Hilo

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 87 near the shore to 66 to 73 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 64 to 73 near the shore to 57 to 62 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny with scattered showers. Highs 80 to 87 near the shore to 66 to 74 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 85 to 90 near the shore to around 73 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 72 to 77 near the shore to 53 to 59 near 5000 feet. North winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Monday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 84 to 90 near the shore to 71 to 76 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 65 to 86. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 65 to 73 near the shore to 58 to 64 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Monday: Breezy. Partly sunny with scattered showers. Highs 65 to 86. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 65 to 86. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 65 to 73 near the shore to 58 to 64 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Monday: Breezy. Partly sunny with scattered showers. Highs 65 to 86. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 87 near the shore to around 71 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Isolated showers in the evening. Lows around 76 near the shore to around 55 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Monday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 70 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 87 near the shore to 66 to 73 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 64 to 73 near the shore to 57 to 62 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny with scattered showers. Highs 80 to 87 near the shore to 66 to 74 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the morning. Highs 85 to 92 near the shore to 69 to 75 above 4000 feet. North winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Gusts up to 35 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 76 near the shore to 54 to 59 above 4000 feet. East winds 10 to 20 mph decreasing to up to 20 mph after midnight.

Monday: Sunny. Highs 85 to 92 near the shore to 69 to 76 above 4000 feet. North winds around 10 mph.

Detailed Forecast

Synopsis

Moderate to locally breezy trade winds are expected to persist through mid-week. A band of low clouds and trade showers will continue to move from east to west across the state today. This will produce wet conditions over most windward and mauka sections, with a few showers moving over leeward sections of the smaller islands. By this afternoon, clouds and scattered showers will also likely develop over upslope sections of the leeward Big Island. A rather typical trade wind weather pattern is expected from Monday through mid-week, with low clouds and brief trade showers favoring windward and mauka areas, especially during the nights and mornings.

Discussion

A 1029 mb surface high pressure system remains almost stationary near 36N 166W, or about 1250 miles north-northwest of Honolulu. The relatively tight pressure gradient south of this feature is producing moderate to locally breezy trade winds across the main Hawaiian Islands. The trade wind inversion has eroded early this morning based on the soundings from Hilo and Lihue. An area of enhanced moisture continues to push from east to west over the state. Loops of satellite imagery and radar reflectivity data show a band of broken to overcast low clouds with embedded scattered trade showers moving across the state. This has produced wet conditions over most windward amd mauka areas overnight. In addition, a few showers have been transported over leeward sections of some of the smaller islands.
The forecast guidance indicates the surface high will likely maintain the moderate to locally breezy trade winds through mid- week. We expect the wet conditions will persist over most windward and mauka areas through early Monday morning. After this area of enhanced moisture moves west of the area, a weak mid- tropospheric ridge above the region will keep the atmosphere relatively stable and dry. This will likely usher in a slightly drier trade wind weather pattern from Monday into mid-week. So, expect low clouds and light trade showers to mainly affect windward and mauka areas, especially during the nighttime and early morning hours. In addition, expect a typical pattern of clouds and a few showers developing over the upslope sections of the leeward Big Island each afternoon, followed by gradual clearing each night.

Aviation

Little change to the forecast this morning with a surface high remaining north of the islands. Expect moderate to locally breezy trade winds to continue for the next several days, with ridging aloft helping to maintain a stable airmass over the islands.
An area of moisture being carried in on the trade wind flow is bringing some increased clouds and showers to the windward and mountain areas of the islands early this morning and that is expected to continue into mid-morning. AIRMET Sierra for mountain obscuration is in effect for the east side of most islands as a result of these clouds and showers. Expect improving conditions later this morning.
AIRMET Tango remains in place for low-level turbulence over and downwind of the terrain on all islands. VAD wind profiles continue to suggest this turbulence is at border line strength to warrant an AIRMET, but with little change expected, the AIRMET is likely to remain posted today.

Marine

Surface ridging far north of the state will continue to produce moderate to locally strong trade winds the next several days. A Small Craft Advisory (SCA) remains in effect through early Monday morning for the typical windy areas around Maui County and Big Island. The SCA will likely be extended through mid-week.
No significant swells are expected this week. A small, long period south swell (190 degrees) will pass through the coastal waters late Monday through Wednesday. This will allow for a modest bump in surf along south facing shores, though still well below seasonal norms. Surf will remain small and choppy along east facing shores, driven by the locally strong trade winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov