Photo Credit: James Grenz

Hilo

Today: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to around 68 at 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows 63 to 69 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Friday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to around 69 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs around 82 near the shore to around 66 near 5000 feet. North winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 68 to 73 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs around 82 near the shore to around 66 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly cloudy with isolated showers. Highs around 78 near the shore to 64 to 75 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 61 to 66 near the shore to 53 to 63 near 3000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Friday: Breezy. Mostly cloudy with isolated showers. Highs around 79 near the shore to 65 to 75 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Kohala

Today: Breezy. Mostly cloudy with isolated showers. Highs around 78 near the shore to 64 to 75 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 61 to 66 near the shore to 53 to 63 near 3000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Friday: Breezy. Mostly cloudy with isolated showers. Highs around 79 near the shore to 65 to 75 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 70 near the shore to around 51 near 5000 feet. Northeast winds 10 to 25 mph.

Friday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 82 near the shore to around 66 near 5000 feet. East winds up to 20 mph.

Puna

Today: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to around 68 at 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows 63 to 69 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Friday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 80 near the shore to around 69 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs 78 to 86 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Partly cloudy. Breezy. Lows around 71 near the shore to 50 to 58 above 4000 feet. Southeast winds up to 20 mph.

Friday: Sunny in the morning then becoming partly sunny. Highs 78 to 85 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 15 mph.

Detailed Forecast

Synopsis

Moderate to breezy easterly trade winds will continue into the weekend, with clouds and showers favoring windward and mauka locations overnight through the morning periods. Trade winds will trend down and shift out of the southeast late Sunday into Monday, then out of the south Tuesday through Wednesday as a front stalls west-northwest of the islands. Plenty of deep moisture being drawn northward combined with an upper disturbance will translate to a potential wet pattern setting up next week.

Discussion

Guidance remains in decent agreement into the upcoming weekend and shows the subtropical ridge holding north of the area. This combined with upper ridging and plenty of dry air will limit windward and mauka shower coverage and accumulations each day (PWs hovering around or just above an inch) – best shower chances being overnight through the early morning hours as pockets of moisture move through.
A transition period is anticipated through the second half of the weekend as the ridge breaks down and shifts southward in response to a front passing to the north and an upper low dropping southeastward toward the region. Low-level southeasterly flow will give way to a land and sea breeze regime Sunday through Monday for some areas (western end of the state). Although the dry air will limit rainfall accumulations, some leeward clouds and showers will be possible through the afternoon and early evening periods where sea breezes form. Otherwise, clouds and showers will continue to focus over windward and southeast facing slopes/areas.
For the extended (late Monday through midweek), strengthening southerly winds expected due to a front to the west and an upper trough in the area will draw up plenty of deep tropical moisture across the islands, which will drive rainfall chances up. Although confidence remains low being this far out due to model differences shown (GFS being the wetter solution), this wet pattern may linger well into the second half of the week. If this scenario evolves, expect some much needed rainfall across our dry leeward areas (especially for Kauai/Oahu).

Aviation

Breezy, mostly dry trade winds conditions are expected to persist through Friday. Occasional bands of weak showers will impact mainly east and northeast facing slopes and coasts. A well-defined trade wind inversion around 06 kft will inhibit most local shower development. Brief MVFR CIG or VIS are expected in passing showers; otherwise VFR conditions will prevail.
AIRMET Tango for moderate low-level mechanical turbulence over and in the lee of higher terrain remains in effect and is expected to persist through Friday.

Marine

A high pressure system far northeast of the Hawaiian Islands will continue to produce moderate to locally strong trade winds through Saturday. Wind speeds will begin to diminish Sunday as the high weakens and a cold front approaches the islands from the northwest. Wind directions will veer southeast early next week. The Small Craft Advisory (SCA) has been expanded to include the Kaiwi Channel and Maui Windward waters based on latest ASCAT pass and model guidance through tonight. The SCA will continue for the typical windier waters and channels around Maui County and the Big Island through tomorrow night.
Trade wind swell will generate choppy surf conditions along east facing shores through tomorrow, followed by a slight downward trend over the weekend and into early next week as trade winds begin to weaken.
The next small medium period northwest swell is slated to arrive late this afternoon and will help keep surf heights on the small side along all north and west facing shores through tomorrow then trend down over the weekend and into early next week.
South shore surf heights will remain small through today. Background south swells will keep surf from going flat along south facing shores through the weekend. Increasing surf trends are expected early next week as several overlapping 1 to 2 foot medium to long period south swells fill in.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov