West Side

Tonight: Partly cloudy. Isolated showers in the evening. Lows 65 to 73. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 73 to 85. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy. Isolated showers in the evening. Lows 64 to 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

South Side

Tonight: Mostly clear. Lows 66 to 71. Northwest winds up to 10 mph.

Sunday: Mostly sunny with isolated showers. Highs 76 to 87. North winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly clear. Lows 66 to 71. North winds 10 to 15 mph.

North Shore

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 70 near the shore to around 53 near 5000 feet. East winds up to 20 mph shifting to the southeast 10 to 15 mph after midnight. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 78 to 83 near the shore to around 65 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Sunday Night: Partly cloudy with scattered showers. Lows 67 to 72 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Central Maui

Tonight: Mostly clear. Breezy. Lows around 68. East winds up to 20 mph decreasing to up to 10 mph after midnight.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 81 to 87. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Sunday Night: Mostly clear. Lows 65 to 70. Northeast winds around 10 mph.

Upcountry

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 44 at the visitor center to around 41 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 49 to 68. East winds up to 10 mph. Chance of rain 50 percent.

Sunday Night: Partly cloudy. Lows around 44 at the visitor center to around 41 at the summit. East winds 10 to 15 mph.

East Maui

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 70 near the shore to around 53 near 5000 feet. East winds up to 20 mph shifting to the southeast 10 to 15 mph after midnight. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 78 to 83 near the shore to around 65 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Sunday Night: Partly cloudy with scattered showers. Lows 67 to 72 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Lanai City

Tonight: Partly cloudy. Isolated showers in the evening. Lows 59 to 67. Light winds. Chance of rain 20 percent.

Sunday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 69 to 80. Northeast winds up to 15 mph. Chance of rain 40 percent.

Sunday Night: Partly cloudy. Lows 59 to 66. Northeast winds up to 10 mph in the evening becoming light.

Kaunakakai

Tonight: Partly cloudy. Isolated showers in the evening. Lows 56 to 72. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 68 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly clear. Lows 55 to 72. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

A complex upper-level low over the islands will produce unsettled weather with moderate wet trades prevailing for the next several days. Heaviest showers will impact primarily windward and mountain areas, though leeward sides may also see brief periods of showers. Expect only slight variations in shower activity throughout the forecast period.

Discussion

The latest water vapor imagery continues to reflect model guidance, showcasing a complex upper-level low centered over the islands that is producing unsettled weather across the region. The soundings from the 2 PM HST (00Z) balloon launches at Hilo and Lihue show a temperature inversion around 12,000 feet and 8,000 feet, respectively, allowing for continued bands of showers to move through the state today. Current satellite and radar imagery imagery shows a dissipating band of clouds and showers over the Big Island and Maui slowly moving westward, as well as a few isolated thunderstorms just outside the coastal waters south of Kauai. Elsewhere, partly to mostly cloudy skies prevail, with light to locally moderate showers mainly over windward sections of the islands.
Winds have shifted slightly out of the east-southeast today and are beginning to decreasing slightly in strength. A pocket of drier air moving through the smaller islands today has kept shower activity less prevalent and intense there, along with enough of an easterly component to the wind direction to prevent much island shadowing and subsequent leeward sea breezes. Enough instability remains over the eastern end of the state to keep a slight chance of thunderstorms in the forecast into this evening over interior Big Island.
The previously mentioned upper-level low remains quasi-stationary throughout the weekend and into next week with only slight variations in activity across the island chain. Trades are expected to decrease slightly to more moderate levels tonight into early next week. Shower trends will also decrease in coverage a bit from Sunday to Tuesday across most islands as the upper low briefly weakens and drier air moves in. Global models are hinting at another upper low moving over the islands around Wednesday with increasing shower trends for the second half of next week.

Aviation

Moderate east to east-southeast trades will continue to hold through Sunday. Trade winds will be light enough for localized land breezes tonight and daytime sea breezes across select areas during the day Sunday. A plume of moisture currently located over the Big Island will be spreading across the rest of the island chain through tonight. Expect periods of MVFR conditions with any showers. Due to an upper level low adding some instability, brief IFR conditions will also be possible with the heavier showers.
AIRMET Sierra for mountain obscuration remains over the Big Island and will likely hold through this evening. Conditions should improve tonight. AIRMET Sierra will be possible for the other islands tonight as the moisture spreads westward and showers increase across windward and mountain areas.

Marine

High pressure will reside to the northeast of the state through early next week, with another high building to the north by the middle of the week. A trough far northwest of the islands will slightly ease the trades tonight through Monday and could allow for some east-southeast winds at times. Light to moderate trades are expected through at least the middle of next week.
Surf along north and west-facing shores will remain very small during the next 7 days as small northwest swell fades. Surf along south facing shores will hold at background levels through today before a series of small south and south-southwest swells modestly boost south shore surf on Sunday. A further boost up to seasonal averages are possible during the middle to latter part of next week.
Surf along east-facing shores will remain rough and choppy during the next 7 days.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov