West Side

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs 80 to 86. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 69 to 75. Northeast winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 80 to 85. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Side

Today: Sunny and breezy. Highs around 89. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Partly cloudy. Lows 68 to 76. North winds 10 to 15 mph.

Monday: Sunny. Highs around 87. Light winds.

North Shore

Today: Mostly sunny with scattered showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 72 near the shore to around 52 near 5000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 80 to 85 near the shore to around 66 near 5000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Central Maui

Today: Sunny and breezy. Highs 81 to 89. Northeast winds 10 to 20 mph.

Tonight: Mostly clear. Lows 68 to 73. Northeast winds around 10 mph in the evening becoming light.

Monday: Sunny. Highs 81 to 88. Northeast winds up to 10 mph.

Upcountry

Today: Breezy. Sunny with isolated showers. Highs around 65 at the visitor center to around 69 at the summit. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 45 to 55. East winds up to 15 mph.

Monday: Sunny. Highs around 63 at the visitor center to around 58 at the summit. Northeast winds up to 10 mph in the morning becoming light.

East Maui

Today: Mostly sunny with scattered showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 72 near the shore to around 52 near 5000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 80 to 85 near the shore to around 66 near 5000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Lanai City

Today: Sunny and breezy. Highs 73 to 82. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy. Lows around 66. Northeast winds 10 to 15 mph.

Monday: Mostly sunny. Scattered showers in the afternoon. Highs 73 to 81. Northeast winds up to 10 mph in the morning becoming light. Chance of rain 30 percent.

Kaunakakai

Today: Mostly sunny. Highs 73 to 90. Northeast winds 10 to 15 mph.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 59 to 75. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 73 to 89. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate winds will prevail through the rest of today. A broad surface trough will develop northeast of the state early next week, then propagate across the island chain. As this occurs, winds will weaken and become east-southeasterly, resulting in a daytime sea breeze and nighttime land breeze regime. Moderate trade winds will return near the end of the week.

Discussion

Latest observations and advanced scatterometer pass of the islands indicate light to locally moderate easterly trades prevail across the region this morning — just weak enough to support localized sea breezes later today. Meanwhile reflectivity shows isolated showers trickling into the windward and mauka area of most islands, producing little to no precipitation. The only notable exception being the Hilo area on the Big Island, where a heavier shower developed briefly. This morning's 12z sounding from Hilo shows the temperature inversion heights ranging from 6000 to 7000 feet, with precipitable water values slightly lower than yesterday, at around 1.24 inches.
Light to locally moderate trades will continue through today. Latest model guidance of the GFS and ECMWF continue to depict a broad surface trough developing just northeast of the islands on Monday, with a well-defined low aloft. Models project this trough to slowly meander westward toward the islands and passing over between Monday and mid-week, then becoming less defined as it and the associated low aloft exits well north of the state. Winds across the islands during this time will become noticeably weaker, veering east-southeasterly, and transitioning to a more pronounced land and sea breeze pattern across the entirety of the Hawaiian Islands. In such a pattern where the local scale winds are virtually absent, island heating will support sea breezes during the day, which will enhance leeward and interior shower activity, and overnight cooling will drive land breezes at night, clearing the night skies and limiting showers.
The land/sea breeze regime is progged to continue through the latter half of the week until the aforementioned surface trough and associated low aloft exit the vicinity of the islands late Friday. Thereafter, moderate trades are expected to return to the islands just in time for the weekend, persisting through the remainder of the outlook period.

Aviation

Light to locally moderate trades continue to prevail across the Hawaiian Islands, bringing periods of MVFR conditions in isolated showers across windward and mauka locations. Winds will begin to diminish into a more land and sea breeze pattern toward the latter end of the TAF outlook, increasing clouds and shower activity across leeward and interiors of the islands. Localized MVFR is possible within any shower activity, however, most sites will remain VFR.
No AIRMETs are currently in effect.

Marine

High pressure the northeast will continue to bring moderate east- northeast trades to the region today. A dissipating front and trough to the northwest will continue to weaken today. A new trough is expected to develop northeast of the state over the next couple of days, and then move to the southeast, and will weaken winds to light and variable through the first half of next week.
The current moderate, medium-period north-northwest (330 degree) swell continues to fill in, and is expected to peak today below High Surf Advisory (HSA) levels. The swell will then slowly fade over the next few days. A small medium to long-period swell from the northwest (320 deg) is expected to fill in Monday, peak Tuesday and decline through the middle of next week.
The current small, long-period southwest (210 deg) swell will continue to slowly decline into early next week. A small, long- period southwest swell may arrive late today, and build into early next week before subsiding. Another small long-period southwest (200 deg) swell is possible by the later half of next week. Surf along east-facing shores will remain below average over the next several days, even with the slight boost today with the brief uptick in trades.

Fire weather

Wind speeds and humidity will remain below critical fire weather thresholds for the next several days. Temperature inversion heights across the state will range from 6000 to 7000 feet through tonight.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov