Hilo

Tonight: Partly cloudy with isolated showers. Lows 62 to 69 near the shore to 51 to 58 at 4000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 78 to 83 near the shore to 65 to 72 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows 61 to 69 near the shore to 51 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Kona

Tonight: Mostly clear. Lows around 72 near the shore to 45 to 52 near 5000 feet. Light winds.

Wednesday: Mostly sunny with isolated showers. Highs 82 to 87 near the shore to around 69 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows around 71 near the shore to 46 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs around 79 near the shore to 70 to 78 near 3000 feet. Light winds. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

Kohala

Tonight: Mostly clear. Isolated showers in the evening. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs around 79 near the shore to 70 to 78 near 3000 feet. Light winds. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows 62 to 70 near the shore to 53 to 61 near 3000 feet. Light winds. Chance of rain 20 percent.

South Big Island

Tonight: Mostly clear. Lows around 73 near the shore to around 52 near 5000 feet. Northeast winds up to 10 mph.

Wednesday: Mostly sunny with isolated showers. Highs around 84 near the shore to around 69 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows around 72 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Puna

Tonight: Partly cloudy with isolated showers. Lows 62 to 69 near the shore to 51 to 58 at 4000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 78 to 83 near the shore to 65 to 72 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening. Lows 61 to 69 near the shore to 51 to 58 at 4000 feet. Light winds. Chance of rain 20 percent.

Waikoloa

Tonight: Mostly clear. Lows around 72 near the shore to 49 to 54 above 4000 feet. Light winds.

Wednesday: Sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to 66 to 73 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Lows 69 to 74 near the shore to 49 to 54 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

Dry and stable conditions will persist statewide through Wednesday, with a deep-layer ridge remaining in place over much of the region. This will result in a land and sea breeze regime, with afternoon clouds and a potentially a few brief showers over interior and leeward areas. An approaching cold front could result in slightly better shower coverage over Kauai and Oahu on Thursday, with dry weather continuing elsewhere. Another cold front will approach and potentially reach the islands by early next week.

Discussion

A progressive pattern over the North Pacific is expected to continue over the next few days as a series of fronts pass nearby to our north. Meanwhile, ridging is in place over the islands, resulting in dry and stable conditions, as seen in the afternoon 00z Lihue and Hilo soundings. As the next front approaches from the northwest, light southerly low-level flow is prevailing ahead of it over the state, resulting in a daytime sea breeze and nighttime land breeze regime. Additionally, latest satellite imagery shows a band of clouds southwest of Oahu that has been streaming northward throughout the day, though little to no rainfall has occurred.
For the next day or so, little change is expected with light winds and a mostly dry land/sea breeze pattern continuing. The best chances for clouds will be over interior and leeward locations during the afternoon hours each day. While a few brief afternoon showers can't be ruled out, accumulations will be minimal due to the dry and stable conditions.
Guidance indicates that an approaching front could graze the northern islands as it dissipates on Thursday. This could result in a few more showers for Kauai and Oahu, though latest ensemble guidance shows only light accumulations. Based on model trends and ensemble data, QPF and shower chances were trended down a bit for Thursday. Otherwise, the general forecast philosophy remains in tact with only minor changes through the next several days.
The progressive pattern across the North Pacific will persist into the weekend, with another front approaching and potentially reaching the islands late Sunday into early next week. However, an overall dry and light wind pattern will persist through the end of the week. Easterly trades look to return by Monday of next week.

Aviation

Light winds will prevail during the next couple days, allowing for the development of sea breezes during the day and land breezes overnight. Rather dry weather will continue through the period, with limited shower activity primarily confined to windward and southeast facing slopes of the Big Island today and then to island interiors with the sea breeze activity tomorrow.
AIRMET Tango remains in effect for moderate upper level turbulence over the Big Island. Conditions will likely improve later this morning.

Marine

Mainly gentle and variable winds will prevail into the weekend. A surface ridge will remain parked over the state through Wednesday, leading to gentle to locally moderate southwest winds around Kauai, light and variable winds around Oahu and Maui County, and mostly gentle southeast winds for Big Island waters. A dissipating front will be pushed near Kauai and Oahu on Thursday, and a weak following surface high will produce gentle northerly winds, followed by a brief period of trades on Friday. A surface ridge will be pushed back over the islands during the weekend. Fresh trades may redevelop late Sunday or Monday.
A series of large to extra large northwest to north-northwest swells is due this week. Long-period northwest (315 degrees) swell has been slowly building at the NOAA buoys northwest of Kauai today, with the latest observations measuring 6 to 7 feet at 17 to 19 seconds and additional energy at longer wave periods. Two drifter buoys located over 400 nm northwest of Kauai showed that the swell was a couple feet above above GFS-Wave. Given these observations and a typical low bias in the guidance, we have opted to issue a High Surf Warning (HSW) for most north and west facing shores from Kauai to Maui. Surf may exceed the advisory threshold as early as the overnight hours and is expected to reach High Surf Warning levels Wednesday afternoon or evening. We will monitor the need for an HSA on leeward Big Island late Wednesday as more buoy data comes in. A series of storm lows passing northwest of Hawaii will produce several larger pulses of north- northwest swell that will should keep surf above warning levels Thursday through the weekend. For now, the HSW runs through Thursday afternoon but it will be extended. While winds will remain rather light this week, seas will be above the 10 foot Small Craft Advisory threshold for waters exposed to the large swells.
Aside from areas exposed to wrapping northwest swell, surf along east and south facing shores will remain small through much of the week. The best chance for a small rise in southwest swell will be on Thursday and Friday.

Fire weather

Critical fire weather conditions are not anticipated through the rest of the week due to light winds. Additionally, an increase in moisture across the western end of the state as a front approaches on Thursday will also mitigate any fire weather concerns.

HFO Watches/Warnings/Advisories

High Surf Warning from 6 AM HST Wednesday to 6 PM HST Thursday for north and west facing shores of Niihau, Kauai, Oahu, and Molokai, and for north facing shores of Maui.
Small Craft Advisory from 6 AM Wednesday to 6 PM HST Friday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.

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Data Courtesy of NOAA.gov