Photo Credit: James Grenz

Hilo

Today: Mostly cloudy with numerous showers. Highs around 81 near the shore to 64 to 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Numerous showers in the evening, then showers after midnight. Lows 65 to 73 near the shore to around 59 at 4000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 71 at 4000 feet. East winds 10 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 70 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 around 56 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Saturday: Sunny in the morning, then cloudy with scattered showers in the afternoon. Highs around 85 near the shore to around 69 near 5000 feet. North winds up to 10 mph in the morning becoming light. Chance of rain 40 percent.

Waimea

Today: Mostly cloudy with scattered showers. Highs 68 to 87. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 65 to 71 near the shore to 57 to 65 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 68 to 86. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Mostly cloudy with scattered showers. Highs 68 to 87. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 65 to 71 near the shore to 57 to 65 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 68 to 86. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph.

Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 73 near the shore to around 54 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Breezy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 85 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy with numerous showers. Highs around 81 near the shore to 64 to 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Cloudy. Numerous showers in the evening, then showers after midnight. Lows 65 to 73 near the shore to around 59 at 4000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 71 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny in the morning then becoming partly sunny. Highs 82 to 89 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 10 mph.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 73 near the shore to 52 to 58 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 82 to 88 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure system far north of the Hawaiian Islands will keep moderate to locally breezy winds in the forecast into much of next week. A cloud band from an old front will diminish over the islands today as we return to a more typical passing trade wind showers. Wetter trends may develop by next Wednesday as deep tropical moisture could track into the state from the Eastern Pacific and enhance rainfall across the island chain.

Discussion

The satellite picture this morning shows a diminishing band of clouds stretching eastward from Maui. Local radar imagery shows isolated to scattered showers across the state. Another weak wave in the easterlies will move into the Big Island and Maui by this evening, increasing shower activity over windward sections of both islands through Saturday morning. The subtropical jet stream remains active northwest of Kauai with high level cirrus clouds, made of ice crystals, enhancing Hawaiian sunrise and sunset colors.
The high pressure system far north of Kauai will slowly drift eastward through Wednesday. Trade winds will remain in the moderate to locally breezy range over the state with slight day to day changes in the wind speeds. Shower activity will change to a more typical passing shower regime for most areas through Tuesday. The one exception will be over the windward Big Island and eastern Maui on Friday night and Saturday as a weak wave in the easterly wind flow will bump up shower activity a bit for the eastern islands especially in the overnight to early morning hours. A brief drying trend is expected on Sunday due to increasing stability from stronger subsidence, resulting in lower trade wind inversion heights, and slightly stronger wind speeds as the temperature inversion shrinks the boundary layer.
The weather pattern trends wetter from Wednesday onward, as deeper tropical moisture (remnants of Tropical Cyclone Bonnie) drift over the region. Global models continue to agree that this unstable moisture will move into the eastern islands by Wednesday afternoon and spread westward into Oahu and Kauai by Wednesday night. If this deeper moisture tracks as the long range model solutions predict, then we could see decent rainfall amounts across all islands. The far extended range forecast guidance even hints at another surge of deeper tropical moisture moving up into the region by the following weekend around July 16th. Stay tuned for changes to the long range weather forecast as these systems get closer to the islands.

Aviation

High pressure to the north of the state will allow for breezy trade winds to persist through the forecast period. Thus, expect scattered showers to mainly affect windward locations, with isolated activity elsewhere. There may be periods of MVFR ceiling and visibility that accompany some of the heavier showers, though not expecting anything widespread.
AIRMET Tango remains in effect for low level turbulence to the lee of higher elevations statewide.

Marine

No significant changes to the forecast this morning, and the forecast philosophy remains the same. High pressure to the north will maintain moderate to locally fresh trade winds into the weekend, with an uptick in wind speeds expected this weekend. This uptick is expected to persist into the start of the new week. A Small Craft Advisory (SCA) is in effect for the windier waters near Maui County and Big Island through Monday. The SCA may need to be expanded to include additional coastal waters this weekend with the uptick in winds.
No significant swells are expected over the next few days. As trades strengthen this weekend, some east facing shores may see a little bump, but nothing significant is expected. A long period southwest to south swell is expected to reach the islands early next week, boosting surf to near to slightly above normal for the summer months. A small, medium period, east swell generated by Hurricane Bonnie, currently in the East Pacific, may arrive early next week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov