Marine Weather and Tide Forecast for Kupreanof, AK

PREV DISCUSSION
ISSUED AT 550 AM AKDT Mon Aug 3 2026...

SYNOPSIS

Key Messages:

- A front passing through northern panhandle has brought cooler and cloudier conditions for the north with a few showers. Warm and dry weather will continue for the southern panhandle.

- Periods of elevated winds and seas continue for much of the outer coastal waters and inner channels, especially Clarence Straight, Cross Sound, Icy Straight and Lynn Canal. Small Craft Advisories are in effect.

- Trending cooler and wetter from north to south mid to late week.

SHORT TERM
Conditions this morning are very similar to the past few days with high pressure over the area and marine layer persisting.
One of the main differences this morning is the more significant breaks in the marine layer across the panhandle. Some of these breaks have allowed for somewhat cooler temperatures. These breaks are expected to stick around today which will allow for some increased warming compared to the past few days which could allow for some locations to jump up to the 70s during the day. Elsewhere, the chance for light rain and or drizzle remains especially across the NE Gulf coast down to Icy Strait and Sitka. Any precip that does fall is expected to be fairly light with very marginal accumulations.

LONG TERM
/ Thursday through Monday/... With an area of high pressure in the Gulf of Alaska, a fairly benign weather pattern is expected to continue. Some shower activity is expected for western portions of the Panhandle. However, rainfall totals look fairly light with this activity. With the ridge of high pressure in the Gulf, expecting northwesterly winds of 5-10 kts in Clarence Strait, and perhaps up to 15 kts on the western side of Prince of Wales Island.

By Saturday, the ridge of high pressure looks to move, and that will lead to onshore flow, and some higher shower chances for the Northern and Central Panhandle. Some showers moving in from British Columbia also appear possible, but confidence in this occurring is low due to model disagreements.

MARINE
Outside (Gulf and Coastal Waters): On the outside, northwest winds of moderate to fresh breezes persist, with daily fluctuations of southerly swell near 15s at 2 to 3 ft in the morning and building northwest wind waves in the afternoon.
Significant heights remain near 4 to 6ft. Highest seas along prominent capes along our coast, especially along the west coast Prince of Wales and into Dixon Entrance. Along the coast, northwest winds are likely bringing some upwelling, bringing periods of fog. Mariners planning on operating near Cape Spencer should be prepared for periods of dense fog reducing visibility below 1nm at times. Outside of fog concerns, a marine layer reforms in the overnight hours.

Inside (Inner Channels): Sea breezes, fog, and/or a low marine layer remain the primary forecast challenge through the next several days as a surface high resides along our coast. Anticipate lighter winds in the morning hours with building winds in the afternoons into the late evening.
For speeds, while most of the inner channels will see gentle to moderate winds (10 to 15 knots) in the afternoon. For western Icy Strait, portions of Glacier Bay, and Northern Lynn Canal we will continue to see sustained winds reach 15 to 25 knots, with gusts into the 20 to 30 knot range. Mariners planning on operating near Cape Spencer, Elfin Cove, and Pelican should be prepared for areas of fog.

AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...None.
MARINE...None.