Hilo

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to 64 to 71 at 4000 feet. North winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 63 to 72 near the shore to around 55 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 87 near the shore to 65 to 72 at 4000 feet. Northeast winds around 10 mph. Chance of rain 40 percent.

Kona

Today: Mostly sunny. Isolated showers in the afternoon. Highs 84 to 89 near the shore to around 69 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 71 to 76 near the shore to 48 to 55 near 5000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs around 87 near the shore to around 71 near 5000 feet. East winds around 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 70 to 80 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to 70 to 80 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

South Big Island

Today: Sunny and breezy. Isolated showers in the afternoon. Highs around 87 near the shore to around 68 near 5000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Isolated showers in the evening. Lows around 74 near the shore to around 52 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Tuesday: Sunny and breezy. Isolated showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to 64 to 71 at 4000 feet. North winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 63 to 72 near the shore to around 55 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 87 near the shore to 65 to 72 at 4000 feet. Northeast winds around 10 mph. Chance of rain 40 percent.

Waikoloa

Today: Sunny. Isolated showers in the afternoon. Highs around 87 near the shore to 66 to 72 above 4000 feet. Northeast winds up to 15 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 74 near the shore to 51 to 57 above 4000 feet. Northwest winds up to 10 mph shifting to the east after midnight. Gusts up to 30 mph. Chance of rain 20 percent.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 84 to 90 near the shore to 66 to 75 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon. Gusts up to 35 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate and slightly unstable trades will bring locally heavy showers to windward and mauka areas through the morning. More stable trades take over later this evening, becoming breezy to locally strong Wednesday and Thursday. A return to more typical trade pattern is expected Friday through the coming weekend.

Discussion

Water vapor satellite imagery early this morning shows the upper level trough northeast of the state continuing to move away to the northeast. This will allow drier mid-level air to move in from the east and showers to trend down over the eastern half of the state later this morning.
At the surface, a hybrid trade and land/sea breeze pattern continues. Current infrared satellite imagery and radar show mostly clear conditions over leeward areas of Maui County and the Big Island due to localized land breezes. For the remainder of the state, a weak shortwave trough embedded in the trades is moving westward across Kauai and Oahu, bringing increased showers into windward areas, with some clouds and a few showers making it over to leeward areas at times. Expect a gradual decreasing trend to the showers through late morning, as the shortwave exits off to the west of the state.
Winds will transition to a more stable flavor of trades later this evening through the remainder of the week, as mid-level ridging builds back in over the region. Trades are forecast to become breezy to locally strong around mid-week, in response to lowering pressure just north of the equator and an expansive, 1031 mb high centered northeast of the state near 35N. A more typical moderate to locally breezy trade pattern is expected to return Friday through the upcoming weekend.

Aviation

High pressure far northeast of the state will maintain moderate trade winds through Monday. Clouds and showers will favor mainly windward and mauka areas through the early morning hours. Afternoon sea breezes are once again expected to develop today, with scattered showers possible over terrain sheltered areas. Will see predominately VFR conditions with brief MVFR under passing showers.
No AIRMETs are currently in effect.

Marine

Moderate to fresh easterly trades will increase into the fresh to strong category Tuesday through the rest of the week. Small Craft Advisory conditions will be likely for the typically windier channels and waters around Maui County and the Big Island Tuesday, then for most exposed waters Wednesday into the second half of the week.
Surf along exposed north and west facing shores have been trending up overnight as a small northwest swell builds down the island chain. Observations at the Hanalei and Waimea PacIOOS buoys reflect this trend with the peak energy centered around the 12 second band. Expect this trend to continue with a peak expected later today. Guidance shows the swell lingering Tuesday out of the north-northwest, then easing through midweek. For the upcoming weekend, a small west-northwest (300-310 degrees) swell arriving will be possible. This will be in response to Tropical Storm Damrey racing eastward toward the Date Line from Japan over the next couple of days.
Surf along south facing shores will remain small throughout the week. A modest increase is expected tonight into Tuesday as a small south-southwest swell moves through the state. Another tiny long-period southwest swell is possible Friday into the weekend.
Surf along east facing shores will remain small through the first half of the week, then trend up through the second half as the trades ramp up locally and upstream of the state. Additionally, expect some groundswell mixed in with 10 second periods next weekend from Tropical Storm Irwin tracking westward across the eastern Pacific.

Fire weather

Breezy to locally strong trade winds will develop Wednesday and continue through Thursday. An initially moist airmass on Wednesday will eventually give way to an influx of much drier air arriving from the east late Wednesday and Thursday. Red Flag conditions, characterized by sustained winds of 20 mph or greater and afternoon RH values below 45 percent, will be possible on Wednesday, but more likely Thursday.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov