West Side

Today: Sunny and breezy. Highs 81 to 86. East winds up to 20 mph.

Tonight: Partly cloudy. Breezy. Lows 68 to 74. East winds 10 to 20 mph.

Friday: Mostly sunny. Isolated showers in the morning. Highs 80 to 85. East winds up to 15 mph. Chance of rain 20 percent.

South Side

Today: Sunny and breezy. Highs 86 to 91. North winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows 68 to 75. North winds 10 to 20 mph shifting to the northeast after midnight.

Friday: Sunny and breezy. Highs around 87. North winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

North Shore

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 72 near the shore to around 52 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Central Maui

Today: Sunny and breezy. Highs 81 to 89. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Breezy. Lows around 70. Northeast winds 10 to 20 mph.

Friday: Sunny and breezy. Highs 80 to 88. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Upcountry

Today: Sunny. Highs around 66 at the visitor center to around 69 at the summit. Northeast winds up to 15 mph.

Tonight: Mostly clear with isolated showers. Lows 44 to 55. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Friday: Sunny. Isolated showers in the morning. Highs around 64 at the visitor center to around 71 at the summit. Northeast winds up to 10 mph. Chance of rain 20 percent.

East Maui

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 72 near the shore to around 52 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Lanai City

Today: Sunny and breezy. Highs 73 to 82. Northeast winds up to 15 mph increasing to 10 to 25 mph in the afternoon.

Tonight: Partly cloudy. Breezy. Lows 63 to 68. Northeast winds 10 to 25 mph decreasing to up to 15 mph after midnight.

Friday: Sunny and breezy. Highs 73 to 81. Northeast winds 10 to 20 mph.

Kaunakakai

Today: Sunny and breezy. Highs 74 to 90. East winds 10 to 20 mph.

Tonight: Partly cloudy. Breezy. Lows 61 to 74. Northeast winds 10 to 20 mph.

Friday: Mostly sunny. Highs 72 to 89. Northeast winds 10 to 15 mph.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds will persist through today, weaken Friday, and likely restrengthen early to mid week next week. Limited shower activity will be focused over windward areas, and with the exception a few showers on the South Kona slopes each afternoon, leeward areas will be mostly dry. An increase in mainly windward and mauka rainfall is possible this weekend into Monday.

Discussion

Broad high pressure far north of the state will keep moderate to locally breezy trades through the day today, before easing slightly tomorrow and maintaining slightly reduced speeds through the weekend as the pressure gradient relaxes in response to the approach of a weak surface trough from the east. The influence of a mid level ridge to our south and the lack of any organized moisture being brought in on the trades will help to keep relatively dry and stable conditions in place across the island chain through tomorrow night.
The aforementioned trough (situated about 550 miles to the east of the Big Island as of 3 AM HST this morning) will dampen out some before arriving at the eastern end of the state by Saturday afternoon, lifting the low level temperature inversion and providing a source of moisture. As such, windward and mauka shower activity will likely increase a notch Saturday afternoon through Sunday across the eastern end of the state, and transition to the western end of the state by early next week as the weakening trough gradually progresses up the island chain.
Model guidance continues to show strengthening trade winds early to mid week next week. However, uncertainty remains in the forecast for next week due to the possible development of disturbances in the tropics.

Aviation

Moderate to locally breezy trade winds will persist through Friday, focusing limited low clouds and showers over windward and mountain areas. VFR conditions will generally prevail, with only brief MVFR conditions expected in isolated windward showers.
AIRMET Tango is in effect for moderate low level turbulence over and lee of island mountains through the morning. Conditions will likely improve later today, though may remain borderline.

Marine

A high pressure ridge north of the islands will continue to produce moderate to locally strong trades across the region through the rest of today. The Small Craft Advisory is in effect until 6PM this evening for the typical windy waters around Maui County and Big Island. The ridge will gradually weaken Friday, easing wind speeds into the gentle to fresh range and holding into early next week.
Pulses of background long period south and southwest swells will keep surf above flat levels along south and west facing shores through the weekend. Back to back gale force lows east of New Zealand are expected to send a series of small, long period south swells that could begin to fill in late Tuesday and produce above average surf along south facing shores through the second half of next week. In addition, tropical disturbances tracking south of the state from east to west Sunday into next week may also send small, short to medium period south to southeast swells.
Small choppy surf along east facing shores will trend down slightly as winds ease.
Afternoon peak monthly high tides associated with the lunar cycle, combined with water levels that are running higher than predicted may cause minor flooding for shorelines and low-lying coastal areas mainly around Maui County and the Big Island. A Coastal Flood Statement remain in effect for these areas through this evening.

Fire weather

A stable, somewhat dry, and locally breezy trade wind flow will persist through today. Under this typical late July pattern, expect elevated, though not critical, fire weather conditions over drier leeward and some interior areas. A decrease in winds and increase in humidity are possible this weekend as an area of shallow moisture moves near or over the islands. Trade winds are expected to restrengthen early next week.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov