Hilo

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to 66 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to around 48 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs 81 to 86 near the shore to around 72 near 5000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 62 to 69 near the shore to around 49 near 5000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Tuesday: Mostly sunny in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs 80 to 85 near the shore to around 71 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 82 near the shore to 72 to 79 near 3000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 61 near the shore to 47 to 55 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 82 near the shore to 72 to 79 near 3000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 61 near the shore to 47 to 55 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

South Big Island

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

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 64 near the shore to around 48 near 5000 feet. Southeast winds up to 10 mph shifting to the east after midnight. Chance of rain 30 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to around 72 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Puna

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to 66 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to around 48 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 40 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 81 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny with isolated showers in the morning, then partly sunny with scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to 67 to 74 above 4000 feet. North winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 64 to 69 near the shore to 44 to 52 above 4000 feet. North winds around 10 mph shifting to the east after midnight. Chance of rain 30 percent.

Tuesday: Mostly sunny in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 82 near the shore to 66 to 73 above 4000 feet. East winds up to 10 mph in the morning becoming light. Chance of rain 40 percent.

Detailed Forecast

Synopsis

A weakening cold front continues to approach the islands from the northwest today, then stalling out and dissipating near Kauai on Tuesday. Short wave upper level troughs will also pass through the region from Monday through Wednesday time period decreasing stability across the region on increasing cloud and rainfall trends. Another high pressure system will build in north of the state and pass slowly to the east. This system will briefly increase trade winds into the moderate range from Tuesday onward, becoming locally breezy by the weekend. Drier trends are forecast for the end of the week as an upper level high pressure ridge builds in more stable and dry conditions.

Discussion

The regional satellite picture this morning shows an area 200 miles north of the islands where scattered thunderstorms are developing near the east side of an upper level trough. A weakening cold front northwest of Kauai continues to slowly approach the islands. High level cirrus clouds moving into the area are highlighting an upper level trough just north of the state. These two features will combine forces to produce a slight increase in shower activity over all islands over the next few days. The latest local scale radar imagery shows limited showers this morning.
The cold front northwest of the islands will continue to weaken and slow as it approaches Kauai, dissipating and stalling out over the Garden Isle on Tuesday. High pressure building in further north, behind the cold front, will bring increasing trade wind speeds from Monday to Tuesday.
For today, expect a hybrid trade wind and sea breeze pattern with converging winds over island mountain and interior sections. Isolated to scattered showers are possible in the afternoon hours as converging winds and island surface heating cause clouds to form. The passing upper level trough will tend to enhance this convective shower activity with isolated afternoon thunderstorms possible over the Big Island. Increasing trade winds will shift shower trends to a more windward and mountain flavor by tonight.
By Tuesday, the weakening cold front stalls out over Kauai with strengthening trade winds bleeding out ahead of the diminishing frontal cloud band. Increasing trade winds will focus shower activity over northern and eastern slopes of the island. Expect periods of showers for north through east section of Kauai to last through the afternoon hours. Moderate trade winds will spread across the rest of the state with more clouds and passing showers favoring windward and mountain areas. Isolated thunderstorms remain in the forecast for the Big Island on Tuesday afternoon.
Wednesday through Sunday: The high pressure surface ridge will remain anchored in place just north of the state keeping light to moderate trade winds in the forecast for most areas through Friday, then becoming locally breezy by this weekend. An upper level ridge will gradually build over the region, lowering the trade winds subsidence inversion heights, with drying trends lasting through the weekend.

Aviation

Mostly dry and stable pattern with light winds will support VFR conditions through the morning hours. Spotty afternoon showers associated with a weakening front moving into the area and daytime sea breezes could result in brief periods with MVFR CIGS/VSBYS. Moderate north-northeast winds accompanying the front are expected over the western end of the state later this afternoon. Easterly trades will then return statewide tonight into Tuesday as high pressure builds north of the area behind the front.
AIRMET Tango for tempo moderate turbulence remains in effect through the morning hours. Conditions will gradually improve through the day as the upper trough passes to the north.

Marine

An approaching cold front will keep light and variable winds in place across the smaller islands today, while light to locally moderate east-southeasterly winds prevail near the Big Island. The front will stall out and dissipated near Kauai tonight and Tuesday as a new high builds north of the islands. This will bring a return of moderate to fresh trade winds to the state, with the potential for a brief period of Small Craft Advisory levels winds not out of the question near Kauai. A new front to the distant northwest will weaken the gradient slightly Tuesday night through Thursday, with the trades generally holding at moderate speeds. The ridge may strengthen north of the islands Friday through next weekend, potentially bringing locally strong trades to portions of the marine area.
The current northwest swell will decline today, followed by a pair of northwest swells that will produce north shore surf around March average during the peaks. The first swell will arrive tonight, peak Tuesday, and decline Wednesday and Thursday. The second northwest swell will arrive Thursday, peak Friday, then gradually decline through the upcoming weekend. Mainly background south swells are expected through Tuesday, with a slight bump possible Wednesday through Friday. East shore surf will remain below seasonal levels through next weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov