Hilo

Tonight: Occasional showers. Lows 59 to 69 near the shore to 52 to 59 at 4000 feet. North winds up to 15 mph. Chance of rain near 100 percent.

Tuesday: Occasional showers until late afternoon, then scattered showers late in the afternoon. Highs 75 to 80 near the shore to around 62 at 4000 feet. Northeast winds up to 15 mph. Chance of rain near 100 percent.

Tuesday Night: Mostly cloudy with numerous showers. Lows 57 to 67 near the shore to 48 to 55 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Tonight: Partly cloudy. Scattered showers early in the evening. Lows 69 to 74 near the shore to 49 to 54 near 5000 feet. West winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Tuesday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 40 percent.

Tuesday Night: Mostly cloudy. Isolated showers in the evening. Lows around 70 near the shore to 47 to 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy. Breezy. Isolated showers early in the evening, then occasional showers in the late evening and overnight. Lows 61 to 70 near the shore to 54 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 90 percent.

Tuesday: Partly sunny. Windy. Occasional showers early in the morning, then scattered showers in the late morning and afternoon. Highs 61 to 82. East winds 10 to 30 mph decreasing to up to 30 mph in the afternoon. Chance of rain 90 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows 58 to 68 near the shore to 51 to 59 near 3000 feet. East winds up to 25 mph becoming 10 to 20 mph after midnight. Chance of rain 50 percent.

Kohala

Tonight: Mostly cloudy. Breezy. Isolated showers early in the evening, then occasional showers in the late evening and overnight. Lows 61 to 70 near the shore to 54 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 90 percent.

Tuesday: Partly sunny. Windy. Occasional showers early in the morning, then scattered showers in the late morning and afternoon. Highs 61 to 82. East winds 10 to 30 mph decreasing to up to 30 mph in the afternoon. Chance of rain 90 percent.

Tuesday Night: Breezy. Mostly cloudy with scattered showers. Lows 58 to 68 near the shore to 51 to 59 near 3000 feet. East winds up to 25 mph becoming 10 to 20 mph after midnight. Chance of rain 50 percent.

South Big Island

Tonight: Mostly clear. Breezy. Isolated showers early in the evening. Lows around 73 near the shore to around 54 near 5000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Tuesday: Windy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 30 mph. Chance of rain 20 percent.

Tuesday Night: Mostly cloudy. Windy. Lows around 71 near the shore to around 52 near 5000 feet. East winds up to 30 mph.

Puna

Tonight: Occasional showers. Lows 59 to 69 near the shore to 52 to 59 at 4000 feet. North winds up to 15 mph. Chance of rain near 100 percent.

Tuesday: Occasional showers until late afternoon, then scattered showers late in the afternoon. Highs 75 to 80 near the shore to around 62 at 4000 feet. Northeast winds up to 15 mph. Chance of rain near 100 percent.

Tuesday Night: Mostly cloudy with numerous showers. Lows 57 to 67 near the shore to 48 to 55 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Partly cloudy. Lows 69 to 74 near the shore to around 53 above 4000 feet. East winds up to 15 mph.

Tuesday: Mostly sunny. Windy. Isolated showers late in the afternoon. Highs 80 to 87 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 30 mph with gusts to 50 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy in the evening then becoming mostly cloudy. Windy. Lows 68 to 73 near the shore to 48 to 53 above 4000 feet. East winds up to 30 mph.

Detailed Forecast

Synopsis

Strong trades tonight and Tuesday will ease during late week eventually veering to southeasterly. A band of showers will focus showers primarily windward and mauka tonight.

Discussion

Longwave ridging centers over the islands through late this week in maintenance of a rather transient period of trade wind weather. A brief period of strong trades anchored along the lead edge of building high pressure will sweep through the area tonight through Tuesday bringing with it a convergent band of showers. This band is seen on afternoon visible imagery immediately offshore and approaching the islands from the east and is poised to arrive late this evening. Solid presentation on satellite suggests a high coverage of showers some of which be ushered leeward at times by strengthening trades within a weakly stable boundary layer.
Progression of mid-latitude troughing across the N Central Pacific then ushers governing high pressure east causing trades to weaken through midweek then veer to SE this weekend. The gradient over the western end of the state further weakens as attendant surface pressure falls spread eastward potentially favoring a couple days of a land/sea breeze pattern over the smaller islands early next week.
Modeling suggests the Pacific jet will once again nose into the lower latitudes in the introducing potential for low pressure west of the islands and a potentially more active pattern reemerging by mid/late next week.
.AVIATION…
Breezy trade winds continue across Hawaii into Tuesday. AIRMET Tango for tempo moderate turbulence downwind of terrain on all islands below 8000 feet will likely continue through then.
Increasing showers late tonight as an old boundary embedded in the trade wind flow brings MVFR ceilings and visibility to most windward areas. AIRMET Sierra has been posted for tempo mountain obscurations above 2500 feet this afternoon, with other islands expected to be included in AIRMET Sierra tonight. Brief mountain obscurations may also occur as clouds and showers pass to leeward sides of the smaller islands at times. Expect improving conditions to VFR Tuesday morning.

Marine

Fresh to strong easterly trade winds will prevail through Tuesday night. Trades have held in the moderate to locally strong range today as robust high pressure far north-northwest of the islands drifted eastward and broad area of low pressure northwest of Kauai remained nearly stationary. Trade winds will increase overnight as a band of moisture moves over the area from the northeast, with widespread fresh to strong winds holding through Tuesday night. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Big Island and Maui and will expand to most waters tonight as winds and seas increase. The high will weaken as it passes north of Hawaii on Wednesday, and the low to the northwest will lift northward, leading a gradual decline in trade winds locally. Winds may decline further and shift out of the southeast late Friday and Saturday as the low redevelops and pushes a surface ridge toward Kauai.
A small north swell will continue to gradually decline into Wednesday. A moderate, medium period north-northeast (010-030 degrees) swell will arrive late Wednesday and peak Thursday and Friday. Surf along north facing shores could approach the High Surf Advisory level during the peak, with the largest swells favoring the eastern end of the island chain, and a Marine Weather Statement may be needed for harbor surges at Kahului and Hilo. The north swell will decline over the weekend as a small northwest swell arrives.
For east facing shores, wrapping north swell will produce small surf across exposed coastlines tonight, while building trade winds lead to an increase in short period trade wind energy. Breezy trades will produce rough conditions above seasonal average Tuesday and Wednesday. Short period trade wind swell will decline by Christmas, but wrapping northerly swell will affect exposed eastern shores into Friday. Surf along south facing shores will remain very small through the week.

Fire weather

Strong trades tonight through Tuesday ease Wednesday through the end of the week. RH remains elevated through the period.

HFO Watches/Warnings/Advisories

Small Craft Advisory from 6 PM this evening to 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters.
Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov