Hilo

Tonight: Mostly cloudy with numerous showers. Lows 63 to 70 near the shore to 51 to 57 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 67 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with numerous showers. Lows 64 to 70 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 70 percent.

Kona

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Haze through the night. Lows around 72 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Sunny. Haze through the day. Scattered showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. Light winds. Chance of rain 30 percent.

Wednesday Night: Partly cloudy. Scattered showers in the evening. Haze through the night. Lows around 72 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Haze in the evening. Scattered showers. Lows 63 to 71 near the shore to 55 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 80 near the shore to 69 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kohala

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Haze in the evening. Scattered showers. Lows 63 to 71 near the shore to 55 to 61 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 80 near the shore to 69 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 63 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Haze through the night. Lows around 72 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Sunny. Haze through the day. Isolated showers in the afternoon. Highs around 85 near the shore to around 65 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Haze. Lows around 72 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph.

Puna

Tonight: Mostly cloudy with numerous showers. Lows 63 to 70 near the shore to 51 to 57 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 85 near the shore to around 67 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with numerous showers. Lows 64 to 70 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 70 percent.

Waikoloa

Tonight: Mostly clear. Haze through the night. Lows around 72 near the shore to 50 to 55 above 4000 feet. Light winds. Gusts up to 30 mph in the evening.

Wednesday: Sunny. Haze through the day. Isolated showers in the afternoon. Highs 84 to 89 near the shore to 63 to 72 above 4000 feet. Light winds. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Isolated showers in the evening. Haze through the night. Lows 70 to 75 near the shore to 49 to 55 above 4000 feet. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light trades prevail across the Hawaiian islands as a surface trough persists just to the north. As this trough exits the vicinity of the islands by mid-week, high pressure will build to the north in its wake, backing trades to a more easterly component and increasing to a more moderate to breezy range through the remainder of the week. Expect drier conditions during this time as well. By the weekend and into next week, trades could become moderate to strong as high pressure is forecast to build further.

Discussion

Light trades prevail across the state in response to a surface trough that has persisted north of the islands that has deteriorated the pressure gradient. Some localized sea breezes may occur throughout the day again today, triggering possible leeward and interior area showers, but will be far less energized in comparison to earlier this week as the surface trough weakens and exits the vicinity to the west. Thereafter, the surface high well north of the island chain will rebuild, allowing trades to gradually back out of the east and strengthen slightly to moderate to localized breezy conditions.
As the week progresses, expect drier conditions to ensue as drier air is progged to move into the vicinity of the islands. Despite this, typical trade showers can be expected across windward and mauka areas, but at modest levels given the lack of available moisture. This trend will continue through the weekend and into next week.
Meanwhile, latest model guidance of the GFS and Euro remains in pretty good agreement that trades will strengthen further, becoming breezy to localized strong at times into early next week. The conjunction of drier conditions with these stronger trades could elevate fire weather concerns. While this is still several days out, and confidence remains low at the moment, conditions will be monitored by future shifts leading up to the weekend and into next week.

Aviation

Light trades will prevail, however, as a diffused surface trough exits the region to the west, the trades will strengthen slightly and gradually back out of the east. Some leeward and interior sea breeze clouds and showers will be possible again, but will likely be less active than yesterday. Brief periods of MVFR conditions will be possible in any showers, but overall VFR conditions should prevail.
No AIRmets are in effect at this time.

Marine

A weak high pressure ridge anchored north of the Hawaiian Islands will keep gentle to fresh easterly trade winds in the forecast through Friday. The ridge will build in north of the island chain by Saturday, increasing trade winds into the fresh to locally strong range into early next week. There are no Small Craft Advisories (SCA) currently in effect, however stronger winds forecast to arrive this weekend will likely bring a return to SCA conditions for wind over the typically windier waters around Maui and the Big Island.
A small long period south swell will hold around 2 feet through Wednesday. Another smaller longer period south swell then builds into the regional waters from Thursday onward, keeping surf heights along south facing shores fairly steady. Surf heights along E shores matches trade wind trends, subsiding and remaining small this week then increasing slightly this weekend. Surf heights along west facing shores will see some south swell wrap, with north facing shores remaining nearly flat.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov