textproduct: Juneau

SYNOPSIS

Key Messages:

- Outflow winds increase through Tuesday afternoon for the northern channels and NE gulf coast. Strong gusty winds expected for downtown Juneau/south Douglas and Skagway Tuesday afternoon into Wednesday.

- Drier conditions and clearing skies across the central and northern panhandle through Tuesday.

- Another system pushes into the far southern panhandle by Tuesday night into Wednesday, bringing another round of wintry precipitation to Ketchikan, Annette, and Prince of Wales Island.

LONG TERM.../Wednesday through Friday/

Confidence is increasing for northern panhandle to see drier pattern continuing with outflow conditions. The southern will continue to see waves of rain/snow showers through the period a low lingering off the coast out in the eastern gulf sends multiple troughs/fronts lifting north through the southern panhandle. In terms of precipitation, most of the southern panhandle will see snowfall at nights as low temperatures remain in the low 30s and as colder air aloft lingers over the area. During the daytime, much of this will transition to more of a rain snow mix, as temperatures will increase to the high 30s to low 40s throughout the week, alongside snow levels raising to 400 to 600 ft by Friday. These warmer temperatures along with the low QPF amounts expected will likely not bring as much snow accumulation over the area, particularly into the end of the week as the southern panhandle continues to see some warming. By late week, low-end snow chances return to the north, mainly along Icy Strait corridor on south, as the drier outflow pattern weakens and we see the potential for some of the moisture and troughs/fronts across the south creeping north.

Outflow winds remain largely unchanged in the forecast, with the continued gusty winds for the Gastineau Channel and Downtown Juneau with increased confidence in a mountain wave event into Wednesday. 30 to 40 kt cross barrier flow over Gastineau Channel and Taku Inlet, alongside a critical level forming at around 500 mb. The conditions overall look favorable for some 15 to 30 kt winds with gusts up to 45 kt at the peak for downtown Juneau and southern Douglas. The gusty winds also continue for Skagway and Klondike highway on Wednesday as the gradient remains tight across Lynn Canal.

By the end of the week, expect a moderating trend as the gradient relaxes. High temps across the north will be in the 20s to low 30s on Wednesday, climbing to the 30s by Friday. Across the south, afternoon highs in the 30s to around 40 on Wednesday, climbing to the upper 30s to mid 40s by Friday.

AVIATION

/through 12z Wednesday/ A low pressure system remains in the gulf just west of Baranof Island. This low is bringing precipitation over parts of the gulf, but only high ceiling over areas of the central to northern panhandle. This low will slowly move southwestward through the day. Until then, this low will continue to bring broken to overcast clouds to areas from Sitka northward, not including Yakutat. Even with this cloud deck, flying conditions are very likely to remain VFR. There is a very slight chance that areas may see short times of light snow, but no impacts are anticipated. As for the rest of SE AK, VFR conditions prevail throughout the TAF period. Ceilings over the far southern panhandle may begin to lower at the very end of the period, late Tuesday night. This is due to another low that will move north and then sit west of Prince of Wales Island.

The most impactful thing today will be northerly winds from Skagway through Lynn canal and easterly winds out of Taku Inlet. These increased winds are due to increasing outflow across the area. Winds will begin to increase late morning with the strongest winds anticipated late Tuesday night into early Wednesday with wind gusts of 40 to 50 mph. Along with this LLWS will also be present near the Juneau airport. This set up could make for a challenging flight over Gastineau Channel with the strongest winds occurring over Downtown Juneau.

MARINE

Inside (Inner Channels): Split regime ongoing across the inner channels as a low pulls westward away from Baranof Island. Along and south of Sumer Strait, winds are generally SE-ly near 10 to 15kts. Northward towards Lynn Canal, N winds have increased overnight as outflow conditions have begun with Eldred Rock already increasing to 25kts, only increasing further into Tuesday afternoon. Outflow conditions will become predominate through Tuesday, with wave heights building through the day up to 5 to 7 feet within N/S oriented channels by Wednesday morning. As these outflow conditions continue through the week, expecting freezing spray threat to increase as far south as Rocky Island and Taku Inlet. Freezing spray should start off light through the morning, increasing overnight Tuesday into Wednesday with potential for isolated areas of heavy freezing spray within Lynn Canal by Wednesday afternoon.

Outside (Gulf and Coastal Waters): A weakening low is currently located of the coast of Baranof Island this morning, approximately 56N 139W with satellite derived winds around this low around 20 to 30kts. Wave heights around this low near 7 to 10ft, diminishing through the afternoon, this low will continue to slide SW towards the N PAC and weakening. Outflow conditions become predominate by the late afternoon along the N Gulf, increasing through the gaps in terrain up to Gale force with Storm Force gusts, especially along the NE Gulf coast near Dangerous River Valley, Alsek River Valley and out of Yakutat Bay. Wave heights should remain around 5 to 8 ft, however in outflow prone areas will reach upwards of 11 to 12ft through Tuesday evening. Like a broken record, these outflow winds will continue through the week, with potential for moderate to heavy freezing spray Wednesday out of interior passes.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory from 10 PM this evening to 4 PM AKDT Wednesday for AKZ318. Wind Advisory from 4 PM this afternoon to 10 AM AKDT Wednesday for AKZ325. MARINE...Gale Warning for PKZ012-013-053-643-644-651-663-664-671. Small Craft Advisory for PKZ011-021-022-031>033-035-642-662-672.