Hilo

Today: Showers likely, mainly before noon. Cloudy, with a high near 75. East wind 8 to 10 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Frequent showers. Low around 63. Light west southwest wind. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

Sunday: Frequent showers, mainly before noon. High near 76. East wind around 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Kona

Today: Isolated showers after noon. Partly sunny, with a high near 79. West wind around 7 mph. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly before midnight. Mostly cloudy, with a low around 62. East southeast wind around 7 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Isolated showers after noon. Partly sunny, with a high near 79. West wind around 7 mph. Chance of precipitation is 20%.

Waimea

Today: Scattered showers. Mostly cloudy, with a high near 74. Northeast wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 53. East wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Sunday: Scattered showers. Mostly cloudy, with a high near 74. East northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Frequent showers. High near 70. Northeast wind 11 to 13 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Frequent showers. Low around 46. East wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Sunday: Frequent showers. High near 70. Northeast wind around 13 mph. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.

South Big Island

Today: Isolated showers. Partly sunny, with a high near 76. Windy, with an east northeast wind around 24 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 71. Windy, with an east northeast wind around 24 mph, with gusts as high as 31 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers. Partly sunny, with a high near 76. Windy, with an east northeast wind around 24 mph, with gusts as high as 31 mph. Chance of precipitation is 30%.

Puna

Today: Showers likely. Cloudy, with a high near 75. East northeast wind around 9 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Frequent showers. Low around 62. Calm wind. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Sunday: Frequent showers. High near 75. East northeast wind around 9 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Mostly sunny, with a high near 80. West northwest wind around 7 mph.

Tonight: Partly cloudy, with a low around 63. East northeast wind around 7 mph.

Sunday: Mostly sunny, with a high near 80. Northwest wind around 7 mph.

Detailed Forecast

Synopsis

A strong high north of the area will build southeast through Monday, then weaken over the second half of next week. An increase in clouds and showers is expected later today, lasting through Monday.

Discussion

No significant changes to the forecast with the morning package. High pressure far to the north will help to boost trade winds over the next couple of days. Meanwhile, a surface low to the northeast will linger into the middle of the next week. Moisture from an old front will ride in on the trades and is expected to boost clouds and showers later today through Monday.
Some high clouds are moving in from the west, and are expected to increase in coverage state wide today. An upper level trough will swing through the state Sunday, and bring colder temperatures aloft to the region. The models show drier precipitable water (PW) moving in from the north during this time, and the high should be boosting trade winds. While the colder temperatures could indicate some instability moving in, the drier airmass and trades would be limiting factors to the development of any thunderstorms.
The surface low to the far northeast is expected to weaken during the second half of the week. Meanwhile the high to the north will be strengthening during the first part of the week, which will help to maintain a breezy trade wind pattern. As the low dissipates during the second half of the week, leftover moisture will get carried in on the trades, which could boost showers from time to time.
The global models agree that PW values will be below 1 inch most of the new week. A shortwave looks to swing through the islands midweek, but with limited PW, and upper level temperatures not plummeting, it should have minimal impacts on our weather.

Aviation

High pressure far north of the state will strengthen over the next day or so, leading to an increase in trade winds. Isolated to intermittently scattered MVFR conditions will be mainly confined to windward terrain. Aside from afternoon and evening clouds and showers on the Kona slopes of the Big Island, VFR will predominate over leeward areas through the day.
No AIRMETs are currently in effect. Building trade winds during the weekend will likely produce an increase in low level turbulence over and downwind of terrain, and require the issuance of AIRMET Tango. An upper level trough passing just northeast of the state may enhance windward rainfall today and lead to AIRMET Sierra for mountain obscuration.

Marine

A moderate northeast trade wind flow is expected to bump up a notch today to locally strong as a broad area of surface high pressure builds southward across the islands. This bump will require a Small Craft Advisory (SCA) that will go into affect shortly, covering the waters around Maui County and the waters south of the Big island. The SCA is good to until 6 am HST Monday. Another boost in the trades will come Monday, where moderate to strong trade wind will encompass all, if not most of the Hawaiian nearshore waters. With this in mind, expect an expansion of the SCA to cover most, if not all of the remain nearshore waters. It should be noted the SCA also cover elevated seas of 10 feet or higher as explained blow.
The breezy/windy trade winds are being supported by a strengthening surface high of 1037 mb located far north of the islands. There is a slight southward shift of the high center through Monday but it is overall nearly stationary through Tuesday of next week. The second boost will bring on very rough and choppy seas to the island waters.
Further more, a surface low about a thousand miles northeast of the islands will strengthen to gale force later today. A moderate to large swell will then be generated toward the islands. This swell is expected to reach our north and northeast facing shores Sunday night through Monday. The combination of this swell and the boost in the trade winds will result in seas at or above 10 feet, the other threshold for a SCA. In addition to the SCA, a High Surf Advisory is very likely for the east facing shores. Surf along the north facing shores will reach up to moderate heights.
The trade winds will begin trending slightly weaker Tuesday night/Wednesday of next week. The surf and seas will follow shortly after.
As for the weekend, surf along east facing shores is expected to be in the small to medium range today, then slightly higher on Sunday. The north facing shores will see a similar rise as this aforementioned north-northeast to northeast swell nears the islands.
A background south swell with long periods of around 15 seconds will maintain small surf along the south facing shores through Tuesday.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov