Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 64 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then frequent showers after midnight. Lows around 63 near the shore to around 49 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Thursday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Partly sunny. Scattered showers in the afternoon. Highs around 80 near the shore to around 70 near 5000 feet. North winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers. Lows 63 to 68 near the shore to around 50 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Partly sunny. Scattered showers in the afternoon. Highs around 80 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 63 to 79. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 62 near the shore to 48 to 56 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs 63 to 79. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 63 to 79. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 62 near the shore to 48 to 56 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs 63 to 79. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Partly sunny. Breezy. Isolated showers in the afternoon. Highs around 81 near the shore to around 71 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening. Lows around 65 near the shore to around 49 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Thursday: Partly sunny. Breezy. Isolated showers in the afternoon. Highs around 81 near the shore to around 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 64 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then frequent showers after midnight. Lows around 63 near the shore to around 49 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Thursday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Partly sunny. Breezy. Highs around 80 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 67 near the shore to 45 to 53 above 4000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Thursday: Partly sunny. Breezy. Isolated showers in the afternoon. Highs around 80 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy easterly trade winds will continue through the weekend, with clouds and showers favoring windward and mauka locations as pockets of moisture move through. Expect some showers to carry over into leeward areas periodically with the strong winds in place. An upper disturbance moving through may lead to a brief period with mostly cloudy skies and an increase in shower coverage tonight through Thursday night.

Discussion

Guidance remains in good agreement and shows breezy easterly trades persisting through the second half of the week as surface high pressure remains anchored north of the state. Plenty of mid- level dry air along with a strong subsidence inversion positioned between 7000 and 9000 ft and PWs hovering around an inch will limit rainfall accumulations today. Upper heights will lower tonight through Thursday night as an upper trough lurking to the west advances eastward through the area. Added instability associated with this upper feature moving through combined with a slight increase in moisture will support a brief period with mostly cloudy skies (mostly in the form of high clouds) and increasing shower coverage. The statistical QPF guidance supports this upward trend in shower coverage through this period, then depicts a more stable/dry pattern returning Friday.
Trades should persist this weekend through early next week, but some notable differences shown between the various sources of guidance, regarding the strength and direction, lowers the forecast confidence. Additionally, increasing moisture along with another upper level trough moving in from the west could translate to a period with cloudy skies and increasing shower coverage Sunday through the first half of next week.

Aviation

Moderate to locally breezy trade winds will continue through the remainder of the week. Clouds and showers will favor windward coasts and slopes, and be most active in the late night and early morning hours. In the afternoon and early evenings, leeward sea breezes and daytime heating will encourage cumulus build-ups along south and west facing slopes of the Big Island, but a strong inversion will limit their growth and rainfall potential.
AIRMET Sierra for mountain obscuration is now in effect for north through east sections sections of all islands. Conditions are expected to persist through mid-morning, possibly longer on Kauai.
AIRMET Tango remains in effect for moderate low-level turbulence to the lee of higher terrain, and will likely be needed through the remainder of the week.

Marine

Strong surface high pressure will continue to provide fresh to strong easterly trades making for rough conditions across the Hawaiian waters through the week. A Small Craft Advisory (SCA) has been issued for all exposed waters through Thursday due to a combination of a declining medium- period northeast swell and locally generated wind waves. Seas will drop slightly through Thursday as the northeast swell moves out. Most zones may remain in the SCA due to consistent fresh to strong trades through the end of the week.
Surf along exposed east facing shores will remain rough through the week, although the High Surf Advisory (HSA) has been cancelled as the northeast swell continues to move out.
Surf along north facing shores will remain small into Friday, except for shores exposed to northeast swells today as the swell continues to decline. An upward trend is expected late Friday through the weekend due to a combination of expected north- northeast and west- northwest swells. The north- northeast swell should steadily fill in late Friday, then peak over the weekend. The west- northwest swell is forecast to build down the island chain through the day Saturday, producing surf which will peak near HSA threshold across exposed north and west facing shores late Sunday.
Surf along south facing shores will remain small through midweek, with mainly background energy moving through. An upward trend is expected Thursday afternoon as a long-period south-southwest swell arrives. This swell will peak late Friday into Saturday, then ease Sunday.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Thursday for all Hawaiian waters,

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Data Courtesy of NOAA.gov