textproduct: Juneau

UPDATE

06z Aviation update Flying conditions across the region are in a much better spot than the previous several days, with widespread VFR and very sporadic snow showers slowly coming to an end in the south. Primary threat tonight remains in northerly outflow winds across the northern Panhandle, creating some chop coming down Gastineau; no significant LLWS is forecasted for PAJN. One note of great uncertainty is the potential for a shallow marine layer in PAKT bringing a brief period of IFR to LIFR CIGS. Have included this potential in the 06z TAF package, will need to watch trends over the next few hours and update.

VFR prevails Thursday for the majority of the region, have included the potential for a brief hit of IFR snow across the northern coast as a cluster of showers drifts east across the Gulf during the afternoon. However, these showers could miss PAYA and remain just offshore.

Thursday night IFR SHSN is expected along and south of Frederick Sound, with higher confidence for Prince of Wales and Ketchikan/Metlakatla areas.

PREV DISCUSSION......ISSUED AT 253 PM AKDT

SYNOPSIS...

Key Messages:

- Scattered convective showers continue for mid week, with chances of snow continuing to decrease from north to south as the week continues to progress.

- Outflow conditions will continue through the week, peaking today through this evening. Outflow brings colder & drier weather for the northern half of the panhandle.

SHORT TERM.../ through Thursday night / Broad complex multi center low over the gulf of Alaska rotating its centers with a slow southeast slide as well. Snow shower activity primarily limited from near Sitka East- Southeast towards Kake then Southeast towards Misty Fjords. The favored locations through the area is Southern Baranof Island and Price of Wales island. Do anticipate another trough from one of the gulf to spread in late Thursday with likelihood of enhanced showers that could have moderate accumulations from showers and also for this evening.

Outflow pattern and drier weather for the northern panhandle, and cooler temperatures. Local Freezing spray through Thursday night.

LONG TERM.../Friday through Monday/...The long range forecast starts out relatively calm before a more impactful system moves up into the southeastern gulf at the end of the weekend and into early next week. Remaining outflow winds in the northern inner channels will be diminishing through Friday, allowing for a quiet and mostly clear day. These conditions will persist through Saturday, with clouds beginning to move in through Saturday night. At this time, outflow winds will also start to increase again through the northern inner channels into Sunday morning. Yakutat may also see some minor precipitation with a lingering surface level disturbance in the northern gulf on Saturday. These winds won't get too high before a large area of low pressure jumps up into the southeastern gulf and sends a front into the southern panhandle.

Through Sunday morning, a gale force front is expected to funnel into the southern panhandle and bring areas of moderate to heavy precipitation through Monday and into Tuesday. Temperatures start off cold enough for this to fall as snow, which could give parts of the southern panhandle anywhere between 1 to 5 inches through Sunday. As the front moves in bringing warmer air, these temperatures will likely increase to highs in the high 30s and low 40s, which will turn this precipitation to rain. Going into Monday, temperatures in the southern and parts of the central panhandle are expected to be solidly above freezing through the day. Parts of the central panhandle may see over half an inch of precipitation through Monday, while parts of the southern panhandle may see over an inch of rain. The northern panhandle is still expected to stay below freezing for this timeframe, so any precipitation that makes it up there will be snow. Lingering outflow winds in the northern part of the channels may limit them amount of precipitation that can fall during this early week period. Uncertainty still remains on how far this precipitation will make it north, and if these temperatures are going to warm up as fast as anticipated.

AVIATION.../Through Thursday afternoon/

Scattered snow showers continue to impact the panhandle south of Frederick Sound Wednesday afternoon, bringing IFR and occasionally LIFR conditions to the area in heavier showers. Training showers have lead to these conditions persisting for an hour or more at times over a TAF site, while at other times less than half an hour. Thus is the nature of these convective showers. The primary limiter in conditions continues to be significant VIS reductions in the heaviest of showers, though lowered CIGs AoB 1000 feet are also not out of the question, particularly for southern Clarence Strait and Prince of Wales Island. The panhandle north of Frederick Sound will continue to see VFR conditions through the period with northerly outflow continuing to bring more dry conditions. This also means brisk headwinds will continue for Haines and Skagway, along with some gusty northeast ridge top winds for the rest of the panhandle north of Angoon.

As a surface trough gradually moves southward, it will drag shower activity further south Wednesday night, clearing out more of the panhandle by Thursday afternoon. However, another weak wave will bring more snow showers Thursday night.

MARINE... Outside Waters(Eastern Gulf and Coastal Waters): A generally benign pattern is in store for the next several days over the eastern gulf. The exception will be the northeastern gulf, which will see some northeasterly gap flow winds of up to between around 25 to 35 kt for the next couple days, giving waves of up to 9-11 ft, which will diminish to to 15-25 kt & 3-6 ft by Friday as the northerly outflow gradient diminishes. The rest of the eastern gulf will see winds of 10 to 15 kt & waves between 4 & 7 ft through the next several days.

Inside Waters(Inner Channels): For the northern Inner Channels, a northerly outflow pattern is in place from an area of high pressure centered over the Yukon of Canada, giving a tightened north-south pressure gradient between it & lower pressure to the south. This is giving between small craft(~25-30kt) & gale-force(~35kt) winds & seas up to between 7 & 11 ft for north-south oriented Inner Channels north of Frederick Sound, like Lynn Canal, northern Chatham Strait, & Stephens Passage until that pressure gradient loosens up / relaxes on Friday. Winds will diminish to 10-20 kt & seas will precipitously subside by the end of the week. Due to the gusty winds and cooler temperatures, Freezing spray for Lynn Canal, Glacier Bay and parts of North Chatham Strait, Stephens Passage, and western Icy Strait. For the rest of the Inner Channels(the south), expect winds of around 10-15 kt with seas of around 2-3 ft for the next several days under a relaxed pressure field.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Gale Warning for PKZ012-013-651. Small Craft Advisory for PKZ011-022-031-053-643-644-663-664-671- 672.