Hilo

Today: Mostly sunny with isolated showers. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 60 to 65 near the shore to around 51 at 4000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. Light winds. Chance of rain 20 percent.

Kona

Today: Mostly sunny. Highs 80 to 85 near the shore to around 68 near 5000 feet. West winds up to 10 mph.

Tonight: Mostly clear. Lows 66 to 71 near the shore to around 52 near 5000 feet. Light winds.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 80 to 85 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Sunny with isolated showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 61 near the shore to 51 to 59 near 3000 feet. Light winds. Chance of rain 20 percent.

Monday: Sunny. Highs around 81 near the shore to 68 to 78 near 3000 feet. Light winds.

Kohala

Today: Sunny with isolated showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 61 near the shore to 51 to 59 near 3000 feet. Light winds. Chance of rain 20 percent.

Monday: Sunny. Highs around 81 near the shore to 68 to 78 near 3000 feet. Light winds.

South Big Island

Today: Mostly sunny. Highs around 85 near the shore to around 72 near 5000 feet. South winds up to 10 mph.

Tonight: Partly cloudy in the evening then becoming clear. Lows around 66 near the shore to around 51 near 5000 feet. Light winds.

Monday: Sunny. Highs around 85 near the shore to around 72 near 5000 feet. Light winds.

Puna

Today: Mostly sunny with isolated showers. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 60 to 65 near the shore to around 51 at 4000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. Light winds. Chance of rain 20 percent.

Waikoloa

Today: Sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. West winds up to 10 mph.

Tonight: Mostly clear. Lows around 69 near the shore to 48 to 55 above 4000 feet. Light winds.

Monday: Sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

Light winds will persist across the area today through Tuesday. Remnant moisture from a series of fronts dissipating north of the islands will seep down over Kauai and Oahu tonight through Tuesday, then reaching Maui County Monday night and Tuesday. Most of the showers will occur during the day, especially the afternoons due to the addition of daytime heating. Most of the clouds and showers will dissipate or be nudged off the land mass to near the coast at night by a land breeze. First sign of trade winds is Tuesday, which will gradually strengthen to locally strong by Thursday, and hold into the upcoming weekend.

Discussion

A surface ridge has settled over the islands, providing light winds to the area that will hold through Monday night. Satellite imagery shows a thin line of broken low clouds just off the Kauai’s north shore. Due to the light wind, a land breeze has developed and is keeping this band from coming ashore. Some of these clouds will eventually move ashore in the next few hours. Oahu is in a similar situation as some scattered low clouds are poise to come ashore. As the day progresses, the light wind will promote a onshore sea breeze. Coupled with the moisture and sunshine, will result in scattered showers over the interior and lee areas of Kauai and Oahu this afternoon. The rest of the island will be mostly sunny to partly cloudy and dry. As night approaches, most of these clouds and showers will dissipate and or be nudged off the island from a developing land breeze. So tonight’s Halloween looks good. There could be a few lingering showers early in the evening, but generally dry otherwise.
About 200 miles north of Kauai is another dissipating front, advancing toward Kauai County. Remnant moisture from this front is not expected to reach Kauai until late Monday morning, just in time for max heating, while the remnants from the previous front should have advanced to Maui County. So, Monday afternoon is on tap for some isolated to scattered showers. On Monday night, a new dissipating front approaches Kauai from the north, reaching Kauai Tuesday evening. Remnants from the dissipating front now north of Kauai, will have settled over Maui County Tuesday. As noted earlier, the first sign of trade wind is Tuesday, where the rainfall pattern will be shifting to a trade wind mode, meaning showers will start favoring the windward and mountain areas after sunset. During the day Tuesday, during this transitioning phase on Tuesday, the trades will still weak so that the interior and lee areas of the smaller islands will have some afternoon cloudiness and a few showers. Locally strong trades will be returning to the eastern islands by Thursday, and hold into the weekend with the likelihood of another trade wind boost over the upcoming weekend.

Aviation

A ridge over the islands is bringing a dry and stable airmass with light winds to the region. Light and variable winds are producing afternoon sea breezes leading to some cloud and shower development over the interior of the islands, and overnight land breezes largely clearing out the islands. We have continued to see a few more clouds and showers west of Molokai, but a recent adaptive day/night pass with the VIIRS satellite shows few clouds over and near the islands. A narrow band of clouds is approaching Kauai from the north, and could bring some clouds to the northern half of the island in the new couple of hours. In large part, expect VFR conditions to prevail, however afternoon cloud and shower development could produce some pockets of MVFR.
AIRMET Tango was cancelled overnight as the upper level turbulence diminished. At this time, no other AIRMETs are anticipated throughout the forecast period.

Marine

Light and variable winds are here to stay into Tuesday due to an active pattern across the northern Pacific featuring a couple of fronts passing to the north. This pattern will translate to overnight land breezes and daytime sea breezes prevailing near the coasts. Guidance depicts the background flow shifting from a northerly direction to a westerly direction over the western end of the state today through Monday as the weak ridge inches southward into the area. A return of fresh to locally strong easterly trade winds is expected late Tuesday through Wednesday – likely holding through the second half of the week.
Seas will trend up toward the 10 ft Small Craft Advisory level by tonight as a new, long-period north-northwest swell arrives and builds down the island chain. A larger, northwest swell arriving Monday night into Tuesday will likely exceed the advisory level Tuesday through Wednesday before lowering into the second half of the week.
Surf along exposed north and west facing shores of the smaller islands will trend up through the day with the arrival of a long- period, north-northwest swell, then peak around the advisory thresholds late today through tonight as it moves through and peaks. Observations at the offshore buoys to the northwest are reflecting this new energy centered around the 16 to 18 second bands this morning with a swell height trending up to around 5 to 6 ft. Given the later than predicted arrival, the surf forecast has been adjusted accordingly, with a peak now expected this evening through tonight.
A more significant northwest swell is expected Monday night through midweek, which will likely drive surf heights to warning levels for exposed north and west facing shores of the smaller islands beginning Tuesday. Recent satellite data showed a decent sized area of storm- to near hurricane-force winds aimed at the islands within the 310 to 330 degree directional bands. Guidance suggests warning-level surf will be likely Tuesday into Tuesday night, advisory levels Wednesday, then dipping below by Thursday as the swell moves out. Swell direction will shift more out of the north Wednesday through Thursday in response to the source tracking by far north of the state Monday through Tuesday.
Surf along south facing shores will remain small with mainly a combo of background/small (long period) southerly swells and short- period southeast energy moving through.
Surf along east facing shores will remain near flat levels through much of the week. Although trades are expected to return through the second half, the lack of the typical upstream fetch will limit the surf to just small and choppy conditions Wednesday through next weekend.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.

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Data Courtesy of NOAA.gov