward areas of the Big Island as showery low clouds move ashore as alluded to above.

Marine

Light to moderate easterly trade winds may briefly return to fresh to near strong levels over the eastern end of the state later today through tonight as the ridge retreats northward. This should be enough to prevent sea breezes from developing near/along the coasts in most areas east of Kauai through the late morning and afternoon period today. The ridge will quickly break down and shift back toward the islands Friday into the weekend in response to an ongoing progressive pattern over the northern Pacific featuring a series of cold fronts passing to the north. This will translate to light to moderate easterly trades returning statewide Friday through Saturday (localized land/sea breezes possible).
Guidance shows the background winds shifting out of a northerly direction late Saturday, then quickly increasing into the fresh to locally strong category Sunday through Sunday night as a ridge noses eastward trailing the aforementioned front passing to the north. Winds should gradually veer to more of a typical northeast trade wind direction early next week, potentially strong enough for a Small Craft Advisory over the windier waters and channels.
Surf along exposed north and west facing shores will steadily rise through the day as a northwest swell builds down the island chain. The overnight and early morning observations at the offshore NDBC buoys to the northwest reflected this upward trend with the peak spectral energy centered around the 13-15 second band and swell heights exceeding predicted levels. This energy extrapolated out in time suggest surf heights will reach advisory levels for Oahu and Kauai by daybreak today, then for Maui County by mid- to late-morning as the swell builds down the island chain. The High Surf Advisory may need to be extended into Friday in later packages. Swell heights will near Small Craft Advisory levels over exposed waters of the smaller islands today, especially for the Kauai waters. This swell will hold Friday, then slowly ease over the weekend.
A second north-northwest swell associated with a belt of strong- to gale-force winds setting up within the 315-330 degree directional band over the northwest Pacific today could drive surf heights back to or near advisory levels for the north and west facing shores of the smaller islands Sunday. If this materializes, it will hold into the start of next week at it slowly fades.
Surf along east facing shores will remain small through the weekend due to the weaker trades locally and upstream of the state. A slight increase will be possible by early next week if the fresh to strong trades return.
Surf along south facing shores will remain at seasonal levels (near flat) into early next week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Friday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.

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Data Courtesy of NOAA.gov