Hilo

Today: Partly sunny. Breezy. Scattered showers in the morning. Highs 83 to 89 near the shore to around 74 at 4000 feet. Northeast winds up to 20 mph. Gusts up to 45 mph in the afternoon. Chance of rain 30 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 70 near the shore to around 55 at 4000 feet. Northwest winds up to 20 mph with gusts to 45 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 83 to 89 near the shore to around 74 at 4000 feet. North winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon. Gusts up to 50 mph. Chance of rain 20 percent.

Kona

Today: Sunny in the morning then becoming partly sunny. Highs 83 to 88 near the shore to around 71 near 5000 feet. West winds up to 10 mph.

Tonight: Partly cloudy. Lows 73 to 78 near the shore to around 56 near 5000 feet. Northwest winds up to 10 mph shifting to the east after midnight.

Tuesday: Mostly sunny. Highs 83 to 88 near the shore to around 71 near 5000 feet. South winds up to 10 mph shifting to the west in the afternoon.

Waimea

Today: Windy. Partly sunny with scattered showers in the morning, then mostly sunny in the afternoon. Highs around 83 near the shore to 77 to 82 near 3000 feet. East winds up to 35 mph. Gusts up to 50 mph increasing to 60 mph in the afternoon. Chance of rain 30 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Very windy. Isolated showers. Lows around 70 near the shore to 58 to 63 near 3000 feet. East winds 10 to 40 mph with gusts to 65 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Very windy. Isolated showers in the morning. Highs around 83 near the shore to 77 to 82 near 3000 feet. East winds 10 to 40 mph increasing to 20 to 40 mph in the afternoon. Gusts up to 65 mph. Chance of rain 20 percent.

Kohala

Today: Windy. Partly sunny with scattered showers in the morning, then mostly sunny in the afternoon. Highs around 83 near the shore to 77 to 82 near 3000 feet. East winds up to 35 mph. Gusts up to 50 mph increasing to 60 mph in the afternoon. Chance of rain 30 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Very windy. Isolated showers. Lows around 70 near the shore to 58 to 63 near 3000 feet. East winds 10 to 40 mph with gusts to 65 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Very windy. Isolated showers in the morning. Highs around 83 near the shore to 77 to 82 near 3000 feet. East winds 10 to 40 mph increasing to 20 to 40 mph in the afternoon. Gusts up to 65 mph. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny. Windy. Highs around 87 near the shore to around 72 near 5000 feet. East winds up to 30 mph increasing to 10 to 30 mph in the afternoon. Gusts up to 50 mph.

Tonight: Partly cloudy. Windy. Lows 69 to 75 near the shore to around 54 near 5000 feet. East winds up to 30 mph increasing to 10 to 35 mph after midnight. Gusts up to 55 mph.

Tuesday: Mostly sunny. Windy. Highs around 87 near the shore to around 72 near 5000 feet. East winds 10 to 35 mph with gusts to 55 mph.

Puna

Today: Partly sunny. Breezy. Scattered showers in the morning. Highs 83 to 89 near the shore to around 74 at 4000 feet. Northeast winds up to 20 mph. Gusts up to 45 mph in the afternoon. Chance of rain 30 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 70 near the shore to around 55 at 4000 feet. Northwest winds up to 20 mph with gusts to 45 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Highs 83 to 89 near the shore to around 74 at 4000 feet. North winds up to 20 mph shifting to the northeast 10 to 20 mph in the afternoon. Gusts up to 50 mph. Chance of rain 20 percent.

Waikoloa

Today: Sunny and windy. Highs 84 to 89 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 30 mph with gusts to 60 mph.

Tonight: Mostly clear. Windy. Lows 73 to 78 near the shore to 52 to 59 above 4000 feet. East winds up to 35 mph with gusts to 65 mph.

Tuesday: Sunny. Very windy. Highs 84 to 89 near the shore to 71 to 77 above 4000 feet. East winds up to 40 mph with gusts to 65 mph.

Detailed Forecast

Synopsis

Breezy easterly trade winds are forecast to become strong and gusty later today through midweek as Hurricane Dora passes far to the south. Outside of a few windward showers this morning, very dry air arriving from the east will limit rainfall chances through Wednesday. A return of a more typical trade wind pattern is anticipated later in the week through the weekend.

