textproduct: Juneau

UPDATE

Aviation Discussion for 06z TAF Issuance.

LONG TERM

/Friday through Monday/ Drier conditions continue through the weekend as a ridge remains over the Gulf of Alaska. The exception to this will continue to be over far northern areas, near Yakutat, where times of light precipitation may occur with slight onshore flow. Little to no accumulation is anticipated as most of the moisture is pushing west of the area. Along with this, there continues to be a high chance of a continued marine layer across the gulf, near the coast, allowing for a low stratus deck to remain.

Looking at temperatures, with dry and clear conditions anticipated, near average to slightly warmer than average temperatures are anticipated. Maximum temperatures will increase to the low to high 50s beginning this weekend lasting into the start of next week. Southern areas, including Prince of Wales Island, Ketchikan, and Annette Island, even have a 40 to 60% chance of temperatures reaching the 60s this weekend. These conditions will also increase the chances of late morning to afternoon sea breeze development in localized areas. These sea breezes can slightly increase winds by 5 kts to 10 kts during afternoon hours. This pattern will continue into next week until an upper level trough pushes into the northern gulf. There is still high variability on whether the ridge will be strong enough to hold, keeping precipitation out of the area, so stay tuned for further forecast updates.

AVIATION

Very few changes in conditions from Wednesday afternoon across the panhandle. Flow around the north side of the ridge in the gulf is bringing MVFR conditions and light rain to Gustavus and southern Glacier Bay and keeping CIGs between 1500 and 2500 ft. Northwest flow is also bringing MVFR conditions to Sitka from a stable marine layer around 2000 ft. This is expected to continue through the overnight hours before improving by late Thursday morning. Similar lowered conditions have been observed around Juneau, though these are not expected to last as long. Along the northern coast, Yakutat is likely to see CIGs gradually drop as light rain attempts to push in from the west. No significant LLWS for the period besides occasional light mechanical turbulence due to daytime heating, with seasonal sea breezes expected by late morning and peaking in the afternoon.

MARINE

Outside (Gulf and Coastal Waters): Ridging has set up over the eastern gulf waters, directing moderate to fresh southerly breezes (11 to 21 kts) in the central gulf north towards the coast before splitting in two directions. Flow that turns to the west as it reaches the coast will remain elevated, creating a barrier jet along the coastline west of Icy Bay and steadily increasing from fresh breezes to strong breezes and eventually low end gale force speeds through Thursday into Friday.

Flow that follows the ridge will arc to the east over the northeastern gulf and decrease until it has flipped northwesterly, before re-strengthening as it flows southeast along the coastline of the panhandle. The ridge will shift slightly to the southeast overnight Wednesday as a low along the western gulf coast shoots north, leading the stronger swath of winds along the eastern gulf coast to also shift towards the southeast. Moderate to fresh breezes will persist from Cape Decision through Dixon Entrance, along the coast of Prince of Wales Island, and through southern Clarence Strait, continuing southward and increasing into Hecate Strait. Moderate breezes are currently flowing into Cross Sound, but are expected to decrease as the ridge shifts southeast. The swath of winds in the northern and central gulf and the swath of winds just south of the panhandle are expected to stay elevated into the weekend, while the rest of the coastal waters from Yakutat Bay down to Sitka Sound stays relatively light from Thursday onwards.

Wave heights of 5 to 8 ft (the highest waves following the stronger winds through Dixon Entrance) will steadily subside to 4 to 7 ft through Wednesday night. As winds continue to strengthen in the northern and central gulf into Thursday, wave heights will begin to increase again to 8 to 10 ft in the northern and central gulf and 6 to 7 ft along the eastern coastline. West to southwesterly swell of 2 to 4 ft Wednesday will weaken initially before strengthening to 5 to 6 ft on Thursday with 7 to 9 ft in the central gulf going into the weekend. Wave period will follow the swell trends, with a 10 to 12 second period increasing to 12 to 15 seconds through the end of the week. A persistent marine layer just offshore will result in the potential for reduced visibility at times over the coastal gulf waters and pushing into Cross Sound.

Inside (Inner Channels): Moderate to fresh west to northwesterly breezes through Sumner and Clarence Strait are expected to persist through Wednesday night and into the day Thursday, decreasing to gentle to moderate breezes (7 to 16 kts) by Thursday night and into Friday. Ridging looks to strengthen again Saturday, which may bring these wind speeds back up through the weekend. The rest of the inner channels are seeing relatively calm northwesterly winds through the period, with the exception of the northern channels. Westerly winds in Cross Sound and southerly winds in Lynn Canal and Taiya Inlet will continue to decrease Wednesday night from the current moderate breeze, becoming calm into Thursday morning. These winds have a chance of increasing for a few hours through the rest of the week, as clearing skies over the panhandle will allow for a gentle sea breeze to pick up through afternoon hours. Light rain showers will continue to be possible through Wednesday night, particularly near Sitka and Yakutat. A low marine layer has been persisting through the coastal gulf waters, which has the chance of pushing into channel entrances through the morning hours and potentially reducing visibility, particularly in the Cross Sound area.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ641-651-652-661-663-664-671-672.