textproduct: Juneau

AVIATION...06z TAFs

Flight conditions have been VFR this evening across Southeast Alaska thanks to a ridge of high pressure in the Gulf of Alaska. The main concern for aviation tonight will be the development of fog with mostly clear skies and fairly light winds. Fog appears most likely for Yakutat, Gustavus, Juneau, and Petersburg. Fog is also possible for Klawock, but confidence in this occurring is lower. Any fog that develops should dissipate with daytime heating by 16Z Thursday at the latest.

As the ridge in the Gulf continues to develop for Southeast Alaska, expect there to be a tightening pressure gradient and stronger winds Thursday. An area of high pressure is expected to develop in the Yukon, and this will lead to a stronger pressure gradient, and the highest winds in Lynn Canal. Confidence for the highest winds is currently for Skagway. Winds are generally expected to decrease in strength by the end of the TAF period.

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.

PREV DISCUSSION...ISSUED AT 326 PM AKDT Wed Sep 2 2026

SYNOPSIS...

Key Messages:

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

- Temperatures will drop overnight across the north, with near freezing temps possible early Thursday morning near Yakutat.

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

SHORT TERM.../through Friday night/...High pressure will build into and slowly shift east across the Gulf through the short term, bringing warm, dry and mainly clear weather. Seasonably mild temps this afternoon with high generally in the 60s. Increasing 850 heights and temps for the end of the work week will bring warm temps with highs in the upper 60s to 70s. Friday looks to be the peak of the mini warm wave with highs for the southern panhandle in the mid to upper 70s, with interior locations possibly reaching 80 degrees. With the clear skies and drier northerly outflow winds, most areas will see good radiational cooling and large diurnal temps swings (20-30+ degrees). Temps dipped into the low to mid 30s across Yakutat this morning. Expect the same if not a couple of degrees cooler tonight for Yakutat and have issued a Frost Advisory overnight into early Thursday morning. Have lowered overall nighttime lows 5 to 12 degrees tonight, Thursday night and Friday night from NBM guidance to be closer in line to MOS guidance which is handling the temps better. Lower confidence on the cooler temps Friday night as some guidance is trying to weaken and shift the ridge slightly Friday night as a low pushes east across south- central AK, allowing more onshore flow and marine airmass for the northeast Gulf coast and towards Icy Strait and Sitka. Gusty outflow winds possible Thursday, especially across Haines and Skagway.

MARINE... Outside: West to northwest winds continue to impact the coast as a high begins to dominate. Primary threat to mariners is winds of moderate breezes building along the northern coast, with northwest winds of fresh breezes along the Chichagof to Prince of Wales Coast. Marines planning to navigate the Chatham and Sumner ocean entrances should be aware of northerly winds flowing out of the inner channels, with speeds likely near moderate to fresh breezes.

West to northwest wind waves near 7 to 9 seconds continues to dominate the coast, with underlying southerly swell from the south pacific and hurricane activity in the central Pac being buried. Significant heights of 4 to 7 ft continue, with 4 ft along the northern coat and 7 ft closer to Dixon Entrance. By Sunday/Monday the jet will shift into the Aleutian storm track, serving up a series of lows. Expect building southwesterly seas of 8 to 12 ft by the start of next week.

Inside: Certainly, a complex forecast for the inner channels Wednesday night into Friday. Primary challenge has been diagnosing northerly wind onset, strength, and duration. Mariners planning to navigate the inside Thursday should be aware of northerly 15 to 25 knot winds impacting most north-to-south orientated channels, with Clarence Strait persisting a bit longer into Thursday night. One note on these northerly winds, there is ample opportunity to miss wind strength and/or localized areas like southern Chatham Strait and northern Glacier Bay. Stay tuned to NOAA weather radio and weather.gov/Juneau for updates. If you get pinned down somewhere, just wait. Northerly winds will subside north to south late Thursday afternoon into Friday morning.

Lets get into the details...overnight Wednesday a quick transiting high will slide into the Yukon, bringing a north/south pressure gradient between our Canadian neighbors and the Gulf. Guidance suggests a mean pressure gradient difference between CYXY and PAJN near 5.8mb, with PAGY to PAJN near 3.5 mb. Historically, this suggests small craft conditions from strong breezes to near- gales (22 to 33 knot winds). However, we are missing a few critical ingredients mainly a deep stable winter airmass in Canada. This means guidance is likely overdoing wind speeds but could have drastic consequences if our forecast under performs, especially with the number of small skiffs currently operating in our waters. For now, anticipate building northerly winds in Lynn late Wednesday night, with sustained wind speeds likely reaching strong breezes. Gusts could reach as high as gale force for a few hours in Lynn. Expect northerly winds to continue to build in Chatham and Stephens Thursday morning, filling into Clarence Strait a little later. Overall, winds of moderate to strong breezes (15 to 25 knots) should be expected in major north-south channels, with the current forecast leaning toward 25 knots for Lynn and fresh breezes for southern Clarence Strait. Winds slowly diminish Thursday from north to south. Again, Clarence Strait will hold onto stronger northerlies until Friday morning. For seas, the northerly winds will have ample room to put in some work on the long fetch of Lynn and Chatham, with choppy seas building to near 4 to 5 ft Thursday morning. Watch the flooding tides and the northerly winds, which could bring locally higher seas.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Frost Advisory from 2 AM to 8 AM AKDT Thursday for AKZ317. MARINE...Small Craft Advisory for PKZ012-661.