Hilo

Tonight: Mostly cloudy. Chance of showers in the evening, then showers likely after midnight. Lows 58 to 65 near the shore to 48 to 54 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 70 percent.

Saturday: Mostly cloudy with a 50 percent chance of showers. Highs 76 to 81 near the shore to 61 to 68 at 4000 feet. Northwest winds around 10 mph in the morning becoming light.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of showers. Lows 59 to 67 near the shore to 50 to 56 at 4000 feet. Light winds.

Kona

Tonight: Mostly cloudy. Chance of showers in the evening, then slight chance of showers after midnight. Lows around 68 near the shore to 43 to 49 near 5000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Saturday: Partly sunny. A 20 percent chance of showers in the afternoon. Highs 80 to 85 near the shore to around 67 near 5000 feet. Light winds.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Lows around 69 near the shore to 44 to 50 near 5000 feet. Light winds.

Waimea

Tonight: Mostly cloudy with a 50 percent chance of showers. Lows 58 to 67 near the shore to 50 to 57 near 3000 feet. East winds up to 10 mph.

Saturday: Partly sunny with a 20 percent chance of showers. Highs 61 to 80. East winds around 10 mph.

Saturday Night: Partly cloudy with a 20 percent chance of showers. Lows 60 to 68 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph.

Kohala

Tonight: Mostly cloudy with a 50 percent chance of showers. Lows 58 to 67 near the shore to 50 to 57 near 3000 feet. East winds up to 10 mph.

Saturday: Partly sunny with a 20 percent chance of showers. Highs 61 to 80. East winds around 10 mph.

Saturday Night: Partly cloudy with a 20 percent chance of showers. Lows 60 to 68 near the shore to 52 to 59 near 3000 feet. East winds up to 10 mph.

South Big Island

Tonight: Mostly cloudy. A 20 percent chance of showers in the evening. Lows around 69 near the shore to around 48 near 5000 feet. East winds up to 15 mph.

Saturday: Mostly sunny in the morning, then partly sunny with a 20 percent chance of showers in the afternoon. Highs around 83 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph.

Saturday Night: Partly cloudy. Lows around 70 near the shore to around 49 near 5000 feet. East winds 10 to 15 mph.

Puna

Tonight: Mostly cloudy. Chance of showers in the evening, then showers likely after midnight. Lows 58 to 65 near the shore to 48 to 54 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 70 percent.

Saturday: Mostly cloudy with a 50 percent chance of showers. Highs 76 to 81 near the shore to 61 to 68 at 4000 feet. Northwest winds around 10 mph in the morning becoming light.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. A 20 percent chance of showers. Lows 59 to 67 near the shore to 50 to 56 at 4000 feet. Light winds.

Waikoloa

Tonight: Mostly cloudy. Lows 66 to 71 near the shore to around 49 above 4000 feet. Northeast winds up to 15 mph shifting to the southeast after midnight.

Saturday: Partly sunny. A 20 percent chance of showers in the afternoon. Highs 81 to 86 near the shore to 63 to 70 above 4000 feet. South winds around 10 mph shifting to the northwest in the afternoon.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Lows 67 to 72 near the shore to around 50 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

Light to moderate trade winds today will gradually weaken over the next few days with light and variable winds expected by Sunday into early next week. Conditions should remain fairly stable with passing low clouds and light showers especially during the afternoon. Rain chances increase mid to late next week as a front moves slowly across the islands.

Discussion

Latest satellite imagery shows some afternoon low clouds with a few light sprinkles across interior and leeward areas. These low clouds should decrease this evening as land breezes develop. The combination of clearing skies and a stream of high clouds due to the subtropical jet could produce a unique sunrise on Saturday morning.
For this weekend, A mid- level ridge near the state will continue to produce stable and mostly dry conditions. Some low clouds and a few light showers will be possible, especially during the afternoon due to sea breeze convergence over the interior and mountain areas. Trade winds will continue to gradually decrease with light and variable winds expected by Sunday.
A weak front passing just north of the state may bring some gentle southerly winds and a slight increase of showers on Monday. Otherwise, a stronger front will begin to approach the state on Wednesday, which should bring an uptick of showers. Guidance continues to show this front reaching Kauai Wednesday night or Thursday then either stalling or slowly moving across the state and dissipating into Friday. Moderate to locally breezy trade winds look to return behind the front.

Aviation

Light to moderate trades will continue this afternoon and then weaken through the weekend, allowing for localized land and sea breeze development. Shower activity will increase overnight as another band of moisture rides in on the trades, bringing brief periods of MVFR conditions to windward areas. Otherwise, VFR conditions will prevail.
AIRMET Sierra for mountain obscuration may be needed for select windward areas tonight.
AIRMET Tango is in effect for tempo moderate turbulence between FL250 and FL450 across the state.
SIGMET Papa for severe upper level turbulence is in effect for an area just west of the main Hawaiian Islands this afternoon. This area of severe turbulence is expected to move over the island chain late tonight into Saturday morning.

Marine

Gentle to locally fresh background winds are prevailing over the coastal waters as a front approaches from the northwest. This front is expected to stall and then weaken northwest of the coastal waters this weekend, and light background flow will shift to blow out of the southeast by Sunday. Another front approaching from the northwest early next week will keep gentle south winds in place.
An extra-large northwest (310-320) swell continues to fill in across the island chain this afternoon, with the nearshore buoy at Hanalei reporting in the 19 to 20 ft range mid-afternoon. This swell is leading to rapid rises in surf along north and west facing shores. The swell is expected to peak this evening through tonight. With this afternoon's forecast updates, surf heights have generally been adjusted slightly upward along north and west facing shores for most islands for tonight through early Saturday morning based on the latest buoy and surf observations. The High Surf Warning (HSW) has been extended through 6pm HST tomorrow, and has also expanded to include west facing shores of the Big Island. Expect the potential for periodic overtopping of vulnerable coastal roadways and wave runup to coastal properties, especially around high tide early Saturday morning. A gradual downward trend is expected this weekend, with surf potentially dipping below the advisory levels by the end of the weekend. In addition, a Small Craft Advisory (SCA) is in effect for most coastal waters for seas greater than 10 ft. This SCA is expected to hold through Saturday.
Looking ahead into next week, a stretch of elevated north and west shore surf is expected, produced by overlapping northwest pulses ranging from large to potentially extra-large, particularly from Wednesday onward.
Surf along east facing shores will remain slightly elevated through the weekend due to the lingering short-period north- northeast swell. Early next week, east facing shore surf will remain small.
Surf along south facing shores will see an uptick heading into next week from a series of consecutive southwest pulses. This will result in small to moderate surf, peaking Monday and Tuesday.

Fire weather

Critical fire weather conditions are not expected through early next week due to light winds. Some rainfall is possible over leeward areas towards the middle of next week as a front approaches the state.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST Saturday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Koolau Windward, Molokai Windward, Molokai North, Molokai West, Windward Haleakala.
Small Craft Advisory until 6 PM HST Saturday for all Hawaiian waters except Maalaea Bay,

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Data Courtesy of NOAA.gov