Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Occasional showers in the morning, then showers likely in the afternoon. Highs 80 to 87 near the shore to around 69 at 4000 feet. East winds up to 15 mph. Chance of rain 80 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 72 near the shore to 55 to 60 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny with scattered showers. Highs 79 to 87 near the shore to around 69 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 83 to 89 near the shore to 65 to 70 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 74 near the shore to 50 to 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 89 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Mostly cloudy. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 73 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 64 to 85. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Kohala

Today: Mostly cloudy. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 73 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 64 to 85. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Breezy. Partly sunny with scattered showers. Highs around 87 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 74 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Occasional showers in the morning, then showers likely in the afternoon. Highs 80 to 87 near the shore to around 69 at 4000 feet. East winds up to 15 mph. Chance of rain 80 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 72 near the shore to 55 to 60 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny with scattered showers. Highs 79 to 87 near the shore to around 69 at 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 84 to 89 near the shore to 65 to 72 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 75 near the shore to 51 to 57 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 84 to 89 near the shore to 66 to 73 above 4000 feet. North winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate trade winds will continue over the next few days, with breezy to locally windy trades returning by early next week. A weak disturbance riding in on the trades will increase clouds and shower activity through this evening. Another weak disturbance will move across the islands on Tuesday. Significant rainfall is not expected from either disturbance, but they should provide some beneficial rain for windward and mauka areas.

Discussion

A weak trough over the Kaiwi Channel will continue to move across the rest of the state today. Clouds and embedded showers continue to move into Windward Big Island early this morning with localized areas of moderate to heavy rainfall across the Hamakua Coast down to Puna and along the Kau Coast. The highest rainfall total over the last 12 hours was 4.2 inches near Honolii. The wetter weather has started to move into East Maui over the last few hours. The 12Z sounding at Hilo contained 1.81 inches of precipitable water under a weakly unstable atmosphere, with CIMSS MIMIC PWATs showing similar values over the Alenuihaha Channel. This setup continues to support areas of moderate to locally heavy rainfall totals over Windward Big Island and East Maui today, but flooding concerns remain minimal. Otherwise, the rest of the state can expect a slight uptick in windward clouds and showers through tonight as the moisture plume continues to move east across the islands. Leeward areas will mainly see an increase in cloud cover through tonight with some passing showers.
Drier conditions return Sunday with breezy trades expected by Monday. Breezy to locally windy trade will then continue through much of the upcoming week as high pressure strengthens far northeast of the state.
Another disturbance associated with an area of deeper moisture currently near 137 degrees West is expected to move across the state on Tuesday, with model PWATs around 1.8 inches. This system should bring more widespread clouds and showers to windward and mauka areas of all islands. With the stronger trades in place expect some of these showers to spillover into leeward areas at times. Expect a return to more typical trade wind weather conditions behind the disturbance with strong trades continuing through the end of the upcoming week.

Aviation

Moderate to locally breezy trades will continue into the weekend. A passing disturbance is expected to bring an increase in windward SHRA to the east end of the state through the rest of today. Low cigs should favor windward and mauka areas with brief periods of MVFR possible. Otherwise, VFR should prevail.
AIRMET Sierra for mtn obsc is in effect for windward Big Island. Conds should improve by mid morning.

Marine

A high pressure system far north of the Hawaiian Islands will will begin to strengthen the trade winds into the fresh to locally strong afternoon as the high center strengthens. Trade wind speeds will be strong enough to support Small Craft Advisory (SCA) conditions over the windier waters and channels near Maui and the Big Island starting this evening and lasting through much of next week. An SCA was issued for these waters starting tonight.
Background south swell energy pulses are forecast to continue with surf remaining below average through much of next week. Small, choppy surf is expected for east facing shores for the next several days due to continued trade winds. Surf then becomes increasingly rough along east facing shores as locally strong trades increase early next week.
Spring tides will peak this weekend, and local tide gauges indicate water levels are already running above guidance. Water levels are currently running at least 1 foot higher than the Mean Higher High Water (MHHW) threshold at Hilo, Kahului, and Honolulu and have exceeded the 1 foot threshold at Honolulu. The Coastal Flood Statement for isolated minor flooding has been extended through Monday evening.

HFO Watches/Warnings/Advisories

Small Craft Advisory from 6 PM this evening to 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters.

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Data Courtesy of NOAA.gov