textproduct: Juneau

UPDATE

Increased winds across the waters through the Inner Channels as some locations have already increased significantly compared to what was forecasted earlier in the day. Update to the aviation section to include the 06z set of TAFs.

SYNOPSIS

Key Messages:

- An incoming system tonight brings mostly light rain to the gulf coast and Icy Strait corridor. Less likelihood for rain in the southern panhandle.

- A stronger front moves in Tuesday, bringing moderate to heavy rain and breezy conditions to the panhandle. Skagway could see wind gusts up to 50 mph.

- For the latter half of the week, high pressure returns with more sun and high temperatures in the mid 60s to low 70s.

LONG TERM.../ Thursday through Monday /

Low pressure will continue to remain over the gulf before diving to the south Thursday morning. As this low dives south along the coast towards Haida Gwaii, high pressure will start to build into the Yukon and British Columbia from the Alaskan Interior. With the ridge on the heels of the low, there looks to be a tight pressure gradient forming Thursday night into Friday morning. The orientation of this gradient looks to favor north-south oriented water ways at this time so we could see some significant northerly winds for the end of the week and into the start of the weekend. With the flow becoming offshore during this time, we should dry out again thanks to drier air moving in from Canada. Some forecast guidance is also leaning into 850mb temperatures dropping down to 0C as this air moves along the Coast Mountains but agreement on this is still on the lower end. With the offshore winds and clearing skies, daytime temperatures look to get back into the 60s and potentially some 70s for some locations.

Heading towards the start of next week, GEFS and some members of the EPS want to develop a low over the Northern Gulf but agreement on this idea is still low. Otherwise, high pressure looks to remain in the area heading into next week allowing for a fairly quiet pattern to set up for the area.

AVIATION...06Z TAFs

A weakening front is passing through the northern and central panhandle at this time. This feature will bring periodic MVFR ceilings and visibilities along with some light rain and drizzle tonight. By 15Z-18Z, a stronger front will approach the region and bring predominantly MVFR to IFR conditions in rain, lower ceilings, and frequent visibility reductions. Winds will also increase, especially at PAGY and adjacent locales, where gusts to 40kt are possible after 18z. Low level wind shear is possible for a period Tuesday afternoon and evening, but we did not include it at this time due to primarily unidirectional flow and little change in speeds from just above the surface to 2000ft AGL. This will be monitored for potential inclusion in future forecasts.

MARINE

Outer Waters:

The first of a pair of fronts has turned winds to the south across the Gulf this afternoon and into tonight. Currently winds are picking up to 15-20 kt before a lull later tonight before the second, stronger front makes it pass on Tuesday. Winds Tuesday will reach 25-30 kt out of the south. This continued strong flow will build higher seas in the central Gulf. In that area wave heights of 9-12 ft will occur Tuesday night before winds turn to the west on Wednesday. This will coincide with the higher 9-12 ft seas to spread towards the southeastern Gulf as well. These westerlies will also be moderately weaker than the southerlies of Tuesday, sitting in the 10- 20 kt range.

Inside Waters:

Much like the outer waters, the inside channels will experience a tale of two fronts. Today, winds are experiencing a surge associated with a weaker frontal passage. Gusts in northern Lynn Canal have been recorded up to 25 kt, with some 15-20 kt gusts near ocean entrances, such as in southern Clarence Strait. Wave heights are generally 2-3 ft in the northern channels, reaching 5 ft near ocean entrances and in Lynn Canal. Tuesday will again see a much stronger wind and sea response with a stronger front. Gale force winds are expected in northern Lynn, and most other portions of the inside channels will see 20-25 kt winds. Seas will also reach 3-5 ft throughout.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory from 1 PM Tuesday to 1 AM AKDT Wednesday for AKZ318. MARINE...Gale Warning for PKZ012. Small Craft Advisory for PKZ011-013-021-022-031-032-053-641>644- 651-652-661>664-671-672.