Photo Credit: Travis Guthrie

West Side

Today: Sunny, with a high near 92. Heat index values as high as 95. East northeast wind 5 to 8 mph becoming calm in the afternoon.

Tonight: Isolated showers before midnight. Mostly clear, with a low around 75. Light and variable wind becoming east northeast 5 to 10 mph in the evening. Chance of precipitation is 20%.

Wednesday: Sunny, with a high near 92. Heat index values as high as 96. East wind 5 to 10 mph becoming light and variable.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 85. Calm wind becoming southwest around 6 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 69. Light and variable wind. Chance of precipitation is 20%.

Wednesday: Isolated showers after noon. Mostly sunny, with a high near 85. Calm wind becoming east northeast 5 to 9 mph in the afternoon. Chance of precipitation is 20%.

North Shore

Today: Isolated showers after noon. Mostly sunny, with a high near 86. Breezy, with an east northeast wind 10 to 18 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 70. Breezy, with an east wind 14 to 17 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers. Mostly sunny, with a high near 85. Windy, with an east wind 15 to 24 mph, with gusts as high as 32 mph. Chance of precipitation is 20%.

Central Maui

Today: Mostly sunny, with a high near 87. Breezy, with a northeast wind 7 to 12 mph increasing to 15 to 20 mph in the afternoon.

Tonight: Isolated showers after 7pm. Partly cloudy, with a low around 71. Breezy, with a northeast wind 9 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers before 7am, then isolated showers after 1pm. Mostly sunny, with a high near 86. Breezy, with a northeast wind 11 to 16 mph increasing to 17 to 22 mph in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 20%.

Upcountry

Today: Mostly sunny, with a high near 74. Light and variable wind becoming west 5 to 8 mph in the afternoon.

Tonight: Partly cloudy, with a low around 56. West wind around 6 mph becoming calm in the evening.

Wednesday: Mostly sunny, with a high near 75. Light and variable wind becoming west southwest 8 to 13 mph in the afternoon.

East Maui

Today: Scattered showers. Partly sunny, with a high near 80. East southeast wind 7 to 11 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 72. East wind 10 to 13 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 79. East wind 10 to 13 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Scattered showers after noon. Partly sunny, with a high near 78. Light and variable wind becoming east northeast 8 to 13 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Partly cloudy, with a low around 65. Northeast wind 7 to 13 mph.

Wednesday: Isolated showers after noon. Mostly sunny, with a high near 79. Breezy, with a northeast wind 7 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

Kaunakakai

Today: Sunny, with a high near 89. East wind 7 to 11 mph.

Tonight: Mostly clear, with a low around 73. East wind around 8 mph.

Wednesday: Sunny, with a high near 89. Breezy, with an east southeast wind 7 to 12 mph increasing to 13 to 18 mph in the afternoon. Winds could gust as high as 26 mph.

Detailed Forecast

Synopsis

Light to moderate trades will hold in place today, with localized sea breezes developing in the more sheltered leeward areas. Fairly dry conditions should prevail in most areas, although a slight increase in showers is expected over the eastern end of the state this afternoon as a band of moisture moves in from the east. This band of moisture will then move westward bringing an uptick in windward showers to the remaining isles tonight. Trades will get a boost back to moderate and breezy levels Wednesday through much of the holiday weekend, with the strongest winds expected Friday and Saturday. A return of more typical windward and mauka focused showers is expected as well, with a stray shower reaching leeward areas from time to time.

Discussion

Currently at the surface, a ridge of high pressure is located a couple hundred miles north of Kauai, while, a weakening trough of low pressure is nearly stationary around 350 miles northwest of Garden Isle. The resulting gradient is producing light to moderate trade winds across the island chain early this morning, with land breezes present in some of the more sheltered leeward areas. Infrared satellite imagery shows clear to partly cloudy skies in most areas, with a bit more cloud cover over leeward Big Island. Radar imagery shows a few isolated showers moving into windward areas, with very little if any shower activity in leeward areas. Main short term concerns revolve around rain chances and trade wind trends during the next few days.
The trade winds will gradually trend upward during the next couple days, as the ridge of high pressure north of the islands lifts slowly northward and the trough to the northwest dissipates. Light to moderate trades will hold in place through today, with some localized land and sea breezes developing in the most sheltered leeward areas. High pressure building northeast of the state will strengthen the trades to moderate and breezy levels Wednesday through much of the Holiday Weekend, with the strongest winds expected Friday and Saturday.
As for the remaining weather details, rather dry conditions should persist in many areas today, although a band of moisture currently around 150 miles east of the Big Island, should bring an increase in shower activity to the eastern end of the state this afternoon. The band of moisture will continue to shift westward tonight, bringing an increase in showers to windward areas of the remaining islands, with a stray shower possibly reaching leeward locales. A more typical trade wind shower pattern appears to resume Wednesday through the Holiday Weekend, with showers favoring windward and mauka areas mainly during the overnight and early morning hours, and a stray shower reaching leeward areas from time to time.

Aviation

The surface ridge north of the state is expected to gradually strengthen, leading to a modest increase in trade wind speeds over the next twenty-four to forty-eight hours. These east to northeast winds will steer scattered clouds and isolated showers towards mainly windward slopes and coasts.
Meanwhile, a weak eddy in the wake of the Big Island will keep the Kona and Kohala coasts more in than out of clouds through the morning hours. In the afternoon, daytime heating and light sea breezes will encourage cumulus build-ups over the Islands interior.
Localized MVFR CIG and VIS are to be expected in brief showers, otherwise VFR conditions will prevail all areas. No AIRMETs are currently in effect or anticipated at this time.

Marine

A surface ridge is a couple of hundred miles north of the islands this morning. The trough just to the north of the ridge is rapidly falling apart, allowing the area of high pressure to expand westward and strengthen. So the trade winds will continue to strengthen today, becoming locally strong by daybreak Wednesday. By Thursday night, the ridge will be a good 600 nm north of Kauai, where it remains nearly stationary into the upcoming weekend. So the trades are here to stay, at least through the 4th of July weekend. Due to the strong trades, a Small Craft Advisory (SCA) will be hoisted later today, covering the typical nearshore waters of Maui County and waters south of the Big Island. The trades may pick additonal speed towards Friday night, to widespread moderate to strong as the surface high strengthens northeast of the islands. There is a good possibility that the SCA will be expanded to most, if not all of the nearshore waters, and this will likely last through the 4th of July weekend.
Small pulses from the west-northwest to north are expected to reach our west and north facing shores through early next week. These small pulses will maintain some wave action along the north and west facing shores. The largest of the swells is slated for this Friday.
There will be a series of south swells coming in through early next week. One of two larger pules is due in tonight with a period of 16 seconds. The second pulse is a long 19 second period slated to arrive Sunday. This swell is likely to produce a significant increase in surf heights along south facing shores, just in time for the Forth of July celebration. Strengthening trade winds means the surf along east facing shores will be on the rise, but staying below high surf advisory. Certainly the waters will become dangerously rough and choppy, especially over the weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov