Breezy trade winds will continue through most of the week. Showers will favor windward and mauka areas, most frequently at night and during the early morning hours. Late this week into the weekend, an upper-level disturbance may bring a slight uptick in trade wind shower coverage.
Radar and satellite imagery show low-level clouds and isolated to scattered showers moving into windward and mauka areas on the east-northeasterly trade wind flow this afternoon. A weak surface trough remains near Kauai, allowing for a higher concentration of low-level clouds and showers to move over this end of the state. This boundary is expected to gradually lift north and dissipate by midweek. Otherwise, ridging at the surface and aloft will maintain stable, breezy trade wind weather across the state through at least Thursday with isolated to scattered showers favoring windward and mauka areas.
Heading into the weekend, model guidance suggests that a mid- to upper-level cutoff low will move over the region, bringing cooler temperatures aloft and increasing instability. At the same time, precipitable water values are expected to climb to 1.5 to almost 2 inches over the eastern end of the state. However, with ridging expected to continue to dominate at the surface, this setup will likely only amount to an uptick in trade wind shower activity through the weekend.
Stable trade wind weather will continue tonight and Tuesday. Isolated to scattered showers will continue to ride in with the trade winds, especially over windward sides of Kauai and Oahu. AIRMET Sierra remains in effect for mountain obscurations above 3000 feet along north through east sections of Kauai this afternoon. Brief mountain obscurations likely to occur across windward sides elsewhere tonight, but VFR will be prevailing condition.
AIRMET Tango is also in effect for low-level turbulence downwind of island terrain. This AIRMET will likely be needed through the next several days.
High pressure remains in place north of the Hawaiian Islands this week in maintenance of fresh to locally strong trades continuing into next weekend. The Small Craft Advisory has been extended through tomorrow.
Small short period NW swell has been slow to arrive this afternoon but should bring elevated surf this evening into tonight for favored exposures. A long period NW swell arrives late Wednesday and peaks Wed night into early Thurs.
A small long period S swell has likewise been slow to arrive with long period energy just barely registering on the Barber's Point PacIOOS buoy. S swell energy remains at background levels into the weekend before a medium to long period SSW swell builds late Sunday into early next week. Slightly elevated surf along E facing shores continues until trades weaken this weekend.
Small Craft Advisory until 6 PM HST Tuesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.
