Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 76 to 83 near the shore to 61 to 69 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then showers after midnight. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. Northeast winds 10 to 20 mph decreasing to up to 10 mph after midnight. Chance of rain 90 percent.

Tuesday: Mostly cloudy. Showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 62 to 69 at 4000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Kona

Today: Mostly sunny. Scattered showers in the late morning and afternoon. Highs 80 to 87 near the shore to around 67 near 5000 feet. Southeast winds around 10 mph in the morning becoming light. Chance of rain 40 percent.

Tonight: Mostly clear with isolated showers. Lows 68 to 73 near the shore to 46 to 53 near 5000 feet. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 20 percent.

Tuesday: Mostly sunny. Scattered showers in the afternoon. Highs 80 to 87 near the shore to around 67 near 5000 feet. East winds around 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Waimea

Today: Windy. Partly sunny with scattered showers. Highs 63 to 84. East winds 15 to 30 mph with gusts to 50 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Windy. Scattered showers in the evening, then showers after midnight. Lows 61 to 70 near the shore to 53 to 62 near 3000 feet. East winds 15 to 30 mph decreasing to 10 to 20 mph after midnight. Chance of rain 80 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 70 percent.

Kohala

Today: Windy. Partly sunny with scattered showers. Highs 63 to 84. East winds 15 to 30 mph with gusts to 50 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Windy. Scattered showers in the evening, then showers after midnight. Lows 61 to 70 near the shore to 53 to 62 near 3000 feet. East winds 15 to 30 mph decreasing to 10 to 20 mph after midnight. Chance of rain 80 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 64 to 84. East winds 10 to 20 mph. Chance of rain 70 percent.

South Big Island

Today: Sunny and windy. Isolated showers in the late morning and afternoon. Highs around 83 near the shore to around 67 near 5000 feet. East winds 10 to 30 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Windy. Isolated showers in the evening. Lows 69 to 74 near the shore to around 49 near 5000 feet. East winds 10 to 30 mph becoming 15 to 20 mph after midnight. Chance of rain 20 percent.

Tuesday: Sunny and breezy. Isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 76 to 83 near the shore to 61 to 69 at 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then showers after midnight. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. Northeast winds 10 to 20 mph decreasing to up to 10 mph after midnight. Chance of rain 90 percent.

Tuesday: Mostly cloudy. Showers in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 62 to 69 at 4000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Waikoloa

Today: Sunny and windy. Highs 80 to 87 near the shore to 65 to 70 above 4000 feet. Northeast winds 10 to 30 mph.

Tonight: Mostly clear. Windy. Isolated showers in the evening, then scattered showers after midnight. Lows around 71 near the shore to 48 to 54 above 4000 feet. Northeast winds up to 30 mph becoming east up to 10 mph after midnight. Chance of rain 50 percent.

Tuesday: Sunny. Highs 80 to 87 near the shore to 65 to 70 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon.

Detailed Forecast

Synopsis

A strong high pressure system to the north will generate breezy to strong trade winds into Tuesday. Brief passing showers are expected mainly over windward and mountain areas through Wednesday. A cold front will sweep from west to east down the island chain from Wednesday evening through Thanksgiving Day, delivering a period of showers for all islands, followed by another round of strong and gusty northeast winds that will ease by Friday night. Lighter winds are forecast from Sunday onward as the ridge north of the region weakens.

Discussion

A strong high pressure system north of the state will produce breezy to strong trade winds across the region into Tuesday. An approaching cold front will weaken the ridge north of the state and decrease wind speeds to more moderate levels from Tuesday night through Wednesday.
A wind advisory remains in effect until 6 PM HST this evening for portions of Oahu including most areas in Maui and Hawaii Counties. Trade wind temperature inversion heights will lower later today with decreasing shower activity lasting into Tuesday night. Expect brief passing showers mainly over windward and mountain areas, favoring the overnight to early morning hours in this pattern. One exception to this forecast will be more numerous showers over windward areas of East Maui and the windward Big Island through Wednesday. Shower activity will then trend upwards across all islands by Wednesday afternoon as prefrontal convergence bands produce showers ahead of the approaching cold front.
A vigorous cold front will sweep from west to east across the state from Wednesday night through Thursday. Expect a 6 hour or less period of rainfall for all islands as the frontal cloud band moves quickly through the region. A strong high pressure ridge will build in behind the front with another round of strong and gusty winds in the forecast from Thanksgiving Day into Friday. These strong northeast winds will likely exceed our wind advisory thresholds and create problems for outdoor holiday events. Please consider indoor party planning for this Thanksgiving as winds this strong may blow away small items and tents.
Winds are expected to ease from Friday into the weekend as a cut off low forms on the front northeast of the islands, and the high rapidly weakens. Light winds will develop from Sunday onward with land and sea breezes forming over all islands.

Aviation

Strong, gusty trades will continue through the forecast period and will focus clouds and showers mainly over windward and mauka areas. Shower intensity will tend to be limited over the western end of the state due to increasing stability. However, pockets of deeper moisture within the comparatively low stability environment over the eastern end of the state will favor periods of heavier showers over Windward Big Island and Maui. This will especially be the case this evening when an expanding coverage of showers will likely bring widespread MVFR to these areas.
AIRMET Tango for lee turbulence will remain in effect through the forecast period.
AIRMET Sierra for mountain obscuration may be needed this evening.

Marine

A tight pressure gradient across Hawaii will result in strong to gale force trade winds across the coastal waters through tonight. A Gale Warning is in effect for Pailolo and Alenuihaha channel through this evening. A Small Craft Advisory (SCA) is also in effect for all Hawaiian waters through today, with the likelihood that at least some of the waters will be extended into beyond then. A slight weakening in the winds is forecast Tuesday through the day Wednesday as the driving high moves away. In its place, a vigorous cold front will impact the area beginning Wednesday night and continuing through Friday, which will produce gale force winds and rough seas in combination with a large north northwest swell.
Currently, a long-period northwest swell (310 degrees) will fill in throughout the morning. A High Surf Advisory (HSA) is now in effect through 6 am Tuesday as the offshore buoys have indicated the swell coming in slightly above guidance. The swell is expected to decline Tuesday and Wednesday. A much larger north northwest swell will build overnight Wednesday night into Thanksgiving Day. The peak of this swell could reach warning levels and it could coincide with the spring high tide during the early morning hours Thursday. Adding the potential for gale force winds along the cold front, there could be significant overwash issues and large wave run up along north facing shorelines both on the mornings of Thanksgiving and Friday. Latest wave run up forecast from PACIOOS is indicating wave run- up heights exceeding 8 feet and approaching 10 feet. Above 8 feet, overtopping of lower roadways closer to the shore should be expected. Areas exposed to north swells on other shorelines should see a significant rise in surf as the north northwest swell moves in.
Surf along east facing shores will see a steady rise during the next few days as the trades strengthen. Other than some wind swell wrap, south facing shores will see minimal energy for the foreseeable future.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 AM HST Tuesday for north and west facing shores of Niihau, Kauai, Oahu and Molokai.
Red Flag Warning from 9 AM HST this morning to 6 PM HST this evening for all leeward areas.
Wind Advisory until 6 PM HST this evening for portions of Oahu and most areas of Maui and Hawaii Counties.
Small Craft Advisory until 6 PM HST this evening for all Hawaiian coastal waters.
Gale Warning until 6 PM HST this evening for Pailolo Channel, Alenuihaha Channel.

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Data Courtesy of NOAA.gov