Photo Credit: James Grenz

Hilo

Today: Frequent showers, mainly before noon. High near 75. Calm wind becoming east 5 to 7 mph in the afternoon. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Frequent showers. Low around 61. Light and variable wind becoming west 5 to 7 mph after midnight. Chance of precipitation is 90%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Frequent showers, mainly before noon. High near 76. Light and variable wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 77. East southeast wind 5 to 9 mph becoming west northwest in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly before midnight. Partly cloudy, with a low around 59. East wind around 6 mph becoming calm after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Scattered showers, mainly after noon. Mostly sunny, with a high near 78. Light and variable wind becoming west southwest 5 to 7 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers. Partly sunny, with a high near 72. Breezy, with a north northeast wind 11 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 50. Breezy, with a north northeast wind 13 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday: Showers likely, mainly after 1pm. Partly sunny, with a high near 73. Breezy, with a northeast wind 15 to 22 mph, with gusts as high as 31 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Frequent showers. High near 68. Windy, with an east northeast wind 11 to 16 mph increasing to 18 to 23 mph in the afternoon. Winds could gust as high as 32 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Frequent showers. Low around 43. Very windy, with an east northeast wind 26 to 33 mph, with gusts as high as 48 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Frequent showers. High near 69. Very windy, with an east wind 32 to 37 mph decreasing to 22 to 27 mph in the afternoon. Winds could gust as high as 55 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Scattered showers. Mostly sunny, with a high near 77. Windy, with an east wind 18 to 24 mph, with gusts as high as 31 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Partly cloudy, with a low around 67. Breezy, with an east northeast wind 16 to 22 mph, with gusts as high as 28 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Scattered showers. Partly sunny, with a high near 78. Windy, with an east northeast wind around 23 mph, with gusts as high as 30 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Puna

Today: Frequent showers, mainly before noon. High near 74. West northwest wind 6 to 9 mph becoming east in the afternoon. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Frequent showers. Low around 59. West wind 5 to 9 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday: Frequent showers. High near 75. Northwest wind 8 to 14 mph becoming east northeast in the morning. Winds could gust as high as 18 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Isolated showers after noon. Mostly sunny, with a high near 78. South southeast wind 5 to 8 mph becoming calm. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 59. Calm wind becoming east southeast 5 to 8 mph after midnight.

Saturday: Isolated showers after noon. Mostly sunny, with a high near 79. Light and variable wind becoming north northeast 8 to 13 mph in the afternoon. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

A high to the north will maintain breezy trade winds over the area through the weekend. The trade winds are pushing remnants of a front over the islands, focusing showers over mainly windward areas. Rainfall may become heavier and more widespread as deeper moisture spreads over the area from the southeast starting Sunday. Next week, a new high may produce windy weather.

Discussion

A 1033 mb surface high northwest of the main Hawaiian islands is producing breezy northeast to east trade winds over the islands. Radars are showing numerous showers moving over the islands from the northeast. These showers are part of an old frontal band caught up in the trade winds. Breezy trade winds will continue through the weekend. Windward areas will remain rather wet with some showers spreading leeward on the smaller islands, mainly during the nights and early mornings.
The global models are showing deeper moisture spreading over the islands from the southeast starting on Sunday. It is too soon to know the details of this developing pattern, but it looks as if rainfall will become heavier and more widespread starting on the Big Island, then spreading northwest over the other islands. Heavy rain and thunderstorms will be possible on the Big Island with ice and snow over the upper elevations.
Moisture over the islands will subside by the middle of next week. High pressure building far north of the area and a trough developing near the islands may produce very windy weather through mid-week.

Aviation

The remnants of a front remain over the islands overnight, and it continues to bring clouds and showers to the region. Showers are primarily being brought in by the trade winds, with the majority of MVFR conditions being found on the east sides of the islands. Showers have been heaviest west of Maui over the last several hours. AIRMET SIERRA was recently expanded and is now in effect for mountain obscuration for Kauai, Oahu and Molokai.
Conditions on the remaining islands are predominantly VFR, but that could change as parts of the front move down the island chain. High clouds continue to move over the islands from west to east, and are expected to remain overhead through today. No other AIRMETs are in effect or expected in the near term.

Marine

A strong high pressure system far north of the Hawaiian Islands will drift slowly southeastward over the next several days. Trade wind speeds will increase into the fresh to strong range through tonight, and into the strong to near gale range from Sunday through Wednesday. Gale conditions may develop over the windier eastern waters and channels next week.
A Small Craft Advisory (SCA) was expanded in coverage this morning to include all windward waters and most eastern channels today due to a combination of strengthening trade winds and elevated seas. SCA conditions will likely continue for most coastal waters from Sunday onward due to strengthening trade winds and building seas.
The current northwest swell will decrease today as an overlapping northerly swell moves into the region starting later this afternoon through Saturday. This new overlapping northerly swell will bring surf heights along north facing shores to near High Surf Advisory (HSA) levels by Saturday before slowly diminishing on Sunday. The forerunners of the next northwest swell will arrive on Sunday with overlapping northwest and north swell energy producing continued medium size surf along north and west facing shores on Sunday and Monday, then decreasing to smaller size surf on Tuesday and Wednesday.
Strengthening trade winds will increase surf along east facing shores this weekend with a building trade wind swell. Surf will likely reach HSA levels along exposed east facing shores on Tuesday and possibly exceed High Surf Warning levels on Wednesday.
Background south swells will provide small surf to south facing shores through Wednesday.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM Saturday for all Hawaiian waters except Maui County and Oahu leeward waters.

Data Courtesy of NOAA.gov