Photo Credit: Tyler Rooke

West Side

Today: Mostly sunny with isolated showers. Highs 79 to 85. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 70. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 80 to 86. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Mostly sunny. Isolated showers in the morning. Highs around 85. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows around 65. Northwest winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny. Highs around 86. Light winds becoming northwest up to 15 mph in the afternoon.

North Shore

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 77 to 82 near the shore to around 64 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows 62 to 68 near the shore to around 51 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny. Isolated showers in the morning. Highs 81 to 86. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 63 to 68. Northeast winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny. Highs 82 to 87. Northeast winds up to 10 mph.

Upcountry

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 59 at the visitor center to around 55 at the summit. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows around 47 at the visitor center to around 42 at the summit. Light winds becoming east up to 10 mph after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny with isolated showers. Highs around 61 at the visitor center to around 57 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

East Maui

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 77 to 82 near the shore to around 64 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows 62 to 68 near the shore to around 51 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 72 to 79. North winds up to 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Lows around 65. Northeast winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny. Scattered showers in the afternoon. Highs 74 to 81. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 30 percent.

Kaunakakai

Today: Mostly sunny with isolated showers. Highs 72 to 82. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 57 to 69. East winds up to 10 mph in the evening becoming light.

Sunday: Mostly sunny. Isolated showers in the afternoon. Highs 74 to 84. Light winds becoming east up to 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

The kona low will weaken into a trough west of the state today, with some lingering moisture and instability bringing the chance for a few brief downpours across the state today, with a thunderstorm possible on the Big Island. A return to trade wind weather will begin tonight, with showers favoring windward slopes and coasts. The trades will gradually strengthen Sunday and Monday, with breezy conditions expected Tuesday and Wednesday. An approaching front will gradually ease the trade winds and shift them around to the southeast late next week.

Discussion

Currently at the surface, a decaying kona low is located around 425 miles west-northwest of Kauai, while a 1028 mb high is centered around 1700 miles northeast of Honolulu. Land breezes prevail over the western islands this morning, while light to moderate east-southeast winds are in place over the eastern half of the state. Infrared satellite imagery shows partly to mostly cloudy skies across the area, with coverage the highest over Maui County. Meanwhile, radar imagery and rain gage observations indicate mainly dry conditions prevail across the state. Main short term focus revolves around rain chance and thunder potential.
The kona low will gradually weaken into a trough today, with ridging building in north of the state. East-southeasterly winds will gradually shift around to light to moderate trades late today, then hold at these levels through Sunday. The trades will begin to strengthen on Monday and become breezy Tuesday and Wednesday as a new high builds in north of the state. The trades will gradually ease and shift southeasterly Thursday through next Friday as a front approaches from the northwest.
As for the remaining weather details, the air mass over the state will remain somewhat unstable today so daytime heating may be enough to allow some brief downpours to develop across the state, with a thunderstorm not out of the question on the Big Island. Tonight we will be transitioning back to a trade wind pattern featuring mainly windward and mauka showers and the occasional leeward spillover, with this pattern holding in place through Thursday. An approaching front could shift the shower focus to south and southeast facing slopes and coasts next Friday.

Aviation

The kona low to the northwest of Kauai will gradually weaken today, decreasing the threat for periods of heavy rain and isolated thunderstorms across the state. As such, conditions are expected to generally gradually improve through the day. However, enough moisture and instability may stick around to support some isolated thunderstorms this afternoon, most likely on the Big Island.
Will continue to see turbulence and icing associated with any thunderstorms that develop. AIRMET Tango for moderate mid-level turbulence will continue through at least the morning due to wind shear in the layer between 100-FL270. The wind shear in this layer will likely weaken later today. Light icing in layered clouds between 120-FL270 will also remain a threat today, but diminish heading into this evening as some drier air filters in at mid levels.
With diminishing showers across the area early this morning, AIRMET Sierra for mountain obscuration across the Maui County islands and the Big Island has been cancelled. As showers and perhaps a few isolated thunderstorms develop later today, another AIRMET Sierra may be needed for mountain obscuration.

Marine

The kona low west of the state will continue to weaken as a ridge of high pressure builds just north of the state this weekend. The threat for thunderstorms has diminished for the most part, but a few isolated thunderstorms will be possible over the northwest offshore waters through the weekend. As the ridge builds just north of the state today, light to moderate trade winds should return and is expected to further strengthen late Sunday into Monday. A new high will build far northwest of the state and will strengthen the trade winds to strong speeds by Tuesday of next week. Small Craft Advisories will return for the typical windy waters around Maui County and the Big Island on Tuesday and could potentially expand to other areas late Tuesday into Wednesday.
A new long-period northwest (320 degree) swell is expected to fill in later this afternoon and peak on Sunday at High Surf Advisory levels along north facing shores. A developing Hurricane Force Low currently in the northwest Pacific is expected to track eastward as it further intensifies over the next few days. The north- northwest (330 to 340 degree) swell from this source should arrive late Monday and peak Monday night into Tuesday near High Surf Warning levels. This swell should slowly decline Tuesday night through rest of the week, while the swell direction veers more northerly.
Small background surf will continue along south facing shores throughout next week. Strengthening trades should bring an increase of choppy and rough surf along east facing shores Tuesday into middle of next week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov