Photo Credit: Tyler Rooke

West Side

Today: Sunny with isolated light showers. Highs 80 to 90. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 69 to 76. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 90. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

South Side

Today: Sunny and breezy. Highs around 90. North winds 10 to 20 mph.

Tonight: Mostly clear. Breezy. Lows 67 to 75. North winds 10 to 20 mph.

Thursday: Sunny and breezy. Highs around 90. North winds 10 to 20 mph.

North Shore

Today: Partly sunny. Light showers likely in the morning, then scattered light showers in the afternoon. Highs 78 to 86 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows around 71 near the shore to 47 to 54 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 85 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Central Maui

Today: Sunny and breezy. Isolated light showers in the morning. Highs 83 to 91. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 67 to 72. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 83 to 90. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Scattered light showers in the morning, then isolated light showers in the afternoon. Highs around 62 at the visitor center to around 59 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 47 at the visitor center to around 45 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 62 at the visitor center to around 58 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

East Maui

Today: Partly sunny. Light showers likely in the morning, then scattered light showers in the afternoon. Highs 78 to 86 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with showers likely. Lows around 71 near the shore to 47 to 54 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 85 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Lanai City

Today: Sunny. Isolated light showers in the afternoon. Highs 73 to 81. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 63 to 68. Northeast winds 10 to 15 mph.

Thursday: Sunny. Isolated showers in the afternoon. Highs 73 to 81. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaunakakai

Today: Sunny. Isolated light showers in the morning. Highs 69 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 58 to 75. East winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 70 to 90. East winds 10 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will focus low clouds and brief showers over windward and mauka areas, especially during nights and mornings. Leeward communities will be mostly dry, but afternoon clouds and a few showers will develop over leeward portions of the Big Island. High clouds will occasionally transit island skies.

Discussion

Morning soundings show a strong and low subsidence inversion based between 5 and 7 thousand feet, with PWAT a seasonable 1.2″. Regional satellite images show scattered to locally broken low clouds streaming westward at about 17 kt/20 mph, with increased low cloud coverage noted over waters E of Maui County. Surface high pressure to the distant NE is supporting a moderate to breezy trade wind flow. Radar shows widely scattered relatively light showers, while infrared imagery shows thin high clouds streaming ENE over the islands from Oahu to Maui, associated with a persistent TUTT (tropical upper-tropospheric trough) NW of Kauai.
Model guidance has been consistent in projecting little significant change to the current pattern into next week. At the surface, trade wind speeds look to remain remarkably consistent near their current levels. In the mid-levels, a strong ridge will remain over the islands, keeping the subsidence inversion low and strong. Brief showers will favor windward areas, especially during nights and mornings, with sensible weather highly dependent on the arrival of difficult-to-anticipate low cloud clusters. We do anticipate that an area of increased low-level moisture (PWAT currently near 1.9″), associated with the remnants of former Hurricane Adrian now near 20N 130W, will move through the area Monday into Tuesday. This would bring an increase in primarily windward showers if it were to verify. Leeward areas will remain mostly dry, except for the typical afternoon clouds and showers on the Big Island's leeward slopes, but even these should be limited.
There are some changes expected in the upper-level pattern, but impacts on sensible weather will likely be negligible. The nearly- stationary TUTT NW of Kauai will begin to move E later today, passing over the islands tonight and Thursday. This will bring periods of high clouds into Thursday, and some instability aloft, but it is highly unlikely that surface parcels tap into this. There could be some low-impact afternoon cloud/shower formation over the Big Island's summits and upper slopes Thursday. A new low developing within the TUTT this weekend may lead to more high clouds streaming over the islands within the associated subtropical jet.

Aviation

Moderate to locally breezy trade winds are expected to persist today and tonight. The atmosphere remains relatively dry and stable across the island chain early this morning. There are patches of scattered to broken low clouds with embedded isolated light showers being transported by the low-level trade wind flow into the windward sides of some of the islands. This may produce brief periods of MVFR conditions along some windward facing slopes and coastal areas, but VFR conditions will likely prevail across most of the state today.
No AIRMETs are currently in effect. We are monitoring observations from the VAD wind profiles in case we need to issue AIRMET Tango for moderate low-level mechanical turbulence later today.

Marine

A high pressure ridge will remain locked in place far north of the Hawaii region, producing moderate to locally strong trade winds over and upstream of the Hawaiian Islands lasting into early next week. A Small Craft Advisory (SCA) was extended in time through Thursday night for the typically windier waters around Maui County and the Big Island. This SCA will likely continue through the weekend.
Surf along all shores are expected to remain tiny through Friday. In the long range, a series of moderate period south-southeast (150 degree) to south (190-200 degree) swells are expected starting this weekend producing a good boost to south shore surf heights. Another long period south (180-190 degree) swell will move into the region from Monday to Tuesday of next week. North facing shores may see a slight pulses out of the north-northwest (330 degree) through the weekend keeping surf above flat levels starting on Friday.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov