West Side

Today: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 86. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 68 to 76. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 80 to 85. Northeast winds around 10 mph. Chance of rain 20 percent.

South Side

Today: Mostly sunny. Breezy. Highs around 88. North winds 10 to 20 mph.

Tonight: Mostly clear. Lows 70 to 77. North winds 10 to 15 mph.

Thursday: Sunny. Highs around 87. North winds 10 to 15 mph.

North Shore

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 86 near the shore to around 69 near 5000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 72 near the shore to around 53 near 5000 feet. Northeast winds around 10 mph in the evening becoming light. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers. Highs 79 to 86 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Central Maui

Today: Mostly sunny. Breezy. Highs 81 to 88. Northeast winds 10 to 20 mph.

Tonight: Partly cloudy. Lows 69 to 74. Northeast winds around 10 mph in the evening becoming light.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 88. Northeast winds around 10 mph. Chance of rain 20 percent.

Upcountry

Today: Sunny. Isolated showers in the morning. Highs 61 to 72. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 51 at the visitor center to around 47 at the summit. East winds 10 to 15 mph.

Thursday: Sunny. Isolated showers in the afternoon. Highs 61 to 71. East winds around 10 mph. Chance of rain 20 percent.

East Maui

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 86 near the shore to around 69 near 5000 feet. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 72 near the shore to around 53 near 5000 feet. Northeast winds around 10 mph in the evening becoming light. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers. Highs 79 to 86 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Breezy. Highs 74 to 83. Northeast winds 10 to 20 mph.

Tonight: Mostly clear. Lows around 67. Northeast winds 10 to 15 mph.

Thursday: Mostly sunny with isolated showers. Highs 75 to 82. Light winds. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the morning. Highs 74 to 90. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 61 to 75. Northeast winds 10 to 15 mph in the evening becoming light.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 74 to 90. East winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge north of the Hawaiian Islands will bring moderate to locally breezy trade winds today. A low level trough will move through the region on Thursday, weakening the trades and increasing clouds and showers through Friday. High pressure will build back in across the region will bring a return to moderate to locally breezy trade winds into early next week. Another brief increase in clouds, showers and humidity levels will develop from Sunday into Monday as another low level trough moves westward through the islands; this system is associated with the remnants of former Tropical Storm Ivo. Stable drying trends return from Tuesday onward.

Discussion

Looking at the latest morning satellite imagery in the water vapor channel, we see a narrow upper level trough with several embedded weak upper lows in a southwest to northeast orientation just north of the Hawaiian Islands. Infrared band satellite imagery shows bands of shallow clouds under a stable ridge riding into the islands on the east-northeasterly trade winds. Local radar imagery shows only minimal shower activity this morning.
By Thursday the weather pattern changes a bit as an easterly wave drifting in on the easterly trade winds moves from east to west down the island chain. Trade winds will decrease and local scale island heating will drive and expand afternoon sea breezes across leeward areas of each island. Clouds and showers will increase from east to west across the island chain as dynamics associated with this passing trough lift temperature inversion heights to around 8,000 feet through Thursday night near Maui and through early Friday morning near Kauai. During this time period the upper level trough lifts northward and a very stable upper ridge moves directly over the Hawaiian Islands, decreasing clouds and showers as large scale subsidence (downward vertical atmospheric motions) lower temperature inversion heights to around the 5,000 to 6,000 foot elevation level by Friday afternoon. These drier weather conditions will continue through Sunday morning.
By Sunday afternoon, yet another disturbance will move from east to west through the islands. This trough will have slightly different island by island impacts as deeper moisture and dynamics are associated with the remnants of former tropical cyclone Ivo that formed and diminished in the Eastern Pacific basin. This trough will increase humidity levels across the state from Sunday afternoon through Monday. Temperature inversion heights will lift to around 8,000 to 9.000 feet elevation, enhancing clouds and showers in a moderate trade wind weather pattern.
A high pressure ridge will swiftly build back into the region on Tuesday, just as the remnant trough continues on its westward journey away from the state. This returning ridge will bring strong stable trends with drier humidity levels, and a return to more typical dry summer weather across the state through the middle of next week.

Aviation

Moderate to locally breezy trade winds continue tonight with mainly VFR conditions with only brief passing showers are expected. Cloud and shower trends will increase from east to west across the islands on Thursday as a weak disturbance drifts westward down the island chain.
AIRMET Tango remains in effect moderate to locally breezy trades over and immediately south through west of all island mountains. This AIRMET may be cancelled later tonight as wind speeds decrease.

Marine

A ridge north of the state is generating moderate to locally strong trade winds across the state. A Small Craft Advisory (SCA) remains in effect for the windier waters and channels around Maui County and the Big Island through this afternoon. A weak surface trough will advance westward across the state around Thursday, resulting in a brief period of light easterlies which may become variable in direction at times. Moderate to locally fresh trades return Friday becoming locally strong over the weekend.
The current south swell will continue to gradually decline today. Background small, long period south southwest swell should fill in Thursday keeping surf slightly below average. A couple of small, long- period southerly swells is expected to fill by the weekend, keeping surf heights near average into early next week, though likely remaining below advisory level.
Surf along east facing shores will see a slight uptick later today through Friday due to a small, medium period northeast swell. Short period chop increases this weekend again as stronger trades develop. Surf along north facing shores will remain tiny through the forecast period.

Fire weather

Weather conditions will likely remain below critical fire weather thresholds into early next week. A low level disturbance will move into the region from Thursday to Friday morning producing a slight increase in clouds and showers. Another low level disturbance associated with the remnants of former tropical cyclone Ivo will increase humidity levels and shower trends on Sunday and Monday. A return to lower humidity levels will develop by Tuesday as a stable upper level ridge builds back over the island chain.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for the windier waters and channels around Maui and the Big Island.

Data Courtesy of NOAA.gov