West Side

Tonight: Partly cloudy with isolated showers. Lows 65 to 71. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Sunny. Isolated showers in the morning. Highs 76 to 81. East winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Mostly clear. Lows 64 to 71. East winds around 10 mph in the evening becoming light.

South Side

Tonight: Mostly clear. Lows 63 to 73. North winds up to 10 mph.

Saturday: Sunny. Highs around 85. North winds up to 10 mph.

Saturday Night: Clear. Lows 62 to 73. North winds around 10 mph.

North Shore

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Partly cloudy with scattered showers. Lows around 67 near the shore to around 50 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Central Maui

Tonight: Mostly clear. Lows around 66. Northeast winds up to 15 mph.

Saturday: Sunny. Highs 80 to 86. Northeast winds up to 15 mph.

Saturday Night: Clear. Lows around 65. Northeast winds around 10 mph in the evening becoming light.

Upcountry

Tonight: Mostly clear. Scattered showers in the evening, then isolated showers after midnight. Lows around 44 at the visitor center to around 41 at the summit. East winds up to 10 mph. Chance of rain 50 percent.

Saturday: Sunny. Isolated showers in the morning. Highs around 62 at the visitor center to around 64 at the summit. Light winds. Chance of rain 20 percent.

Saturday Night: Mostly clear with isolated showers. Lows around 45 at the visitor center to around 43 at the summit. Light winds. Chance of rain 20 percent.

East Maui

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 68 near the shore to around 50 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Partly cloudy with scattered showers. Lows around 67 near the shore to around 50 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Lanai City

Tonight: Mostly clear. Lows around 63. Northeast winds up to 10 mph in the evening becoming light.

Saturday: Sunny. Highs 72 to 79. Light winds becoming northeast up to 10 mph in the afternoon.

Saturday Night: Clear. Lows around 63. Light winds.

Kaunakakai

Tonight: Mostly clear with isolated showers. Lows 55 to 71. East winds 10 to 15 mph. Chance of rain 20 percent.

Saturday: Sunny. Highs 68 to 85. East winds up to 10 mph.

Saturday Night: Mostly clear. Isolated showers in the evening. Lows 54 to 70. East winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Mostly dry and stable trade wind conditions will continue into Saturday, with clouds and a few brief showers possible over windward and mauka areas. Trade winds will gradually weaken and shift out of the east-southeast late Saturday through the second half of the weekend as a weakening front approaches from the northwest. Although most of the moisture and higher rainfall chances associated with the front will remain north of the islands as it stalls late Sunday into Monday, a few afternoon showers may develop over interior and leeward areas where sea breezes form. This general pattern of light to moderate east-southeast winds may persist through much of the upcoming week, as another front develops and passes well northwest of the state.

Discussion

Model guidance remains in reasonable agreement, indicating a continuation of mostly dry and stable trade wind weather through much of Saturday as the surface ridge remains to the north. Clouds and light showers will favor windward and mauka areas during this time. Some increase in low-level moisture approaching from the east could lead to a slight uptick in windward showers overnight into early Saturday, though rainfall amounts should remain light overall.
By late Saturday through the rest of the weekend, the low-level flow will gradually weaken and shift to an east-southeasterly direction as the surface ridge weakens and settles southward over the islands in response to an approaching cold front. This front is expected to weaken and stall just north of the islands late Sunday into Monday.
With the bulk of the moisture and instability associated with the this front expected to remain north of the state, combined with rising mid- to upper-level heights and warming aloft, will help keep overall rainfall chances on the lower side Sunday into Sunday night. If this boundary were to settle farther south than predicted, higher rainfall chances could be realized over and around Kauai by Monday. Otherwise, expect a continued focus for light showers over windward areas overnight and into the early morning hours, followed by some interior and leeward afternoon clouds and showers where sea breezes form. This general weather pattern may hold well into the upcoming week as another frontal boundary develops and passes northwest of the region.

Aviation

Moderate easterly trades will hold into Saturday, with clouds and showers favoring windward and mauka locations. Expect brief periods with MVFR CIGS/VSBYS in showers. The low-level flow will gradually weaken and shift to an east-southeasterly direction later Saturday as a cold front approaches from the northwest. A transition to a land and sea breeze pattern is then expected Saturday night into Sunday.
AIRMET Tango remains in effect for moderate turbulence from FL250-350 near and south of the Big Island.

Marine

Trade winds will continue their gradual decline through the weekend. On Saturday, an approaching cold front will push the surface ridge north of the islands further to the south. Then, on Sunday, the front will stall just northwest of Kauai, causing winds to ease further and possibly become variable around Kauai and Oahu by Sunday night. Gentle to moderate east to east- southeast winds are expected to develop late Monday and continue into Wednesday.
The current moderate medium period (12 to 14 sec) northwest swell is expected to peak overnight then gradually decline through the remainder of the weekend. On Sunday, it will be followed by a new, larger and longer period (16 to 18 sec) northwest swell. While the current northwest swell is expected to peak below High Surf Advisory (HSA) levels, this second, larger swell will likely produce waves at or above High Surf Warning thresholds during the peak Sunday night and Monday. A SCA may be needed for some waters during the peak as seas reach 10 feet. On Tuesday and Wednesday, swell energy out of the northwest will fade, even as a new moderate north swell builds in.
Choppy east shore surf, already below seasonal average, will decline during the weekend as trade winds ease, and remain small through the coming week. Seasonably small surf will persist on southern shores, though a tiny bump will be possible during the middle of next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov