West Side

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 66 to 72. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs 78 to 83. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear with isolated showers. Lows 66 to 72. East winds 10 to 15 mph. Chance of rain 20 percent.

South Side

Tonight: Breezy. Partly cloudy with isolated showers. Lows 64 to 73. North winds 10 to 20 mph. Chance of rain 20 percent.

Thursday: Sunny. Isolated showers in the morning. Highs around 86. North winds 10 to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 64 to 74. North winds 10 to 15 mph.

North Shore

Tonight: Occasional showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds up to 15 mph. Chance of rain near 100 percent.

Thursday: Occasional 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 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain near 100 percent.

Thursday Night: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Central Maui

Tonight: Mostly cloudy with scattered showers. Lows around 67. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Mostly sunny. Scattered showers in the morning. Highs 80 to 87. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Thursday Night: Mostly clear. Isolated showers after midnight. Lows 64 to 69. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 43 at the visitor center to around 40 at the summit. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with isolated showers. Highs around 60 at the visitor center to around 63 at the summit. East winds 10 to 20 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with scattered showers. Lows around 44 at the visitor center to around 41 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

East Maui

Tonight: Occasional showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds up to 15 mph. Chance of rain near 100 percent.

Thursday: Occasional 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 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain near 100 percent.

Thursday Night: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Lanai City

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 64. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 72 to 80. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows around 64. Northeast winds 10 to 15 mph.

Kaunakakai

Tonight: Breezy. Partly cloudy with scattered showers in the evening, then mostly cloudy with isolated showers after midnight. Lows 55 to 71. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs 68 to 86. East winds 10 to 20 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 56 to 72. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

Locally breezy trade winds will persist through early next week as high pressure remains far north of the state. Somewhat active showers will continue across windward and mauka areas into the weekend. The gusty trades will carry brief showers over most leeward areas, while the leeward slopes of the Big Island experience spotty showers mainly in the afternoon and evening.

Discussion

A somewhat active shower pattern continues within the locally breezy trade wind flow. Persistent robust surface high pressure centered about 1200 miles to the northwest has the islands locked within a locally breezy and gusty trade wind flow, and broad upper-level troughing over the region has weakened and elevated the inversion, supporting a field of shower-bearing cumulus over and 500 miles east of the state. A loosely organized area of moisture within this cloud field moved over last night and this morning, producing roughly one quarter to three quarters of an inch of rainfall over wetter windward and mauka locales. The gusty winds periodically carried some rainfall over leeward areas from Kauai to west Maui, but accumulations were well below a tenth of an inch. The leeward slopes of the Big Island are transitioning toward a more summerlike pattern of spotty showers, some briefly heavy, during the midday through evening hours, followed by diminished rainfall overnight.
Breezy and somewhat wet trade winds will persist through at least Friday as additional pockets of moisture move through and the weak uper-level trough keeps the inversion elevated. A ridge aloft will develop over the region during the weekend, bringing an increase in stability. The GFS and ECMWF are suggesting that a band of moisture drifting in from the northeast could keep windward rainfall more active over windward Kauai and Oahu, but the increasingly stable conditions may limit leeward rainfall, even as the trades remain breezy and gusty. Typical trade wind weather looks to continue into early next week.

Aviation

Moderate to locally breezy trades will continue through the next several days and generally focus clouds and showers over windward areas. Periods of MVFR ceilings and visibilities will be possible as showers increase this evening through early Thursday. Otherwise, VFR conditions are expected to prevail.
AIRMET Tango remains in effect for moderate low-level turbulence over and immediately SW through NW of all island mountains due to the locally breezy trade winds. This AIRMET will likely continue for the next few days. In addition, AIRMET Sierra for mountain obscuration across north through east sections of the islands may be needed later tonight into early Thursday as showers increase.

Marine

Fresh to strong trades will persist through the weekend as a surface ridge remains north of the islands. A Small Craft Advisory will persist each day for the typical windier waters and channels around Maui County and the Big Island.
Surf along north and west-facing shores will remain up around average through Thursday due to a medium-period northwest swell that filled in Tuesday afternoon. This swell will gradually shift out of the north over the next couple of days.
Surf along south-facing shores will remain below average through Friday. A fresh long-period south- southwest swell is expected to arrive over the weekend, bringing an upward trend with above- average surf. Forerunners should begin filling in Friday, with the swell peaking late Saturday through Sunday. This swell has peaked slightly above guidance at the American Samoan buoy, which will translate to a peak locally late Saturday into Sunday.
Surf along east-facing shores will remain rough and choppy, with heights around average into the second half of the week. Heights could dip below average by the weekend due to a weakness forming in the ridge northeast of the area, leading to the upstream trades diminishing. A return to average levels is expected later this weekend and into early next week as the trades strengthen upstream.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov