textproduct: Juneau

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.

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

A trough southwest of Yakutat has brought IFR to MVFR ceilings to western portions of the Gulf Coast. While some lower ceilings (between 500-1000 feet) are possible for Yakutat and Gustavus, an approaching low pressure system approaching decreases confidence in this occurring.

As the low pressure in the North Pacific moves toward Haida Gwaii, then it will increase shower chances and generally deteriorate conditions to MVFR (ceilings between 1500-2500 feet), around 10Z for areas south of Fredrick Sound and likely after 15Z for areas north of Fredrick Sound.

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.