Hilo

Today: Cloudy. Isolated showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs 80 to 87 near the shore to 64 to 74 at 4000 feet. West winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Tonight: Cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly cloudy with scattered showers. Highs 80 to 87 near the shore to 65 to 73 at 4000 feet. West winds up to 10 mph shifting to the east around 10 mph in the afternoon. Chance of rain 40 percent.

Kona

Today: Cloudy. Scattered showers and isolated thunderstorms in the afternoon. Highs 84 to 89 near the shore to around 70 near 5000 feet. East winds up to 10 mph in the morning becoming light. Chance of rain 50 percent.

Tonight: Cloudy. Isolated showers in the evening. Lows around 74 near the shore to 51 to 56 near 5000 feet. Light winds becoming northeast up to 10 mph after midnight. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 84 to 89 near the shore to around 70 near 5000 feet. Northeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 40 percent.

Waimea

Today: Cloudy. Isolated showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to 70 to 80 near 3000 feet. Southeast winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 72 near the shore to 56 to 64 near 3000 feet. East winds up to 10 mph. Chance of rain 30 percent.

Thursday: Partly sunny with scattered showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. Southeast winds up to 10 mph shifting to the north in the afternoon. Chance of rain 40 percent.

Kohala

Today: Cloudy. Isolated showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to 70 to 80 near 3000 feet. Southeast winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 72 near the shore to 56 to 64 near 3000 feet. East winds up to 10 mph. Chance of rain 30 percent.

Thursday: Partly sunny with scattered showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. Southeast winds up to 10 mph shifting to the north in the afternoon. Chance of rain 40 percent.

South Big Island

Today: Cloudy. Isolated showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. Northeast winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy. Isolated showers in the evening. Lows around 74 near the shore to around 53 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to around 67 near 5000 feet. Northeast winds around 10 mph shifting to the south in the afternoon. Chance of rain 40 percent.

Puna

Today: Cloudy. Isolated showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs 80 to 87 near the shore to 64 to 74 at 4000 feet. West winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Tonight: Cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Thursday: Mostly cloudy with scattered showers. Highs 80 to 87 near the shore to 65 to 73 at 4000 feet. West winds up to 10 mph shifting to the east around 10 mph in the afternoon. Chance of rain 40 percent.

Waikoloa

Today: Cloudy. Isolated showers and thunderstorms in the afternoon. Highs 84 to 90 near the shore to 67 to 73 above 4000 feet. Southeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Tonight: Cloudy. Lows around 75 near the shore to 53 to 58 above 4000 feet. East winds up to 10 mph.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 85 to 90 near the shore to 67 to 74 above 4000 feet. East winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Two upper lows will linger just north of the Hawaii Region, producing trough reflections at the surface. These surface troughs will continue to weaken the ridge farther north of the state, keeping light to moderate trade winds in the forecast at least through Friday. High pressure will build in from the northwest this weekend and will strengthen trade wind speeds into the moderate to locally breezy range from Sunday onward. Passing shower activity will return to windward and mountain areas, favoring the overnight to early morning hours.

Discussion

Satellite water vapor imagery this morning continues to show two upper level lows spinning just northwest and north of the Hawaii Region. These upper level lows are strong enough to produce trough reflections in the surface pressure gradient north of the island chain, weakening the ridge farther north of the state through Friday. A subtropical jet stream over the region will continue to spread high level cirrus and middle level clouds across the state for the foreseeable future, enhancing sunrise and sunset colors in most areas. Isolated thunderstorms are possible for the higher elevation slopes of Mauna Kea and Mauna Loa.
A local scale land and sea breeze weather pattern will continue through Friday for most areas in a light large scale trade wind weather pattern. Trade wind temperature inversion heights from the 12Z (2 AM HST) morning balloon soundings from Lihue and Hilo range from 4,000 to 5,000 feet. Boundary layer moisture levels are fairly dry and a lack of instability will limit rainfall amounts today. Clouds and moisture under the subtropical jet steam does not seem to have a good surface connection to produce any shower enhancement over the Big Island or Maui at this time. One exception mights be the higher elevation slopes on the Big Island where if enough moisture moves in then isolated thunderstorms may develop during maximum heating in the afternoon hours.
The weather pattern changes on Saturday as the high pressure ridge north of the region builds back in from the northwest. Strengthening trade winds will produce brief passing showers along windward and mountain slopes, favoring the overnight to early morning hours. Trade wind temperature inversion heights during this time will range from 6,000 to 8,000 feet elevation as the trade winds return favoring a scattered to occasionally numerous overnight shower pattern.

Aviation

A light trade wind flow will continue, which will allow daytime sea breezes and nighttime land breezes to develop. Limited low clouds and showers will favor interior and leeward areas during the afternoon through the early evening, then windward areas overnight through early morning. VFR conditions will prevail, with ISOL MVFR VIS/CIG in SHRA. Increased moisture moving over the Big Island today may fuel an isolated thunderstorm over the slopes this afternoon.
AIRMET TANGO for moderate turbulence between FL300 and FL450 will be dropped this morning as the potential for turbulence is diminishing.

Marine

A few surface troughs between the islands and surface high pressure northeast of the state will keep gentle to locally fresh easterly trade winds through Thursday. Surface high pressure far northwest of the state will push southeast near 170W, as a ridge builds north of the state. This will reinforce the local pressure gradient as moderate to locally fresh trades look to hold through the weekend.
A long period south swell has filled in across the state as surf along south- facing shores reach near High Surf Advisory levels through today. The swell will gradually decline Thursday and Friday.
No other significant swells are expected through the week. A tiny northwest swell will keep north facing shores above summer time averages. East facing shores will remain small, as trade remain relatively light. Long range forecasts indicate the potential for a moderate, long period easterly swell from rapidly intensifying Hurricane Jova in the east pacific arriving early next week.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov