Hilo

Today: Cloudy with numerous showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 78 to 83 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Scattered showers in the evening, then occasional showers after midnight. Lows 65 to 71 near the shore to around 55 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 82 near the shore to 63 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 72 near the shore to 52 to 57 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 84 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 67 to 85. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 66 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 66 to 84. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 67 to 85. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 66 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 66 to 84. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny. Breezy. Highs around 87 near the shore to around 67 near 5000 feet. East winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 72 near the shore to around 51 near 5000 feet. Northeast winds up to 20 mph.

Wednesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 85 near the shore to around 65 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Cloudy with numerous showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 78 to 83 near the shore to 65 to 72 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Scattered showers in the evening, then occasional showers after midnight. Lows 65 to 71 near the shore to around 55 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 82 near the shore to 63 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs 82 to 91 near the shore to 68 to 77 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows 69 to 74 near the shore to 50 to 58 above 4000 feet. East winds up to 25 mph.

Wednesday: Sunny in the morning then becoming partly sunny. Breezy. Highs 81 to 87 near the shore to 64 to 74 above 4000 feet. Northeast winds up to 25 mph.

Detailed Forecast

Synopsis

High pressure north of the islands will slowly drift eastward, allowing locally strong trade winds to weaken through the remainder of the week. Clouds and limited showers will favor windward slopes through tonight. Showers will then expand in areal coverage through the remainder of the work week, as an upper trough moves north of the region.

Discussion

The area of high pressure well north of the islands will maintain the locally strong easterly trades anchored across the region into Wednesday. This area of high pressure will slowly drift eastward through the reminder of the work week, relaxing the gradient and allowing the currently stronger trades to begin to weaken into the weekend.
Current satellite trends continue to show a broken layer of shallow low level moisture flowing into the state from the northeast, maintaining partly to mostly cloudy conditions across windward locations. This area of lower clouds will continue to maneuver across the islands this morning underneath a sharp low level trade wind inversion, before diminishing some later this afternoon. Radar trends and surface obs continue to show mainly isolated showers focused along windward locations this morning. These showers are expected to diminish in coverage again this afternoon in the typical diurnal trade wind pattern, though remaining across favored windward areas and in channel between islands. Rainfall amounts and rates will be limited again through tonight, as the airmass remains stable with an upper ridge in place and depth of moisture remains shallow.
Otherwise, showers are then expected to increase in areal coverage, mainly along windward areas Wednesday through Friday, as a weakly organized upper trough drifts north the state from east to west. This combined with the increasing trade wind inversion heights may also allow some showers to affect the drier leeward areas Thursday and Friday.
By the weekend, drier and more stable conditions filter back across the islands and limit showers and clouds to mainly windward locations into the beginning of next week.

Aviation

Gusty easterly trade winds will continue today, with clouds and light showers favoring windward and mauka locations. The broken to overcast low-level cloud deck (shallow) that has been impacting most windward areas through much of the night has begun to break up early this morning. If this trend continues, AIRMET Sierra for mountain obscuration may be cancelled.
AIRMET Tango remains in effect for low-level turbulence over and downwind of the terrain of all islands today.

Marine

The High Surf Warning for south facing shores has been downgraded to a High Surf Advisory (HSA) as the current south swell continues to slowly subside through today. The HSA may need to be extended through tonight if offshore buoys remain elevated through the day. Surf is expected to drop below the HSA threshold of 10 feet for the south- facing shores on Wednesday. No additional south swells are expected for the Thursday through Saturday time frame. A small, long period south swell is possible late this weekend into early next week.
East-facing shores will continue to see elevated short period choppy surf through today and may drop a notch tomorrow as trades weaken slightly. Models are indicating that a small, long period east swell from tropical cyclone Estelle, located in the far eastern Pacific, may provide a slight boost in surf for east facing shores late this week into the weekend. No other significant swells are expected.
High pressure to the far north of the islands will maintain moderate to locally strong trades through today. The Small Craft Advisory (SCA) has been extended for the typically windier waters around the Big Island and Maui through Wednesday afternoon. The high is expected to weaken slightly and shift to the far northeast later this week, resulting in weaker trades and the possibility of dropping the SCA.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kohala, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, Kipahulu, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 PM 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