textproduct: Juneau

SYNOPSIS

Key Messages:

- Another batch of moderate to heavy rain expected through Saturday, highest rain chances across the N Panhandle. Thunderstorms continue along the coast through the early afternoon.

- Brief break in the persistent rain is possible Sunday night into Monday, however another front and round of heavier rain and wind push across the Gulf by Tuesday.

- Increasing potential for a more impactful/strong area of low pressure developing over the Gulf of AK Tuesday through midweek.

LONG TERM.../Monday through Thursday/

An active fall-time weather pattern will continue across SEAK next week. Monday will start off with a ridge of high pressure over most of the panhandle, which could lead to fog development, with weaker onshore flow and light showers ahead of the next system. A progressive low and cold front will trek across the Gulf and reach Yakutat Monday afternoon before sweeping southeast across the panhandle Monday night into early Tuesday before weakening and stalling across southern panhandle, with onshore flow behind bringing steady rain into the panhandle. Total precipitation with this initial system will remain relatively limited, though a brief period of moderate to heavy rain and increasing southerly winds will develop ahead of the frontal boundary. Behind this initial system, a stronger low is forecast to deepen rapidly (~960 mb) as it lifts northeast into the northern Gulf of Alaska on Tuesday, stalling through midweek before gradually weakening and dissipating on Thursday. This strong low will quickly send another front and deeper moisture feed toward and through SEAK Tuesday into Wednesday, bringing moderate to heavy rain and strong gusty winds, along with severe marine hazards. South to southeasterly winds will intensify significantly on Tuesday, producing gale-force conditions in inner channels such as northern Lynn Canal and Clarence Strait, with gales (34-47 kt) and possibly storm-force winds (4855 kts) and combined seas exceeding 20 feet along outer coastal waters, mainly from Cape Spencer northward. By Thursday, conditions will improve behind the frontal passage and as the low in the northern Gulf weakens, though lingering onshore flow will sustain rain showers, while winds and seas slowly subside.

Persistent onshore flow with mainly cloudy skies and rain will keep temperatures cool and consistent through the period, with daytime highs in the mid to upper 40s (low 50s possible on Tuesday) and overnight lows in the upper 30s to low 40s.

AVIATION.../Through 12z Sunday/

SE AK is currently separated by two different weather stories. The northern panhandle is starting to see rain and lowered ceilings due to an approaching low pressure system. The southern panhandle is seeing lower visibilities, and very low ceilings, due to fog development overnight. As the low continues to approach, it will be the main driver of ceilings and visibilities across all of SE AK. Currently, because of the fog, areas south of Frederick sound are seeing IFR conditions with ceilings around 200 ft and visibilities below 1 SM at times. Some of these southern airports have already seen improvements due to the approaching low bringing a higher overcast cloud deck. Until that low moves farther eastward, and increases cloud cover, fog will remain into early Saturday morning. Now looking at the northern panhandle, this morning ceilings remain between MVFR to VFR with broken to overcast Skies AoA 2500 ft. As rain continues, and the low moves farther east, ceilings will fall to around 2000 ft. There may be some drops in visibilities, with heaviest rain, but overall visibility will remain around 4 to 6 SM. One thing to note this morning is LLWS over the Yakutat area. This mornings sounding showed 30 kt winds around 2000 ft. This LLWS is anticipated to diminish late this morning. Similar conditions will persist into late Saturday/early Sunday, before the low weakens allowing conditions to improve.

MARINE

Outer waters: A 990mb low located 120nm SE of Cape Suckling continues to transit across the northern Gulf this morning, with reported wave heights 9 to 11 ft, sustained wind speeds 20 to 30 kts at NDBC buoys 46082, 46083, and 46084, and isolated thunderstorms observed across the Fairweather Grounds towards Cross Sound. Through Saturday, this low will continue to transit NE towards Yakutat Bay and weaken through the afternoon, with a transition to general southwesterly flow across the Gulf and outer coast into Saturday night. Highest forecast wave heights between Cape Spencer to Cape Edgecumbe, 11 to 15 feet by early Saturday afternoon as the front pushes inland, diminishing from northwest to southeast across the Gulf as high pressure moves across the area, widespread 5 to 8 feet by Sunday afternoon

Inside Waters: Winds remain light this morning across the inner channels, aside from the usual trouble spots of Eldred Rock and Scull Island reporting sustained 20 kts. However, expecting this to change over the coming hours as a low in the Northern Gulf sends a front across the inner channels. Winds will turn predominately southerly by early this afternoon with the front tracking into the NE Gulf Coast, increasing to around 15 to 25 kts with strongest expected winds within Lynn Canal and Stephens Passage. Winds diminish slightly into the evening and overnight period, around 10 to 20kts within the N/S oriented channels continuing into Sunday afternoon. Wave heights across the inner channels remain largely 2 to 4 feet, locally higher to 5 feet within Northern Lynn, portions of Stephens Passage near Scull Island and between Point Ardent and Five Finger Light House. Following suit of the diminishing wind, wave heights across the inner channels decrease into Sunday afternoon to widespread 1 to 3 feet.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-013-022-031-053-641>644-651-652- 661>664-671-672.