West Side

Today: Sunny. Highs 80 to 86. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 70 to 76. East winds up to 15 mph shifting to the northeast after midnight.

Wednesday: Sunny. Highs 79 to 86. Northeast winds up to 15 mph.

South Side

Today: Sunny and breezy. Highs around 89. North winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows 68 to 78. North winds up to 20 mph.

Wednesday: Sunny. Highs around 89. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

North Shore

Today: Partly sunny with scattered showers. Highs around 82 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 55 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 82 near the shore to 66 to 71 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Sunny. Highs 82 to 88. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 68 to 75. Northeast winds up to 15 mph.

Wednesday: Sunny. Highs 82 to 89. Northeast winds up to 15 mph.

Upcountry

Today: Partly sunny with scattered showers. Highs 61 to 80. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 50 at the visitor center to around 44 at the summit. Northeast winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Sunny with isolated showers. Highs 62 to 80. North winds up to 10 mph. Chance of rain 20 percent.

East Maui

Today: Partly sunny with scattered showers. Highs around 82 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 55 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 82 near the shore to 66 to 71 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny. Isolated showers in the afternoon. Highs 73 to 81. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 69. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Wednesday: Sunny. Highs 76 to 83. Northeast winds up to 15 mph.

Kaunakakai

Today: Sunny. Highs 71 to 89. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Mostly clear. Lows 61 to 77. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight.

Wednesday: Sunny. Highs 76 to 88. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

Moderate trades will build back into the region today. A weak trough near the Big Island this morning is producing showers and clouds over the eastern end of the island chain. As this trough weakens and moves westward, expect showers to trend down by tonight. Elsewhere, drier conditions will prevail. Trade winds are anticipated to become breezy by the end of the week as high pressure strengthens north of the state. Slightly wetter trades will be possible this weekend.

Discussion

Early this morning, a surface trough is located over the eastern side of the Big Island. Showers and widespread cloud cover associated with this trough have been moving over Big Island windward locations throughout the night, and will continue throughout the morning. Several locations across the Big Island have picked up over an inch of rain since 8pm HST, with a couple of spots receiving over an inch in a half in the past 24 hours. With that said, radar estimated rainfall rates have been steadily in the light to moderate range, precluding any flooding concerns at this time. To a lesser extent, some of the moisture associated with this weak trough has spread to portions of Maui as well. Elsewhere across the state, drier air remains in place with fewer clouds and showers occurring.
Today the trough will weaken as it moves westward, while a low aloft moves off to the east. Prevailing clouds and showers associated with the trough will diminish later this morning, but lingering moisture nearby may enhance afternoon clouds and shower activity over the Big Island interior. Moderate trade winds will be building back into the region, and may become locally breezy within typically windy areas by this afternoon. A few passing showers will be possible for the smaller islands today, mainly favoring windward and mauka locations.
By Wednesday, conditions are forecast to become drier as the aforementioned features will have moved well away from the islands. Trade winds then are expected to increase Thursday into the weekend as high pressure to the north becomes established and strengthens. As trade winds increase, passing showers will favor windward and mountain areas, and could increase slightly this weekend.

Aviation

Light to occasionally moderate trades will persist through the day. Lighter winds may allow for the development of localized daytime sea breezes within more trade wind-protected leeward areas. Afternoon warmth will create thickening upslope clouds and isolated showers that may introduce brief periods of MVFR ceilings and visibilities. Otherwise, VFR conditions will prevail.
AIRMET SIERRA is in effect for mountain obscuration along Big Island's east and southeast-facing slopes until further notice.

Marine

Gentle to moderate trade winds will persist through Wednesday as as a surface ridge remains anchored far northeast of the state and a weak trough dissipates near the Big Island. Trades will strengthen to moderate to locally fresh Thursday as surface high pressure builds far north of the state. Trades will further strengthen to fresh to locally strong late Friday through the weekend and a Small Craft Advisory (SCA) will likely be needed for the typically windy waters around Big Island and Maui.
A fresh, long period northwest swell will build today, pushing surf along north and west facing shores to near seasonal averages through Wednesday. This swell will decline Thursday and Friday. By late Friday, a medium period north- northwest swell will build and once again help bring surf to near seasonal averages through the weekend.
South shore surf will remain elevated through Wednesday as a long period south- southwest swell slowly declines. Another long period south swell will help produce surf near seasonal average Thursday into early this weekend.
Surf along east facing shores will remain small through Thursday as small wind waves and tiny east swell persist. Choppy surf will increase slightly as trade winds strengthen across the region Friday into the weekend.

Fire weather

Moderate trade winds will continue through the first half of the week. Dry air will keep RH levels near-critical values each afternoon for parts of the state for the next several days, but winds will be a limiting factor. Inversion heights will range from near 5,000 feet over the western end of the state to around 12,000 feet over the eastern end. Winds will increase during the second half of the week, but moisture levels are also expected to increase a bit.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov