Hilo

Today: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 64 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 72 near the shore to around 57 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 60 percent.

Friday: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 63 to 71 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 86 to 91 near the shore to around 71 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Lows 71 to 76 near the shore to around 55 near 5000 feet. Light winds.

Friday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 86 near the shore to around 70 near 5000 feet. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 40 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 68 to 88. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69 near the shore to 56 to 64 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 66 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 68 to 88. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69 near the shore to 56 to 64 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 66 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to around 70 near 5000 feet. East winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 73 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph.

Friday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 64 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 72 near the shore to around 57 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 60 percent.

Friday: Partly sunny with scattered showers. Highs 79 to 84 near the shore to 63 to 71 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 83 to 91 near the shore to 69 to 75 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows 71 to 76 near the shore to 51 to 58 above 4000 feet. Southeast winds up to 25 mph.

Friday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 82 to 89 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Strong trade winds will continue through much of today due to high pressure to the north and a tropical disturbance passing south of the islands. The trade winds will gradually ease, but remain breezy, as the disturbance moves away Friday and Saturday. A trend toward even lighter winds is expected early next week. With limited moisture and a stable atmosphere, little total rainfall is anticipated, with just a few brief windward showers.

Discussion

Locally strong trades will continue through the morning hours in response to a tropical disturbance passing south of the islands. Winds have remained firmly below advisory criteria for several hours now, and although a localized gust up to 50 mph in Maui County or Leeward Big Island cannot be ruled out, confidence falls well short of re-issuing a wind advisory for today. Trades will gradually trend downward during the latter half of the day as the disturbance gradually advances westward, though high cloud cover will trend upward compared to yesterday as associated convective debris is entrained in southwesterly flow aloft. Dry conditions can likewise be expected to continue given limited upstream cloud coverage and high stability noted on the latest soundings out of Lihue and Hilo.
CIMSS PWAT imagery reveals a much drier upstream airmass extending from about 150W to the West Coast and reaching as far south as 15N. As an upper low positioned near 160W over the Aleutian Island chain anchors an expanding corridor of mid-level height falls this weekend through early next week, the governing surface high over the NE Pacific will be forced southward and weaken. In response, winds veer to ESE and usher this airmass into the forecast area, bringing additional stability and reinforcing the existing dry pattern. By early next week, trades become light as a decaying mid-latitude front approaches the islands from the north. At this time, it appears winds may be light enough for island-scale land and sea breezes to dominate the weather over the islands.

Aviation

Gusty easterly trades will continue today, with clouds and light showers favoring windward and mountain areas through the morning hours. Although VFR conditions will prevail for most areas, a persistent band of low clouds impacting windward sections of the Big Island supports AIRMET Sierra for mountain obscuration continuing through the early morning hours.
AIRMET Tango will persist to due to low-level mechanical turbulence over and downwind of mountain ranges.

Marine

With a robust high centered far north-northeast of the islands and an area of low pressure passing to the south, trade winds have been breezy to locally strong and seas have become rough in response. Conditions will gradually ease over the next day or two.
A Small Craft Advisory (SCA) remains in effect for all of the waters surrounding the islands of Maui County and the Big Island, as well as the waters south of Oahu, and south and west of Kauai, through this afternoon. SCA conditions will then continue in the typically windier waters around Maui County and the Big Island into Friday. Trades will taper off to some extent as the low pressure area moves away through Friday, but the SCA may still need to be extended for the same windy waters.
Breezy trades will also cause rough and choppy surf to peak near, or slightly above, the seasonal average along east facing shores through today. Surf heights may trend down along east facing shores as the trade winds ease to moderate speeds. Elsewhere, a very small, long-period south swell and a small, short-period southeast swell will continue to produce modest surf along south facing shores through today. Another small, medium-period south swell may arrive Saturday, which will maintain small surf along south facing shores this weekend. Elsewhere, expect nearly flat conditions to persist along most north facing shores through this weekend.
Monthly high tides are expected to peak during the next day or so, with the maximum astronomical high tides occurring during the afternoon hours. Tide station observations are showing close to the predicted water levels for most stations around Hawaii. We do not plan to issue a Coastal Flood Statement at this time, since the guidance indicates the water level values will likely remain just below the significant impact levels.

Fire weather

Strong trade winds and low relative humidity values are expected to result in critical fire conditions today as KBDI (Keetch- Byram Drought Index) values indicate significant soil moisture deficit. As a result, the Red Flag Warning (RFW) remains in effect.

HFO Watches/Warnings/Advisories

Red Flag Warning until 6 PM HST this evening for Niihau, Kauai Leeward, Oahu South Shore, Waianae Coast, Oahu North Shore, Central Oahu, Waianae Mountains, Molokai Leeward, Lanai Makai, Lanai Mauka, Kahoolawe, Maui Leeward West, Maui Central Valley, Leeward Haleakala, Kona, South Big Island, Kohala, Big Island Interior.
Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Leeward Waters, Kauai Channel, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.

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Data Courtesy of NOAA.gov