Marine Weather and Tide Forecast for Kasaan, AK

SYNOPSIS

Key Messages:

- Convective rain showers moving in from the north Pacific will impact the panhandle overnight and into Thursday morning.
Highest chance for moderate showers in the southern panhandle.

- Some clearing is possible for the Icy Strait corridor Thursday afternoon and overnight. Areas of fog are possible during the overnight hours.

- Slightly above normal temperatures for Friday and Saturday with clearing skies.

SHORT TERM
/Through Friday/...The upper level low is currently meandering southeast, helping direct the developing low pressure towards the southern tip of Haida Gwaii. First, this low is developing along a negatively tilted trough with plenty of vorticity advection aloft even if the wind speeds are lower.
Second, this low is continuing to track further and further south, both reflective in current satellite imagery and model guidance, this changes a few things. As there is plenty of energy surging northward, rain chances are expected to briefly extend north of Angoon all the way into Canada. Not expecting a long timeframe for rain, perhaps around 6 hours of PoPs greater than 60% during Thursday, but the chances have definitely increased.
Second, easterly flow over the Coast Mountains is expected to lead to some mid layer drying. With rain chances for the Icy Strait corridor and Juneau, followed by drying and possible clearing, temperatures could fall much lower than expected. Furthermore, with recent rainfall and higher dewpoints, could see a good case for fog in the Icy Strait corridor, corresponding with the possible clearing.

Further south, still expecting a good douse of rainfall, with around a 60-80% chance for moderate rain showers over Prince of Wales Island, Rev Island, and Annette Island. No flooding or moderate to large scale impacts are expected from this front, with winds staying mostly lighter.

Finally, for Friday, expect to see a warming trend return once again. Currently not expecting temperatures like we saw before the active pattern, as temperatures aloft do not support anything higher than the low to mid 70s for a high. However, will likely see more sun and drier conditions throughout the panhandle.

LONG TERM
/Saturday through Tuesday/...The long term forecast continues to be relatively benign through the weekend, with shower chances building back in Sunday into early next week.
Ridging over the gulf continues to build through the weekend, increasing gulf winds to a northwesterly fresh to strong breeze down the coast through the rest of the extended period and tapering off through Tuesday. The panhandle looks to stay dry Saturday, which will allow for widespread mostly sunny skies, increased daytime high temperatures, and developing sea breezes through midday. Shower potential will still be present through the period as flow turns more westerly and onshore, but Saturday continues to look drier and drier as it gets closer. With these clearing skies this weekend, much of the panhandle may see high temperatures reaching the high 60s and even the low 70s. 10 to 15 kt sea breezes should increase through midday for areas seeing significant clearing and subsequently warm daytime high temperatures. A tightening pressure gradient over Northern Lynn Canal looks to increase winds through Taiya Inlet and into Skagway through the early afternoon of both weekend days, which has the potential to bring winds up to 20 to 25 kts with any sea breeze influence.

The rest of the period is still relatively quiet for Southeast Alaska standards, but shower potential will increase Sunday and last through the early work week. An upper level shortwave trough in the northern gulf doesn't have much in terms of a surface inflection, but as the disturbance with increased vorticity pushes over the panhandle Saturday night, potential for showers increases for the northern panhandle and along the outer coast Sunday and through the rest of the period. Mid-level moisture looks to be lacking through this period, so any showers that do develop will most likely be weak and may not make it all the way inland over the panhandle. For much of the panhandle, this may just manifest as increased cloud cover. Even so, this will still decrease daytime high temperature potential to the low to mid 60s.

AVIATION
/Until 06Z Friday/...A low will continue to push eastward through the southeastern Gulf of Alaska through the 24-hour TAF period, sending bands of rain / rain showers from south to north through the Panhandle, bringing flight conditions mainly down to within the MVFR category. The lowest conditions, approaching the IFR category, will be in the southern Panhandle, closer to the low track & the Outer Coast, including PAKT, PAKW, PASI, & PAYA through late tonight/early Thursday morning. For late this evening into tonight, some isolated to scattered thunderstorms continue to be possible over the east-central Panhandle, including PAWG, PAPG, & the southern portions of the Juneau Ice Field. Those should continue to weaken as they drift northward, remaining over the Juneau Ice Field. Flight conditions will begin to improve Thursday afternoon as the low continues to weaken & move away from the southern Panhandle. For the most part, SFC winds remain benign through the period. The exception is gustier winds in an near any of the stronger showers & thunderstorms. LLWS values look to stay relatively insignificant through the forecast period.

MARINE
Outside (Gulf and Coastal Waters): Winds in the outside waters today have been fairly light with a weak trough southwest of Yakutat. Into Thursday morning, a slightly better organized low pressure system is expected to develop in the North Pacific. Most recent guidance suggests that the will move fairly quickly to the southwest of Haida Gwaii. As a high pressure develops Friday into Saturday behind the low, this will lead to northwesterly winds between to 15-20 kts in the Southern Gulf of Alaska.

Inside (Inner Channels): Winds in the Inner Channels have been fairly light today due to a weak trough in the Gulf of Alaska. The low pressure in the Gulf of Alaska looks to have a more southerly track with the latest guidance, so easterly winds are expected in Dixon Entrance. As the low tracks south, a high pressure will develop, and could lead to some 20 kt westerly winds near Cape Decision beginning Friday evening.

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