Hilo

Tonight: Cloudy with scattered showers. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Saturday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 85 near the shore to around 68 at 4000 feet. Northeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Saturday Night: Cloudy with scattered showers. Lows 62 to 69 near the shore to around 54 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 73 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Saturday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 82 to 88 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 72 near the shore to 48 to 53 near 5000 feet. Northwest winds up to 10 mph shifting to the northeast after midnight. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Mostly cloudy with isolated showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Mostly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Kohala

Tonight: Mostly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Mostly cloudy with isolated showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Mostly cloudy with isolated showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Lows around 73 near the shore to around 52 near 5000 feet. East winds up to 20 mph.

Saturday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 84 near the shore to around 68 near 5000 feet. East winds up to 25 mph.

Saturday Night: Partly cloudy. Breezy. Lows around 73 near the shore to around 51 near 5000 feet. East winds up to 25 mph.

Puna

Tonight: Cloudy with scattered showers. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Saturday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 85 near the shore to around 68 at 4000 feet. Northeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Saturday Night: Cloudy with scattered showers. Lows 62 to 69 near the shore to around 54 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Partly cloudy. Lows 70 to 75 near the shore to 50 to 55 above 4000 feet. North winds up to 15 mph shifting to the east after midnight.

Saturday: Sunny in the morning then becoming partly sunny. Highs 83 to 88 near the shore to 66 to 72 above 4000 feet. Northeast winds up to 15 mph shifting to the northwest in the afternoon.

Saturday Night: Partly cloudy. Lows around 72 near the shore to 50 to 55 above 4000 feet. Northeast winds up to 15 mph.

Detailed Forecast

Synopsis

Expect moderate trades along with periodic showers across windward and mauka areas through the weekend. Trade winds will briefly strengthen next week before settling back down toward next weekend.

Discussion

An upper low well southwest of the islands is pumping up mid-level ridging over the forecast area and is providing a steady supply of high clouds. Today's soundings out of Lihue indicate increased stability compared to 24 hours ago as evidenced by increasingly dry air atop the boundary layer. This is a consequence of the departing surface trough and the downward creep of dry air in response to subsidence beneath developing upper ridging over the islands. The aforementioned surface trough is anchored at the interface between departing moderate NE trades and building easterlies and it resides west of Kauai at press time. Radar imagery indicates that is has been unable to provide much in the way of a trigger for shower activity with even less activity noted across the remainder of the state. This rather dry, moderate trade wind pattern will continue through at least this weekend as dry air builds downward contributing to steadily increasing stability and trades remain on the lighter side. As the upper low SW of the islands pivots westward, so too will the accompanying deck of high clouds. By Saturday morning, expect comparatively less cloud coverage, particularly over central and eastern portions of the state.
Little change in the forecast for the foreseeable future. Breezy trades may briefly return early next week but quickly return to moderate in response to periodic rounds of height falls across the mid-latitude Pacific. The EC and GFS both indicate a ribbon of tropical moisture drawing north early next week resulting in an increased coverage of trade wind showers around Monday night, but upstream visible imagery (around 140W/15N) leaves something to be desired as saturation looks poor and shower coverage minimal as of yet. This brief period of potential for increased windward and mauka showers is handled well in the official forecast with no adjustments required.

Aviation

Moderate trades will continue over the next couple of days. Low clouds and isolated showers will typically favor windward and mountain areas, particularly overnight into the early morning hours. In this lighter wind pattern, sea breezes may also bring afternoon cloud build ups and isolated showers to select leeward interior areas that would then clear out overnight with land breezes. Overall, besides in brief isolated showers, VFR conditions will prevail across the island chain.
No AIRMETs are currently in effect and none are expected through the next 24 hours.

Marine

A series of cold fronts passing across the North Pacific will disrupt surface high pressure north of the islands. This will result in gentle to moderate trade winds through the weekend. High pressure will reestablish itself over the eastern Pacific early next week, increasing trades back to moderate to locally fresh magnitudes by Monday, then becoming locally strong by Tuesday afternoon. Trades may drop off a touch again late next week as the high northeast of the state moves southeast.
A reinforcing bump in north shore surf is expected early Saturday as a small short to medium period north swell (350-360 degrees) fills into the region. However, the next significant north swell (350 degree) that could produce advisory-level surf along north- facing shores is scheduled to arrive Sunday night or early Monday. This swell will likely peak Monday night and then slowly decline through the rest of next week.
A small medium to long period south swell will maintain near waist high surf along south-facing shores for the next couple of days. Surf along west-facing shores will remain elevated as these shores will continue to be influenced by both north and south swell wrap. East-facing shore wind wave chop will remain relatively small under this weaker trade wind regime.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov