Photo Credit: James Grenz

Hilo

Today: Cloudy. Showers early in the morning, then scattered showers in the late morning and afternoon. Highs 75 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 80 percent.

Tonight: Showers. Lows 60 to 69 near the shore to 51 to 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain near 100 percent.

Wednesday: Showers in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain near 100 percent.

Kona

Today: Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs 80 to 85 near the shore to around 65 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows 67 to 72 near the shore to 46 to 53 near 5000 feet. Light winds.

Wednesday: Cloudy. Scattered showers in the afternoon. Highs around 83 near the shore to around 65 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Breezy. Mostly cloudy with scattered showers. Highs 63 to 83. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 62 near the shore to 53 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Wednesday: Cloudy and breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 62 to 83. East winds 10 to 20 mph. Chance of rain 70 percent.

Kohala

Today: Breezy. Mostly cloudy with scattered showers. Highs 63 to 83. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 62 near the shore to 53 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Wednesday: Cloudy and breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 62 to 83. East winds 10 to 20 mph. Chance of rain 70 percent.

South Big Island

Today: Breezy. Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 81 near the shore to around 65 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows around 70 near the shore to around 50 near 5000 feet. Northeast winds up to 15 mph.

Wednesday: Cloudy and breezy. Isolated showers in the afternoon. Highs around 80 near the shore to around 64 near 5000 feet. Northeast winds 10 to 20 mph shifting to the east up to 20 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Cloudy. Showers early in the morning, then scattered showers in the late morning and afternoon. Highs 75 to 81 near the shore to 63 to 68 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 80 percent.

Tonight: Showers. Lows 60 to 69 near the shore to 51 to 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain near 100 percent.

Wednesday: Showers in the morning, then scattered showers in the afternoon. Highs 75 to 81 near the shore to 62 to 67 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain near 100 percent.

Waikoloa

Today: Mostly sunny. Breezy. Highs 78 to 86 near the shore to 64 to 70 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Isolated showers. Lows 65 to 72 near the shore to 48 to 54 above 4000 feet. Southeast winds up to 25 mph. Chance of rain 20 percent.

Wednesday: Breezy. Partly sunny with isolated showers in the morning, then cloudy in the afternoon. Highs 78 to 86 near the shore to 63 to 69 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge north of the Hawaiian Islands will keep moderate to breezy trade winds in the forecast through the weekend. Expect brief periods of showers mainly affecting windward and mountain areas favoring the overnight to early morning hours through the week. An upper level trough and jet stream will keep high clouds over the region through the week.

Discussion

Radar and satellite imagery this morning shows extensive bands of clouds and showers drifting into each island on the trade winds. Expect periods of showers over windward and mountain areas through the morning hours with some of the stronger showers reaching leeward areas. Upper level high cirrus clouds are expected to drift across the state through the week, enhancing sunrise and sunset colors.
In the big picture, the subtropical ridge will remain anchored in place north of the island chain through the weekend. This ridge will keep moderate to breezy trade winds in the forecast for all islands through Sunday. A 1030 mb high pressure center within this ridge pattern is currently located northwest of the state producing northeasterly trade winds. As this high center slowly drifts eastward through Wednesday the trade wind directions will veer from a northeast to east direction. The high center will continue to drift into the East Pacific basin from Thursday through Saturday with a slight east to southeasterly shift in wind directions possible by Friday or Saturday. An approaching cold front will stall out northwest of the islands on Friday with little impacts to our island weather.
The weather pattern through the week remains fairly typical for this time of year. The breezy northeasterly trade winds will keep brief windward and mountain showers in the forecast with pleasant weather for most locations from late morning to afternoon. Some isolated stronger showers may reach leeward sections mainly in the overnight hours. Longer range forecast guidance continues to show some added instability from an upper level low setting up just west of the state. This disturbance may increase shower trends, especially over the western islands, on Thursday and Friday. The weather forecast this weekend has improved with an upper level ridge aloft settling in over the region along with more east- southeast winds producing a slight decreasing trend in shower activity for most islands. Eastern slopes of the Big Island will continue to see passing showers through Sunday.
The gridded weather forecast details look good and there was little change in the morning forecast package. Global models are in good agreement with this trade wind weather forecast lasting through Sunday.

Aviation

Locally breezy trades will focus clouds and showers over windward and mauka zones through the period. This will particularly the case for Oahu where trades are pushing a loosely organized band of showers onshore this morning. Prevailing MVFR has developed over Windward Oahu as showers have increased in coverage there. As a result, AIRMET Sierra for mountain obscuration has been issued. The potential exists for further expansion to neighboring islands, but at this time the expectation is that MVFR will tend to be brief at these locations.
AIRMET Tango remains in effect for both low level lee turbulence as well as moderate upper turb FL280/420.

Marine

Moderate to strong trade winds will continue through the weekend and into early next week, with only minor variations in strength. A Small Craft Advisory (SCA) is now in effect for all waters with the exception of windward Big Island through 6 PM Wednesday. The SCA will likely continue through much of the week for the windier areas around Maui and the Big Island.
Surf along north and west facing shores will remain small today, then trend up tonight through midweek as a new long-period, northwest swell arrives and builds down the island chain. Surf associated with this swell will peak through the day Wednesday, then slowly lower shift around to a more northerly direction during the second half of the week. Another long-period north- northwest swell will give north shore surf a boost to similar levels over the weekend, before declining early next week.
Surf along south facing shores will steadily lower today, then remain small through Friday. A new south swell is forecast to arrive Friday night, with south shore surf building above the summertime average over the weekend and into early next week.
Surf along east facing shores will remain below seasonal levels, due to the lack of a sizable trade wind fetch upstream of the island chain.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Wednesday for most Hawaiian waters.

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Data Courtesy of NOAA.gov