textproduct: Juneau

18Z AVIATION UPDATE

A morning with considerable fog complications is clearing up as the sun rises and winds pick up. There does remain a section of dense fog hampering vsbys as low as 1/4M in the southern panhandle, affecting PAPG and PAWG. Expect this to lighten up over the next hour or two, as some promising trends have already been observed on cameras. The remainder of the TAF valid period will be VFR as cigs lift and cloud cover largely disintegrates for clear skies. The greatest concern will be winds towards the northern panhandle where north winds will gust 20-25 kt at PAGY/PAHN. The remainder of the region will see north to northwest winds sustained at 10-15 kt. With these stronger offshore winds, will be monitoring for LLWS at AJN this afternoon/evening. With these higher winds, not expecting a widespread resurgence of fog and vsby issues on Friday morning as we experienced this morning.

SYNOPSIS

Key Messages:

- Northerly winds build across the inner channels Thursday, strongest marine winds expected in Lynn Canal. - High pressure returns through the end of the week with drier conditions, more sunshine, and high temperatures in the mid 60s to low 70s.

LONG TERM.../Saturday through Tuesday/

Still no major changes are expected in the long term forecast, as a high pressure ridge dominates the Gulf for the foreseeable future, bringing consistently dry and benign weather. Beginning Saturday morning, winds across the inner channels and coastal waters are expected to weaken and remain at or below 10 knots. Afternoon sea breezes will likely develop with daytime heating, but are not expected to cause significant impacts.

The greatest uncertainty in the long term is whether a weak disturbance will bypass the northern panhandle early next week. Model guidance generally agrees that high pressure will strengthen and block most appreciable precipitation, however, there is a small but increasing chance of light rain reaching the northern panhandle/outer coast region by midweek. Highest confidence is that most precipitation will stay over the mainland interior, though could still see widespread cloud cover move in from the north by Monday. Overall, generally dry conditions with daytime temperatures rising into the mid 60s to low 70s across most of the region, continuing to remain seasonably warm through midweek.

AVIATION.../through 18z Friday/

A morning with considerable fog complications is clearing up as the sun rises and winds pick up. There does remain a section of dense fog hampering vsbys as low as 1/4M in the southern panhandle, affecting PAPG and PAWG. Expect this to lighten up over the next hour or two, as some promising trends have already been observed on cameras. The remainder of the TAF valid period will be VFR as cigs lift and cloud cover largely disintegrates for clear skies. The greatest concern will be winds towards the northern panhandle where north winds will gust 20-25 kt at PAGY/PAHN. The remainder of the region will see north to northwest winds sustained at 10-15 kt. With these stronger offshore winds, will be monitoring for LLWS at AJN this afternoon/evening. With these higher winds, not expecting a widespread resurgence of fog and vsby issues on Friday morning as we experienced this morning.

MARINE

Outer waters: As an area of high pressure begins to slide into the Yukon, and a surface low slides to the south, northerly winds are going to become more prominent through our coastal waters. From Alsek west to Cape St. Elias, winds should remain largely at or below 20 knots. However, expect speeds to reach fresh to strong breezes just offshore of the Chichagof/Baranof Archipelago and out of Chatham Strait. Mariners attempting to round Cape Ommaney or Decision should be aware of this northerly wind component, especially during flooding tides. Favoring the coast will limit fetch potential.

Touching on seas, current buoy observations indicate a dominant WSW group 7 to 10 ft focused near 10 seconds from the Fairweather Grounds to Prince of Wales. A secondary wave system is out of the WNW, generated from near-gale force winds out of Cook Inlet, responsible for 10 ft seas in the central Gulf. These wave systems are burying southerly tropical swell focused at near 14 seconds.

Moving through the next 24 hours, WSW seas trend downward, with the focus shifting to the aforementioned W to NW wave system coming out of Cook Inlet and western Gulf. Expect this group to slowly diminish to 6 to 8 ft by Thursday afternoon. As we move into Friday, southerly forerunners from swell generated from Hurricane Lowell begins to reach the northern coast, with wave heights reaching 2 to 4 ft. Expecting peak swell conditions at 2 to 4 ft 15 seconds along much of the coast into Saturday. Riding on top of this system will be WNW wind waves, bringing some chop into the PoW coast and Dixon entrance.

Inside Waters: While winds are going slack across much of the inside this early Thursday morning, northerly winds will ramp up through the day. Mariners navigating the inner channels should be aware of this northerly threat, with sustained speeds reaching a minimum of fresh breezes for most waters along and north of Frederick by Thursday afternoon; Lynn Canal will see strong breezes by Thursday afternoon. Winds continue to escalate Thursday evening, with strong breezes for much of Chatham Strait and near-gale force conditions for Lynn Canal. These northerly winds will begin to increase as well for Clarence Thursday evening, likely reaching fresh breezes.

Of particular interest is the long fetch of Chatham and Lynn, where northerly winds will generate 4 to 6 ft seas. To reiterate the wave threat, mariners navigating Lynn and Chatham should be aware of the northerly winds and tidal cycles generating higher localized seas, especially near Point Couverden, Cape Ommaney, and Cape Decision. Our wave forecast does not take into consideration tidal influences.

Winds will come down slowly through the day Friday, with sea breezes becoming the primary focus into the weekend.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ011>013-031>033-641>643-661>663.