Photo Credit: James Grenz

Hilo

Today: Scattered showers. Partly sunny, with a high near 83. Calm wind becoming east northeast 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 68. Calm wind becoming west southwest around 6 mph after midnight. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Showers likely, mainly before noon. Partly sunny, with a high near 82. Calm wind becoming east 5 to 8 mph in the afternoon. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Sunny, with a high near 80. Light and variable wind becoming west around 6 mph. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly before midnight. Partly cloudy, with a low around 67. Light and variable wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Scattered showers after noon. Mostly sunny, with a high near 80. Calm wind becoming west northwest around 6 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Isolated showers. Mostly sunny, with a high near 77. Breezy, with a northeast wind 9 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 58. Breezy, with a northeast wind 11 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Thursday: Scattered showers. Partly sunny, with a high near 77. East northeast wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Isolated showers. Mostly sunny, with a high near 70. Breezy, with an east northeast wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Showers likely. Mostly cloudy, with a low around 57. Breezy, with an east northeast wind 13 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Showers likely. Mostly cloudy, with a high near 70. Breezy, with an east wind 11 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 84. Breezy, with an east wind 18 to 21 mph, with gusts as high as 26 mph.

Tonight: Isolated showers. Partly cloudy, with a low around 73. Windy, with an east northeast wind 21 to 24 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.

Thursday: Isolated showers. Mostly sunny, with a high near 85. Windy, with an east wind 21 to 23 mph, with gusts as high as 30 mph. Chance of precipitation is 20%.

Puna

Today: Scattered showers. Partly sunny, with a high near 79. West northwest wind 5 to 9 mph becoming northeast in the morning. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 66. Northeast wind 5 to 7 mph becoming light and variable. Chance of precipitation is 70%. New precipitation amounts between a quarter and half of an inch possible.

Thursday: Showers likely, mainly before noon. Mostly cloudy, with a high near 79. West wind 5 to 13 mph becoming northeast in the morning. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Sunny, with a high near 83. Calm wind becoming west northwest 5 to 7 mph in the afternoon.

Tonight: Isolated showers before midnight. Mostly clear, with a low around 67. North wind 6 to 9 mph becoming east after midnight. Chance of precipitation is 20%.

Thursday: Isolated showers after noon. Sunny, with a high near 84. East wind 6 to 9 mph becoming north in the morning. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

An area of high pressure will remain north of the area through the remainder of the week and on into early next week. Moderate to breezy trade winds will persist throughout the forecast period. Clouds and passing showers will favor windward and mauka areas with the trade winds sufficiently strong enough to blow some brief passing showers over to select leeward areas at times.

Discussion

After a quiet and mostly dry start, breezy trades have begun to focus a low coverage of clouds and showers over windward areas. Satellite trends and the latest model solutions suggest this trend will continue for the next few hours as boundary layer moisture continues to slowly rebound. Upstream, a well-defined surface trough is supporting an organized band of shower-bearing cu and stratocu. These showers, embedded within the trades, are advancing toward the area this morning and will reach the western portion of the state later this morning. This will occur as a mid-level trough sharpens directly overhead and provides enough additional background forcing to give showers an added boost as they move over Kauai and, to a lesser extent, Oahu. CIMMS satellite PWAT analysis averaging around 1.5 inches within the trough adds confidence to model depictions of good saturation extending up to around 9 or 10kft. Pops have been increased into the likely and categorical range this morning for windward sections of Oahu and for most of the day for Kauai. The trough will also carry a pressure signature sufficient to cause trades to weaken to around moderate intensity . This may result in some enhanced convergence over leeward areas worthy of increasing forecast shower probabilities there as well. This moisture will linger over portions of the area into Wednesday night.
The slowly evolving large scale pattern will offer little change for the remainder of the forecast period. Predominantly breezy trades will demonstrate only minor fluctuations while a weak trough aloft provides an added boost to inversion heights during periods of greater shower activity. Overall, expect typical trade wind weather for the balance of the forecast period with showers focused over windward and mauka areas, especially during the night and early morning hours.

Aviation

A high pressure ridge north of the Hawaiian Islands will produce moderate to breezy trade winds across the region. AIRMET Tango is posted for tempo moderate turbulence below 080 south through west of all island mountains due to the wind speeds.
An upper trough north and west of the island chain along with a weak low level disturbance will keep enhanced clouds and showers across the region. VFR conditions will prevail for most airfields with brief periods of MVFR conditions over some windward locations. AIRMET Sierra for tempo mountain obscurations may be necessary today.

Marine

A weak trough of low pressure will briefly lower the trades below Small Craft Advisory (SCA) levels today, before the trades strengthen tonight, bringing SCA level winds back to the typically wind waters around Maui and the Big Island. Moderate to locally strong trades will then hold in place through Thursday night, with the trades increasing further Friday through early next week, allowing SCA conditions to expand to additional marine zones.
Surf will remain well below the summertime average along south facing shores through Thursday. Surf will trend up Friday as a new south swell fills in, with surf heights nearing the summertime average over the weekend. South shore surf will then lower to mainly background levels early next week. Fresh to locally strong easterly trades will maintain rough and choppy surf along east facing shores during the next 7 days. Trade wind swell will remain near the summertime average today through Friday, then rise to slightly above normal levels over the weekend into early next week. No significant swells are expected throughout the forecast period.

HFO Watches/Warnings/Advisories

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

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov