Hilo

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 50 to 58 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. Lows 64 to 71 near the shore to 50 to 57 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 40 percent.

Kona

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 73 near the shore to 49 to 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny. Scattered showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 40 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening. Lows 70 to 75 near the shore to 48 to 54 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Big Island

Tonight: Mostly clear. Breezy. Lows around 73 near the shore to around 54 near 5000 feet. East winds up to 20 mph.

Thursday: Sunny and breezy. Highs around 86 near the shore to around 68 near 5000 feet. East winds up to 20 mph.

Thursday Night: Mostly clear. Breezy. Lows around 74 near the shore to around 55 near 5000 feet. East winds up to 20 mph.

Puna

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 50 to 58 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 87 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. Lows 64 to 71 near the shore to 50 to 57 at 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 40 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Lows 71 to 76 near the shore to around 53 above 4000 feet. Northeast winds up to 20 mph decreasing to up to 10 mph after midnight.

Thursday: Sunny. Isolated showers in the afternoon. Highs around 87 near the shore to 66 to 75 above 4000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows around 73 near the shore to 50 to 55 above 4000 feet. North winds up to 15 mph shifting to the east after midnight.

Detailed Forecast

Synopsis

Moderate trades deliver limited showers windward and mauka through Friday. Trade wind showers potentially increase over the eastern end of the state this weekend in advance of Tropical Cyclone Kiko which is poised to approach the Islands early next week. An associated flash flood threat will be possible.

Discussion

Mid-level ridge axis extending westward from 593dm mid-level ridging anchored east of the islands maintains strongly stable conditions today, particularly over the eastern end of the state. Water vapor provides a clear picture of the stability gradient currently in place with very dry mid-level air pivoting around the high and over Maui and the Big Island while lingering cyclonic flow aloft associated with low pressure west NW of Kauai supplies modest mid- level moisture over the western end of the island chain. The aforementioned mid-level high is displaced south in response to deep troughing advancing eastward over the NE Pacific. This in turn has suppressed the seasonably weak trade wind belt to the south resulting in moderate trades that will persist into early next week. Limited rainfall windward and mauka during this time owing to high stability and a lack of upstream moisture.
The end of the forecast period will feature the passage of TC Kiko, which is presently moving quite slowly westward in the eastern Pacific Basin. The track of this cyclone will be governed by its intensity and interaction with steering flow, the latter of which will be modulated in part by deepening mid-latitude troughing near the islands as it approaches. For official forecasts of track and intensity, consult the National Hurricane Center. A flash flood threat may develop over the islands in the Tuesday-Thursday time frame conditional on the exact track of the system.

Aviation

Moderate trades expected for the next few days. A few low clouds and showers will be possible over windward slopes tonight, but MVFR conditions expected to prevail. No AIRMETS in effect or anticipated overnight.

Marine

A weak surface ridge to the north will remain nearly stationary through the weekend. This will maintain moderate to locally fresh trade winds with some localized sea breezes, especially across leeward waters. Tropical Cyclone Kiko, currently in the Eastern Pacific, is forecasted to move into the eastern waters early next week.
Surf along north facing shores will continue to gradually decline through Thursday as a mix of the north and northwest swells fade. Reinforcing small short- to medium-period north-northwest swells are expected through the end of the week which will keep surf from going flat. In the extended forecast, the northwest Pacific looks to get active as low pressure systems traverse the basin over the weekend sending the potential for a few small to moderate swells during the middle of next week.
Surf along south facing shores will see background medium- to long-period energy through the week before a small to moderate long-period south-southwest swell fills in and peaks over the weekend.
Below average surf is expected to continue along east facing shores through the rest of the week. In the extended forecast, easterly energy from Tropical Cyclone Kiko is expected early next week. This will bring the potential for surf to reach High Surf Advisory criteria.
Peak monthly high tides, combined with water levels running higher than predicted, may lead to minor flooding along the shoreline and in low-lying coastal areas. A Coastal Flood Statement remains in effect through Sunday afternoon.

Fire weather

RH fell into the upper 30s at PHNL this afternoon and may fall to 45% or lower again during the next couple of days. However, winds will remain safely below threshold values as moderate trades prevail through the weekend. Limited rainfall anticipated during this time, though trade wind showers may increase in coverage over windward portions of the Big Island and Maui this weekend. TC Kiko is poised to pass over or near the islands early next week bringing potential for increased winds in addition to heavy rainfall.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov