Photo Credit: Tyler Rooke

West Side

Today: Sunny, with a high near 93. Heat index values as high as 97. East northeast wind 11 to 13 mph.

Tonight: Clear, with a low around 75. East northeast wind around 10 mph.

Friday: Sunny, with a high near 93. Heat index values as high as 97. East northeast wind around 9 mph.

South Side

Today: Isolated showers after noon. Increasing clouds, with a high near 86. Northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Tonight: Mostly cloudy during the early evening, then gradual clearing, with a low around 70. Northeast wind around 11 mph.

Friday: Isolated showers after noon. Sunny, with a high near 86. Northeast wind around 10 mph. Chance of precipitation is 20%.

North Shore

Today: Isolated showers before noon. Mostly sunny, with a high near 84. Breezy, with a northeast wind around 18 mph, with gusts as high as 25 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 72. Breezy, with an east northeast wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Friday: Isolated showers before noon. Mostly sunny, with a high near 85. Breezy, with a northeast wind around 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Central Maui

Today: Sunny, with a high near 85. Breezy, with a northeast wind 16 to 18 mph, with gusts as high as 25 mph.

Tonight: Mostly clear, with a low around 73. Breezy, with a northeast wind around 16 mph, with gusts as high as 22 mph.

Friday: Sunny, with a high near 86. Breezy, with a northeast wind 14 to 16 mph, with gusts as high as 22 mph.

Upcountry

Today: Sunny, with a high near 75. Breezy, with an east wind 14 to 16 mph, with gusts as high as 22 mph.

Tonight: Mostly clear, with a low around 58. East wind around 14 mph, with gusts as high as 18 mph.

Friday: Sunny, with a high near 76. East northeast wind 11 to 13 mph.

East Maui

Today: Showers likely, mainly before noon. Partly sunny, with a high near 78. Breezy, with an east wind around 15 mph, with gusts as high as 21 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 73. East wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Friday: Scattered showers. Partly sunny, with a high near 79. East wind around 11 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Isolated showers after noon. Sunny, with a high near 78. Breezy, with an east northeast wind 13 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 66. Breezy, with an east northeast wind 11 to 15 mph, with gusts as high as 21 mph.

Friday: Isolated showers after noon. Mostly sunny, with a high near 78. Breezy, with an east northeast wind 14 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Kaunakakai

Today: Sunny, with a high near 91. Heat index values as high as 95. Breezy, with an east wind around 17 mph, with gusts as high as 24 mph.

Tonight: Mostly clear, with a low around 74. Breezy, with an east wind 13 to 17 mph, with gusts as high as 24 mph.

Friday: Sunny, with a high near 91. Heat index values as high as 96. Breezy, with an east wind 13 to 16 mph, with gusts as high as 22 mph.

Detailed Forecast

Synopsis

High pressure to the north will keep breezy trade winds over the islands through most of the weekend, with a decrease in wind speed possible early next week. Low clouds will deliver a few showers, mainly to windward areas and especially during nights and mornings, with a few brief showers spreading to leeward areas.

Discussion

Surface high pressure far NNE of the islands will drive breezy trade winds into the weekend, with the high expected to remain nearly stationary through Saturday with a central pressure hovering near 1030 mb. On Sunday into Tuesday, the center of the high is expected to drift toward the NE, while a low-level trough (remnants of former tropical cyclones Hilda and Jimena – see official forecasts issued by the National Hurricane Center) may approach and pass near or N of the islands. This would lead to some reduction in trade wind speeds, but confidence in this outcome remains low.
Model guidance does not highlight any significant moisture sources to bring enhanced rainfall to the islands into early next week. However, stable and showery low clouds will continue to stream toward the islands from the E. While a nearby mid-level ridge will keep a subsidence inversion in place, the base of the inversion will likely waiver between 8000 and 10000 feet. This is sufficiently high to allow showers to develop within the incoming cumuli, while also allowing orographic lift to drive some shower formation. Most of the light to moderate rainfall will remain over and just downwind of the windward mountains, and will be most likely during nights and mornings. Any light rain that occasionally falls over windward coastal areas, or that spreads to leeward communities, will do little to override the drying effects of the breezy trades and strong solar insolation. The exception will be the Kona slopes of the Big Island, where the typical afternoon and evening showers will continue to deliver beneficial rainfall.
Depending on the eventual trajectory of the increased low-level moisture associated with the aforementioned dissipated tropical cyclones, we could see some increase in showers around the middle of next week, but we could just as easily end up seeing the bulk of the moisture passing N of the islands.

Aviation

High pressure far northeast of the region will maintain moderate to locally strong trade winds today, although some weakening is expected. This weakening will likely result in widespread moderate wind speeds across the region. AIRMET Tango remains in place for low level mechanical turbulence downstream of the mountains. Even as winds decrease a bit, expect this AIRMET to remain in place.
VFR conditions are expected to prevail, however brief MVFR conditions are possible with passing clouds and showers. Most likely place for these MVFR conditions to occur will be over east sides of the Big Island and Kauai. At this time, not expecting any conditions that would warrant AIRMETs for mountain obscuration.

Marine

Locally strong trade winds persist across the islands early this morning due to a strong surface high pressure system located far north of the region. This feature is expected to drift slowly north during the next few days, which may cause a slight weakening of the trades as we head into the weekend. A Small Craft Advisory (SCA) remains in effect today for the Kaiwi Channel, as well as the typically windier waters adjacent to the islands of Maui County and the Big Island. The strongest winds are expected to be only in the typical windy zones by tonight, so the SCA has been extended for these zones through Saturday. The latest forecast indicates trade wind speeds may gradually decrease from Sunday into early next week.
The latest nearshore PacIOOS buoys continue to show trade wind swell around 7 feet with a period of about 8 seconds. This is producing rough, slightly elevated surf along east facing shores. The forecast guidance shows the surf along east facing shores dropping to near the summertime average as we head into the weekend due to the slight weakening of the trades. Expect a further decrease in surf heights along east facing shores early next week, due to additional weakening of the trades. Small south and southeast swells will keep small background surf along most south facing shores through early Friday. A new small southwest swell is expected to spread across the area from late Friday into this weekend, followed by the potential for a slightly larger, long-period south swell reaching the state early next week. If this swell does arrive, it may cause surf heights along south facing shores to reach, or possibly exceed, the seasonal average starting next Monday night or Tuesday. Expect nearly flat conditions along most north facing shores into early next week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov