Hilo

Tonight: Mostly cloudy with numerous showers. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Light winds. Chance of rain 70 percent.

Sunday: Mostly cloudy with numerous showers. Highs 77 to 82 near the shore to 62 to 68 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Sunday Night: Numerous showers in the evening, then occasional showers after midnight. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Northeast winds up to 10 mph. Chance of rain near 100 percent.

Kona

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows around 71 near the shore to 45 to 52 near 5000 feet. Light winds. Chance of rain 40 percent.

Sunday: Sunny. Highs around 84 near the shore to around 65 near 5000 feet. Light winds.

Sunday Night: Partly cloudy. Isolated showers after midnight. Lows around 71 near the shore to 45 to 51 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 52 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs around 78 near the shore to 68 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Sunday Night: Mostly cloudy with occasional showers. Lows 60 to 69 near the shore to 51 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 90 percent.

Kohala

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 52 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs around 78 near the shore to 68 to 77 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Sunday Night: Mostly cloudy with occasional showers. Lows 60 to 69 near the shore to 51 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 90 percent.

South Big Island

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows around 72 near the shore to around 50 near 5000 feet. East winds up to 15 mph. Chance of rain 30 percent.

Sunday: Sunny. Highs around 85 near the shore to around 65 near 5000 feet. East winds up to 15 mph.

Sunday Night: Mostly clear with isolated showers. Lows around 72 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with numerous showers. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Light winds. Chance of rain 70 percent.

Sunday: Mostly cloudy with numerous showers. Highs 77 to 82 near the shore to 62 to 68 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Sunday Night: Numerous showers in the evening, then occasional showers after midnight. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Northeast winds up to 10 mph. Chance of rain near 100 percent.

Waikoloa

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows around 71 near the shore to 48 to 53 above 4000 feet. Light winds. Chance of rain 40 percent.

Sunday: Sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 82 to 88 near the shore to 63 to 69 above 4000 feet. Light winds becoming northwest up to 10 mph in the afternoon. Chance of rain 40 percent.

Sunday Night: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 71 near the shore to 48 to 53 above 4000 feet. Light winds. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Trade winds have returned to the islands, but will remain light enough for seas breezes through this evening. Moderate trades then continue through Monday, with clouds and showers favoring windward and mauka areas. Another storm system will approach the state from the northwest towards the middle of next week bringing a chance of heavy rain and thunderstorm Tuesday through Thursday.

Discussion

Radar and satellite imagery continue to show scattered showers across the state this afternoon under light to moderate trade winds as surface high pressure far north of the state builds. However, trades across the region are currently light enough to allow for the development of sea breeze clouds and showers over island interiors. Meanwhile, 00Z upper air obs from Lihue continue to show a relatively unstable (1400 J/kg MUCAPE) and moist (1.36 in PW) air mass across the region as a diffuse upper level trough weakens northeast of the state. This lingering instability and moisture will help to enhance some showers today, with some areas in upcountry Maui getting close to 0.5 in over the last several hours. Expect the threat for localized flooding to continue through this evening.
Otherwise, expect the upper level trough to continue to weaken overnight as upper level ridging expands towards the west. At the surface we will see moderate easterly trade winds expand by Sunday and continue into Monday as clouds and showers favor windward and mauka areas.
The next weather maker will come in the form of a closed-off upper level low that will sink down along and near 170W longitude and come within 600 miles northwest of Kauai. The west-northwest positioning of this low will pull up more moisture-rich air over the state from the southwest. As heights begin to lower and mid to upper layers cool from the west, enhanced instability within a moistened air mass will likely induce another round of widespread heavy showers and thunderstorms. Guidance continues to show the highest rain probabilities across the western half of the state. Expect another round of flood concerns next Tuesday through Thursday as locally heavy rain falls upon saturated soils. If guidance holds would not be surprised if a Flood Watch is issued for portions of the state in the coming days.

Aviation

Moderate trades have returned and will persist through tomorrow, ushering clouds and showers into windward and mauka areas. However, winds will be light enough to support isolated sea/land breeze development that will bring additional clouds and showers to some leeward and interior areas during the afternoon hours and clearing of these areas overnight. MVFR conditions will be possible in any showers, otherwise VFR conditions should prevail.
No AIRMETs are currently in effect.

Marine

Gentle to moderate trades continue through Monday, then veer to southeasterly in advance of a deep low that will develop NW of the islands. Winds further veer through midweek and then hold steady out of the southerly quadrant where they will remain for the balance of the week. There will be a chance of thunderstorms during this time, particularly over the western waters.
A moderate, medium period NNW swell has shifted more N and will gradually trend down through Sunday producing below average surf along N and W facing shores. A tiny, long period NW swell will fill in Monday into Tuesday before subsiding Wednesday which will prevent surf from going flat. In the long range, guidance depicts a gale forming Monday near the Kurils then tracking northeast to the western Aleutians by Wednesday. In this scenario, Hawaii would experience an uptick in the NW swell next weekend.
Surf along E facing shores will remain below the April average through the weekend. E shore surf could becomes tiny by mid week as southerly winds emerge.
A tiny, long period S swell will move through this weekend providing a small boost in surf along S facing shores. A larger, long- period SSW swell will fill in Monday into Tuesday and produce near to above average surf along S facing shores.

HFO Watches/Warnings/Advisories

None.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov