Photo Credit: James Grenz

Hilo

Today: Isolated showers before noon. Mostly sunny, with a high near 85. Calm wind becoming east northeast 5 to 9 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 66. Northeast wind 5 to 7 mph becoming light and variable after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers, mainly before noon. Partly sunny, with a high near 84. Light and variable wind becoming northeast 5 to 9 mph in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Partly sunny, with a high near 80. Light and variable wind becoming west northwest 5 to 9 mph in the morning. Chance of precipitation is 20%.

Tonight: Isolated showers. Mostly cloudy, with a low around 65. West northwest wind 5 to 9 mph becoming light and variable after midnight. Chance of precipitation is 20%.

Wednesday: Isolated showers after noon. Partly sunny, with a high near 80. Light and variable wind becoming west southwest 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

Waimea

Today: Isolated showers after 1pm. Mostly sunny, with a high near 79. Breezy, with a northeast wind 13 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly after 1am. Partly cloudy, with a low around 58. Breezy, with a northeast wind around 18 mph, with gusts as high as 25 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers, mainly before 1pm. Mostly sunny, with a high near 79. Breezy, with a northeast wind 17 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Isolated showers. Mostly sunny, with a high near 65. Breezy, with an east wind 11 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Scattered showers. Partly cloudy, with a low around 53. Breezy, with an east wind 16 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers, mainly before noon. Mostly sunny, with a high near 65. Breezy, with an east wind 13 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers before noon. Mostly sunny, with a high near 85. Breezy, with an east wind 17 to 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 74. Windy, with an east wind 20 to 23 mph, with gusts as high as 30 mph.

Wednesday: Mostly sunny, with a high near 85. Windy, with an east wind 18 to 23 mph, with gusts as high as 30 mph.

Puna

Today: Isolated showers. Partly sunny, with a high near 84. Northwest wind 6 to 11 mph becoming east northeast in the morning. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 64. North wind around 10 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 83. Breezy, with a north northeast wind 9 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Mostly sunny, with a high near 85. East wind 6 to 14 mph becoming west northwest in the morning. Winds could gust as high as 18 mph.

Tonight: Partly cloudy, with a low around 66. Breezy, with an east wind 11 to 16 mph, with gusts as high as 22 mph.

Wednesday: Mostly sunny, with a high near 85. Breezy, with a north northeast wind 6 to 15 mph, with gusts as high as 21 mph.

Detailed Forecast

Synopsis

Trade winds will return today, reaching and holding at moderate levels tonight through early next week. Rather dry conditions will prevail through Wednesday night, with showers mainly confined to windward and mauka areas. The remnants of an old front will likely bring a notable increase in showers to Kauai and possibly Oahu Thursday into Friday. A more typical trade wind pattern is then expected Saturday through early next week, with showers favoring windward and mauka areas, mainly at night and during the early morning hours.

Discussion

Currently at the surface, a weak front is nearly stationary around 250 miles northwest of Kauai. Meanwhile, a 1025 mb high is centered 1600 miles northeast of Honolulu, with a ridge axis extending southwestward through to near the Garden Isle. The resulting gradient is producing light and variable winds over the western islands, with light to moderate trades over the eastern end of the state. Infrared satellite imagery shows clear to partly cloudy conditions in most areas, with a bit more cloud cover over the Big Island and windward Maui. Radar imagery shows a few light trade showers moving into windward sections of Maui and the Big Island, as well as along the leeward Big Island coast. Elsewhere, rain free conditions prevail. Main short term concern revolves around old frontal remnants sinking southward into the western islands Thursday into Friday.
The front northwest of the state will gradually dissipate during the next couple days, as high pressure becomes more dominant north of the state. This will allow trade winds to return from east to west across the island chain today, strengthening to moderate levels statewide by late this afternoon. High pressure will then strengthen as it moves eastward and eventually northeastward Wednesday through early next week, keeping moderate trade winds in place through the period with only minor fluctuations in strength.
As for the remaining weather details, dry and stable conditions will persist today, with a few showers possible near the coast this morning and over the island interiors this afternoon. We should see a transition over to a windward and mauka focused shower pattern tonight through Wednesday night, although it will be much drier than normal with the stable conditions in place. Both the GFS and ECMWF show a band of higher precipitable water values associated with the remnants of an old front sinking southward and into the western islands Thursday and Thursday night, which will likely bring a notable increase in trade wind showers to Kauai and possibly to Oahu, while Maui County and the Big Island remain in a dry trade wind regime. The remnants of the old front may linger over Kauai into the day Friday, before lifting northwest of the islands, putting the entire island chain in a dry trade wind pattern Friday night. A more typical trade wind regime should settle in Saturday through early next week, with showers focused mainly over windward and mauka areas, and a stray shower occasionally reaching leeward communities.

Aviation

Weak land breezes this morning will give way to building trade winds in the afternoon. Trade winds will carry ragged stratocumulus and isolated showers towards the windward slopes and coasts of all islands.
For Leeward Big Island, a weak eddy is detectable on infrared satellite just off the coast, and can be seen steering low topped stratus and stratocumulus back onto west facing slopes and coasts. Conditions are likely to persist for several more hours then rapidly dissipate shortly after sunrise. Later in the day, sea breezes and inland cumulus build-ups will return.
The air mass over the state remains very stable with a well defined inversion aloft between 05 kft and 07 kft. Shower activity will remain minimal, but isolated MVFR ceilings are to be expected. No AIRMETs are currently in effect or anticipated at this time.

Marine

A front washing out across the far northern offshore waters will allow for the return of trade winds that will fill in from east to west across the island chain today. Moderate trades the next couple of days will strengthen to more areawide fresh to locally strong magnitudes through the typically windier channels and bays as early as tonight or Wednesday morning.
The current northwest swell will top out through the day and peak surf along north and west facing shores. This swell will trend down to near flat from Wednesday though Friday. A series of small southerly swells will maintain slightly below normal surf along southern shorelines through mid week. South shore surf could trend up slightly late this week with the arrival of a couple of overlapping slightly larger, higher energy south-southwest swells. East facing shore surf will remain small through today. As trades strengthen through mid to late week over and upstream of the state, there may be a small bump in short period wind waves along eastern exposures.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov