Photo Credit: James Grenz

Hilo

Today: Scattered showers. Partly sunny, with a high near 81. Calm wind becoming east 5 to 7 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 67. Calm wind becoming northeast around 6 mph after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers, mainly before noon. Partly sunny, with a high near 82. Northeast wind 6 to 8 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after noon. Increasing clouds, with a high near 80. Light and variable wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers before midnight. Mostly cloudy, then gradually becoming mostly clear, with a low around 67. Light and variable wind becoming east northeast 5 to 7 mph in the evening. Chance of precipitation is 20%.

Tuesday: Isolated showers after noon. Increasing clouds, with a high near 81. South southwest wind around 5 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Waimea

Today: Scattered showers, mainly after noon. Partly sunny, with a high near 76. East wind 7 to 9 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 59. East wind 7 to 9 mph. Chance of precipitation is 20%.

Tuesday: Scattered showers, mainly after noon. Partly sunny, with a high near 76. Northeast wind 5 to 8 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Showers likely, mainly after noon. Partly sunny, with a high near 70. East wind 8 to 13 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 56. East wind 8 to 10 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 70. East wind 6 to 9 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers after noon. Sunny, with a high near 83. Breezy, with an east wind 17 to 21 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 73. Breezy, with an east northeast wind 14 to 17 mph, with gusts as high as 22 mph.

Tuesday: Sunny, with a high near 83. Breezy, with an east wind 14 to 16 mph, with gusts as high as 21 mph.

Puna

Today: Scattered showers. Partly sunny, with a high near 77. North northeast wind 7 to 10 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 65. Northeast wind 8 to 11 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 77. Northeast wind 11 to 13 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Isolated showers after noon. Increasing clouds, with a high near 84. Northwest wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 67. Calm wind becoming east southeast around 5 mph.

Tuesday: Increasing clouds, with a high near 84. Light north northwest wind.

Detailed Forecast

Synopsis

A weakening surface ridge north of the state will keep light to moderate trade winds and localized sea breezes over terrain sheltered leeward areas in the forecast through Friday. Drier trends remain from Monday onward due to a strong upper level ridge over the region. The ridge builds north of the state this weekend, increasing trade wind speeds into the moderate to locally breezy range.

Discussion

Satellite imagery this morning shows a weak upper low between the islands of Kauai and Oahu, and a cold front stalling far north of the state breaking down the ridge near the islands. Fairly stable clouds are shown drifting towards the islands on weakening trade winds. Radar imagery shows isolated to scattered showers drifting over the state producing limited rainfall amounts.
Weather conditions from Monday through Friday remain the same with light to moderate trade winds. These weaker large scale winds will allow local scale sea breezes to develop along terrain shelters leeward areas of each island. A strong high pressure ridge aloft, shown the the upper level streamlines, will keep the trade wind temperature inversion in the 5000 to 8000 foot range through the week. Temperature inversions at these heights will tend to cap cloud tops and limit shower coverage over all islands. Brief passing showers are still possible with fairly limited rainfall activity. The Kona coast may see extended evening showers from sunset until midnight due to on-shore winds converging with the down slope mountain breezes.
The high pressure ridge strengthens north of the island chain on Saturday with a return to moderate to locally breezy trade winds expected through next weekend. Long range forecast guidance differs on the strength of the ridge and the strength of the returning trades from Saturday into the first half of next week.

Aviation

Light to locally moderate trade wind flow will persist through twenty four hours and beyond. Ragged clouds and scattered showers will favor east and northeast facing slopes and coasts, especially in the late night and morning hours.
The weakness of the background flow will allow localized sea breezes to dominate along leeward coasts in the afternoon and early evening hours. Sea breezes will promote afternoon and evening cloudiness over west and southwest facing slopes and coasts, especially those of the Big Island.
The air mass over the state is expected to become increasingly stable by midweek due to a building upper level ridge. This will further limit shower activity. Isolated MVFR conditions are to be expected in passing showers, otherwise VFR conditions will prevail throughout the forecast period and beyond.
No AIRMETs are currently in effect or anticipated at this time.

Marine

A surface ridge northwest of the area is producing gentle to locally fresh trade winds over Hawaii coastal waters. Winds over the coastal waters will weaken further over the next few days as the ridge shifts slowly southeast. Winds will strengthen again late in the weak as high pressure builds northeast of the area.
The current south swell producing surf above the advisory level will gradually subside through tomorrow. A couple more southern hemisphere swells will produce small surf along the south facing shores through the second half of the week. A new northwest swell will produce small surf along north and west facing shores through tomorrow with another small northwest swell expected Wednesday. Weak trade winds will maintain small surf along east facing shores through mid-week. Surf along east facing shores may increase a bit over the second half of the week as winds strengthen off California.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for all south facing shores.

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Data Courtesy of NOAA.gov