Hilo

Today: Scattered showers. Partly sunny, with a high near 83. West wind 5 to 11 mph becoming east in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 7pm. Partly cloudy, with a low around 63. Southwest wind around 6 mph becoming calm after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers, mainly after 1pm. Mostly sunny, with a high near 83. Calm wind becoming east 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after 1pm. Mostly sunny, with a high near 83. Light and variable wind becoming west 5 to 10 mph in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before 7pm. Partly cloudy, with a low around 63. Light east wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Isolated showers before 7am, then scattered showers after 1pm. Mostly sunny, with a high near 83. Calm wind becoming west 5 to 7 mph in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 75. Northeast wind 5 to 8 mph becoming calm. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before midnight. Partly cloudy, with a low around 52. West southwest wind around 5 mph becoming light and variable. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers, mainly after noon. Mostly sunny, with a high near 75. Southeast wind 5 to 9 mph becoming northwest in the morning. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Scattered showers. Partly sunny, with a high near 67. East wind 5 to 8 mph becoming calm. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before midnight. Mostly cloudy, with a low around 44. West southwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Showers likely, mainly after noon. Partly sunny, with a high near 67. Calm wind becoming north northwest 5 to 9 mph in the afternoon. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 83. Breezy, with an east northeast wind 15 to 20 mph, with gusts as high as 25 mph.

Tonight: Isolated showers. Partly cloudy, with a low around 69. Breezy, with an east wind 7 to 15 mph becoming north in the evening. Winds could gust as high as 18 mph. Chance of precipitation is 20%.

Tuesday: Sunny, with a high near 83. East southeast wind 5 to 9 mph becoming calm in the afternoon.

Puna

Today: Scattered showers. Partly sunny, with a high near 81. West wind 6 to 14 mph becoming east in the morning. Winds could gust as high as 18 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 61. South southeast wind 6 to 9 mph becoming west in the evening. Chance of precipitation is 20%.

Tuesday: Scattered showers, mainly after noon. Mostly sunny, with a high near 81. West wind 5 to 11 mph becoming east in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Scattered showers after noon. Mostly sunny, with a high near 81. East southeast wind 5 to 10 mph becoming light and variable. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers after midnight. Partly cloudy, with a low around 62. West southwest wind around 6 mph becoming calm. Chance of precipitation is 20%.

Tuesday: Scattered showers after noon. Mostly sunny, with a high near 81. Light and variable wind becoming west northwest 8 to 13 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Detailed Forecast

Synopsis

Winds will transition today from trade winds to a light and variable wind pattern. Light large scale winds will allow local scale land and sea breezes to develop through the middle of the week. Clouds will build over island mountain and interior sections each day with a few showers in the afternoon to early morning hours through Wednesday. Trade winds will return from Thursday into the weekend with clouds and showers trending back to typical windward and mountain areas.

Discussion

This mornings satellite imagery shows an upper level low just south of the main Hawaiian Islands. A subtropical jet stream located south of this upper low is producing high level cirrus clouds across much of the state. Stable low level clouds are drifting through the decreasing trade winds with a few showers over the windward and mountain areas through the early morning hours. A weakening cold front roughly 600 miles northwest of Kauai will approach the islands from the northwest, breaking down the high pressure ridge north of the islands, and disrupting the trade wind flow.
A light and variable wind regime continues for the first half of the week. Warm days and cool nights will develop over all islands along with sea breezes during the day and down slope land breezes at night. Island heating and converging sea breezes will build clouds over island mountain and interior sections through the day. A few showers may develop each afternoon and early evening over these areas through Wednesday.
A weakening cold front will slowly approach the islands from the northwest direction through the first half of the week. Forecast guidance tools continue to hint at pre-frontal shower bands developing over the state on Tuesday and Wednesday as the front moves into the state. Global model solutions continue to struggle with how far east the front will move relative to the islands. The latest model solutions bring the dissipating frontal cloud band into Maui late Wednesday into Thursday. In any case, periods of unsettled weather should be expected from the Tuesday to Thursday time periods.
A migratory high moving from west to east across the Central Pacific basin will allow the trade winds to return from Thursday on into the weekend. Remnant showers from the now dissipated frontal band will then drift back over the islands in the trade wind flow on Thursday and Friday. Showers will favor windward and mountain slopes in the overnight to early morning hours.

Aviation

An approaching front will continue to ease the trades this morning, with sea breezes becoming common statewide this afternoon. A few showers will affect windward slopes and coasts this morning, before transitioning over to interior and mountain areas this afternoon and this evening. The approaching front in combination with a disturbance aloft could bring some showers over much of the island chain tonight.
AIRMET Tango remains in effect for moderate upper level turbulence, and will likely continue through much of the day.

Marine

Trade winds will continue to weaken and veer more southerly today in response to an approaching front from northwest of the island chain. The surface ridge currently northeast of the state will move further east and away from the islands Tuesday and Wednesday as the weakening front dissipates across the region. This will result in gentle, variable mid week breezes. High pressure passing north of the state Thursday will reestablish trade winds. Trades will strengthen back to areawide moderate to fresh magnitudes, with possibly locally strong SCA-level winds through the notoriously windier eastern island channels and bays, from Friday into the weekend.
Surf along all Hawaiian Island shores will remain under High Surf Advisory thresholds the next several days. North facing shore surf will remain very low through the day with only background north swell and a lowering trade wind wave swell. The next appreciable west northwest swell will arrive tonight and Tuesday and this will peak mid week surf in the moderate range. Small west swell may be blocked from Oahu eastward due to Kauai shadowing Tuesday but, as this swell veers more northwest on Wednesday and then north northwest Thursday, surf heights along most north and west facing shores will be on the rise. A larger northwest swell arriving from a Northwest Pacific gale Friday and Saturday may peak weekend surf into the double digits (face values in feet) along some northern and western exposures. This swell, in tandem with strengthening trades, may create rough weekend seas. Multi small, long period south southwest swell energy from southern hemispheric storms will be reaching the Hawaiian southern coasts during the middle of the week. These swells will provide a minor boost to mid to late week surf along many southern coastlines. Eastern shoreline surf will also remain around spring season averages through the day but will drop off through mid week as trades weaken over and upstream of the state.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov