textproduct: Juneau

Evening and 06z Aviation Update

Few updates to the marine and general public forecast going forward. Westerly flow aloft is causing enhanced leeside troughing near Haines and Skagway, with gradients between Juneau and Skagway around a 1 to 2 mb difference. This is generating up to 15 knot winds for Lynn Canal from the south, but expecting to see the winds relax as the westerlies aloft relax. These southerly winds have not stopped Haines and Skagway from decoupling, however. Looking towards the latest sounding in Whitehorse, it is clear that an inversion up to 5500 ft with moderately cold temperatures is causing some katabatic flow, undercutting the southerly, more unstable air. Therefore, kept Skagway and Haines north and west through the night with up to 10 knot sustained winds.

AVIATION

/through Friday evening/ A mixed bag of flight conditions this evening with persistent low clouds and isolated showers across the panhandle. Looking at obs around the area, TAF sites range from isolated areas of VFR & IFR to predominate MVFR & LIFR. Flight conditions are highly variable hour by hour with CIGS bouncing between 200ft to 3500ft and visbys between 1/2 SM to 4SM within fog, rain, or mist. Through Thursday night flight conditions will generally remain the same or continue to worsen slightly, continuing the trend of bouncing between MVFR to LIFR flight conditions with CIGS AoB 2500ft and intermittent visbys as low as 1/4SM in fog. By Friday mid-morning, brief break in precip for the area with general MVFR flight conditions across along the northern panhandle. Best flight conditions will be across the southern panhandle, along a line from TAF sites Sitka to Petersburg and southward seeing the greatest chances of VFR conditions by Friday afternoon.

Winds should remain around 10 kts or less overnight, going near calm and variable at most TAF sites. Main exceptions are the usual culprits of Haines and Skagway which will to see increased winds up to 20kts as drainage flow winds continue through the night. No LLWS concerns through the TAF period, however front pushes into the NE Gulf by late Friday evening.

PREV DISCUSSION......ISSUED AT 514 PM AKST Thu Dec 4 2025

SYNOPSIS...

Key Messages: - Very light winds and weak onshore flow remain across the panhandle tonight into tomorrow.

- Light mist with areas of fog are likely to continue across the panhandle with due to weak onshore flow.

- Late week into next weekend, long range models are still suggesting a weather pattern that has been known to produce heavy snow. High uncertainty on timing and amounts, but details are being watched closely.

SHORT TERM...Light mist and rain continue across the panhandle as onshore flow continues. The southern panhandle is seeing more of a break from this light precipitation, but in turn they are seeing continued areas of fog, at times dense below 1 SM. Along with these lowered visibilities and onshore conditions, winds will remain light across the area through tomorrow afternoon. The only exception to this will be over the southern gulf waters as a quick moving, weak low moves east south of the panhandle. This low will bring slightly increased winds across the southern gulf to around 15 to 20 kts late tonight into early Friday. Light winds of 10 to 15 kts, and weak onshore flow, returns late Friday morning before a larger system arrives Saturday.

On Friday night winds will begin to increase as a low pressure system pushes into the north central gulf. This low will quickly increase precipitation rates across the northern panhandle and spread into the panhandle. Along with increasing precipitation rates, decreasing temperatures will transition precipitation to snow starting along the northern panhandle. Confidence is high for a long lived snow even starting this weekend lasting into early next week. Snow initially starts late Friday night, but the heaviest amounts arrive later Saturday into Sunday. See the long term forecast for more details on the snow forecast timing and intensity.

LONG TERM.../Saturday through Tuesday/...A pattern change going into this weekend is still looking to bring cold temperatures, heavy precipitation, and strong winds to the panhandle into early next week. Confidence has improved for snow potential in Skagway and Haines over the weekend, and even more for the northern highways. A winter storm warning has been issued for these areas over the weekend, and a watch has been issued for Yakutat. The special weather statement was also continued for the NE gulf coast and the Icy Strait Corridor.

A system sending a front into the panhandle overnight Friday is still looking to stall in the northern gulf through the weekend, funneling consistent moisture over the panhandle. This front will bring moderate to heavy rain rates to the area, with around an inch to an inch and a half of rain in 24 hours expected for a majority of locations and persisting at similar rates through the weekend. Though these rain amounts may seem typical for a 24 hour period, the persistence at those rates lasting through the weekend and into next week will be watched closely, especially at higher elevations. A cold air mass aloft shifts into the Yukon and continues to moves southward through the weekend. A tightening pressure gradient over the northern panhandle will increase outflow winds through the weekend, helping to funnel the colder air south into the panhandle. Decreasing temperatures with ample available moisture will increase the potential for heavy snowfall in the northern panhandle, extending south through the weekend and into next week. Highest confidence of snowfall remains in the N Panhandle over the weekend. Forecast becomes more of a challenge moving towards the Icy Strait Corridor, starting as rain and transitioning into a mix by Sunday, limiting potentially accumulations. Expecting a transition over to snow going into Monday, though uncertainty remains as to how much available moisture there will be, limiting appreciable amounts. As snow level drops south following the colder temperatures, snow potential will also move further south towards the corridor, and the rain/snow mix will then follow into the central panhandle. Stay tuned to the forecast moving into the weekend as details come into clearer view regarding potential amounts and refined timing.

As the gale force low moves into the northern Gulf and a high sets up to the north of the panhandle into this weekend, a tight pressure gradient allowing for northerly flow begins to set up over the northern panhandle into Lynn Canal. This cold air mass to the north contributes to the colder temperature trend over the weekend and into early next week, alongside bringing stronger winds down Lynn Canal. These winds will begin to increase Saturday into Sunday with northerly gales in northern Lynn Canal with 35 to 40 kt winds by Sunday afternoon as the gradient tightens over the northern panhandle. These gale force winds will last into the beginning of next week as the gradient remains. Winds will increase in Skagway at this time, with 25 to 35 mph sustained winds possible Sunday and Monday. A decent 850-750 mb inversion setting up over Whitehorse to the northeast will allow for these winds to impact Skagway not only from the strong pressure gradient, but from a decent density difference, allowing for more confidence at Skagway having elevated winds over this timeframe with gusts reaching up to 40 to 50 mph at times. Other land areas will see an increase in SE winds as the front moves through, with diminished winds between the waves of precipitation that push through this weekend into early next week. Overall the outflow pattern over the northern panhandle is expected to last into midweek, with more northerly winds and offshore flow beginning to move southward to around Icy Strait Corridor Monday onwards. This cold dry air will help to lessen the precipitation amounts across the northern panhandle midweek into the end of the week when looking ahead.

MARINE... Outside Waters: Calmer conditions tonight into tomorrow last over the Gulf as a weak high remains over the area, before being pushed out by the oncoming system moving in from the west by tomorrow night. This next system will bring southwesterly to southerly fresh to strong breezes (17 to 27 kt) across the Gulf tomorrow night and becoming more southerly by Saturday. As the pressure gradient tightens between the low in the Gulf and the high to the north over Canada Saturday night into Sunday, northeasterly near gale to gale force (30 to 40 kt) offshore winds and gap winds will occur along the NE Gulf Coast between Yakutat Bay and Cape Spencer. The southeastern Gulf will also see an increase from near gales to gales (28 to 36 kt) as a front moves through Saturday night into Sunday morning and again Sunday night into Monday. Seas between 5 and 8 ft tonight will quickly increase tomorrow night into Saturday as the system moves in to between 10 and 14 ft. The seas will continue to see an increase into Sunday to 12 to 16 ft. Southwesterly swell continues tonight through the weekend.

Inner Channels: Predominantly calmer winds tonight and tomorrow anticipated to see a sharp increase Friday night into Saturday as the next system moves into the area. This will bring southeasterly winds across the inner channels between a moderate to fresh breeze into Saturday, and up to a strong breeze (22 to 27 kt) for northern Lynn, Frederick Sound, Stephens Passage, and near the ocean entrances. The channels will see a brief increase as the fronts move across the panhandle this weekend into early next week. Northerly outflow begins to set up over northern Lynn Sunday as the pressure gradient begins to tighten, bringing near gales in the morning becoming gales into the day Sunday. Largely expecting between 35 and 43 kt winds down Lynn Canal lasting from Sunday into early next week, with the stronger northerlies moving southward down to Point Couverden Sunday night into Monday. This will allow some lower level convergence right around Point Couverden from the southeasterly winds up Chatham Strait and the northerly outflow coming down out of Lynn Canal, bringing winds around Rocky Island to around 25 to 30 kt. Frederick Sound near Point Fanshaw and up along Stephens Passage will continue to see strong breezes to near gales throughout the weekend, alongside Clarence Strait seeing near gales as the fronts move through and bring stronger southeasterly winds.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Storm Watch from late Friday night through late Saturday night for AKZ317. Winter Storm Warning from 10 PM Friday to 3 PM AKST Sunday for AKZ318. Winter Storm Warning from 3 AM Saturday to 3 PM AKST Sunday for AKZ319. Dense Fog Advisory until 3 AM AKST Friday for AKZ328-330-332. MARINE...Small Craft Advisory for PKZ661.