Hilo

Today: Showers, mainly before noon. High near 82. Light and variable wind becoming northeast 5 to 10 mph in the afternoon. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers. Low around 69. North northwest wind 3 to 6 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Showers, mainly before noon. High near 81. Light north northwest wind becoming north northeast 5 to 10 mph in the morning. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers, mainly after noon. Increasing clouds, with a high near 81. Light and variable wind becoming west southwest 5 to 10 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 11pm. Mostly cloudy, with a low around 69. Light and variable wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Isolated showers. Increasing clouds, with a high near 81. Calm wind becoming west southwest 5 to 9 mph in the afternoon. Chance of precipitation is 20%.

Waimea

Today: Scattered showers, mainly before noon. Mostly sunny, with a high near 74. Windy, with a northeast wind 20 to 26 mph, with gusts as high as 38 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 61. Windy, with an east northeast wind 20 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday: Scattered showers before noon. Mostly sunny, with a high near 74. Windy, with a northeast wind 20 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Showers likely, mainly before noon. Mostly cloudy, with a high near 69. Windy, with an east northeast wind 22 to 25 mph, with gusts as high as 36 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers. Low around 58. Windy, with an east wind 21 to 26 mph, with gusts as high as 38 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Showers likely, mainly before noon. Mostly cloudy, with a high near 69. Breezy, with an east northeast wind around 22 mph, with gusts as high as 31 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers before noon. Mostly sunny, with a high near 85. Windy, with an east wind 23 to 28 mph, with gusts as high as 36 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 74. Windy, with an east northeast wind 22 to 26 mph, with gusts as high as 34 mph. Chance of precipitation is 20%.

Saturday: Isolated showers before noon. Mostly sunny, with a high near 84. Windy, with an east wind 21 to 25 mph, with gusts as high as 32 mph. Chance of precipitation is 20%.

Puna

Today: Showers, mainly before noon. High near 77. Breezy, with a north northeast wind 9 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Showers. Low around 67. North wind 9 to 13 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday: Showers, mainly before noon. High near 77. Breezy, with a north northeast wind 10 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Sunny, with a high near 85. Windy, with an east northeast wind 9 to 14 mph increasing to 21 to 26 mph in the morning. Winds could gust as high as 38 mph.

Tonight: Clear, with a low around 68. Windy, with an east wind 13 to 23 mph, with gusts as high as 32 mph.

Saturday: Sunny, with a high near 85. Windy, with an east northeast wind 13 to 18 mph increasing to 19 to 24 mph in the afternoon. Winds could gust as high as 34 mph.

Detailed Forecast

Synopsis

A strong high pressure system far north of the Hawaiian Islands will keep moderate to breezy trade winds over the region through Saturday. Weak upper level troughing will also keep brief passing showers in the forecast favoring windward and mountain areas into Saturday. The high center will drift further northeast on Sunday decreasing trade wind speeds a bit into early next week with decreasing shower coverage in the forecast. Increasing shower trends are likely by the middle of next week.

Discussion

This mornings satellite imagery continues to show a large band of unstable clouds east of the islands drifting westward across the state. Local radar imagery shows scattered to numerous showers developing in these cloud bands as they ride into each island on the trade winds. The highest shower coverage is occurring over windward and mountain areas with additional showers developing along island cloud plumes over coastal waters just to the west of island mountains.
A strong high pressure system far north of the islands will keep moderate to breezy trade winds in the forecast through Saturday. These elevated wind speeds and upper level troughing will keep passing showers in the forecast favoring the windward and mountain areas, with just a few showers possible over drier leeward locations. The highest chances for showers will develop in the overnight to early morning hours.
The high center will drift further northeastward away from the islands on Sunday and Monday, decreasing trade wind speeds across the region. More stable conditions aloft will also lead to decreasing shower trends on Sunday and Monday.
Long range model guidance continues to show a low level disturbance with abundant moisture passing through the islands from the middle to end of next week. This deeper moisture and instability is associated with the remnants of a dissipated tropical cyclone. Expect increasing rainfall activity spreading from east to west from late Tuesday onward as this unstable air mass drifts slowly westward across the island chain. The arrival timing may vary a bit for each island.

Aviation

Breezy easterly trade wind conditions will persist into the weekend. As a result, AIRMET Tango remains in place for low- level mechanical turbulence downstream of the mountains. Although VFR conditions will prevail for most areas, MVFR CIGS/VSBYS are possible in and around passing showers (best chances overnight through the morning hours for windward/mauka locations).
AIRMET Sierra for tempo mountain obscuration over windward areas will remain in effect through the morning hours today from Oahu to the Big Island. Gradual improvement is expected through the late morning and afternoon periods.

Marine

High pressure north of the state will keep moderate to strong trades in place through the weekend, although the trades should edge downward on Sunday. A Small Craft Advisory (SCA) is now in effect from the leeward Oahu waters eastward with the exception of the windward Big Island waters through 6 AM Saturday. The SCA continues for the typically windy waters around Maui and the Big Island through 6 AM Sunday, and will likely need to be extended through the remainder of the weekend.
Surf along east facing shores will hold near the summertime average through the weekend. East shore surf will then gradually lower to slightly below normal levels by the middle to latter part of next week.
Small background south swells will keep surf below seasonal levels through Monday. A new long period south swell is forecast to arrive Monday night, with surf approaching the summertime average Tuesday through late next week.
Expect nearly flat conditions along most north facing shores through Monday. A new long-period west-northwest swell is expected to arrive Monday night and give a noticeable boost to north shore surf Tuesday through Thursday.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 AM HST Saturday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov