Hilo

Today: Partly sunny with scattered showers. Highs around 82 near the shore to around 65 at 4000 feet. South winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then scattered showers after midnight. Lows around 65 near the shore to around 51 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 70 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 82 near the shore to around 65 at 4000 feet. South winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 50 percent.

Kona

Today: Partly sunny. Isolated showers in the morning, then showers likely in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 65 to 72 near the shore to around 51 near 5000 feet. Light winds. Chance of rain 40 percent.

Wednesday: Mostly cloudy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Partly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 69 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 64 near the shore to 49 to 58 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 50 percent.

Wednesday: Mostly cloudy. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 69 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 69 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 64 near the shore to 49 to 58 near 3000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 50 percent.

Wednesday: Mostly cloudy. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 81 near the shore to 69 to 75 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Partly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to around 69 near 5000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows around 66 near the shore to around 51 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Wednesday: Partly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Puna

Today: Partly sunny with scattered showers. Highs around 82 near the shore to around 65 at 4000 feet. South winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then scattered showers after midnight. Lows around 65 near the shore to around 51 at 4000 feet. Southeast winds up to 10 mph shifting to the southwest after midnight. Chance of rain 70 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 82 near the shore to around 65 at 4000 feet. South winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to 64 to 71 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 72 near the shore to 46 to 54 above 4000 feet. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Wednesday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to 64 to 71 above 4000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light to moderate trades will prevail with localized leeward sea breezes and land breezes during the next couple days as a pair of fronts approach, stall out, and dissipate far to the northwest of the state. Showers will favor windward and mauka areas through mid week, with scattered leeward and interior shower development expected each afternoon and early evening. Trade winds will strengthen Wednesday night, bringing a return of more typical trade wind weather featuring mainly windward showers and the occasional leeward spillover. This pattern along with moderate to breezy trades will hold in place Thursday through early next week, with potentially windy conditions over the weekend.

Discussion

Currently at the surface, a pair of high pressure systems are centered to the distant north and northeast of the state, while a weakening southwest to northeast oriented front is located between these two features and around 450 miles north of Kauai. The resulting gradient is producing light to moderate trade winds across the state early this morning, with land breezes present in sheltered leeward areas. Infrared satellite imagery shows a mix of high and low clouds producing partly to mostly cloudy conditions, with highest cloud coverage over the eastern islands. Meanwhile, radar imagery shows scattered showers moving into windward areas, with mainly dry conditions in leeward areas. Main short term focus during the next couple days revolves around rain chances.
The weak front north of the islands will gradually dissipate today, while the pair of highs to the distant north and northeast consolidate into a single high far to the northeast of the island chain. Meanwhile, a new front will be approaching from the northwest Tuesday through Wednesday, but will remain far to the northwest of the state. Overall, light to moderate trade winds should prevail across the island chain through Wednesday, strongest over the eastern end of the state. With the low level flow slightly south of due east however, sea breezes and land breezes will likely develop in many leeward areas each day. The trade winds are expected to ramp back up Wednesday night as a new strong high builds northwest of the state, holding at moderate to breezy trades expected through early next week, with windy conditions possible Friday night through the weekend.
As for the remaining weather details, showers should favor windward slopes and coasts at night during the next couple days, with scattered leeward and interior shower development expected each afternoon, with this activity then diminishing in the evening. A more typical trade wind pattern should resume Wednesday night, and hold in place through early next week. Showers will continue to favor windward slopes and coasts, with a few showers reaching leeward areas occasionally due to the strength of the trades.

Aviation

The low-level background flow is becoming more southeasterly this morning. As a result, the local nighttime land breezes will transition to local sea breezes this afternoon. Low clouds and brief showers transported by the southeasterly flow will continue to move primarily over east and southeast facing sections of the state. This may result in brief periods of MVFR conditions due to lower ceilings and reduced visibilities. Otherwise, expect VFR conditions to prevail over most areas this morning. In addition to the low clouds, high clouds (mostly cirrus) are expected to stream across most of the area today.
Later today, the local sea breezes are expected to allow low clouds and showers to form over some leeward and interior sections of the islands. There may be brief periods of MVFR conditions where these clouds and showers develop during the afternoon, with improving conditions occurring over most areas this evening as the land breezes become established.
AIRMET Tango continues for Tempo moderate upper-level turbulence in the layer between FL280 AND FL400 across the state. This is due to developing upper-level dynamics across the region. We will monitor this developing situation, since it is possible that isolated severe upper-level turbulence could develop later today.

Marine

Gentle to moderate ESE winds will prevail in most areas through Wednesday as passing fronts support surface troughing NW of the islands. In this regime, winds will be strongest over windward waters, and over waters around the Big Island, reaching fresh speeds. As the trough weakens Wednesday, high pressure building NW of the islands will support a surge in ENE trade winds Wednesday night and Thursday. Winds may strengthen further by the weekend, reaching near-gale speeds in the windiest areas as the high passes N of the islands. Winds and seas are expected to remain below Small Craft Advisory (SCA) levels for most of the week, but will likely be required in the windier zones by Thursday, and all areas by the weekend.
Relatively small NE swells will persist into Wednesday. A larger, long-period NW swell continues to gradually build at offshore NDBC buoys NW of Kauai and nearshore PacIOOS buoys, and will lead to increasing surf along exposed N and W facing shores through the day today. This swell will likely not reach its peak until Wednesday as it turns toward the NNW, with peak surf heights remaining below High Surf Advisory (HSA) heights. See the statewide surf forecast (SRFHFO) for details on the surf forecast. Another long-period NW swell is expected at the end of the week, with peak surf heights approaching HSA levels. A small, long-period S swell is expected the next couple of days, providing a bit of surf to S facing shores. Short-period wind waves will increase toward the end of the week, leading to increasing choppy surf along E facing shores into the weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov