textproduct: Juneau

SYNOPSIS

Key Messages:

- A weak disturbance will slide south through SE AK late this afternoon into tonight, bringing a chance of showers.

- Quiet weather returns for Tuesday 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 the 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 Wednesday/

The main threat across SEAK this Monday afternoon is a predominant low level marine layer lingering across the central and southern inner channels bringing CIGS from borderline MVFR, between 1,500-3,00ft, to pockets of below 1,000ft. Above these low level clouds are sunny skies, which have peaked through occasionally, bringing brief period of scattered to clear skies. PAYA is expected to begin clearing out Monday evening while PAGY and PAHN are expected to remain clear. PAJN faces the potential of seeing this low layer move through Monday evening before clearing out again overnight. Low level clouds are anticipated to clear out from north to south overnight, with clearing in the Icy Strait corridor likely by midnight through early morning Tuesday in the southern panhandle. As these clouds move across the mountains, spurts of mist and light rain are possible which will briefly reduce visibilities as they move through. As the clouds move out, the main concern shifts to gusty northerly outflow winds, especially across the northern panhandle. PAGY and PAHN could see winds sustained up to 20kts with gusts of 35kts by the end of the period. PAJN could see gusts up to 20kts, as well as PAKT due to their favored northerly direction. LLWS is not a concern for the period due to the lack of directional shear and difference in surface and directional shear, however, PAGY and PAHN could see wind up to 40kts between 1,500-2,000ft.

MARINE

Outside (Gulf and Coastal Waters): High pressure dominates the Gulf of Alaska gradually shifting eastward Monday night into Tuesday, peaking around 1038 mb, centered near 50N, 150W. This feature is currently driving NW'ly 15 to 25 kt winds along the Gulf coast and in the offshore zones. Outflow winds from the inner channels will mainly impact the coastal zones from Cape Spencer southward. These elevated winds will likely persist through late Tuesday before diminishing Wednesday, with the Dixon Entrance region easing last. Seas will build alongside the winds, reaching 8 to 10 ft south of Cape Edgecumbe and 6 to 8 ft to the north. A low marine layer (1000- 2000 ft) has continued to push in along the NE gulf coast overnight, though is expected to be less impactful Tuesday morning due to increased winds along the coast.

Inside (Inner Channels): Light and variable winds persist this afternoon gradually increasing overnight. Outflow winds will strengthen across the panhandle beginning early Tuesday as a weak low slides south down the panhandle. This feature will tighten the pressure gradient between the high pressure in the Gulf and the interior high over the Yukon, primarily favoring N-S oriented inner channels. Winds begin picking up in the north, then spread southward. Lynn Canal will experience the initial increase, followed by Chatham Strait, Stephens Passage, Frederick Sound, and finally Clarence Strait by midday. Winds in these areas are likely to reach strong breezes to near gales, with gale force gusts possible in Lynn Canal and Chatham Strait. Wave heights will also increase, building to 4 to 6 ft, and 6 to 8 ft near ocean entrances. Winds and seas remain elevated across the region through the day Tuesday before diminishing Wednesday.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory from 9 AM to 8 PM AKDT Tuesday for AKZ318. MARINE...Small Craft Advisory for PKZ011>013-031>034-036-641>643-661>664- 671-672.