Discussion

An upper low nearby to the northwest combined with a mid-level trough and a sufficient amount of low-level moisture will support a few light showers favoring windward and mountain locations this morning. Satellite imagery showed the leading edge of a very suppressed and dry air mass approaching from the east, which also marks the leading edge of the easterly wind surge. This drier air (PWs dipping well below normal) combined with a strong pressure gradient between Dora passing to the south and high pressure to the north will support strong and gusty winds later today through midweek. The subsidence inversion is forecast to dip to around 3000 ft, which is well below normal. This stable/dry air and low inversion combined with the strong pressure gradient (50 kt winds shown around the inversion to 850 mb) will generate advisory to warning-level wind speeds this afternoon through Wednesday.
For the second half of the week through the weekend, expect a return of a more typical trade wind pattern, with windward and mountain shower coverage increasing.

Aviation

Surface high pressure north of the state will bring moderate trades across to the islands through the remainder of this morning. Some low level moisture caught up in the flow will bring scattered showers to areas along the windward coasts and slopes with accompaning brief periods of MVFR ceilings and visibility. Elsewhere, expect isolated showers. By this afternoon, drier air filtering in from the east will act to limit shower chances and cloud coverage.
A tight surface pressure gradient will develop across the region this afternoon through Wednesday, due to the combination of strong surface high pressure north of Hawaii and Hurricane Dora passing well south of Hawaii. This scenario will generate strong and gusty trades across all islands for the duration of the aforementioned period.
There are currently no AIRMETs in effect. However, AIRMET Tango for moderate turbulence downstream of terrain will likely be issued later this morning due to the strengthening trade winds.

Marine

Trade winds will strengthen through Tuesday as the ridge builds north of the islands and Hurricane Dora passes south of the Hawaiian Islands from later this afternoon through Wednesday morning on its westward track. Wind speeds will peak on Tuesday with a Gale Warning in effect through Tuesday night over the windier channels and waters around Maui County and the Big Island. Strong wind speeds and rapidly building rough seas will occur over the rest of the coastal waters through Tuesday night as well. A Small Craft Advisory remains in effect for the remaining coastal waters.
Surf along east facing shores will quickly ramp up and become rough today through Wednesday due to a combination of very strong trades, large seas and a moderately sized, moderate period easterly swell generated from Dora. The largest surf is expected over the eastern end of the state, where surf heights will reach warning levels from tonight through Tuesday afternoon. A downward trend is expected from Tuesday night through Thursday as trade winds and seas diminish to more typical conditions. A High Surf Warning was issued for all exposed east facing shores of the Big Island, Maui and Molokai. A High Surf Advisory may be needed starting tonight along exposed east facing shores of Oahu and Kauai.
Surf along south facing shores will remain small today and tonight with background south and southwest swell energy rolling through. A short to medium period southeast swell will fill in on Tuesday from Dora as it passes by far to the south. This will be a short lived event with a peak occurring late Tuesday into early Wednesday. A long period south-southwest swell from the South Pacific will arrive by Wednesday, south shore surf heights approaching advisory thresholds from Wednesday into Thursday, before diminishing through the end of the week.

Fire weather

Very dry fuels (KDBI around 600) combined with strong and gusty easterly winds and low humidities below 45 percent will produce critical fire weather conditions this afternoon through Tuesday night. See the Red Flag Warning for more information.

HFO Watches/Warnings/Advisories

Wind Advisory from 6 AM this morning to 6 AM HST Wednesday for Niihau, Olomana, Kauai East, Koolau Windward, Windward Haleakala, Kipahulu, Big Island East.
Red Flag Warning from 6 AM this morning to 6 AM HST Wednesday for Kauai Leeward, Oahu South Shore, Waianae Coast, Oahu North Shore, Olomana, Central Oahu, Waianae Mountains, Molokai Leeward, Lanai Makai, Lanai Mauka, Maui Leeward West, Maui Central Valley, Leeward Haleakala, Kona, South Big Island, Kohala, Big Island Interior.
High Wind Warning from 6 AM this morning to 6 AM HST Wednesday for Kauai Leeward, Kauai Mountains, Waianae Coast, Oahu North Shore, Central Oahu, Waianae Mountains, Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Haleakala Summit, Kohala, Big Island Interior, Big Island Summits, Kauai North, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Koolau Leeward, Molokai, Lanai Windward, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
High Surf Warning from 6 PM this evening to 6 PM HST Tuesday for Maui Windward West, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, Big Island Southeast, Big Island East, Big Island North.
Small Craft Advisory from 6 AM this morning to 6 AM HST Wednesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.
Gale Warning from 6 AM this morning to 6 AM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov