Petersburg, AK Weather

Update

For 06z TAF Issuance, and Long Term Update.

/06z Update/...A weakening front continues to spread a cloud deck of around 3000 ft out ahead of it over Icy Strait this evening. Along the front itself, the northeast coast is seeing a stable marine layer with CIGs between 500 and 1500 ft at times in Yakutat as well as drops in visibility due to occasional light precipitation. Temperatures there look to remain warm enough to not see any frozen precip at sea level though at this time. For the inner channels, VFR conditions prevail as of 6z, with Gustavus having seen a shallow fog bank briefly roll in off of Glacier Bay earlier in the evening. A repeat occurrence cannot be ruled out later overnight, though with the higher cloud deck moving in overnight, a repeat performance from Saturday night is not expected at this time. Light easterly flow at Sitka ahead of the front is also bringing low end MVFR conditions that should improve once the weakening front pushes into the panhandle through early Monday.

Synopsis

Key Messages:

- A weak disturbance will slide south through SEAK Sunday night through Monday, bringing a chance of showers.

- Quiet weather returns for Tuesday through Thursday, with more sun and dry conditions expected. Northerly outflow winds expected to increase through the inner channels and outer coastal waters.

- A return to a wetter pattern expected by late week into next weekend.

Long Term

/Thursday through Saturday/...

Nothing much to speak of in the middle of the week as a large ridge parks itself over the Gulf. A change in pattern is on the horizon, however, as a front makes its way into the panhandle late Friday, dropping rain through Saturday. This does not have the appearance of a particularly heavy or concerning rain system, but it will end the nice weather. Cold air ahead of the front has the snow level pretty low, but the change to southerly flow and slow arrival of moisture will likely eliminate the confluence of factors necessary for some snow to mix in for low elevation spots early at event onset. Expect a rain event, but as this system gets in range for high res models, the rain/snow line will be something to watch.

Aviation

/through 0Z Tuesday/...VFR conditions continue to prevail, with the exception of PAYA which is seeing the marine layer build as the high pressure in the gulf shifts southeast. Misty conditions have reduced visibilities in Yakutat With broken CIGs sitting around 1,500ft. A scattered layer has been transitioning to broken at about 500ft through the daytime hours and is expected to build again overnight. As the high pressure breaks apart, a weak shortwave is expected to move across the area late tonight into early Monday morning. This bringing low chances of rain to outer coastal sites and increased cloud cover across the panhandle. Rain is expected as early as 9Z and as late as 12Z, with mid level broken to overcast decks moving into the southern panhandle between 12 and 15Z. This first wave of energy is likely not strong enough to reach the inner communities, but a secondary weakening front could increase rain chances across the panhandle through the day Monday. Wind is likely to remain light and variable through the period with no other forecast concerns.