Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 79 to 86 near the shore to 64 to 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 90 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 73 near the shore to 55 to 60 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 78 to 86 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 89 near the shore to around 72 near 5000 feet. East winds up to 10 mph shifting to the west in the afternoon. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows around 74 near the shore to 51 to 58 near 5000 feet. Light winds. Chance of rain 40 percent.

Wednesday: Sunny in the morning, then cloudy with scattered showers in the afternoon. Highs 84 to 90 near the shore to 69 to 74 near 5000 feet. East winds up to 10 mph shifting to the west in the afternoon. Chance of rain 30 percent.

Waimea

Today: Breezy. Mostly cloudy with showers likely in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 85. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 64 to 73 near the shore to 57 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Highs 63 to 85. East winds 10 to 25 mph.

Kohala

Today: Breezy. Mostly cloudy with showers likely in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 85. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 64 to 73 near the shore to 57 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Highs 63 to 85. East winds 10 to 25 mph.

South Big Island

Today: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 86 near the shore to 67 to 72 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then clearing. Lows around 74 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph.

Wednesday: Sunny in the morning then becoming cloudy. Breezy. Highs around 86 near the shore to around 70 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Mostly cloudy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 79 to 86 near the shore to 64 to 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 90 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 73 near the shore to 55 to 60 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 78 to 86 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Isolated showers in the afternoon. Highs 84 to 91 near the shore to 68 to 74 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon. Gusts up to 40 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers in the evening, then clear after midnight. Lows around 75 near the shore to 52 to 57 above 4000 feet. Northeast winds up to 15 mph shifting to the east after midnight. Gusts up to 35 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Highs 84 to 92 near the shore to 68 to 74 above 4000 feet. Northeast winds 10 to 15 mph shifting to the north in the afternoon. Gusts up to 40 mph.

Detailed Forecast

Synopsis

Locally breezy trade winds will continue through the week. Expect limited windward showers, mainly during the overnight and early morning hours. Leeward areas will stay mostly dry with the exception of the Big Island's Kona slopes, where afternoon clouds and showers will linger well into the night before diminishing.

Discussion

A seasonable, stable and breezy trade wind flow will persist. A strong high pressure cell centered far N of the islands will split into two centers over the next couple of days as weak low pressure systems pass between them. The local pressure gradient will remain relatively unchanged through this process, so any changes in wind speed during the second half of the week will be subtle. A mid-level ridge parked overhead will continue to produce stable conditions, with a subsidence inversion holding between 5,000 and 8,000 ft. With precipitable water hovering near to below seasonal average, expect limited rainfall to be confined to windward slopes, while most leeward areas remain dry. The exception will be the Big Island's Kona slopes, where afternoon clouds and showers will linger through the overnight hours. As an example, a rain gage in Kealakekua measured 1″ of rain in the 6 hours ending at midnight.
Only minor changes to the rainfall pattern are due as random pockets of shallow moisture move through. An upper level trough digging southward toward the islands could coincide with an increase in PWAT this weekend, bringing the potential for an uptick in rainfall, mainly windward.

Aviation

High pressure well north of the islands will maintain moderate to locally breezy trade winds for the next several days. AIRMET Tango remains posted for mountain lee turbulence which will likely continue beyond the next 24 hours.
Clouds and showers will tend to favor windward and mauka areas, especially through the early morning hours. Expect mainly VFR conditions, with brief MVFR cigs and vsbys under passing SHRA.

Marine

No significant changes to the marine forecast this morning. High pressure remains far north of the islands. Fresh to locally strong trade winds will continue through the end of the week. A Small Craft Advisory (SCA) remains in effect for the typical windier waters near Maui County and the Big Island. The SCA currently is in effect through Thursday afternoon, but it will likely be extended with no significant change in the winds expected during the second half of the week.
These trade winds will continue to produce rough and choppy surf along east facing shores into the weekend. South facing shores are seeing a bump as a long period southwest (210-220 degree) swell arrives in the islands. This swell is expected to peak later today, and then subside through Friday. Models suggest another long period swell (220 degree) will arrive late in the weekend. Another long period swell is possible next week.
Statewide water levels continue to be running higher than predicted (0.3 to 0.6 ft), and when combined with some of the highest tides of the year, minor coastal flooding is expected. Minor coastal flooding is expected in the typical vulnerable low lying coastal areas and beaches during the peak high tides during the afternoon hours through Wednesday. Please refer to the latest Coastal Flood Statement (CFWHFO) for more details.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov