Photo Credit: James Grenz

Hilo

Today: Frequent showers. High near 81. Calm wind becoming east northeast 5 to 7 mph in the afternoon. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 70. Light east wind. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 82. East northeast wind 3 to 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Mostly sunny, with a high near 81. Light and variable wind. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 70. Calm wind. Chance of precipitation is 20%.

Tuesday: Isolated showers after noon. Mostly sunny, with a high near 81. Light west wind. Chance of precipitation is 20%.

Waimea

Today: Scattered showers. Partly sunny, with a high near 74. East northeast wind around 11 mph. Chance of precipitation is 50%. New precipitation amounts between a half and three quarters of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 61. East wind 10 to 13 mph. Chance of precipitation is 40%. New precipitation amounts between a quarter and half of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 75. East northeast wind 9 to 11 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Showers likely. Mostly cloudy, with a high near 68. Breezy, with an east wind around 17 mph, with gusts as high as 24 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 59. Breezy, with an east wind 11 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Showers likely, mainly after noon. Partly sunny, with a high near 68. East wind 10 to 13 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 85. Breezy, with an east wind 18 to 21 mph, with gusts as high as 26 mph.

Tonight: Mostly clear, with a low around 75. Breezy, with an east northeast wind 17 to 21 mph, with gusts as high as 26 mph.

Tuesday: Sunny, with a high near 85. Breezy, with an east wind around 18 mph, with gusts as high as 24 mph.

Puna

Today: Frequent showers. High near 77. Northeast wind 8 to 13 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 68. North northeast wind 7 to 10 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

Tuesday: Showers likely, mainly before noon. Partly sunny, with a high near 78. Northeast wind 9 to 13 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Mostly sunny, with a high near 84. North northeast wind around 5 mph.

Tonight: Mostly clear, with a low around 69. East wind around 6 mph.

Tuesday: Mostly sunny, with a high near 84. North wind 3 to 5 mph.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will slightly weaken Tuesday and Wednesday, then increase again towards the end of the week. Showers will continue to ride in on the trades, with an increase in shower coverage expected tonight and Monday, especially over the Big Island and windward Maui. Brief downpours are expected during this time.

Discussion

High pressure far northeast of the main Hawaiian Islands will drive moderate to breezy trade winds across local waters today and tonight. Winds will slightly decrease Tuesday into Wednesday as the high weakens. Breezy trades will return over the weekend as the high strengthens once again later in the week.
Models show increased moisture focusing across the Big Island and windward Maui over the next 24 hours. Heavier showers will affect windward and mountain areas as well as Kona slopes of the Big Island through today. Windward Big Island and Maui will likely see several inches of rain over the next few days. Most of the showers are expected to be moderate in intensity, but the frequency of showers may cause some ponding.
Over on the western half of the state, we will continue to see passing showers ride in with the trade winds over the next several days, but overall rainfall amounts are expected to be much less than the eastern half of the state. By the end of the week, a drier airmass will begin to move in. Trade winds will strengthen and we will see a sunny and breezy trade wind pattern over the weekend.

Aviation

Moderate to occasionally breezy east northeasterly trades will help to concentrate showers along the windward coasts and slopes this morning, especially along northeast portions of the Big Island. Periods of MVFR ceilings and visibility will likely accompany this activity. Isolated showers expected elsewhere.
AIRMET TANGO remains in effect for areas below 9000 feet over and immediately south thru west of mountains due to tempo moderate turbulence.
AIRMET SIERRA remains in effect for north thru east sections of Kauai, Oahu, and the Big Island above 2000 feet for mountain obscuration from clouds and showers.

Marine

Surface high pressure located far north of the state will maintain locally strong trade winds and rough seas through tonight, with a Small Craft Advisory remaining in effect for the typically windier waters near Maui County and the Big Island. Trade winds are then expected to weaken Tuesday through Wednesday. Building high pressure to the north and a surface trough passing by well south of the state are expected to result in locally strong trades returning by Thursday.
The trade winds will produce moderate, choppy surf along east facing shores through today, then slowly trend lower tonight through mid-week due to weakening trades near and upstream of the islands. Moderate and choppy surf will return later in the week as trades strengthen.
The current small south swell and associated south shore surf will continue to subside through the day to summer average heights. Through mid-week, short- to medium-period southeast trade wind swell energy from the southern hemisphere will keep small surf along exposed shorelines.
Surf will remain nearly flat along most west and north facing shores through mid-week. Small west-northwest swells, from tropical cyclone activity in the NW Pacific, may arrive along some exposed west and north facing shores starting Thursday or Friday. However, confidence about the timing and the size of these swells remains low at this time.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov