Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 82 near the shore to 59 to 67 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.
Tonight: Mostly cloudy with numerous showers. Lows 59 to 68 near the shore to 52 to 57 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.
Tuesday: Mostly cloudy with scattered showers. Highs 75 to 82 near the shore to 61 to 68 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.
Kona
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 79 to 86 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 50 percent.
Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 70 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Tuesday: Mostly sunny. Scattered showers in the afternoon. Highs 80 to 87 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.
Waimea
Today: Partly sunny with scattered showers. Highs 61 to 81. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 59 to 68 near the shore to 52 to 59 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.
Kohala
Today: Partly sunny with scattered showers. Highs 61 to 81. Northeast winds up to 15 mph. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 59 to 68 near the shore to 52 to 59 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.
South Big Island
Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.
Tonight: Partly cloudy. Isolated showers in the evening. Lows around 71 near the shore to around 50 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.
Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 82 near the shore to 59 to 67 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.
Tonight: Mostly cloudy with numerous showers. Lows 59 to 68 near the shore to 52 to 57 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.
Tuesday: Mostly cloudy with scattered showers. Highs 75 to 82 near the shore to 61 to 68 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.
Waikoloa
Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 87 near the shore to around 67 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 70 near the shore to 49 to 55 above 4000 feet. Northeast winds up to 15 mph becoming around 10 mph after midnight. Chance of rain 20 percent.
Tuesday: Mostly sunny with isolated showers. Highs 79 to 87 near the shore to around 68 above 4000 feet. North winds 10 to 15 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
High pressure to the northwest of the islands will maintain moderate to locally breezy trade winds into Tuesday night. Expect typical trade wind showers to be focused over windward and mauka areas, with fewer showers expected Tuesday. Winds will weaken and turn to the southeast for the second half of the week. An upper level trough will enhance rainfall during the second half of the week.
Discussion
No significant changes to the forecast this morning. Still evaluating the potential for thunderstorms and heavy rainfall starting as early as Wednesday afternoon, and persisting into the weekend.
High pressure to the northeast will continue to bring moderate to locally breezy trades to the islands through tomorrow, with showers being carried in on the trades focused over the windward areas. Little change in the precipitable water (PW) values with the overnight soundings, but the satellite derived PW does show drier air sinking over the islands. Shower activity is on the decline based on radar, and expect this trend to continue over the next 24 hours or so.
The high is expected to starting lifting to the north by Wednesday as a surface low develops to the far northwest. This will weaken the winds and turn the winds to a more southeasterly direction. Expect winds to turn to the southeast near the Big Island Wednesday and then by Thursday for the smaller islands.
The second half of the week continues to look unsettled. The GFS and ECMWF models continue to be in good agreement with an upper level trough being west of the islands near 170W by Thursday morning. The latest run of the GFS continues to depict a much stronger system and cuts off an upper level low to the west of the islands by Friday morning. The ECMWF isn't as strong, but does have a cut off low Thursday. The latest run of the ECMWF brings the cut off low southward as it approaches the islands, which adds another level of uncertainty to how this event is going to play out. The GFS and ECMWF show increasing instability over the islands as early as Wednesday for the western end of the state and adjacent waters. The National Blend of Models (NBM) is still not as completely on- board, but is showing some thunderstorm potential for the second half of the week. Assuming the global model runs continue to show this pattern, expect the NBM thunderstorm probabilities to increase as the event gets closer.
Thunderstorm and heavy rain potential continues to be monitored for this event, but hasn't yet been added to the forecast due to some timing, location and intensity uncertainty with recent model runs with the handling of the upper level feature. This setup will also likely result in increased chances for some heavier showers throughout the time period of Wednesday afternoon into the weekend as the trade wind inversion slips away. The summits of the Big Island will likely see an uptick in winds as the upper trough approaches and moves over the islands. Additionally, temperatures will likely at times be below freezing, so can't rule out some winter weather for the summits either.
That being said, the forecast now reflects showers spreading across the island chain by Wednesday night, and continuing into the weekend.
Aviation
Light to locally moderate trade winds will continue. Clouds and showers will favor north and northeast facing slopes and coasts. Drier air is expected to move into the western half of the state this afternoon in response to high pressure building in from the northwest.
At 2am Monday, satellite imagery revealed thick bands of cumulus draped across most of the state. Radar returns indicated the heaviest showers to be impacting the northeast slopes and coasts of Maui and the Big Island. AIRMET Sierra for mountain obscuration is now in effect for the windward slopes of Kauai, Maui, and the Big Island. Conditions are expected to end over Kauai and Maui by late afternoon, but will likely persist across the Big Island through the evening hours.
Marine
High pressure northwest of the state will keep moderate to fresh trade winds blowing during the next couple days, with locally strong trades in the typically windy waters around Maui and the Big Island. A Small Craft Advisory remains in effect for these windier waters through 6 AM Tuesday but may need to be extended. The trades will gradually ease Wednesday through the end of the work week, with winds potentially becoming light and variable Thursday and Friday as a trough of low pressure develops west of the state.
The current north swell will continue to slowly decline today through the middle of the week. A new moderate sized north- northeast swell is forecast to build Wednesday night, giving a nice boost to north and east shore surf Thursday with a steady decline to follow Thursday night through next weekend.
A series of south-southwest and south-southeast swells will keep south shore surf relatively steady through next weekend, at or slightly below the summertime average.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 AM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
This comments section is a public community forum for the purpose of free expression. Although Big Island Now encourages respectful communication only, some content may be considered offensive. Please view at your own discretion. View Comments
