Photo Credit: James Grenz

Hilo

Today: Mostly sunny with isolated showers. Highs around 80 near the shore to 66 to 71 at 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 77 to 82 near the shore to 65 to 70 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 80 to 87 near the shore to around 68 near 5000 feet. North winds around 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows 66 to 72 near the shore to 44 to 53 near 5000 feet. North winds around 10 mph shifting to the east after midnight. Chance of rain 40 percent.

Saturday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 80 to 85 near the shore to around 67 near 5000 feet. North winds up to 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Waimea

Today: Mostly sunny with isolated showers. Highs 66 to 86. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 84. East winds 15 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny with isolated showers. Highs 66 to 86. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 84. East winds 15 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Sunny. Isolated showers in the afternoon. Highs around 82 near the shore to around 66 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 70 near the shore to around 48 near 5000 feet. East winds 10 to 25 mph.

Saturday: Sunny and breezy. Isolated showers in the afternoon. Highs around 81 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly sunny with isolated showers. Highs around 80 near the shore to 66 to 71 at 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to 51 to 56 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 77 to 82 near the shore to 65 to 70 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny. Isolated showers in the afternoon. Highs 80 to 86 near the shore to 65 to 71 above 4000 feet. East winds 10 to 15 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 64 to 73 near the shore to 46 to 53 above 4000 feet. East winds 10 to 15 mph.

Saturday: Mostly sunny. Highs 79 to 85 near the shore to 64 to 70 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon.

Detailed Forecast

Synopsis

Trade winds will increase today, and then remain moderate to locally breezy through the weekend, delivering just a few windward showers. Little change is expected into next week.

Discussion

As expected, no changes to the forecast this morning. High pressure remains to the north of Kauai, and will be the main feature impacting our weather into next week. Expect the winds to be on the increase today, with moderate to locally breezy trades expected later today. An east to west oriented surface ridge north of the islands will linger through the weekend, maintaining the trade wind flow. Winds may be slightly weaker over Kauai and Oahu due to their proximity to the ridge, with winds a touch stronger over Maui County and the Big Island.
A more stable airmass is setting up over the islands. The overnight soundings from Lihue and Hilo continue to show 500 mb temperatures near normal around -8 celsius. Hilo reported precipitable water (PW) 1.21 inches (near normal) and Lihue reported 1.36 inches (above normal). This pairs well with the satellite derived PW which shows some additional moisture over the western end of the state. Despite the uptick in moisture, not expecting any significant shower activity.
The models are in good agreement with an upper level ridge pushing in over the islands from the west as an upper level trough continues to move away to the east. The upper level ridging looks to remain in place through the weekend, and then weaken some as we head into the middle of next week. A stable airmass with trade winds means that clouds and showers will be focused over the windward sides of the islands.
With no significant rain events on the horizon, drought conditions are worsening, with details contained in the recently updated Drought Information Statement (DGTHFO), which can be found on the web at weather.gov/hfo/DGT.

Aviation

Easterly trades will strengthen across the state through tonight as a ridge of high pressure builds north of the islands. The stable conditions associated with this developing pattern, continues to limit clouds and showers across the TAF sites, while trade winds focus showers over windward areas through tonight. A weaker wind pattern lingering over leeward Big Island, will still allow for some sea breeze clouds and isolated showers to develop inland of the Big Island later this afternoon and evening. Expect mainly VFR conditions through the TAF period with brief MVFR cigs in developing showers.
No AIRMETs are currently in effect, however lingering moist trade wind flow this afternoon, may generate a period of potential tempo mountain obscuration along windward zones.

Marine

A surface ridge is located about 260 nm north of Lihue early this morning. This feature is maintaining light to moderate trade winds across the area. The forecast guidance continues to indicate this surface ridge will build as it drifts slowly north later today and tonight. This will likely cause the trade winds to become locally strong, which will result in Small Craft Advisory (SCA) conditions developing over the typically windier waters adjacent to the islands of Maui County and the Big Island. Therefore, a SCA has been issued for these waters from later this morning through Saturday afternoon. This SCA will likely need to be extended through early Sunday morning based on the latest model guidance. The surface ridge is expected to weaken later this weekend, so the SCA may not be required after Sunday afternoon.
A long-period west-northwest swell continues to spread across the area early this morning. The most recent observations at the National Data Buoy Center buoys located northwest of Kauai appear to indicate the swell may be near the output from the wave model. We expect surf produced by this swell to increase to near the seasonal average along most north and west facing shores during the peak of the swell later today. This west-northwest swell will gradually lower from tonight through early Sunday. The next northwest swell will likely arrive late Sunday, and peak near, or just above, the seasonal average along most north and west facing shores of the smaller islands Monday. This swell will slowly lower from Tuesday through the middle of next week.
The current small, long-period south swell will continue to produce a slight bump in surf heights along south facing shores today. Expect a return to more typical small background surf along south facing shores this weekend. Elsewhere, modest, choppy surf will persist along east facing shores through early next week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov