Synopsis21 Apr 2019 06:30:00 GMT: Trade wind weather prevails over the next several days with a surface high pressure persisting far northeast of the area. Clouds and passing showers will favor windward and mauka areas with most leeward locations remaining dry. Winds may weaken late next week as a front approaches the area from the northwest.
Discussion21 Apr 2019 06:30:00 GMT: Trade wind weather continues across the islands this evening as a high pressure far northeast of the area is providing locally breezy trade winds to the area. Latest satellite imagery revealed patches of low clouds have just reached the islands in the past few hours. These clouds will be providing some passing showers to the area, mainly over the windward and mauka areas. These showers are generally on the light side as the airmass is rather stable due to an upper ridge in place overhead. There are some high clouds passing over the islands at time as well, and will keep the skies a little more cloudy.
As only minor changes to the overall weather pattern are expected into early next week, expect the current trade wind weather regime to prevail. Passing low clouds and showers will affect mainly windward and mauka areas. There will be a slight uptick in clouds and showers during the night. But then, upper level ridging staying nearby will keep the airmass on the stable side. Hence, showers will be light. Most leeward locations will stay dry, though lee areas of the Big Island will see some afternoon and evening showers.
Latest forecast solutions still indicated there will be changes in the weather for the islands toward late next week, as an upper low and its associated surface frontal boundary are still expected to approach the area from the northwest. This will nudge a surface ridge closer to the state, leading to winds becoming lighter across the area. Daytime sea breezes and nighttime land breezes will likely become more widespread. Clouds and showers under this weather scenario will tend to favor interior and mauka areas during the afternoon and evening hours.
Aviation21 Apr 2019 06:30:00 GMT: A ridge of high pressure north of the state will keep moderate to breezy trade winds in place through Sunday. Clouds and showers will favor windward and mauka areas, bringing brief MVFR cigs/vsbys as they move through. A few showers may spill over into leeward areas occasionally, but VFR conditions are expected to prevail here.
AIRMET Tango remains in effect for moderate turbulence below 080 over and downwind of the terrain. This AIRMET will likely remain in effect through the remainder of the weekend.
AIRMET Sierra may be needed for mountain obscuration later tonight.
Marine21 Apr 2019 06:30:00 GMT: The ridge to the north of the islands will maintain fresh to strong trade winds into early next week. The Small Craft Advisory (SCA) is in effect for most of the waters near Maui County and the Big Island now through Sunday, before winds ease slightly and a few zones drop out. The SCA for the more typical windy areas is in effect through Monday, but will likely need to be extended till around midweek.
Surf along all shores is expected to remain below advisory levels for the next week. The current north-northwest swell fade out tonight with only background swell expected for Sunday. A small west-northwest swell will provide small surf along north facing shores early next week. Background south-southwest swells will keep surf small along south facing shores through the weekend, though an upward trend is possible early next week, due to recent activity southeast of New Zealand. Surf along east facing shores will hold steady into the middle of next week due to the fresh to locally strong trades.
HFO Watches/Warnings/Advisories21 Apr 2019 06:30:00 GMT: Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST Sunday for Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.
Footer21 Apr 2019 06:30:00 GMT: