Hilo

Today: Cloudy. Showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to around 65 at 4000 feet. East winds up to 10 mph. Chance of rain 90 percent.

Tonight: Cloudy with showers. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Tuesday: Cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to around 66 at 4000 feet. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Kona

Today: Partly sunny with isolated showers in the morning, then cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 72 near the shore to around 52 near 5000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny in the morning, then mostly cloudy with scattered showers and isolated thunderstorms in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 79 near the shore to 69 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Cloudy and breezy. Numerous showers in the evening, then scattered showers after midnight. Lows around 65 near the shore to 50 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Kohala

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 79 near the shore to 69 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Cloudy and breezy. Numerous showers in the evening, then scattered showers after midnight. Lows around 65 near the shore to 50 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 79 near the shore to 70 to 76 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

South Big Island

Today: Breezy. 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 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 67 near the shore to around 52 near 5000 feet. East winds 10 to 20 mph. Chance of rain 30 percent.

Tuesday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers and thunderstorms in the afternoon. Highs around 84 near the shore to around 70 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Cloudy. Showers in the morning, then numerous showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to around 65 at 4000 feet. East winds up to 10 mph. Chance of rain 90 percent.

Tonight: Cloudy with showers. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.

Tuesday: Cloudy. Numerous showers in the morning, then scattered showers and isolated thunderstorms in the afternoon. Highs around 80 near the shore to around 66 at 4000 feet. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with isolated showers and thunderstorms in the afternoon. Highs around 83 near the shore to 64 to 71 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 67 to 72 near the shore to 47 to 55 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Sunny in the morning, then mostly cloudy with isolated showers and thunderstorms in the afternoon. Highs around 84 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

An upper level low over the islands this morning will weaken on Tuesday. Trade winds have also returned to the region. Expect a wet trade wind weather pattern today with isolated thunderstorms for some areas into the Monday morning hours. Thunderstorms will continue over the Big Island each afternoon through Tuesday. Expect showers in this wet trade wind pattern to slowly decrease in coverage into Wednesday with showers favoring windward and mountain areas. Decreasing trade wind showers are forecast on Thursday, then increasing shower activity again from Friday into next weekend as another upper low sets up northeast of the state.

Discussion

Satellite imagery this morning shows clouds and showers continuing to develop across the region. However, both satellite and local radar imagery show these convective clouds appear less intense compared to the heavier showers and thunderstorms that developed last night. More stable trade winds have also returned at the surface. This means the upper low is likely weakening and the enhanced showers should be less intense today with shower coverage slowly decreasing into Wednesday. Isolated thunderstorms remain in the forecast through the afternoon hours, then only popping up near the Big Island on Tuesday afternoon. The Winter Weather Advisory for the Big Island Summits was extended until this evening due to continued snow showers. These snow showers are forecast to decrease in frequency through the afternoon hours.
Upper air balloon observations from 2 AM HST this morning at Lihue and Hilo show a weak trade wind temperature inversion setting up around the 7,000 foot elevation level. This weak inversion will likely strengthen over the next 24 hours as stability increases and will allow for periods of showers to continue into Wednesday. The highest shower coverage will occur along windward and mountain areas with the highest rainfall amounts favoring the overnight to early morning hours.
Wednesday will likely start a brief transition period to a drier trade wind weather pattern as a weak upper level ridge develops over the islands. Trade wind temperature inversion heights will range from 5,000 to 7,000 feet limiting shower activity. Only brief passing showers are expected mainly over windward areas in the overnight hours. These more typical trade winds will last through Thursday night.
Trade winds continue from Friday into next weekend as an upper level low develops northeast of the Hawaiian Islands. This upper low will lift the trade wind inversion heights and produce periods of showers across the state.

Aviation

A disturbance aloft will shift east of the islands early this morning, allowing conditions to gradually improve over the eastern end of the state. A return of more typical trade wind weather is expected as the day progresses, although it may be a bit more showery than normal, particularly over windward slopes and coasts.
AIRMET Sierra remains in effect for mountain obscuration across Maui County and the Big Island. Conditions should improve in these area later this morning. AIRMET Tango remains in effect for moderate upper level turbulence over the entire state. Conditions should improve over the western islands later this morning, but the turbulence could linger through the day over the eastern end of the state. Finally, a mention of light icing remains in AIRMET Zulu over the eastern end of the state.

Marine

Although trade winds have returned and should hold through the week, added instability associated with an upper disturbance supports locally heavy showers and a few thunderstorms over the next day or two. The best chance of for this activity will transition to windward coasts and waters. Small Craft Advisory level winds (25 kt) will persist through the first half of the week over the windier channels and waters around Maui County and the Big Island. Winds may weaken slightly by next weekend as the ridge settles southward.
Surf along east facing shores will steadily rise through the first half of the week as the easterly trades return locally and upstream across the eastern Pacific (1036 mb high building off west coast today thru Tuesday). Guidance shows this holding into the second half of the week before easing next weekend as the trades upstream trend down.
The quiet conditions across the northern Pacific continues through the first week of April, with minimal swell anticipated. This will translate to the nearly flat conditions continuing for north and west facing shores. The exception will be for north facing shores exposed to trade wind energy wrapping in, which could generate some small surf for the typical standout locations this week, especially starting by Tuesday. For the extended, there is a potential for a short/medium period northerly swell associated with a decent sized area of north-northwest winds setting up and expanding southward from the Aleutians around the Date Line Friday through Saturday. If this materializes, this swell would arrive locally early next week and linger through midweek.
For south facing shores, guidance supports the small conditions continuing well into April with mainly background energy moving through. The European solution does depict a gale setting up south-southeast of New Zealand within our swell window later this week with seas climbing to 30 ft, which could produce a small south-southwest source by mid April.

HFO Watches/Warnings/Advisories

Winter Weather Advisory until 6 PM HST this evening for Big Island Summits.
Small Craft Advisory until 6 AM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov