Today: Mostly sunny with scattered showers. Highs around 85 near the shore to 62 to 67 at 4000 feet. South winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to around 52 at 4000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 85 near the shore to 62 to 67 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.
Kona
Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to around 62 near 5000 feet. Light winds. Chance of rain 40 percent.
Tonight: Partly cloudy. Lows 66 to 75 near the shore to around 53 near 5000 feet. Light winds.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Tuesday: Mostly sunny. Highs around 82 near the shore to around 62 near 5000 feet. Northeast winds around 10 mph shifting to the northwest in the afternoon.
Waimea
Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to 65 to 77 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 70 near the shore to 53 to 60 near 3000 feet. South winds up to 15 mph. Gusts up to 35 mph in the evening. Chance of rain 40 percent.
Tuesday: Mostly sunny with scattered showers. Highs around 84 near the shore to 65 to 77 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.
Kohala
Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to 65 to 77 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 70 near the shore to 53 to 60 near 3000 feet. South winds up to 15 mph. Gusts up to 35 mph in the evening. Chance of rain 40 percent.
Tuesday: Mostly sunny with scattered showers. Highs around 84 near the shore to 65 to 77 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.
South Big Island
Today: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to around 66 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Tonight: Mostly clear. Breezy. Isolated showers in the evening. Lows 67 to 73 near the shore to around 52 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.
Tuesday: Mostly sunny. Breezy. Highs around 81 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph.
Puna
ARTICLE CONTINUES BELOW AD
Today: Mostly sunny with scattered showers. Highs around 85 near the shore to 62 to 67 at 4000 feet. South winds up to 15 mph shifting to the southeast in the afternoon. Chance of rain 50 percent.
Tonight: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to around 52 at 4000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.
Tuesday: Partly sunny with scattered showers. Highs around 85 near the shore to 62 to 67 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.
Waikoloa
Today: Mostly sunny with isolated showers. Highs around 83 near the shore to 63 to 69 above 4000 feet. Southeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy. Isolated showers in the evening. Lows 67 to 74 near the shore to 49 to 57 above 4000 feet. Light winds becoming southwest up to 10 mph after midnight. Chance of rain 20 percent.
Tuesday: Mostly sunny. Highs around 83 near the shore to 63 to 69 above 4000 feet. East winds up to 10 mph shifting to the northwest around 10 mph in the afternoon.
Detailed Forecast
Synopsis
The high pressure ridge over the islands has diminished this morning as a surface low begins to develop just west to northwest of the state. Expect a stable light southerly wind pattern transitioning to east to southeast winds later today and tonight. A surface low will develop today, increasing east to southeast winds through Wednesday. Shower trends will gradually increase through the week in moderate to locally breezy east to southeast wind flow.
Discussion
The high pressure ridge over the islands has diminished this morning as a surface low begins to develop just west to northwest of the state. The weather pattern will change today as the surface ridge is gone and east to southeast winds will increase across the island chain. Satellite imagery this morning shows increasing shower activity along land breeze and island plume convergence zones mainly over the coastal waters. High level cirrus clouds continue to pass over the region due to a subtropical jet stream and an upper level trough stalling out farther to the northwest of the state. These high clouds will decrease surface heating over each island by a few degrees hindering convective showers. Island plume convergence zones will strengthen tonight with stronger diurnal boundary layer forcing.
The upper air balloon soundings from 2 AM HST at Lihue and Hilo show temperature inversion heights around 6,000 to 7,000 feet. These inversion heights will continue to limit cloud heights and shower potential through the overnight hours. Inversion heights will slowly rise through Wednesday, as the surface low deepens to the northwest and stronger winds blow across the region. Shower trends will gradually increase through the week in moderate to locally breezy east to southeast wind flow.
Global models remain fairly consistent that most of the heavier shower activity with this developing low will remain west of Kauai through the week. Chances for showers over the islands will depend upon small scale convergence band development, such as island plumes or wind speed convergence in a less stable environment. Brief periods of showers will favor the overnight to early morning hours as stronger winds return.
Aviation
A stationary front northwest of the Hawaiian islands will maintain southeast flow through today. Winds will gradually strengthen this afternoon and turn more easterly. A couple showers could drift over the islands today, then a slight increase in shower coverage is possible tonight. Overall VFR conditions are expected.
Marine
A surface boundary is stalling northwest of the islands with the pressure gradient north of this stationary front being tight enough to support gale force winds. Gales will primarily impact the far northwest offshore waters north of 24N through the day. Today's moderate winds across the nearshore waters will veer more southeasterly in response to the front. Low pressure will likely develop along the front today as surface high pressure to the north expands east of the islands through the middle of the week. This will tighten the pressure gradient east of the state and strengthen easterly trades Tuesday and Wednesday. A north swell moving through the Kauai waters today will lift seas to Small Craft Advisory (SCA) levels. A SCA is also in effect from tonight through the middle of the week for winds across eastern island windward waters including the notoriously windier areas surrounding Maui County and Big Island. As the weakening low lifts north and away from the area into the latter half of the week, moderate to locally fresh east to southeast winds will occur through Friday. The eastern Pacific pressure gradient is currently forecast to remain tight enough to maintain moderate to possibly locally strong trades into early next week.
A medium size, short period north (360-020 degree) swell generated by the winds behind a stalling front northwest of the islands is arriving this morning. This swell will produce small to moderate size surf along most smaller island north-facing shores through tonight and will gradually decline Tuesday. A mix of small north northwest swells may maintain modest surf along many exposed north and west-facing shorelines Wednesday into Friday. These north swells may wrap around and subtly increase surf along east-facing shores with more northern exposures through Tuesday. Strengthened mid week trades will result in more choppy wind waves along east-facing shores. A very small, long period south (190 degree) swell arriving today will result in an additional foot or two of surf along many south- facing shores through Tuesday before gradually lowering on Wednesday.
HFO Watches/Warnings/Advisories
Small Craft Advisory from 6 AM this morning to 6 PM HST this evening for waters around Kauai exposed to north swell.
Small Craft Advisory from 6 PM this evening to 6 PM HST Wednesday for most windier waters and channels around Maui and the Big Island.
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