Hilo

Today: Showers likely, mainly before noon. Partly sunny, with a high near 83. Calm wind becoming east northeast 5 to 8 mph in the morning. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 67. West wind around 7 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 83. West wind 5 to 8 mph becoming east northeast in the morning. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after 1pm. Partly sunny, with a high near 84. Calm wind becoming west 5 to 9 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 1am. Mostly cloudy, with a low around 70. East wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Isolated showers before 7am, then scattered showers after 1pm. Partly sunny, with a high near 85. East wind 5 to 9 mph becoming west in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers. Partly sunny, with a high near 77. Windy, with a northeast wind 20 to 25 mph, with gusts as high as 36 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 57. Breezy, with an east wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 77. Windy, with a northeast wind 16 to 25 mph, with gusts as high as 36 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Showers likely, mainly before noon. Mostly cloudy, with a high near 68. Windy, with an east wind 23 to 29 mph, with gusts as high as 41 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 51. Windy, with an east wind around 24 mph, with gusts as high as 34 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 69. Windy, with an east wind 24 to 29 mph, with gusts as high as 41 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers. Mostly sunny, with a high near 81. Windy, with an east wind 26 to 29 mph, with gusts as high as 37 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 69. Windy, with an east wind around 28 mph, with gusts as high as 36 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers. Mostly sunny, with a high near 80. Windy, with an east wind 24 to 28 mph, with gusts as high as 36 mph. Chance of precipitation is 20%.

Puna

Today: Showers likely, mainly before noon. Partly sunny, with a high near 79. Northeast wind 8 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 63. Northeast wind around 13 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 78. Northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Isolated showers after noon. Mostly sunny, with a high near 83. Windy, with a northeast wind 19 to 24 mph decreasing to 7 to 12 mph in the afternoon. Winds could gust as high as 34 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 68. East southeast wind around 7 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers after noon. Mostly sunny, with a high near 84. Windy, with a northeast wind 19 to 24 mph decreasing to 6 to 11 mph. Winds could gust as high as 34 mph. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

A high pressure ridge north of the islands will keep moderate to breezy trade winds with brief passing windward and mountain showers in the forecast into Friday. The ridge will weaken from late Friday into the weekend as a dissipating cold front approaches from the north. Lighter wind speed trends are expected along with a slight decrease in shower activity this weekend.

Discussion

The large scale weather picture remains the same this morning as a large high pressure ridge locked in place north of the region with a nearly stationary low pressure system west-northwest of the islands near the Dateline. Satellite imagery shows stable clouds drifting into each island on the trade winds. Local radar shows brief passing showers drifting through the islands mainly affecting windward and mountain sections. Drier conditions are observed over leeward areas.
The large subtropical ridge north of the state will continue to produce moderate to breezy trade winds into Friday. A combination of breezy surface winds and passing mid level disturbances will keep brief passing showers in the forecast favoring windward and mountain areas. Daily rainfall amounts will remain light for most locations.
Weather conditions change a bit from Friday into the weekend as a dissipating cold front approaches the islands from the north. This frontal trough will break down the high pressure ridge north of the islands and decrease the trade winds into the light to moderate range. Shower activity will also trend a bit lower this weekend as wind speeds decrease.
The high pressure ridge builds back in north of the region late Sunday into Monday with moderate trade winds in the forecast. A cloud boundary associated with a dissipated cold front will linger just north of the main Hawaiian Islands. The latest long range guidance continues to suggest any clouds and showers with this feature will remain just north of Kauai with little impact in our local island weather.

Aviation

High pressure north of the state will keep moderate to breezy trade winds in place for the next few days. Very little change in weather pattern is expected, with scattered showers favoring windward slopes and coasts, and a stray shower reaching leeward areas from time to time. Brief MVFR cigs/vsbys will be possible in windward areas, particularly at night and during the early morning hours, but predominantly VFR conditions should prevail.
AIRMET SIERRA is in effect for mountain obscuration over windward sections of Kauai, Oahu, Molokai, Maui and Big Island. Conditions should improve later this morning.
AIRMET TANGO remains in effect for moderate low level turbulence over and downwind of the terrain of all islands. This AIRMET will likely continue for the next few days.

Marine

The tight pressure gradient produced by high pressure north northeast of the islands will maintain these ongoing moderate to fresh trade winds through the work week. A slight strengthening of areawide trades to more sustained fresh to locally strong magnitudes within the channels and bays has the Small Craft Advisory now in effect for all nearshore waters (except for the windward Kauai waters) through Wednesday afternoon.
The recent moderate southwest to south swell has diminished but a series of low background southwest south swells traveling through the next several days will hold slightly below normal surf along many south facing shores. North facing shore surf will remain near flat with some spots benefiting from a trade wind wave wrap through the remainder of the week. The only notable surf will be along eastern exposed shores. Persistent moderate to locally strong trades over and upstream of the islands will push in a higher wind wave swell that will produce east coast choppy conditions and near summertime average surf heights.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for Kauai Northwest Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov