Photo Credit: James Grenz

Hilo

Today: Mostly cloudy until late afternoon then becoming mostly sunny. Showers likely until late afternoon, then chance of showers late in the afternoon. Highs 76 to 81 near the shore to around 66 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Tonight: Partly cloudy with chance of showers in the evening, then mostly cloudy with showers likely after midnight. Lows 62 to 70 near the shore to 52 to 57 at 4000 feet. East winds up to 15 mph. Chance of rain 60 percent.

Wednesday: Partly sunny with chance of showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 79 near the shore to 63 to 69 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny. Slight chance of showers in the morning. Slight chance of showers late in the afternoon. Highs 81 to 86 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear with a 20 percent chance of showers. Lows around 71 near the shore to 49 to 54 near 5000 feet. Light winds.

Wednesday: Mostly sunny with isolated showers. Highs around 83 near the shore to around 65 near 5000 feet. Southeast winds up to 10 mph shifting to the west around 10 mph in the afternoon. Chance of rain 20 percent.

Waimea

Today: Breezy. Partly sunny with chance of showers until late afternoon, then mostly sunny with slight chance of showers late in the afternoon. Highs 64 to 84. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Windy. Partly cloudy with slight chance of showers in the evening, then mostly cloudy with chance of showers after midnight. Lows around 63 near the shore to 54 to 61 near 3000 feet. East winds up to 30 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with chance of showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 84. East winds 10 to 25 mph. Chance of rain 40 percent.

Kohala

Today: Breezy. Partly sunny with chance of showers until late afternoon, then mostly sunny with slight chance of showers late in the afternoon. Highs 64 to 84. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Windy. Partly cloudy with slight chance of showers in the evening, then mostly cloudy with chance of showers after midnight. Lows around 63 near the shore to 54 to 61 near 3000 feet. East winds up to 30 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with chance of showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 84. East winds 10 to 25 mph. Chance of rain 40 percent.

South Big Island

Today: Sunny and windy. A 20 percent chance of showers late in the afternoon. Highs around 82 near the shore to around 65 near 5000 feet. East winds up to 30 mph increasing to 10 to 30 mph in the afternoon.

Tonight: Mostly clear. Windy. Lows around 71 near the shore to around 51 near 5000 feet. East winds 10 to 30 mph.

Wednesday: Sunny and breezy. Highs around 81 near the shore to around 64 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Mostly cloudy until late afternoon then becoming mostly sunny. Showers likely until late afternoon, then chance of showers late in the afternoon. Highs 76 to 81 near the shore to around 66 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Tonight: Partly cloudy with chance of showers in the evening, then mostly cloudy with showers likely after midnight. Lows 62 to 70 near the shore to 52 to 57 at 4000 feet. East winds up to 15 mph. Chance of rain 60 percent.

Wednesday: Partly sunny with chance of showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 79 near the shore to 63 to 69 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny and breezy. Slight chance of showers early in the morning, then chance of showers in the late morning and early afternoon. Highs 78 to 86 near the shore to 65 to 71 above 4000 feet. North winds up to 25 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Windy. Lows 66 to 73 near the shore to 49 to 55 above 4000 feet. Northeast winds up to 30 mph.

Wednesday: Sunny and breezy. Highs 78 to 86 near the shore to 63 to 70 above 4000 feet. East winds 10 to 20 mph shifting to the north in the afternoon.

Detailed Forecast

Synopsis

Strengthening trade wind flow, along with scattered showers, will expand along mainly windward areas of the islands into Tuesday. Otherwise breezy and mostly dry conditions are expected for the remainder of the work week.

Discussion

Breezy trade winds and showers will continue to expand from east to west across the islands tonight, as an area of moisture wraps in across the state around the base of a large area of high pressure situated well northeast of the region. Current radar and satellite data are already showing showers developing as far west as windward Oahu this evening. Model soundings do show inversion heights and precipitable water values increasing some this evening across the state, as compared to the observed 00Z values. However, upper level ridging and dry air aloft are expected to continue hindering rain shower intensity and areal coverage for the overnight hours through early Tuesday.
For the remainder of the work week, breezy and mostly dry conditions will continue as a strong subtropical high remains anchored to the northeast. Additional subsidence will continue to be supplied by upper level ridging, enhancing the stability over the islands and limiting the chance for showers through Friday. A cold front approaching the region from the west on Tuesday will likely stall around 500 miles northwest of Kauai, which will steer winds across Hawaii slightly east/southeast Wednesday through the end of the week. This flow pattern will allow winds to decrease across portions of the smaller islands due to partial upstream blockage from Maui and the Big Island. Winds will focus any incoming clouds and showers over windward slopes.

Aviation

Breezy trade winds will push bands of showery low clouds across mainly windward and mauka sections of the islands. One such band has reached the islands and is spreading cloud cover across the chain. AIRMET Sierra is in effect for tempo mountain obscuration above 2500 feet along north through southeast slopes of Kauai, Oahu, Molokai, Maui and the Big island. AIRMET Tango for moderate low level mechanical turbulence to the lee of higher terrain below 9000 feet remains in effect due to the breezy trades.

Marine

Surface high pressure far northeast of the area will continue to produce moderate to locally strong trade winds over the next several days. A Small Craft Advisory (SCA) is currently posted for the typically windy waters around Maui County and the Big Island through early Wednesday morning. Also, due to an expected surge in trade winds tonight and early Tuesday associated with a band of showers embedded within the trade wind flow, the SCA has been expanded to include windward waters from Oahu eastward through Tuesday.
Short period choppy surf will dominate the Hawaiian shorelines this week with a slight downward trend expected over the weekend as trade winds become lighter. Otherwise, there will be a series of rather small northwest and south swells throughout the forecast period keeping surf above flat levels.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Tuesday for Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.
Small Craft Advisory until 6 AM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov