Photo Credit: Travis Guthrie

West Side

Today: Sunny. A 20 percent chance of showers in the afternoon. Highs 74 to 82. Southwest winds around 10 mph.

Tonight: Mostly clear. A 20 percent chance of showers early in the evening. Lows 63 to 70. Southeast winds around 10 mph shifting to the south after midnight.

Friday: Sunny. A 20 percent chance of showers in the afternoon. Highs 75 to 82. Southeast winds 10 to 15 mph.

South Side

Today: Sunny. Highs around 84. North winds around 10 mph shifting to the west in the afternoon.

Tonight: Mostly clear. Lows 60 to 69. Northeast winds 10 to 15 mph in the evening becoming light.

Friday: Sunny. Highs around 85. North winds around 10 mph shifting to the northwest in the afternoon.

North Shore

Today: Breezy. Mostly sunny with a 20 percent chance of showers. Highs 74 to 81 near the shore to around 65 near 5000 feet. East winds 10 to 20 mph.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows around 66 near the shore to 45 to 52 near 5000 feet. Southeast winds 10 to 15 mph.

Friday: Mostly sunny with a 20 percent chance of showers. Highs 74 to 81 near the shore to around 64 near 5000 feet. East winds 10 to 15 mph.

Central Maui

Today: Sunny. Highs 80 to 85. Southwest winds 10 to 15 mph shifting to the east in the afternoon.

Tonight: Mostly clear. Lows 61 to 66. East winds 10 to 15 mph in the evening becoming light.

Friday: Sunny. Highs 79 to 84. East winds 10 to 15 mph.

Upcountry

Today: Mostly sunny. A 20 percent chance of showers in the afternoon. Highs around 61 at the visitor center to around 56 at the summit. East winds around 10 mph.

Tonight: Mostly clear. A 20 percent chance of showers early in the evening. Lows around 45 at the visitor center to around 41 at the summit. Southeast winds 10 to 15 mph.

Friday: Mostly sunny. A 20 percent chance of showers in the afternoon. Highs around 60 at the visitor center to around 55 at the summit. East winds around 10 mph.

East Maui

Today: Breezy. Mostly sunny with a 20 percent chance of showers. Highs 74 to 81 near the shore to around 65 near 5000 feet. East winds 10 to 20 mph.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows around 66 near the shore to 45 to 52 near 5000 feet. Southeast winds 10 to 15 mph.

Friday: Mostly sunny with a 20 percent chance of showers. Highs 74 to 81 near the shore to around 64 near 5000 feet. East winds 10 to 15 mph.

Lanai City

Today: Mostly sunny early in the morning, then a 20 percent chance of showers in the late morning and afternoon. Highs 71 to 78. North winds around 10 mph shifting to the southwest in the afternoon.

Tonight: Partly cloudy. A 20 percent chance of showers early in the evening. Lows around 62. East winds around 10 mph shifting to the north after midnight.

Friday: Mostly sunny early in the morning, then a 20 percent chance of showers in the late morning and afternoon. Highs 72 to 79. Northeast winds around 10 mph shifting to the east in the afternoon.

Kaunakakai

Today: Mostly sunny. A 20 percent chance of showers in the late morning and afternoon. Highs 66 to 82. Southeast winds around 10 mph.

Tonight: Mostly clear. A 20 percent chance of showers early in the evening. Lows 53 to 69. East winds around 10 mph shifting to the north after midnight.

Friday: Mostly sunny. A 20 percent chance of showers in the late morning and afternoon. Highs 65 to 83. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

Expect mostly dry weather through the weekend, with winds on the lighter side the next day or two. A few windward showers will be possible over Maui County and the Big Island where light to moderate trade winds will prevail. Periods of light and variable winds over Kauai and Oahu will bring mostly clear nights and mornings, with a slight chance of showers over interior areas during the afternoons.

Discussion

A surface ridge extends from a surface high to the distant NE to a few hundred miles N of Kauai, supporting light to moderate E-SE winds. A cold front is approaching from the NW, with the leading edge about 600 miles NW of Kauai. Morning soundings indicate a dry and stable island atmosphere, with a low and strong temperature inversion strongly capping a limited moisture field. Satellite images show limited low clouds approaching from the E-SE, while radars are in clear air mode.
Overall, the forecast over the next week calls for alternating periods of light to moderate trade winds and light and variable winds, and continued mostly dry. This will occur as fast-moving highs and lows passing N of the islands modulate the position of the trade-wind-supporting surface ridge.
In the short term, the approaching front will draw closer through tonight, then stall and dissipate N of the islands on Friday while the island atmosphere remains stable. As the front draws closer, winds will become increasingly light, especially on the W end of the island chain. This will allow island-scale land breezes to clear skies over land at night and in the morning, with afternoon sea breezes leading to a few interior clouds, and possibly a shower or two. Easterly trade winds may remain strong enough to deliver a few windward showers to the Big Island and Maui.
As the front dissipates, high pressure passing N of the area will strengthen the ridge and move it northward Friday night and Saturday, leading to increasing trade winds that will probably deliver a few windward showers. Another front will approach from the NW late in the weekend, forcing the ridge S again, and leading to weakening and veering winds over Kauai and Oahu on Sunday, while light to moderate E trades persist over the Big Island and Maui. The mostly dry pattern appears to hold through the weekend.
Model guidance is still divergent regarding the evolution of the front early next week, with the GFS quite aggressive in depicting a strong trough aloft moving over the islands. However, the latest Hawaii Extended Forecast Discussion (PMDHI) issued by the Weather Prediction Center has noted that there is significant support for a non-GFS evolution, with a much weaker trough aloft most likely. Thus the front is not anticipated to bring significant rainfall or impacts, instead bringing the potential for a slight increase in rainfall Monday night and Tuesday. The surface ridge will likely remain near the islands thereafter, with light winds and mostly dry weather persisting.

Aviation

An overall light southeast wind pattern will continue across the state through the TAF period, as an area of high pressure continues to move NE of the islands. The dry and stable airmass in place will limit chances for precipitation again today, focusing a few isolated showers to mainly windward slopes. The light wind pattern will allow for diurnal daytime sea breeze cloud and isolated rain shower formation across interior leeward areas today, with clouds diminishing in areal coverage during the evening with the development of land breeze circulations. Mainly VFR conditions are expected through the TAF period.
AIRMET Tango continues for higher level turbulence above FL300, supported both by Ellrod guidance and recent PIREPS. These upper level turb conditions are expected to improve after 21z today.

Marine

A cold front approaching the islands from the northwest will weaken the ridge north of the region into the first half of next week. The surface ridge will weaken and drift over the northwestern Hawaiian Islands today, causing the large scale winds to weaken and veer from a more southeasterly direction near Niihau, Kauai and Oahu. Local scale land and sea breezes will develop in the near shore waters of these three islands. Wind speeds have dropped below Small Craft Advisory (SCA) levels across the region this morning and the SCA was cancelled. Light winds remain in the long range forecast for next week with an unsettled troughing pattern setting up north of the state.
The current northwest swell, from a 310 direction, will slowly decrease today and tonight and remain below advisory thresholds through Friday afternoon. The next in a series of northwest swells will arrive by Friday night, pushing surf heights along exposed north and west facing shores into the low end High Surf Advisory (HSA) range. Another larger northwest swell arrives on Tuesday morning with solid HSA conditions expected from Tuesday into Wednesday.
South shore surf will remain very small today and tomorrow, with a small boost possible from Friday into the weekend. Very small surf will continue along east facing shores into early next week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov