Hilo

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 66 to 72 near the shore to 54 to 60 at 4000 feet. East winds up to 10 mph shifting to the west after midnight. Chance of rain 40 percent.

Wednesday: Mostly sunny. Isolated showers in the morning. Highs 80 to 87 near the shore to around 71 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 65 to 71 near the shore to 53 to 60 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 20 percent.

Kona

Tonight: Partly cloudy with isolated showers. Haze. Lows around 74 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs around 86 near the shore to 68 to 73 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows around 74 near the shore to 50 to 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows 65 to 73 near the shore to 56 to 64 near 3000 feet. East winds up to 20 mph. Chance of rain 30 percent.

Wednesday: Mostly sunny. Breezy. Isolated showers in the morning. Haze through the day. Highs around 82 near the shore to 70 to 81 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Breezy. Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 63 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows 65 to 73 near the shore to 56 to 64 near 3000 feet. East winds up to 20 mph. Chance of rain 30 percent.

Wednesday: Mostly sunny. Breezy. Isolated showers in the morning. Haze through the day. Highs around 82 near the shore to 70 to 81 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Breezy. Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 63 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

South Big Island

Tonight: Partly cloudy. Breezy and haze. Lows around 75 near the shore to around 57 near 5000 feet. Northeast winds up to 20 mph increasing to 10 to 20 mph after midnight.

Wednesday: Sunny…breezy and haze. Highs around 88 near the shore to around 70 near 5000 feet. East winds up to 25 mph.

Wednesday Night: Mostly clear. Breezy and haze. Lows around 75 near the shore to around 56 near 5000 feet. Northeast winds up to 20 mph becoming 10 to 15 mph after midnight.

Puna

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 66 to 72 near the shore to 54 to 60 at 4000 feet. East winds up to 10 mph shifting to the west after midnight. Chance of rain 40 percent.

Wednesday: Mostly sunny. Isolated showers in the morning. Highs 80 to 87 near the shore to around 71 at 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 65 to 71 near the shore to 53 to 60 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 20 percent.

Waikoloa

Tonight: Partly cloudy. Haze. Lows around 75 near the shore to around 56 above 4000 feet. East winds up to 15 mph.

Wednesday: Sunny and haze. Highs 86 to 91 near the shore to 68 to 76 above 4000 feet. Northeast winds up to 15 mph.

Wednesday Night: Mostly clear. Haze. Lows around 75 near the shore to around 54 above 4000 feet. East winds up to 15 mph.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will prevail through the week, with showers favoring windward and mauka areas. Aside from scattered afternoon showers on the South Kona slopes of the Big Island, leeward areas will be mostly dry. Winds will begin to weaken later this week leading to more widespread leeward sea breezes and bringing higher chances for interior and leeward showers, mainly across the western islands.

Discussion

A broad surface high well north of the Hawaiian Islands continues to drive moderate to locally breezy easterly trades. Meanwhile, upper-level ridging has settled over the islands resulting in increasingly dry and stable conditions. This has resulted in a decrease in shower activity across the state, with isolated windward and mauka showers this afternoon. Aside from a few showers over the South Kona slopes of the Big Island, leeward areas remain dry.
However, subtle changes are looming in the near future, as a strengthening upper-level trough and associated surface trough propagate just northwest of the islands. This will lead to a shortwave passing in the vicinity of Kauai, resulting in the development of sea breezes in the afternoon for western slopes of island mountains and increased shower activity for leeward areas, despite the overall drier conditions still in place.
Latest model guidance still supports a return of stable summertime trades during the latter half of the week as the aforementioned troughs to the northwest weaken. Trades will be slightly lighter in strength initially, but are progged to increase back to moderate to locally breezy by the end of the forecast period, as well as more typical shower activity to windward and mauka areas.

Aviation

Moderate to locally breezy trades will persist through tomorrow. Expect low clouds and showers to favor windward and mountain areas, where MVFR conditions will be possible, particularly overnight. In addition, with low level winds veering slightly out of the ESE, isolated sea breezes may increase cloud cover over some leeward areas tomorrow afternoon. Otherwise, VFR conditions are expected to prevail.
No AIRMETs are currently in effect.

Marine

Moderate to locally strong easterly trade winds will continue through Friday as surface high pressure remains centered far north of the Hawaiian Islands. A Small Craft Advisory remains in effect for the waters around Maui County and the windier waters around the Big Island. Lighter winds are forecast from Friday night into the weekend.
A long period southwest swell will slightly boost surf heights along south and some west facing shores late tonight through the weekend. Surf along east facing shores will remain small and choppy through the forecast period. Surf along north facing shores will remain nearly flat through the forecast period.
Peak monthly high tides associated with the lunar cycle, combined with water levels that are running higher than predicted may lead to minor flooding along the shoreline and in low-lying coastal areas. Coastal flooding is expected around the daily peak tide each afternoon through Thursday. A Coastal Flood Statement has been issued for Maui County and the Big Island.

Fire weather

Locally breezy, dry, and stable conditions will continue through the week. With near critical relative humidity possible the next couple of days expect elevated fire weather concerns, especially over drier leeward areas. Winds are expected to weaken later this week.
The current KDBI value at the Honolulu International Airport has exceeded the 600 threshold, currently 604, and will remain above this threshold until significant rain occurs, which is unlikely for weeks or possibly months as the peak of the dry season is near.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for 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