textproduct: Juneau

SYNOPSIS

Key Messages:

- Onshore flow bring rain showers tonight into Thursday. Gusty winds and moderate showers possible for northern panhandle.

- High pressure will bring a bit of clearing and drier weather for southern panhandle by Thursday and central panhandle by Friday. Northern panhandle will remain cloudier with showers.

- A stronger system and weak atmospheric river will bring gusty winds, elevated seas and moderate to heavy rainfall for the weekend.

LONG TERM.../Saturday through Tuesday/

A low pressure system will enter the Gulf of Alaska this weekend, bringing gale-force winds to the outer coast along with periods of moderate to heavy rainfall associated with a weak atmospheric river. The initial wave of rain begins late Friday night into early Saturday morning as a front reaches the panhandle, impacting mainly the northern region and more so the NE Gulf coast. A stronger wave then follows, arriving by early Sunday morning. As the low slowly dissipates near south-central AK, it will meander and track multiple fronts across the panhandle. This setup, reinforced by a consistent slew of upper level troughs and divergent flow aloft, keeps precipitation in the forecast for the extended period, although overall impacts are expected to diminish gradually heading into next week. One thing of note is as the low dissipates, the pressure gradient over the northern panhandle becomes more north to south oriented, causing a potential increase in winds within Lynn Canal through Monday and Tuesday.

Impacts associated with this weekend system will initially start along the NE Gulf coast and as far south as Baranof Island, also upwind of higher elevations. From Sunday through Monday, heavier precipitation will push south across most areas, particularly targeting the Misty Fjords region. The highest confidence for 24- hour rainfall accumulations during Sunday's stronger wave ranges between 1.5 to 2.5 inches, with localized amounts reaching 4 to 5 inches over higher terrain. However, at this time there is a low (25%) chance that lower elevation areas surrounding Icy Strait, such as Juneau and Gustavus, could exceed 2.5 inches. A significant southerly jet will move along the coast Saturday, shifting southwesterly by Sunday morning and likely bringing 35 to 40 knot sustained winds from Cape Spencer north to Cape Suckling. Overnight Saturday into Sunday presents the greatest concern for elevated and gusty winds over the southern panhandle and inner channels, then trending on the decline Monday morning.

AVIATION

/through Thursday evening / After 06z TAF package Issuance.

Scattered to isolated showers moving into the panhandle from the eastern part of the gulf, while a slightly more organized feature is moving through the NE Gulf Coast. As the front moves through and the pressure gradient tightens, a period of gusty winds is expected for late Wednesday night and early Thursday. Mainly VFR conditions with localized marginal ceilings. As the shower activity picks up, heavier showers may reduce flight visibilities tonight and early Thursday.

MARINE

Outside: For Wednesday, a low continues to persist along our coast, driving onshore flow and continued showers. Winds are at moderate breezes along the coast, with dominant seas out of the WSW focused 5 to 7 ft near 9 seconds. Underneath is the usual southerly swell from the south Pacific with some energy focused near 15 to 18 seconds from tropical activity in the central and eastern Pacific.

Wednesday night, expect westerly winds to build in in the central Gulf to fresh breezes, helping increase WSW seas a bit, perhaps 7 to 8 ft near 9 seconds. Winds and seas begin diminishing again Thursday morning into Friday. Through Friday a gale force low will slide along the Aleutian Storm Track, with winds becoming southerly in the eastern Gulf. Anticipate easterly gales to build along Cape St. Elias by Saturday morning. From Cross sound south to Dixon, southeasterly winds build to near gale force to strong breezes. Large and confused seas near 11 to 14 ft impacting much of our coast Saturday into late Sunday.

Inside: Simply put, Friday will likely be the best low wind day across the inside. The exception, per usual, is northern Lynn Canal where we will likely hold on to fresh breezes into Friday.

For Wednesday, a low-pressure system along the northern coast will keep the northwest-southeast pressure gradient over the region, driving southerly flow through the inner channels and easterly flow out of Icy Strait/Cross Sound. Overall, winds strengthen through Wednesday night, driving fresh to strong breezes over much of the central and northern inner channels. Dominant feel of Lynn Canal will be strong breezes, with a few hours of near-gale force conditions tonight. Thursday afternoon, winds start to diminish over the region as high-pressure forms over the area, bringing a break from higher winds into Friday night. By the weekend a gale force low will position itself in the Gulf, freshening up southerly winds across the inside once again; strong breezes to near-gale force likely with areas of gale force.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory from 7 AM to 1 PM AKDT Thursday for AKZ318. MARINE...Small Craft Advisory for PKZ012-013.