Hilo

Today: Scattered showers. Partly sunny, with a high near 80. North northeast wind 6 to 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly after 1am. Mostly cloudy, with a low around 67. North wind 5 to 8 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Showers likely, mainly before 1pm. Partly sunny, with a high near 81. East northeast wind 6 to 9 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Sunny, with a high near 79. West southwest wind around 6 mph.

Tonight: Isolated showers. Partly cloudy, with a low around 67. South wind around 7 mph becoming north northwest after midnight. Chance of precipitation is 20%.

Monday: Isolated showers after noon. Increasing clouds, with a high near 79. South southwest wind around 8 mph becoming west in the afternoon. Chance of precipitation is 20%.

Waimea

Today: Scattered showers. Partly sunny, with a high near 75. Breezy, with a northeast wind 13 to 15 mph, with gusts as high as 21 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 northeast wind around 15 mph, with gusts as high as 21 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Monday: Scattered showers, mainly after noon. Partly sunny, with a high near 76. Breezy, with an east northeast wind 13 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Showers likely, mainly after noon. Mostly cloudy, with a high near 69. Breezy, with an east wind 14 to 16 mph, with gusts as high as 22 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 55. Breezy, with an east wind around 20 mph, with gusts as high as 28 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Showers likely, mainly after noon. Mostly cloudy, with a high near 69. Breezy, with an east wind 14 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 82. Breezy, with an east wind 17 to 20 mph, with gusts as high as 25 mph.

Tonight: Isolated showers after 7pm. Partly cloudy, with a low around 72. Breezy, with an east wind 20 to 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Monday: Isolated showers before 1pm. Mostly sunny, with a high near 83. Breezy, with an east wind around 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Puna

Today: Showers likely, mainly before noon. Partly sunny, with a high near 76. Northeast wind around 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, mainly after midnight. Mostly cloudy, with a low around 64. North northeast wind around 10 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Monday: Showers likely, mainly before noon. Mostly cloudy, with a high near 76. Northeast wind 11 to 13 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Sunny, with a high near 83. Northeast wind 7 to 9 mph becoming north northwest in the afternoon.

Tonight: Clear, with a low around 66. East northeast wind 8 to 11 mph.

Monday: Sunny, with a high near 83. Northeast wind 8 to 10 mph becoming south in the afternoon.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will continue this week. Low clouds and showers will focus over windward areas, with showers more active during nights and mornings. Daytime heating will produce clouds and a few showers over the leeward slopes of the Big Island during the afternoons and evenings. Increasing rainfall is possible by midweek.

Discussion

Lowered the PoPs for today a bit to be in better alignment with the high resolution models. Radar has been showing some showers riding in on trades overnight, but rain gages show rainfall totals on the lighter side. Satellite derived precipitable water (PW) continues to show drier than normal PW values over and more than 300 miles upstream of the islands this morning. These were all factors into decreasing the PoPs for today and tonight.
High pressure remains to the north of the islands. This high is expected to move to the east through the middle of the week, and then become stationary. The high will maintain a trade wind flow across the region. Winds have dropped off a bit from a few days ago, but are expected to increase a bit as early as tomorrow. Further strengthening of the winds is possible as we head into the middle to later part of the week.
A frontal system near the dateline is expected to move east, which will help push the above mentioned high eastward. The front is not expected to reach the islands, but moisture from the front will likely get fed into the trade wind low, which will boost rainfall totals. An upper level low forming near the dateline and pushing towards the islands could help to further enhance shower activity. The trade wind flow will help to focus showers over the windward and mountain areas, but as the trades pick up, some of those showers could reach leeward areas from time to time.

Aviation

Moderate easterly trades will continue through Monday, with clouds and showers favoring windward coasts and slopes. MVFR CIGS and VSBYS will be possible in and around showers moving through, especially through the late night and early morning periods.
AIRMET Sierra can’t be ruled out through the late night and early morning hours for windward areas.

Marine

A high north of the islands will move east and weaken through Wednesday. The high will then become stationary and strengthen far northeast of Hawaii. Moderate to fresh easterly trade winds will persist through the week.
Surf will remain well below High Surf Advisory levels along all shores through the week. A rather short-period north swell will produce small surf along north facing shores tonight through Wednesday night. Southern hemisphere swells will maintain small surf along south facing shores through mid-week. Surf along the south facing shores will build through the second half of the week. Moderate trade winds upstream of the islands will produce small and choppy surf along east facing shores through the coming week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov