textproduct: Juneau

UPDATE

Morning update and update to aviation discussion following 18z TAF issuance.

Winds across inner channels remain elevated with locations, specifically across Lynn Canal and Stephens Passage, seeing winds near 25 to 30 kts with gusts up to 35 kts. These stronger winds are anticipated to remain into this afternoon before they start to diminish. Inner channel winds are likely to then remain below 20 kts into the weekend with the exception of isolated areas that could see a few stronger sea breezes.

SYNOPSIS

Key Messages:

- High pressure out in the Gulf will bring warm, dry and mainly clear weather through the end of the work week.

- Gusty northerly outflow conditions for Thursday, especially across the northern panhandle.

- Daytime high temperatures across the southern panhandle on Thursday and Friday expected to hit the 70s.

LONG TERM.../Saturday through Tuesday/

The long term forecast begins mainly uneventful as an area of high pressure lingers over the Gulf through Saturday morning, bringing northwesterly flow, dry conditions, and mild temperatures. However, clouds will certainly be on the increase along the northern Gulf coast as onshore flow gradually attempts to return there, along with perhaps some patchy light rain or drizzle. Clouds will then slowly increase farther south and east by Saturday night. We still anticipate local sea breezes to form, especially over Lynn Canal, where speeds could increase to about 20 knots from about midday Saturday through early evening. High temperatures Saturday will range from the low 60s in the far northern panhandle to the mid and upper 70s in the extreme southeast under ample sun. For Sunday, onshore flow may strengthen a bit as a marine air mass becomes more fully established. As a result, there will probably be a few more areas of light rain and drizzle, particularly from Cape Edgecumbe northward. Under increased cloudiness, high temperatures will also be somewhat cooler.

The pattern turns more active by Labor Day as the next organized low pressure system begins to impact the area. The Canadian model still wants to break down the ridge of high pressure soonest, but it has come closer in timing with the GFS and ECMWF. We have higher confidence that rain chances increase for much of the region after about 12Z-18Z Monday, except over the southeast. This wetter and cooler pattern will continue into Tuesday. Although it is still a bit early to discuss rainfall amounts for Mon-Tue, latest guidance suggests around 2 inches for the northeast Gulf coast to about 0.75" in the central panhandle with lighter amounts farther south.

AVIATION

VFR conditions prevail today across the panhandle, with the shallow overnight fog having lifted earlier in the morning. The main concern today remains as the elevated northerly winds continue to impact N-S channels and areas with no protection from northerly winds. Generally the winds are higher along Lynn Canal itself, while Skagway and Haines are expected to only see around 10 to 15 kt winds with gusts up to 25 kt. This has already begun to weaken for Skagway, and there is potential for sea breeze effects during the day combating this northerly flow and keeping winds more variable and lighter, which was seen yesterday in Skagway too. Other areas are expected to see some sea breeze development later in the morning through the day with the clear skies and warm land temperatures, with breezy conditions beginning to diminish into the evening to predominantly light winds overnight.

With the moisture available and light winds, fog is again a concern for tonight, alongside a marine layer offshore over the Gulf potentially impacting coastal areas from PAYA down to PASI. Fog development, much like last night, is expected to remain rather shallow and patchy. The highest likelihood for VIS restrictions due to fog or low stratus is along the outer coast and for areas tucked away and more protected from northerly winds around Icy Strait Corridor and from Frederick Sound southward (specifically PAPG, PAWG, and PAKW). The main restriction to the confidence in this fog development is the potential for drier conditions, particularly over areas further inland from the Gulf coast.

MARINE

Outer Waters:

An area of high pressure dominates the outer waters forecast for the second half of this week. Northwest and North winds are widespread throughout the outer waters today and into Friday, though as the center of the high edges eastward, the northern Gulf from Icy Bay to Cape Fairweather will turn to the west on Friday, and then southwest late on Saturday. These sustained winds will sit 10-15 kts. The continued northwest flow over several days will feed into slightly higher seas towards Dixon entrance at 6-8 ft wave heights through Friday, settling down to 6-7 ft this weekend. The remainder of the waters will be generally 6 ft or less through the weekend.

Inner Channels:

Northerly winds are the order the day today and Friday. Strongest winds in Lynn Canal have really accelerated in the last couple of hours, blowing 20-25 kt sustained and gusting up to 35 kt. A small craft advisory has been expanded to southern Lynn to address the larger area of strong winds being observed this morning. There are some stronger winds of 15-20kt gusting to 30 kt in portions of Stephens Passage as well. The remainder of inner channels are experiencing 10-20 kt winds this morning, and seas of 2-3 ft in the northern channels, 1-2 ft south. Later this evening winds will subside, and with it wave heights will drop below 2 ft for practically the entirety of the inside. Winds will turn from north to south on Saturday, but will largely remain between 5-10 kt.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-013-661-662.