Photo Credit: James Grenz

Hilo

Today: Scattered showers. Partly sunny, with a high near 77. Calm wind becoming east northeast 5 to 7 mph in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 63. Northeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Scattered showers. Partly sunny, with a high near 77. Calm wind becoming northeast around 6 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Sunny, with a high near 79. Calm wind becoming southwest around 6 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 61. West wind around 5 mph becoming calm in the evening. Chance of precipitation is 20%.

Saturday: Isolated showers after noon. Sunny, with a high near 79. Calm wind becoming south southwest around 5 mph. Chance of precipitation is 20%.

Waimea

Today: Isolated showers. Mostly sunny, with a high near 74. Northeast wind around 6 mph becoming calm. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 52. Light and variable wind. Chance of precipitation is 20%.

Saturday: Scattered showers, mainly after 7am. Partly sunny, with a high near 74. East northeast wind 3 to 8 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Scattered showers, mainly after noon. Partly sunny, with a high near 70. Calm wind becoming west 5 to 9 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 45. Light and variable wind. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Saturday: Scattered showers. Partly sunny, with a high near 70. Light and variable wind. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 75. East wind 9 to 14 mph becoming light east southeast in the afternoon.

Tonight: Mostly clear, with a low around 70. Calm wind becoming east northeast 5 to 7 mph in the evening.

Saturday: Isolated showers after noon. Sunny, with a high near 76. Breezy, with an east wind 7 to 16 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Puna

Today: Scattered showers. Partly sunny, with a high near 76. West wind around 6 mph becoming calm in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 61. Light and variable wind. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Saturday: Scattered showers. Partly sunny, with a high near 76. Light and variable wind becoming northeast around 6 mph in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Sunny, with a high near 80. Calm wind becoming west southwest 5 to 9 mph in the afternoon.

Tonight: Mostly clear, with a low around 61. West wind around 6 mph becoming calm.

Saturday: Isolated showers after noon. Mostly sunny, with a high near 80. East southeast wind around 6 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

Clouds associated with a dissipated cold front will move in from the northwest. Trade winds will decrease today as a small increase in clouds and showers are forecast over the smaller islands through Saturday. Trade winds will strengthen from Saturday to Sunday, and then weaken to a light and variable pattern from Monday into Wednesday as another cold front approaches the islands from the northwest.

Discussion

Cloud bands associated with a dissipated cold front are drifting into the islands from the north this morning. A larger low pressure area and stronger cold front remains far north of the Hawaii region. A high pressure center also lingers far northwest of the state with a weakening ridge axis north of the islands.
Trade will weaken today with localized sea breezes developing over each island. Weak cloud bands drifting in from the north will bring a small increase to cloud and shower activity through Saturday. This slight increase in shower activity should diminish by Sunday morning as these clouds diminish and drift westward with returning trade winds.
Another change in our weather pattern will occur early next week as another cold front approaches the Hawaiian Islands from the northwest direction. This frontal system will break down the weak ridge north of the island chain and produce a light and variable wind pattern from Monday into Wednesday. Light large scale winds will allow local scale daytime sea breezes to develop over all islands. Converging sea breezes and island heating will build clouds over island mountain and interior sections each day with a few showers favoring the afternoon to early evening hours.
Long range forecast guidance shows the forward motion on the front stalling out as it approaches the state. Differences between the American (GFS) and the European (ECMWF) models in the eastward frontal movement continue in the latest operational forecast model runs. Both models are showing better agreement on the frontal movement, however as expected some differences remain. The GFS model continues to be more progressive and brings cloud and showers ahead of the slow moving front into Kauai and Oahu on Tuesday and Wednesday. While the latest ECMWF model stalls the front over the island of Kauai. Shower coverage and trends with the frontal cloud band will favor Kauai and Oahu. Precipitation amounts remain modest in both global model solutions. We blended both model GFS and ECMWF solutions into the precipitation forecast for Tuesday and Wednesday in order to minimize forecast errors from any one model solution.

Aviation

A surface ridge far north of the islands will maintain light to moderate low-level northeasterly trade winds today. The background flow may be weak enough to allow local sea breezes to form over leeward sections of some of the islands this afternoon. The leading edge of remnant moisture from a dissipated front appears to be just northwest of Kauai early this morning. As this moisture continues to push down toward the islands, expect broken low clouds and scattered showers to begin spreading across Kauai. As a result, MVFR conditions due to lower ceilings and reduced visibilities may become more widespread over north through east facing sections of Kauai later this morning.
Elsewhere, the northeasterly flow will continue to transport scattered low clouds and isolated showers into north through east facing sections of the islands east of Kauai. This may result in brief MVFR conditions along some north through east facing slopes from Oahu to the Big Island today. Otherwise, expect VFR conditions to prevail over most of the islands east of Kauai.
The remnant moisture from the former front may eventually spread across portions of Oahu and the islands of Maui County later today and tonight. Depending on the cloud cover and shower activity, MVFR conditions may become more widespread over some north through east facing sections of Oahu, Molokai and Maui, especially after sunset this evening.
No AIRMETS are currently in effect, and none are anticipated at this time. AIRMET Sierra for mountain obscuration may be needed on Kauai later this morning if there is a significant increase in cloud cover and shower activity.

Marine

Low pressure moving into the area north of the state will weaken trade winds and swing them to northerlies today into Saturday. Northeast winds are expected by Sunday as the low moves off to the northeast and the high reestablishes itself north of the islands. Light winds will dominate Monday and Tuesday as remnants of a frontal boundary approach from the northwest.
Short period north swells will maintain well-below advisory level surf along north shores into next week. The north swells will also bring an uptick in surf to exposed east and west shores. Background southerly swells will maintain small surf along south facing shores with a slight bump possible over the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov