textproduct: Juneau

SYNOPSIS

Key Messages:

- Showers will continue for Wednesday, with clearing skies expected from North to South Thursday into Friday

- A system may clip part of the southern panhandle Wednesday night into Thursday, but should move out of the area fairly quickly.

- Clearer skies expected to persist into the weekend, with precipitation potentially moving back into the northeastern gulf coast Sunday.

LONG TERM.../Friday through Tuesday/

At the mid and higher level steering levels of the atmosphere the upper level trough which was in the gulf travels east in British Columbia by Friday morning, as a building mid level ridge builds and moves east over the gulf. The ridge axis should shift east of the panhandle by early Sunday. A weakening closed low over Bering Sea moves east to be north of the Pribilof Islands and stalling by Sunday as well. A trough about this low will rotate south over the Aleutians and into the North Pacific, then to the western gulf Mon-Tue time frame depending on the model solution following.

So what does this mean weather wise for Southeast...showers from the midweek into Thursday, tapering off/ending as improvements Friday - early Saturday period due to the ridge moving through and clearing weather out. Models beginning to come to agreement of fairly organized from to push through the eastern gulf Sunday to Monday. Gusty winds for the coastline Sunday, and then likely showers to start the upcoming week. The very long forecast is showing hints that will be need to watched closely to see how that situation develops.

Temperature-wise at or just below normal values, with higher elevations of the Klondike and the higher Canadian Haines Highways to possible see snow or snow rain mix for the weekend period.

AVIATION.../through Wednesday night/

Showery weather continues across the panhandle today, bringing brief periods of MVFR VIS and CIGs. In between showers, patchy areas of fog and low ceilings have developed overnight, mainly across the southern TAF sites, with occasional IFR or lower flight conditions through around 18Z. A disturbance lifting north towards Haida Gwaii looks to bring steadier rain and MVFR VIS/CIGs to the southern TAF sites tonight. The northern TAF sites will see showers and occasional MVFR flight conditions. Winds will generally be less than 10kt through the period.

MARINE

Outside: As of Wednesday morning onshore flow continues to weaken across the eastern gulf of Alaska. Buoy wave height observations indicate seas of 7 to 10 ft; highest seas in the eastern gulf. Weakening winds and diminishing westerly swell will see seas gradually diminish from NW to SE across the gulf of Alaska through the day Wednesday.

Light winds and lower sea state persist into Thursday afternoon, as a low develops and moves into the British Columbia coast while a surface high shifts into the Gulf. For us humble folks in Southeast Alaska, expecting a tight north to south pressure gradient to develop, driving northerly winds across the coast, inner channels, and into Dixon Entrance. Main impact for the eastern Gulf will be along coastal waters as northwest winds build to fresh to strong breezes, driving stair master fresh seas of 10 to 13 ft, focused from Cape Edgecumbe to Dixon Entrance, highest northwest seas impacting western Dixon.

By Thursday, underneath the northwest fresh seas will be westerly ground swell from Typhoon Choi Wan, followed shortly by additional westerly ground swell from an extra-tropical transitioning Choi Wan, likely about 1 ft near 17 to 19 seconds.

Inside: Winds have begun to weaken across a good portion of the inner channels Wednesday morning. As the supporting low in the northwest Gulf dies out, leaving behind a weak surface pressure gradient, much better conditions should be in store Thursday morning with light winds, some fog, and diminishing rain. Thursday afternoon into Friday northerly winds build across the inner channels, particularly impacting north-south orientated channels like Lynn, Stephens, Chatham, and Clarence. At this time northerly winds should hold near moderate to fresh breezes (11 to 21 kt), with Lynn Canal likely picking up a few hours of near- gale force conditions Friday. Forecast was based on surface pressure gradient between Whitehorse/Juneau and Skagway/Juneau, with a stable but warmish boundary layer profile to the north of the coast range, limiting wind potential. No freezing spray concerns as water temperatures are still above 45F, with air temperatures above freezing.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ641>644-661>664-671.