Hilo

Today: Showers likely, mainly before 1pm. Partly sunny, with a high near 81. East northeast wind around 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly after 7pm. Mostly cloudy, with a low around 67. East northeast wind 5 to 9 mph becoming light northeast. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Mostly cloudy, with a high near 81. East wind 5 to 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Increasing clouds, with a high near 79. South southwest wind around 8 mph becoming west in the afternoon.

Tonight: Partly cloudy, with a low around 67. West northwest wind 5 to 8 mph becoming southwest after midnight.

Tuesday: Isolated showers after noon. Increasing clouds, with a high near 80. Southwest wind 5 to 7 mph. Chance of precipitation is 20%.

Waimea

Today: Scattered showers, mainly after noon. Partly sunny, with a high near 74. Breezy, with an east northeast wind 13 to 15 mph, with gusts as high as 21 mph. 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 57. East northeast wind around 11 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Mostly sunny, with a high near 75. East northeast wind around 11 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Scattered showers. Mostly cloudy, with a high near 69. Breezy, with an east wind 14 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly before midnight. Mostly cloudy, with a low around 55. Breezy, with an east wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Partly sunny, with a high near 69. Breezy, with an east wind 13 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers before noon. Mostly sunny, with a high near 83. Breezy, with an east wind around 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 72. Breezy, with an east northeast wind 14 to 18 mph, with gusts as high as 23 mph.

Tuesday: Sunny, with a high near 83. Breezy, with an east wind 15 to 20 mph, with gusts as high as 25 mph.

Puna

Today: Showers likely, mainly before noon. Mostly cloudy, with a high near 77. Northeast wind 11 to 13 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly after midnight. Mostly cloudy, with a low around 64. North northeast wind around 8 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Tuesday: Showers likely, mainly before noon. Mostly cloudy, with a high near 76. Northeast wind 8 to 11 mph. 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. Northeast wind 8 to 10 mph becoming south in the afternoon.

Tonight: Clear, with a low around 66. East northeast wind around 7 mph.

Tuesday: Sunny, with a high near 83. Northeast wind around 8 mph becoming south southeast in the afternoon.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will continue this week. Low clouds and showers will focus over windward areas, with showers more active during nights and mornings. Daytime heating will produce clouds and a few showers over the leeward slopes of the Big Island during the afternoons and evenings.

Discussion

No changes to the forecast in the near term with the morning package. For the weekend, have started to trend the winds down just a bit, with recent runs of both the ECMWF and GFS showing weaker winds than what we had in the forecast.
Satellite shows the clouds near Maui County and Big Island last evening have crept north to Oahu overnight, and have been moving to the west. As such, skies over Maui County and the Big Island area starting to clear out. Precipitable water (PW) values remain below normal, and that is evident in the rainfall totals seen statewide. The highest totals overnight were found at gages on the Big Island, but even those were under half an inch in 6 hours.
High pressure remains north of the islands, and is expected to be the driving force for trade winds through much of the week. Expect moderate to breezy trade winds. A band of increased PW is about 220 miles northeast of the smaller islands, and is making its way towards the islands. Expect this moisture to reach the islands late today or tonight.
The high is expected to move eastward across the north central Pacific as a complex low and front linger near the dateline. Look for clouds and limited showers to remain focused over windward areas, with some making it to leeward areas from time to time. An upper low northwest of the islands is forecast to move toward the state over the next few days as a separate frontal boundary approaches from the north. This would lead to an increase in shower coverage and intensity starting Tuesday night, initially for Kauai and Oahu, and then spreading to Maui County over the second half of the week. Trade winds will continue through this time period, so showers will remain focused over windward and mountain areas.
As mentioned above, the trend in the global models is for a weakening of the trade wind flow due to the high to the northeast lifting northward through the weekend.

Aviation

Moderate easterly trades will continue through Tuesday, with clouds and showers favoring windward coasts and slopes. MVFR conditions will be possible in and around showers moving through, especially through the late night and early morning periods.
There are no AIRMETs currently in effect, however, AIRMET Sierra can’t be ruled out through the overnight and early morning periods for mountain obscuration over windward areas.

Marine

High pressure north of the islands maintain moderate to fresh trade winds over most of the coastal waters through next weekend. Winds may reach Small Craft Advisory thresholds at times around Maui and the Big Island.
Surf along south facing shores will remain small through Wednesday, then rise, possibly reaching High Surf Advisory levels next weekend. A short-period north swell will produce small surf along north facing shores through Wednesday night. Surf along north facing shores will be minimal through the rest of the week, but a small northwest swell is possible early next week. Trade winds upstream of the islands will produce only small and choppy surf along east facing shores through the week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov