Photo Credit: Tyler Rooke

West Side

Today: Sunny, with a high near 87. East wind 5 to 7 mph becoming calm in the morning.

Tonight: Isolated showers after midnight. Mostly clear, with a low around 70. Calm wind becoming east northeast 5 to 7 mph in the evening. Chance of precipitation is 20%.

Tuesday: Isolated showers before noon. Mostly sunny, with a high near 88. East northeast wind 5 to 10 mph becoming southwest in the morning. Chance of precipitation is 20%.

South Side

Today: Sunny, with a high near 88. West wind 3 to 6 mph.

Tonight: Mostly clear, with a low around 69. Calm wind becoming west around 5 mph after midnight.

Tuesday: Isolated showers after noon. Mostly sunny, with a high near 89. West wind 5 to 10 mph becoming east in the afternoon. Chance of precipitation is 20%.

North Shore

Today: Isolated showers before noon. Mostly sunny, with a high near 86. Windy, with a northeast wind 18 to 24 mph, with gusts as high as 34 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 70. Breezy, with an east wind 16 to 21 mph, with gusts as high as 30 mph. Chance of precipitation is 20%.

Tuesday: Scattered showers, mainly before noon. Partly sunny, with a high near 87. Breezy, with an east northeast wind 13 to 22 mph, with gusts as high as 30 mph. Chance of precipitation is 30%.

Central Maui

Today: Sunny, with a high near 87. Breezy, with a north northeast wind 16 to 20 mph, with gusts as high as 28 mph.

Tonight: Isolated showers after 1am. Partly cloudy, with a low around 68. Breezy, with a northeast wind 15 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 20%.

Tuesday: Isolated showers. Mostly sunny, with a high near 88. Breezy, with a northeast wind 11 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 20%.

Upcountry

Today: Sunny, with a high near 72. West southwest wind 5 to 8 mph.

Tonight: Mostly clear, with a low around 57. West southwest wind around 6 mph becoming calm.

Tuesday: Mostly sunny, with a high near 74. West wind 5 to 13 mph becoming east in the afternoon.

East Maui

Today: Scattered showers. Partly sunny, with a high near 81. East wind around 9 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 67. East wind 6 to 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Mostly cloudy, with a high near 82. East wind 7 to 11 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

Today: Isolated showers after noon. Sunny, with a high near 77. Breezy, with a northeast wind 9 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 65. Northeast wind 9 to 13 mph.

Tuesday: Isolated showers after noon. Partly sunny, with a high near 77. Breezy, with a northeast wind 10 to 17 mph, with gusts as high as 23 mph. Chance of precipitation is 20%.

Kaunakakai

Today: Isolated showers before 8am. Sunny, with a high near 86. Breezy, with an east wind 11 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 73. East wind 10 to 13 mph.

Tuesday: Mostly sunny, with a high near 87. Breezy, with an east wind 10 to 20 mph, with gusts as high as 28 mph.

Detailed Forecast

Synopsis

Trade winds will persist through the rest of the week, although the trades will trend down from locally strong to moderate speed around mid week. This is the result of the weakening of the surface high centered far north of Kauai. Locally breezy trades will return over the weekend as the high strengthens north and northeast of the islands. Showers will continue to favor the windward and mauka areas, with higher frequency of these showers coming during the nights and mornings.

Discussion

The moderate to locally breezy trades are currently being sustained by a weakening 1032 mb surface high located 1130 miles north- northwest of Kauai. This high will dissipate in the next 24 and be replaced by a new 1037 mb high located further north and west from the current high. In response, the locally strong trades will trend down to moderate speed by Thursday. It will hold at this strength to until Friday night or Saturday where trades will get a fresh boost to locally strong as the high drops south and closer to the islands.
The slightly weaker trade winds in the coming days may favor some locally daytime sea breeze over the west end of the smaller islands, leading to some spotty afternoon showers. Otherwise, the moderate trades will continue to usher some scattered showers into the windward and mountain areas. The frequency of these trade showers will be highest during the overnight and early morning hours. Mid level ridging over the islands is strong and will persist through the week, thus maintaining ordinary trade showers.
Current satellite imagery shows the pool of moisture that moved into Kauai late yesterday afternoon continuing to exit Kauai County. We anticipate the bulk of these clouds and showers to be west of Kauai shortly after sunrise. During the evening hours, ending at 2 am HST, rain gages across the lower elevations of windward Kauai pickup an average of a quarter inch. The highest amount recored was at North Wailua with 1.35 inches.
On Oahu, the showers eased up after 10 pm HST, joining the rest of the islands with limited trade showers. Satellite imagery shows an area of potential scattered showers, however, just upwind of windward Big Island. Models suggest scattered showers for windward Big Island and Maui later this morning, continuing into this afternoon. There should be more sunshine for Kauai and Oahu today, especially over on the south and lee side of the islands.

Aviation

High pressure north of the state will keep moderate to locally breezy trade winds in place through today and tonight. A band of enhanced moisture is moving through Kauai early this morning, bringing more frequent showers along with some reduced cigs/vsbys to windward slopes and coasts. Low clouds and showers are more sparse over windward sections from Oahu eastward to the Big Island. Drier conditions should develop over windward areas of Kauai later this morning, with VFR conditions then prevailing through the remainder of the day. Elsewhere, predominantly VFR conditions should prevail during the next 24 hours.
AIRMET Sierra remains in effect for windward sections of Kauai. Conditions should improve here later this morning.
AIRMET Tango remains in effect for low level turbulence over and downwind of the terrain of all islands. This AIRMET will likely continue through the day.

Marine

A strong surface high pressure system centered far north- northwest of the islands will maintain locally strong trade winds across the state into the middle of this week. As a result, a Small Craft Advisory (SCA) remains in effect for the typically windier waters adjacent to the islands of Maui County and the Big Island through Wednesday afternoon. The surface high will drift slowly northwest during the next few days, so the latest forecast indicates the trade winds will weaken slightly by Thursday.
A long-period south-southwest swell continues to spread up across the area early this morning. Recent observations from the nearshore buoys along the south shores show the swell height is around 4 feet with a wave period of approximately 18 seconds. This swell will continue to build through tonight, and then will likely peak on Tuesday, followed by a slow downward trend from Tuesday night through Wednesday. As a result of the elevated surf produced by this swell, a High Surf Advisory (HSA) is in effect for the south facing shores of all Hawaiian Islands through Wednesday afternoon. The south-southwest swell will continue to gradually lower from Thursday into next weekend.
Small northwest swells are expected early this week, which will likely keep surf just above typical summertime flat conditions along most north facing shores into Wednesday. Strong easterly trades in the vicinity of, as well as upstream of, the islands will continue to produce slightly elevated choppy surf along east facing shores through this evening. As the trades weaken, expect surf along east facing shores to gradually trend downward from Tuesday through late in the week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Wednesday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, Kipahulu, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov