Hilo

Today: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to around 71 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Monday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86 near the shore to around 70 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 83 to 89 near the shore to around 71 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 74 near the shore to 51 to 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 82 to 89 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Breezy. Partly sunny with isolated showers. Highs 64 to 86. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 62 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Partly sunny with isolated showers. Highs 65 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Kohala

Today: Breezy. Partly sunny with isolated showers. Highs 64 to 86. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 62 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Partly sunny with isolated showers. Highs 65 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Highs around 87 near the shore to around 72 near 5000 feet. East winds up to 15 mph.

Tonight: Partly cloudy. Lows around 74 near the shore to around 53 near 5000 feet. Northeast winds around 10 mph.

Monday: Mostly sunny. Highs around 86 near the shore to around 69 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon.

Puna

Today: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 86 near the shore to around 71 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Monday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86 near the shore to around 70 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Breezy. Highs 83 to 91 near the shore to 67 to 77 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Partly cloudy. Lows around 75 near the shore to 52 to 57 above 4000 feet. Northeast winds up to 10 mph.

Monday: Mostly sunny. Highs 83 to 90 near the shore to 67 to 75 above 4000 feet. North winds up to 10 mph.

Detailed Forecast

Synopsis

A large area of high pressure generally north of the Hawaiian Islands will hold through early Monday. This will maintain the ongoing typically dry summertime trade wind pattern. Windward and mauka area light showers will primarily occur during the early morning and overnight hours. A vicinity upper level disturbance developing northeast of the state Monday will weaken mid to late week winds to more gentle speeds and increase island-wide rain chances.

Discussion

There remains little variance in forecast philosophy under this near static Central Pacific synoptic pattern. Stable conditions will stay in play as a result of ridging anchored north of the state. Summertime dry trades will hang on for another day as a pair of surface highs centered northwest and northeast of the islands drive these stubborn breezy easterlies. Relatively lower inversion near 5k ft foot heights will result in a regional shallow boundary layer as evidenced by this morning's lower level stratocumulus and quiet radar. Somewhat dry mid to upper level moisture (30% to 40% RH) advecting in across the chain has bets hedging toward a stable enough island environment that will generally support more windward area and mauka clouds with showers focused on the higher elevations. The usual caveats still apply of cloudier, slightly more wet afternoon Kona and Ka'u slope conditions with infrequent leeward short-lived light showers and partly cloudy skies riding over local area ridge tops.
The development of an upper level disturbance forming in the middle of the northern ridging tomorrow will be the impetus to gradually weakening trades. The surface reflection of weak troughing, along with the proximity of the subtropical jet, may work in favor of increasing more areawide pockets of better organized shower activity through the week. The main question marks to latter week increased shower activity relieving us from this recent dry spell will be whether or not there will 1) be ample column moisture within a deepened, marginally-destabilized boundary layer and 2) the location of the upper disturbance in relation to the islands. The wettest period is shaping up to be later in the week, Thursday and Friday. Late week inversions are progged to be slightly higher, lower level lapse rates the greatest within a more moist air mass. These three elements best come in-line over Big Island and Maui Counties as we close out the week.

Aviation

Breezy to locally windy trades will continue over the next few days. SHRA amd low cigs will favor windward and mauka locations with a few SHRA making it leeward. Some brief MVFR conds are possible in SHRA, otherwise VFR conds should generally prevail.
AIRMET Sierra is in effect for mtn obsc for N through SE sections of the island chain. Low cigs and a slight increase in SHRA are expected through the night into the morning hours.
AIRMET Tango for mod low-level turb lee of terrain is in effect and will likely be needed for the next several days due to the strong trades under a strong inversion.

Marine

A strong high pressure ridge remains north of the islands, and will continue to drive fresh to locally strong trade winds into Wednesday. The Small Craft Advisory (SCA) for all Hawaiian Coastal Waters will remain in effect through Monday. This SCA will decrease in coverage after 6 AM HST this morning to the typical windier waters near Maui County and the Big Island.
The current long period south swell continues to fill in and a High Surf Advisory remains in effect for the south facing shores of all islands through Monday. West facing shores will see a decent south swell wrap, boosting surf heights as well, with the Big Island west facing shores forecast to remain just below HSA levels through Monday. A gradual downward trend in south swell activity is expected Tuesday through midweek.
Due to the strong trade winds upstream of the state, surf along east facing shores will remain rough and choppy through Tuesday. A downward trend is possible by Wednesday as the upstream fetch weakens and the local trades begin to ease.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 AM HST early this morning for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.
Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov