textproduct: Juneau

UPDATE

For 18z TAF Issuance, aviation discussion update.

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/

Convective snow showers in the gulf associated with multiple disturbances continue to be the primary aviation hazard through the period. A weak circulation off Cape Suckling will continue to bring light snow showers to Yakutat through the morning leading to off and on MVFR VIS and CIGs before likely shifting offshore in the afternoon. For the panhandle north Sitka and Kake, some mid level clouds remain but otherwise VFR conditions will continue to dominate with only some gusty outflow winds to contend with, particularly for Haines and Skagway.

For Sitka, some more robust convective showers may approach the area from the west through the late morning bringing localized gusty erratic winds. These will be watched closely for necessary TAF amendments.

For the southern panhandle, conditions have largely improved to VFR with isolated snow showers offshore. A small short wave sitting off PoW could throw some of these into the outer coast through the early afternoon hours. However, there is more confidence in another short wave in the southern gulf moving inland over PoW later Thursday evening and southern Clarence Strait Friday morning. This will bring a more organized band of snow showers and deteriorating conditions down to at least MVFR, though VIS restrictions in heavier snow showers could easily cause IFR or occasional LIFR conditions.

MARINE

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. 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 few days under a relaxed pressure field.

Outside Waters(Eastern Gulf & Outer Coastal Waters): A generally benign pattern is in store for the next few 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 day or so, 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 few days.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Gale Warning for PKZ012-013-651. Small Craft Advisory for PKZ011-021-022-031-032-053-643-644-652- 664-671-672.