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 Monday/

A low pressure system originating from a mid-level North Pacific trough will move along the Alaska Peninsula and into the Gulf of Alaska this weekend. Reinforced by a stronger system behind it, it will produce prolonged rainfall from Saturday into early next week, fueled by tropical moisture and weak but continuous divergent flow aloft. Models continuing to favor landfall along the north-central coast near Cordova. The system could bring moderate to heavy rain, with the highest totals expected along the northeast Gulf coast and higher terrain, though most of the region will be impacted. Warm advection seems apparent through many levels of the atmosphere along this system, which will allow for a very slight warming in temperatures, but not expecting much of a difference due to persistent cloud coverage across the region this weekend.

Climatological guidance is trending higher, though values remain within seasonal norms. The NE Gulf Coast may see locally heavy, long duration rainfall instead of showery bursts due to limited cold air aloft and minimal convective activity. For the heaviest period (Saturday evening to Sunday evening), 24-hour QPF averages 1.5-3 inches, with up to 4-5 inches at higher elevations. GEFS and Euro ENS indicate PWATs around 175% of normal. The GEPS is trending more aggressive, while the GEFS and Euro ENS align more on timing and intensity. Stronger winds and building seas are also increasingly likely along the outer coast and northern inner channels ahead of the low. The active pattern will persist into next week as the following Bering Sea low reinforces onshore flow, though rain chances should taper off by mid week.

AVIATION.../Through 0z Friday/

VFR to MVFR conditions continue for the panhandle, with scattered showers bringing CIGs down to 1500 to 3000 ft as they pass through. Showers are still heavy at times, which may drop VIS to 2-4SM. More significant breaks are being observed in between showers, with multiple layers of broken CIGs persisting for most sites. Gusty winds are still possible for much of the northern and parts of the central panhandle with these showers, and PAGY and PAHN will continue gusting up to 25 to 35 kts overnight. A more organized band of precipitation is sitting just offshore this afternoon, and will be pushing into the northern and central panhandle through the next few hours. This will bring much of the panhandle down to MVFR conditions, with CIGs of 1500-2500 ft expected overnight and into early Thursday morning. Some of the southern panhandle is seeing a break for the next few hours, but will have a chance of seeing some of these lower conditions creep into the area through the early morning. Conditions should improve behind the bulk of the showers towards the end of the period.

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.