Photo Credit: James Grenz

Hilo

Today: Scattered showers. Partly sunny, with a high near 77. Calm wind becoming north northeast 5 to 9 mph in the morning. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly after 1am. Mostly cloudy, with a low around 63. North northeast wind around 7 mph becoming west after midnight. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly before 7am. Partly sunny, with a high near 77. Light and variable wind becoming north northeast 8 to 13 mph in the morning. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after noon. Increasing clouds, with a high near 79. South southeast wind 5 to 8 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers before midnight. Mostly cloudy, then gradually becoming mostly clear, with a low around 61. Light south southeast wind becoming east southeast 5 to 10 mph after midnight. Chance of precipitation is 20%.

Wednesday: Scattered showers after noon. Increasing clouds, with a high near 79. Southwest wind 9 to 14 mph becoming light and variable in the afternoon. Winds could gust as high as 18 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers, mainly before 1pm. Partly sunny, with a high near 74. Breezy, with a northeast wind 15 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly after 7pm. Mostly cloudy, with a low around 52. Breezy, with a northeast wind 15 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Scattered showers, mainly before 1pm. Mostly sunny, with a high near 74. Breezy, with a northeast wind 11 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Scattered showers. Partly sunny, with a high near 70. Breezy, with a northeast wind 17 to 20 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.

Tonight: Showers likely, mainly after midnight. Mostly cloudy, with a low around 45. Breezy, with an east northeast wind 17 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 70. Windy, with an east northeast wind 21 to 26 mph decreasing to 14 to 19 mph in the afternoon. Winds could gust as high as 38 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 75. Breezy, with an east wind 17 to 20 mph, with gusts as high as 25 mph.

Tonight: Mostly clear, with a low around 70. Windy, with an east northeast wind 20 to 24 mph, with gusts as high as 31 mph.

Wednesday: Sunny, with a high near 76. Windy, with an east wind 24 to 26 mph, with gusts as high as 34 mph.

Puna

Today: Scattered showers. Partly sunny, with a high near 76. North northeast wind 8 to 13 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 61. Northeast wind around 11 mph becoming west northwest after midnight. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 76. Breezy, with a north northeast wind 9 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Isolated showers after noon. Increasing clouds, with a high near 80. Breezy, with an east northeast wind 13 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 61. Breezy, with an east northeast wind 20 to 22 mph, with gusts as high as 31 mph.

Wednesday: Mostly sunny, with a high near 80. Breezy, with an east northeast wind 16 to 21 mph decreasing to 8 to 13 mph in the afternoon. Winds could gust as high as 29 mph.

Detailed Forecast

Synopsis

High pressure northwest of the state and a building ridge aloft will produce stable northeasterly trade winds today through Thursday, with showers favoring typical windward slopes. An increase in showers and a decrease in winds is possible Friday and Saturday.

Discussion

The shortwave trough that brought locally heavy showers and a few thunderstorms to the state during the last 48 hours has shifted east of the state resulting in an increase in stability over the forecast area. Local satellite and radar imagery indicates most of the existing trade showers topping out below 10kft as mid- level subsidence increases, although a few pockets of deeper convection containing locally heavy showers will remain possible through early this morning. Moderate to locally breezy trades will trend increasingly dry during the next several days as the upstream mid- level ridge gradually migrates eastward. Forecast soundings from the GFS have been on target early in the forecast period. Inversion heights will continue to come down across the area as stability increases. Already at Lihue, the morning RAOB indicates the trade inversion is around 6.5kft, down from 11kft yesterday afternoon. Likewise, PWATs are following suit as they are forecast to hover near the low end of normal for April (around 0.75 to 1″) for the next several days which further increases confidence in a benign dry trade wind type pattern. Dewpoints will also remain pleasantly low, in the upper 50s to low 60s, during this time. This will favor a cooler feel in the afternoons and crisp, cool mornings.
Global models are in general agreement that longwave amplification over the north Pac during the latter portion of the week will force the front near 35N southward toward the Hawaiian Islands by this weekend. This will result in weakening trades areawide by Friday and Saturday. While typical uncertainty exists with respect to forward progress of the boundary through the state, consensus exists that wet trades will be in store for at least Kauai and Oahu by the end of the week.

Aviation

A moderate to locally breezy northeasterly trade wind regime will return to the island chain today as a shortwave trough that has been over the state for the past couple of days shifts east. Meanwhile, high pressure northwest of the state will slowly strengthen over the next couple of days. Therefore, showers and cloud coverage will favor the typical north through east sections of the islands. Although brief MVFR ceilings and visibility will be possible in any showers that do form, VFR conditions are expected to prevail throughout the forecast period.
There are currently no AIRMETs in effect. Although model data suggests that there could be some moderate upper level turbulence briefly this morning in the vicinity of the Big Island, confidence is not high enough to warrant an AIRMET Tango at this time.

Marine

Northeast trade winds will strengthen through tomorrow as a high far northwest of the area moves east. Wind speeds are expected to exceed the Small Craft Advisory threshold through tomorrow night in the windy areas around the Big Island and Maui. Winds will subside later in the week as a cold front approaches from the north.
The current northwest swell is forecast to slowly subside through Thursday. A larger, but shorter-period north swell arriving Thursday night will persist through the weekend, then slowly subside next week. Surf from these swells along north and west facing shores will remain well below the advisory thresholds.
Surf will remain small along east facing shores through mid-week. The north swell will wrap around to some east facing shores later in the week. Swells from distant southern hemisphere storms will produce moderate surf along south facing shores today, with small surf continuing through the rest of the week.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov