Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs 78 to 84 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 85 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows 70 to 75 near the shore to 51 to 57 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 67 near 5000 feet. Southwest winds up to 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 65 to 85. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 70 near the shore to 55 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 65 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 65 to 85. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 70 near the shore to 55 to 63 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 65 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 73 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Thursday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers. Highs 78 to 84 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 72 near the shore to 53 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 85 near the shore to 64 to 71 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Breezy. Highs 84 to 90 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Partly cloudy. Breezy. Lows around 73 near the shore to 50 to 56 above 4000 feet. Southeast winds up to 20 mph.

Thursday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 84 to 89 near the shore to 66 to 72 above 4000 feet. North winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Relatively dry moderate trades will continue through Thursday before weakening slightly this weekend. Lighter winds Friday and Saturday will be accompanied by increased shower activity.

Discussion

Cyclonic flow around the southwest periphery of an upper low to the northeast of the islands remains entrenched over the area for the time being. While this may provide weakly favorable background conditions for a few taller or slightly heavier showers over windward areas, the lack of boundary layer moisture per this afternoon’s soundings and latest satellite imagery suggests relatively dry moderate trades will prevail through the near term. The latest CIMMS PWAT analysis indicates a narrow ribbon of moisture in the mid- latitudes currently extending to around 20N/145W over the north central Pacific. This moisture has become entrained within northeasterly flow around building high pressure and will advect into the area Thursday night through Saturday. At the same time, the aforementioned upper low will will remain in the vicinity serving to gradually erode both the local pressure gradient and the trade inversion coincident with the arrival of increased mid-level moisture. As a result, Friday through Saturday will be characterized by gentle to moderate trades and an increase in shower coverage and intensity over windward and mauka areas, especially overnight and in the early morning hours. Likewise, there will be increased potential for clouds and showers Friday and Saturday afternoon over favored sheltered leeward areas.

Aviation

A boost in the trade winds in the evening warranted an AIRMET Tango for low level turbulence below 6k feet a little sooner. AIRMET Tango will remain in place through at least 0400z this afternoon.
Current satellite and radar imageries show widely dispersed shower- bearing clouds affecting the islands, particularly the windward and mountain areas, leading to very brief MVFR ceilings. Tops of these clouds and showers are around 8k feet with higher tops to 12k feet in heavier showers. Expect the frequency of these showers to be becoming less as the morning progessess, while the opposite happens on the lee side of the Big Island as the sky turns cloudy this afternoon with a few showers.

Marine

High pressure centered north of the state will keep moderate to occasionally fresh trades in place through the weekend. The winds will be locally strong across the windier waters around Maui and the Big Island through early Thursday morning, and as a result a Small Craft Advisory remains in effect for these areas.
A series of overlapping south swells will keep south shore surf near seasonal levels through the remainder of the work week, with surf dropping to slightly below normal levels this weekend through early next week. East shore surf will remain very small during the next 7 days. Surf along north facing shores will remain nearly flat through Saturday, with a small north swell giving north shore surf a slight boost Sunday through early next week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov