Hilo

Today: Scattered showers. Partly sunny, with a high near 83. Calm wind becoming east 5 to 7 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 66. Calm wind becoming west around 5 mph after midnight. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Scattered showers, mainly before noon. Mostly sunny, with a high near 83. East northeast wind 5 to 7 mph becoming calm in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after noon. Partly sunny, with a high near 79. North northeast wind around 8 mph becoming west northwest in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before midnight. Partly cloudy, with a low around 65. West northwest wind 7 to 9 mph becoming east in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Isolated showers after noon. Mostly sunny, with a high near 79. East northeast wind 5 to 9 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Waimea

Today: Scattered showers. Partly sunny, with a high near 78. Northeast wind 10 to 14 mph, with gusts as high as 20 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 58. Northeast wind 11 to 13 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Monday: Scattered showers, mainly before 7am. Mostly sunny, with a high near 78. Northeast wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Scattered showers. Partly sunny, with a high near 64. East wind 8 to 11 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Partly cloudy, with a low around 53. East wind 7 to 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Scattered showers, mainly before noon. Partly sunny, with a high near 64. East wind 8 to 13 mph. Chance of precipitation is 30%.

South Big Island

Today: Isolated showers. Mostly sunny, with a high near 84. Breezy, with an east wind 16 to 21 mph, with gusts as high as 25 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 74. Breezy, with an east northeast wind 20 to 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Monday: Sunny, with a high near 84. Breezy, with an east wind 15 to 21 mph, with gusts as high as 26 mph.

Puna

Today: Scattered showers. Partly sunny, with a high near 82. West northwest wind 6 to 10 mph becoming east northeast in the afternoon. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 64. East northeast wind 5 to 9 mph becoming northwest after midnight. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Scattered showers. Mostly sunny, with a high near 82. Northwest wind 5 to 9 mph becoming east northeast in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Scattered showers after noon. Mostly sunny, with a high near 84. Light and variable wind becoming west northwest 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers before midnight. Partly cloudy, with a low around 66. Light and variable wind becoming east southeast 5 to 9 mph after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Isolated showers after noon. Mostly sunny, with a high near 84. East northeast wind 5 to 10 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

Light to moderate trades will hold in place through Tuesday, with localized land and sea breezes developing in the more sheltered leeward areas. A couple bands of moisture will move through today and again on Tuesday, bringing a slight increase in showers to both windward and leeward areas, with fairly dry conditions expected statewide on Monday. Trades will get a boost back to moderate and locally breezy levels Tuesday night through next weekend, and this should bring a more typical windward and mauka focused shower pattern, with a stray shower reaching leeward areas from time to time.

Discussion

Currently at the surface, a ridge of high pressure is located around 150 miles north of Kauai, and extends to a 1022 mb high to the distant northeast. Meanwhile, a nearly stationary front is located around 320 miles northwest of Kauai. The resulting gradient remains loose across the islands, with light to locally moderate trades in most windward areas, and land breezes in leeward locales and all of Kauai. Infrared satellite imagery shows partly to mostly cloudy skies across the islands, with cloud cover most prevalent over windward areas from Oahu eastward and over leeward sections of the Big Island. Radar imagery shows scattered windward showers and even a few isolated showers from Oahu eastward to the Big Island, with rain free conditions over Kauai. Main short term concerns revolve around rain chances and trade wind trends during the next few days.
The trade winds will trend up a slightly today through Tuesday as the ridge of high pressure lifts slowly off to the northwest and further away from the islands. The trades will likely remain light enough during this time that localized sea breezes and land breezes will occur in the more sheltered leeward areas. The front northwest of the islands will dissipate Tuesday night and Wednesday, allowing the ridge axis to make more substantial progress northwest of the islands. This will bring a return of moderate to locally breezy trade winds which will linger into next weekend.
As for the remaining weather details, a band of moisture will spread westward across the island today, bringing a scattered showers to windward areas, with localized sea breezes also bringing a few showers to leeward locales during the afternoon and early evening hours. Many areas will dry out pretty good tonight, although a few windward showers will remain possible, as well as near the coast of leeward Big Island. The band of moisture will be moving through Kauai tonight however, so shower coverage is expected to be higher here.
A fairly dry trade wind pattern is expected over the entire island chain Monday and Monday evening, with an increase in trade showers developing later Monday night as another band of moisture moves in from the east. This band of moisture will shift eastward across the islands on Tuesday, bringing scattered showers to windward areas, as well as an increase in daytime heating driven showers over leeward areas. A more typical trade wind shower pattern appears to resume Tuesday night and hold through next weekend, with showers favoring windward and mauka areas mainly during the overnight and early morning hours, and a stray shower reaching leeward areas from time to time.

Aviation

Light trade flow will allow for isolated showers to persist along windward areas through late this morning. Sea breeze development this afternoon will act to shift shower development towards the interior of the islands. This activity may bring brief periods of MVFR ceilings and visibility.
No AIRMETs are currently in effect.

Marine

A high pressure ridge will build and lift slowly northwest of the islands over the next few days, slowly increasing trade winds across the region. Light to moderate trade winds will strengthen into the moderate to strong range from Tuesday night onward, with the strongest winds expected across the typical windier waters around Maui County and the Big Island.
The current northwest swell will gradually decrease over the next few days. Another small northwest swell is possible towards the end of the week. A series of small south and southeast swells are expected throughout the forecast period, with a slightly larger south swell possible late Tuesday and Wednesday. Surf will remain small along east facing shores though the first half of the week, due to the lack of significant trade winds over and upwind of the area. Surf heights for east facing shores may trend up during the second half of the week as the trade winds slowly strengthen.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov