Hilo

Today: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 87 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows 64 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88 near the shore to around 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 84 to 89 near the shore to 68 to 73 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 50 to 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 84 to 89 near the shore to 68 to 73 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly cloudy with isolated showers. Highs 65 to 87. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly cloudy with isolated showers. Highs 65 to 86. East winds 10 to 20 mph. Chance of rain 20 percent.

Kohala

Today: Breezy. Mostly cloudy with isolated showers. Highs 65 to 87. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 64 to 72 near the shore to 56 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly cloudy with isolated showers. Highs 65 to 86. East winds 10 to 20 mph. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to around 71 near 5000 feet. East winds 10 to 20 mph.

Tonight: Partly cloudy. Breezy. Lows around 74 near the shore to around 53 near 5000 feet. East winds 10 to 20 mph.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 87 near the shore to around 71 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 87 near the shore to around 72 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows 64 to 72 near the shore to around 58 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88 near the shore to around 72 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs 83 to 90 near the shore to 66 to 76 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Partly cloudy. Lows around 75 near the shore to around 54 above 4000 feet. Northeast winds up to 10 mph.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Highs 84 to 90 near the shore to 66 to 76 above 4000 feet. East winds up to 10 mph shifting to the north in the afternoon. Gusts up to 30 mph.

Detailed Forecast

Synopsis

A high pressure surface ridge north of the islands will keep moderate to locally breezy easterly trade winds in the forecast through Wednesday. A low pressure system moving in far to the north of the island chain will break down this ridge, decreasing wind speed trends from Thursday on into the weekend. An easterly wave will move through the islands by this weekend increasing cloud and shower trends across the state.

Discussion

Fairly stable bands of clouds are drifting through the Hawaiian Islands on the easterly trade winds in the early morning hours. Upper air balloon soundings from 2 AM HST (12Z) this morning show subsidence temperature inversion height around the 6,000 foot level at both Lihue, Kauai and Hilo, Hawaii. These stable conditions aloft will limit vertical cloud and shower development through Friday. Brief shower activity will favor windward and mountain areas in the overnight to early morning hours. Long range model solutions continue to show a trough marching from east to west through the islands by this weekend; likely boosting cloud and shower activity through Sunday.
In the larger scale weather pattern, the surface ridge will remain north of the islands this week, keeping moderate to locally breezy easterly trade winds in the forecast through Wednesday. A low pressure system developing far north of the state on Thursday, will break down the ridge and weaken wind speeds across the region into the early next week. Expect mid morning through afternoon onshore sea breezes to expand in coverage as the large scale winds weaken across the region. Sea breezes will build clouds over interior sections of each island during the day with a some enhanced shower activity over typically drier leeward areas, especially this weekend as the afternoon sea breezes interact with the passing trough forecast to move through the state.

Aviation

Trade winds will remain moderate to locally strong through at least mid-week. Embedded showers will favor windward and mauka areas. Isolated spillover showers are to be expected across the smaller islands this morning. On the Big Island, afternoon and early evening cloud cover may generate moderate showers along south and west facing slopes.
AIRMET Tango remains in effect for mid-level turbulence over and immediately south through southwest of Big Island Summits due to strong winds above the inversion layer. Another AIRMET Tango is in effect for low levels immediately south and west of all islands due to the breezy trade winds. No other AIRMETS are in effect.

Marine

A surface ridge along 27-28N will support moderate to locally strong trade winds through midweek. The ridge may weaken somewhat thereafter, with trade wind speeds slowly diminishing in response. A Small Craft Advisory posted for most waters around Maui and the Big Island will likely remain in place through at least Wednesday.
The medium-period S swell of the past several days continues to move through island waters, with offshore and nearshore buoys indicating a fresh pulse of swell that will continue to support elevated surf today. A slow trend down is expected Tuesday into Wednesday. A small, longer-period SSW swell is expected next weekend.
A small, short-period (~10 seconds) NNW swell will peak today, then diminish Tuesday into Wednesday. Another small, short-period NNW swell may arrive around Thursday. Short-period wind waves will support small to moderate surf along E facing shores for the next couple of days. Small, long-period E swells from increased E Pacific tropical cyclone activity may arrive from Wednesday onward, leading to a subtle increase in surf heights.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov