Hilo

Tonight: Mostly cloudy. Occasional showers in the evening, then numerous showers after midnight. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 90 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 83 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 62 to 69 near the shore to 52 to 58 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Tonight: Mostly clear. Lows around 71 near the shore to 45 to 52 near 5000 feet. Light winds.

Tuesday: Sunny. Highs 83 to 88 near the shore to around 68 near 5000 feet. West winds up to 10 mph.

Tuesday Night: Mostly clear. Isolated showers after midnight. Lows around 71 near the shore to 46 to 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 25 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 63 to 83. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 40 percent.

Tuesday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 62 to 71 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 25 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 63 to 83. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 40 percent.

Tuesday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then isolated showers after midnight. Lows 62 to 71 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Tonight: Mostly clear. Breezy. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds 10 to 20 mph.

Tuesday: Sunny and breezy. Isolated showers in the afternoon. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Tuesday Night: Mostly clear. Breezy. Lows around 73 near the shore to around 51 near 5000 feet. Northeast winds 10 to 20 mph.

Puna

Tonight: Mostly cloudy. Occasional showers in the evening, then numerous showers after midnight. Lows 62 to 69 near the shore to 52 to 57 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 90 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 83 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tuesday Night: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 62 to 69 near the shore to 52 to 58 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Lows 70 to 75 near the shore to 49 to 54 above 4000 feet. Southeast winds up to 20 mph.

Tuesday: Sunny and breezy. Highs 82 to 88 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 25 mph.

Tuesday Night: Mostly clear. Lows 70 to 75 near the shore to around 52 above 4000 feet. East winds up to 10 mph.

Detailed Forecast

Synopsis

Breezy easterly trade winds are expected to persist through the week, with showers favoring windward and mauka locations as areas of moisture move through. The trade winds are forecast to become strong and gusty starting around mid-week and lasting into the weekend.

Discussion

This afternoon, high pressure centered roughly 1300 miles northeast of Honolulu is producing locally breezy easterly trade winds across the islands. Meanwhile, a strong low pressure system is moving across the far North Pacific, and an associated cold front extends from roughly 45N, south-westward to the date line, and into the West Pacific.
Generally stable conditions remain in place over the islands this afternoon with very strong inversions between 7,000 and 8,000 feet. However, the shallow band of low-level moisture and associated low clouds and showers that was located across the western end of the state this morning has become more diffuse as it moves through this afternoon. Showers have remained generally light today, however, with the exception of typically wetter areas such as the Kauai mountains and select windward locations.
The shallow band of moisture that is currently moving through will gradually diminish and shift west of the area through Tuesday as drier air fills in from the east. Meanwhile, the aforementioned low in the North Pacific and its associated cold front that extends southward will quickly move east tonight through Tuesday night. Strong (1036 mb) high pressure will build behind the front north of the islands Tuesday night, then slowly translate eastward through the rest of the week. This strong high will result in strong and gusty trades across the state from mid-week through the weekend. Fortunately, guidance indicates that humidity levels will likely remain sufficiently high throughout the rest of the week, mitigating the need for fire weather headlines.
Showers for the rest of the week will largely favor typical windward and mountain areas, though some showers could reach leeward communities at times during the second half of the week when trades increase. Additionally, the tail end of the front could settle southward into the area Friday through Saturday. This increase in moisture could enhance shower activity over windward areas Friday into the weekend. Shower chances have been adjusted upward accordingly to bring them more in line with the National Blend of Models (NBM) for Friday through the weekend.

Aviation

Breezy trade winds will continue through tonight with low clouds and showers favoring windward and mauka areas, especially during the overnight and early morning hours. Brief spillover showers are possible over leeward areas during the overnight hours. Condition remain predominately VFR, with brief MVFR under heavier showers.
AIRMET Sierra for tempo mountain obscuration remains in effect for windward sections of Kauai. Windward sections of the remaining islands may need to be added later tonight.
AIRMET Tango for moderate low-level turbulence remains in effect over and downwind of all island terrain.

Marine

High pressure remains established north of the islands through the forecast period, strengthening during mid-week. This translates to locally strong E trades continuing through Tuesday with near-gales from Wednesday onward. The existing Small Craft Advisory remains in effect and will eventually require an expansion in coverage as trades strengthen.
Existing medium to long period NW (320 degrees) swell will hold steady just shy of the High Surf Advisory (HSA) threshold through the first half of tonight. This swell will then subside late tonight into Tuesday. The lull in elevated surf will be short- lived as a larger long period NW (320) begins filling in during the day Tuesday. This swell is forecast to peak above the HSA threshold for N and W facing shores. During its peak, this swell will mix with a small, long period N (340-350) swell that will also peak Tuesday night into Wednesday.
Surf along E facing shores will be dominated by wind waves and short period fresh swell emanating from strong upstream trades. As trades further strengthen from Wednesday onward, surf will build to the HSA threshold (10 ft) along E facing shores perhaps as early as Tuesday night but confidence is higher in reaching the HSA threshold by Wednesday. Surf will build toward the High Surf Warning threshold for E facing shores by the end of the week.
Surf along S facing shores remains small through the period except where there is wrapping of longer period NW swell energy.
Finally, peak monthly tides are forecast during the Nov 14th to Nov 18th period. This will exacerbate coastal inundation impacts for E facing shores of all islands as surf potentially approaches the High Surf Warning threshold, particularly for vulnerable locations and during early morning high tides.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Wednesday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov