Hilo

Tonight: Mostly cloudy with showers likely. Lows 63 to 71 near the shore to 54 to 59 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Thursday: Partly sunny with scattered showers. Highs 80 to 88 near the shore to 66 to 71 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Thursday Night: Mostly cloudy with occasional showers. Lows 65 to 73 near the shore to 56 to 61 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 90 percent.

Kona

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 74 near the shore to 49 to 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 89 near the shore to 67 to 72 near 5000 feet. Light winds. Chance of rain 40 percent.

Thursday Night: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows around 75 near the shore to 50 to 56 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 56 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 65 to 87. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 65 to 73 near the shore to 58 to 64 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Kohala

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 56 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 65 to 87. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 65 to 73 near the shore to 58 to 64 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

South Big Island

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 74 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs around 87 near the shore to around 70 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Isolated showers in the evening. Lows around 75 near the shore to around 54 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with showers likely. Lows 63 to 71 near the shore to 54 to 59 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Thursday: Partly sunny with scattered showers. Highs 80 to 88 near the shore to 66 to 71 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Thursday Night: Mostly cloudy with occasional showers. Lows 65 to 73 near the shore to 56 to 61 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 90 percent.

Waikoloa

Tonight: Partly cloudy. Lows around 75 near the shore to 51 to 56 above 4000 feet. Northeast winds up to 10 mph.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 84 to 91 near the shore to 66 to 76 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows around 76 near the shore to 53 to 58 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy to locally windy trade winds will continue to bring limited and brief showers to mainly windward areas through Friday. Heading into the weekend and beyond, weather across the state will be highly dependent on the track and intensity of a tropical cyclone that is expected to develop far east-southeast of the islands sometime tonight or Thursday.

Discussion

For the short term forecast, a stable and breezy to locally windy summertime trade wind weather pattern will prevail across the state through Friday as deep-layer ridging prevails over the region. Brief showers will favor windward areas as they ride in on the trades, mainly during the overnight to early morning periods.
From late Friday through the weekend, confidence in forecast details remains on the lower end of the spectrum, but models are gradually coming into slightly better agreement on some of the larger scale features. A tropical cyclone (TC) is likely to form well east- southeast of the islands sometime tonight or Thursday and head generally westward while getting better organized and intensifying over the next couple of days…potentially passing dangerously close to the islands over the weekend.
While it's too early for forecast specifics with respect to potential timing and impacts for the islands (especially since this potential TC still has not developed), our confidence is gradually growing for the following scenarios: – Winds increasing state-wide this weekend (especially Saturday night into Sunday), with gusts of 40 mph possible Saturday and gusts in excess of 50 mph possible Saturday night into Sunday. – The potential for heavy rain over windward Big Island late Saturday into Sunday, which could create flash flooding concerns. For the rest of the state, our confidence for flooding impacts is lower, but flooding is still possible and will be dependent on the track of the potential TC. – Drier air filtering in across the state on Saturday ahead of any potential TC moving close to the islands could elevate fire weather concerns. – High surf impacting east-facing coasts.
It's really important to keep in mind that there is still a lot of forecast uncertainty, so the scenarios above that are based on current forecast trends may not be accurate.
If a TC does form, note that public and marine forecasts from WFO Honolulu will be updated on a modified schedule, in conjunction with the latest TC forecast issued at 5 am/pm and 11 am/pm HST. Throughout the life cycle of any TC near Hawaii, forecast information can be found on the web at hurricanes.gov.
It is the peak of hurricane season here in Hawaii, and now is a good time to make sure that you and your family are prepared. For more information, visit weather.gov/safety/hurricane-plan.

Aviation

Moderate to locally breezy trades will remain through the forecast period with scattered showers mainly over windward and mountain areas. Brief MVFR conditions will be possible with any showers, but generally VFR conditions should prevail.
AIRMET Tango is in effect for moderate low level turb downwind of the terrain of all islands. Otherwise, no other AIRMETs are in effect.

Marine

Fresh to locally strong trades persist into this weekend in response to high pressure expanding into the area. The existing Small Craft Advisory (SCA) has been extended through Friday accordingly. There is a high probability that a tropical cyclone will emerge in the vicinity of 140W longitude and track toward the area late this week into this weekend. In such a scenario, conditions would become quite windy with gales / tropical storm force winds developing over eastern portions of the area, particularly in channels. This week's marine forecasts will be highly dependent upon the potential evolution, development and track of a potential tropical cyclone.
Shorter period energy filling in behind this morning's forerunners is fostering moderate surf along north and west-facing exposures today into early Thursday. The existing S (190) swell that peaked yesterday has since leveled out and will hold through today before fading on Thursday. Short period chop will be on the rise through mid-week for east- facing shores due to strengthening trades.
Short period E swell, perhaps around 12 seconds or less, of several feet will be possible in a tropical cyclone scenario this weekend and would potentially warrant a High Surf Advisory or High Surf Warning for some east-facing exposures, particularly those of the Big Island. As is the case with wind, upper end potential for high surf will be entirely dependent on the system's track and intensity.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov