West Side

Tonight: Mostly clear. Isolated showers early in the evening. Lows 66 to 72. East winds up to 15 mph. Chance of rain 20 percent.

Monday: Sunny and breezy. Isolated showers in the afternoon. Highs 78 to 83. East winds up to 20 mph. Chance of rain 20 percent.

Monday Night: Mostly clear. Isolated showers early in the evening. Lows 66 to 73. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

South Side

Tonight: Mostly clear. Isolated showers early in the evening. Lows 65 to 74. Northwest winds up to 10 mph. Chance of rain 20 percent.

Monday: Sunny. Isolated showers in the afternoon. Highs around 86. North winds up to 15 mph. Chance of rain 20 percent.

Monday Night: Mostly clear. Isolated showers early in the evening. Lows 65 to 74. Northeast winds up to 15 mph. Chance of rain 20 percent.

North Shore

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs 77 to 82 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 40 percent.

Monday Night: Partly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 40 percent.

Central Maui

Tonight: Mostly clear. Isolated showers early in the evening. Lows 64 to 69. East winds up to 15 mph. Chance of rain 20 percent.

Monday: Sunny and breezy. Isolated showers in the afternoon. Highs 81 to 87. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Monday Night: Mostly clear. Breezy. Lows around 67. East winds 10 to 20 mph.

Upcountry

Tonight: Mostly cloudy with numerous showers early in the evening, then partly cloudy in the late evening and overnight. Lows around 44 at the visitor center to around 41 at the summit. East winds up to 15 mph. Chance of rain 70 percent.

Monday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 59 at the visitor center to around 62 at the summit. East winds up to 15 mph. Chance of rain 40 percent.

Monday Night: Mostly clear. Scattered showers early in the evening, then isolated showers late in the evening. Lows around 45 at the visitor center to around 41 at the summit. East winds up to 15 mph. Chance of rain 40 percent.

East Maui

Tonight: Partly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs 77 to 82 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 40 percent.

Monday Night: Partly cloudy with scattered showers. Lows around 69 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 40 percent.

Lanai City

Tonight: Partly cloudy. Lows around 64. Northeast winds up to 10 mph in the evening becoming light.

Monday: Sunny and breezy. Isolated showers in the afternoon. Highs 72 to 80. Northeast winds up to 20 mph. Chance of rain 20 percent.

Monday Night: Mostly clear. Isolated showers early in the evening. Lows around 64. Northeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.

Kaunakakai

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

Monday: Sunny. Isolated showers in the afternoon. Highs 69 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday Night: Mostly clear. Isolated showers early in the evening. Lows 56 to 72. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to breezy trades deliver clouds and showers to windward and mauka areas through next week. Localized areas of heavy rainfall may develop in the afternoon early this week and again toward the end of the week.

Discussion

Relatively low stability environment prevails this afternoon, a consequence of the weak upper low that has stagnated over the state during the last few days. This low has allowed pockets of heavy rain to develop over portions of leeward Big Island and Oahu during the last couple of days as transient bands of trade wind moisture have capitalized on the softened inversion. At press time, the islands reside between shower bands leaving little in the way of moisture to work with as the last vestiges of cyclonic flow aloft depart to the northeast. Residing on the southwest periphery of said cyclonic flow, Leeward Big Island may see another healthy convective response on Monday as another band of enhanced moisture transits the forecast area. This potentially amounts to nuisance type flooding, mainly limited to more flood prone areas.
Height rises then commence on Tuesday as shortwave ridging builds during mid-week. This period of mid/upper subsidence will be brief and unlikely to make a considerable difference in the existing thermodynamic profile, but a temporary decrease in shower intensity is still likely as increasing stability puts a firmer lid on convective depths.
During the latter half of next week, guidance indicates another closed low developing over, or in the vicinity of, the islands. Of mid-latitude origin, this low will feature a notably colder mid- level cold pool and has the potential to bring more meaningful instability to the area as moderate to breezy trades persist at the surface.

Aviation

Moderate east to east-southeasterly trades will persist through Monday, with wind speeds decreasing slightly. Expect VFR conditions to prevail, though MVFR conditions may arise in any shower activity.
No AIRMETs are currently in effect.

Marine

High pressure will remain centered far northeast of the state throughout much of this week. A weakening cold front to the northwest will weaken the ridge over the next few days, allowing trades to ease to gentle to fresh east to southeast winds across the region through Monday night. An upper level disturbance lingering near the islands will keep brief periods of wet weather in the forecast for coastal and offshore waters throughout the next several days.
A series of small south and south-southwest swells will maintain small south shore surf through Monday. A slightly larger south swell will further boost south shore surf up to seasonal averages during the middle to latter part of the week.
Surf heights along north and west-facing shores will remain small during the next 7 days. Surf heights along east-facing shores will remain choppy, particularly from Tuesday onward as trade winds increase a bit once again.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov