Hilo

Today: Frequent showers in the morning, then numerous showers in the afternoon. Highs 78 to 84 near the shore to 67 to 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain near 100 percent.

Tonight: Frequent showers. Locally heavy rainfall possible after midnight. Lows around 71 near the shore to around 57 at 4000 feet. East winds 10 to 15 mph. Chance of rain near 100 percent.

Tuesday: Cloudy with frequent showers. Locally heavy rainfall possible. Highs 76 to 81 near the shore to around 68 at 4000 feet. East winds 10 to 15 mph. Chance of rain 90 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 72 near 5000 feet. Light winds. Chance of rain 30 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 71 to 76 near the shore to around 57 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Mostly cloudy. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 84 near the shore to around 71 near 5000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Breezy. Mostly cloudy with numerous showers. Highs around 80 near the shore to 72 to 79 near 3000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Frequent showers in the evening, then showers likely after midnight. Locally heavy rainfall possible after midnight. Lows around 70 near the shore to 57 to 64 near 3000 feet. East winds 15 to 20 mph. Chance of rain near 100 percent.

Tuesday: Breezy. Cloudy with frequent showers. Locally heavy rainfall possible. Highs 66 to 81. East winds 15 to 20 mph. Chance of rain 90 percent.

Kohala

Today: Breezy. Mostly cloudy with numerous showers. Highs around 80 near the shore to 72 to 79 near 3000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Frequent showers in the evening, then showers likely after midnight. Locally heavy rainfall possible after midnight. Lows around 70 near the shore to 57 to 64 near 3000 feet. East winds 15 to 20 mph. Chance of rain near 100 percent.

Tuesday: Breezy. Cloudy with frequent showers. Locally heavy rainfall possible. Highs 66 to 81. East winds 15 to 20 mph. Chance of rain 90 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 73 near 5000 feet. East winds 10 to 20 mph. Chance of rain 30 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 near the shore to around 56 near 5000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Breezy. Mostly cloudy with scattered showers. Highs around 83 near the shore to around 72 near 5000 feet. East winds 15 to 25 mph. Chance of rain 50 percent.

Puna

Today: Frequent showers in the morning, then numerous showers in the afternoon. Highs 78 to 84 near the shore to 67 to 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain near 100 percent.

Tonight: Frequent showers. Locally heavy rainfall possible after midnight. Lows around 71 near the shore to around 57 at 4000 feet. East winds 10 to 15 mph. Chance of rain near 100 percent.

Tuesday: Cloudy with frequent showers. Locally heavy rainfall possible. Highs 76 to 81 near the shore to around 68 at 4000 feet. East winds 10 to 15 mph. Chance of rain 90 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs around 84 near the shore to 68 to 74 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 74 near the shore to 53 to 60 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Cloudy. Isolated showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs around 83 near the shore to 67 to 73 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A strong surface high pressure area located far northeast of the islands will maintain strong and gusty trades for another day before trending down to locally strong by Wednesday night and hold for the rest of the week. A wet trade wind pattern with locally heavy showers will develop tonight and continue through Tuesday night. A more typical trade wind shower pattern, that is with lighter rainfall, will be returning Wednesday, then continue for the rest of the week.

Discussion

Moderate to strong trade winds will hold for another day before trending softer to locally strong by Wednesday night. This comes about as the surface high, located far northeast of the islands weakens. The surface high currently has a central pressure of 1038 mb, and is roughly 1700 miles northeast of the islands. Locally strong trades will continue through the rest of the week.
Satellite imagery shows the leading edge to a large low cloud field nearing Cape Kumukahi and the Big Island. This moisture field will be spreading westward with the trades, likely reaching Oahu late this afternoon, and Kauai in the evening, bringing with it a boost in trade showers.
To make things more interesting, an upper level disturbance will glance the Big Island and Maui tonight though Tuesday, supplying enough instability to enhance these clouds and showers. Add in terrain influence as well will result in locally heavy showers. Thus the forecast package now include locally heavy showers for windward Maui and windward Big Island between late tonight through Tuesday. An isolated thunderstorm is also part of the forecast for the interior and higher elevations of the Big Island Tuesday afternoon. Along with the increase in trade showers, the dew point will be rising into the lower 70s tonight. It is the good thing the trade winds will be mildly strong. Latest models support the heavy showers to begin easing up Tuesday night, followed by somewhat drier conditions on Wednesday.
The trade winds have weakened just enough so that the Wind Advisory covering the northern part of the Big Island and parts of Maui County, is now canceled. But keep in mind, it is still pretty breezy and gusty, and is expected to hold through Tuesday.

Aviation

With robust high pressure remaining far north and northeast of the state, trade winds will be breezy to locally strong across the island chain, though they will weaken somewhat today through Tuesday. MVFR in showers and lower ceilings will mainly affect windward and mauka sections, with some showers making their way over leeward areas from time to time as well.
AIRMET TANGO remains in effect for areas over and immediately south through west of mountains on all islands for tempo moderate turbulence below 8000 feet.
AIRMET SIERRA remains in effect for the Big Island along north through east facing slopes for tempo mountain obscuration above 2500 feet due to clouds and showers.

Marine

Strong high pressure north of the state will continue to drive fresh to strong trade winds across the waters through the work week. We should see the trades dip slightly lower over the weekend. A Small Craft Advisory (SCA) is now in effect for all waters through 6 AM Wednesday due to winds/seas or a combination of the two. The SCA will be scaled back as seas lower later in the week, although winds will likely remain at SCA levels over the typically windy waters around Maui and the Big Island through the work week.
East shore surf remains very rough this morning, and with persistent strong trade winds extending far to the east and northeast of the islands, east shore surf will be slow to lower. In fact, surf along east facing shores should hold fairly steady through Tuesday, so we have extended the High Surf Advisory (HSA) through 6 PM Tuesday. As the trades trend downward over and upstream of the islands, east shore surf will follow suit, slowly lowering during the middle and latter part of the work week, and dropping to below normal levels over the weekend.
A series of overlapping south swells will keep south shore surf above normal through mid week, before dropping to mostly background levels Friday through next weekend.
Aside from some trade wind swell wrap, north shore surf will remain very small through Thursday. A small long-period northwest swell due in Thursday night, will give a small boost to the surf along north and west facing shores Friday through the weekend.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Tuesday for Olomana, Kauai East, Kauai South, East Honolulu, Koolau Windward, Koolau Leeward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, South Haleakala, Big Island Southeast, Big Island East, Big Island North.
Small Craft Advisory until 6 AM HST Wednesday for all Hawaiian waters,

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Data Courtesy of NOAA.gov