Hilo

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows 63 to 70 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Tuesday: Mostly sunny with scattered showers early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 81 near the shore to 66 to 71 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 30 percent.

Tuesday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows 63 to 70 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Kona

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 69 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning then becoming partly sunny. Isolated showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy early in the evening then becoming partly cloudy. Isolated showers. Lows around 69 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 66 near the shore to 53 to 62 near 3000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 79 near the shore to 66 to 76 near 3000 feet. Light winds. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy early in the evening then becoming mostly clear. Isolated showers in the evening. Lows around 66 near the shore to 53 to 62 near 3000 feet. Light winds. Chance of rain 20 percent.

Kohala

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 66 near the shore to 53 to 62 near 3000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 79 near the shore to 66 to 76 near 3000 feet. Light winds. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy early in the evening then becoming mostly clear. Isolated showers in the evening. Lows around 66 near the shore to 53 to 62 near 3000 feet. Light winds. Chance of rain 20 percent.

South Big Island

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 70 near the shore to around 54 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning then becoming partly sunny. Isolated showers. Highs around 83 near the shore to around 70 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy with isolated showers. Lows around 70 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows 63 to 70 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Tuesday: Mostly sunny with scattered showers early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 81 near the shore to 66 to 71 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 30 percent.

Tuesday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy with scattered showers after midnight. Lows 63 to 70 near the shore to around 54 at 4000 feet. Light winds. Chance of rain 30 percent.

Waikoloa

Tonight: Partly cloudy. Isolated showers in the evening. Lows 67 to 73 near the shore to 49 to 59 above 4000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 83 near the shore to 67 to 73 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy. Isolated showers early in the evening. Lows 67 to 73 near the shore to 49 to 59 above 4000 feet. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Dry and stable conditions continue through Wednesday, with a deep- layer ridge remaining in place over much of the region. This will result in a land and sea breeze regime, with afternoon clouds and a few showers over interior and leeward areas. Increased moisture from a cold front will lead to better rain chances on Thursday, particularly for northern and windward slopes as northerly winds accompany it.

Discussion

Dry and stable conditions, with a deep-layer ridge over the region, will continue through Wednesday. A weak upper-level low near the Big Island continue to bring some enhanced showers to windward Big Island this afternoon, with little impact elsewhere. This low will continue to slide south of the area. The surface ridge will weaken and also shift south in response to a progressive pattern across the North Pacific defined by a series of fronts passing nearby to the north. The low-level flow will transition to the south to west-southwest tonight through Wednesday. Expect land and sea breezes to continue through Wednesday with the best chance for clouds shifting to interior and leeward locations during the afternoon hours. While a few afternoon showers can't be ruled out each day in these areas, accumulations will be minimal.
Guidance continues to show higher moisture (albeit shallow) and rain chances later this week as the tail-end of a cold front settles south into the islands from Wednesday night through Thursday. Probabilistic QPF guidance shows the best chances for accumulations along northern and windward slopes, but no significant rainfall is expected at the moment. The progressive pattern will persist into the weekend with another front impacting the region.

Aviation

A ridge north of the islands will maintain light winds through Wednesday night, with local land and sea breezes forming. Relatively dry weather will prevail, with a few light showers possible near the coast at night, with a slight chance for a shower over interior and mauka areas during the afternoon hours. Anticipate a transition back to a more typical trade wind regime on Thursday.
AIRMET Tango remains in effect for moderate upper level turbulence for Maui County and the Big Island. Conditions may improve over Maui County this evening, but are expected to linger over and near the Big Island into tonight. Not anticipating any additional AIRMETs tonight.

Marine

A strong zonal jet across the north Pacific will support powerful, fast-moving surface lows that will pass well N of the islands over the next 7-10 days. This pattern will push the surface ridge over the islands, with the resultant light winds favoring a S-SW direction over Kauai and Oahu waters, and an E-SE direction over Maui and the Big Island waters. A dissipating cold front associated with one of the lows will enter Hawaiian waters Wednesday night and Thursday, pushed southward on a gentle to moderate N-NE flow supplied by a weak high centered NW of the islands. As the front and high dissipate Friday, the surface ridge will move over the islands, with light and variable winds resuming.
The strong lows passing N of the area will have significant fetches aimed toward the islands. Although their fast-moving nature limits the ability of these powerful (up to hurricane force at times) lows to generate fully developed seas, there will still be several bouts of large to extra-large surf along N and W facing shores through the weekend. Given recent wave model guidance underpredicting the peak heights of NW swells, especially with hurricane-force lows, the official forecast indicates swell heights that are 1-3 feet larger.
While small surf will prevail in the short term, increasing swell energy from the NNW is expected to bring a modest increase in surf tonight and Tuesday. Surf will then rise more significantly from Tuesday night through Friday, necessitating a High Surf Warning for exposed shores during its peak Thursday and Friday. Another XL swell is anticipated next weekend. Combined seas will exceed 10 feet late Wednesday into Thursday, requiring a Small Craft Advisory for many zones into the weekend.

Fire weather

No critical fire weather conditions anticipated through the week despite dry and stable conditions due to a combination of light winds (first half of the week) and increasing moisture as a front settles southward into the area (second half of the week).

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov