textproduct: Juneau

SYNOPSIS

Key Messages:

- Chances of showers linger before a front brushes the southern panhandle with light rain and gusty winds Sunday

- Leaning towards drier and slightly warmer conditions for early next week, particularly for the northern panhandle.

LONG TERM.../Tuesday through Saturday/

The forecast for the work week remains largely consistent with yesterdays forecast, though precipitation accumulations are trending slightly drier as upper-level support weakens. Starting Tuesday morning, persistent onshore flow is likely to develop as the low in the Gulf dissipates and high pressure replaces it. Additionally, a weak front is forecast to track across the southern panhandle bringing with it lighter precipitation rates. The pressure gradient will tighten across the northern region with this frontal passage, leading to elevated winds for Lynn Canal and Taiya Inlet, though current trends suggest weaker than initially thought.

Due to a lack of upper-level forcing, any showers throughout the week are anticipated to be primarily terrain-driven, characterized by onshore flow and mainly isolated to the higher elevations. The region looks to sit under a weak upper-level trough until Wednesday morning, after which a surface ridge is expected to begin building on Thursday. Winds will pick up Friday afternoon as another weak front moves through, preceding the strengthening of the ridge. Moderate rain showers are then forecast to move across the panhandle from Friday evening through Sunday.

While temperatures will remain seasonably cool through the week, there is higher confidence in a slight warming trend for the upcoming weekend as the region settles under an upper-level ridge and 850mb temperature anomalies trend warmer. Increased cloud cover will also help to keep minimum temperatures warmer. By the end of the week, a stronger Aleutian low is expected to track toward the western Gulf. This system is expected to weaken as it enters the Gulf and recent model guidance is starting to agree on its track trending westward, which should reduce its impact on Southeast Alaska.

AVIATION.../Until 00Z Monday/

For the northern Panhandle, a marine layer low stratus deck continues to be the primary concern through the forecast period. This will continue to bring down CIGs & sometimes VISs to well within the MVFR flight category. CIGs may temporarily dip down into IFR, as well, at times. The main exception will be the northern Lynn Canal area, especially PAGY, which will start out as VFR and eventually lower to MVFR tonight. These locations will improve up to VFR by late Sunday morning as the marine layer retreats. For the southern Panhandle, they are also being impacted by the same marine layer, but their flight conditions should improve from mainly around the MVFR/VFR category range to the VFR category sometime between late tonight & mid Sunday morning when the marine layer retreats from there. Some of these sites may also temporarily go down into the IFR category this evening & during the overnight hours. As for SFC winds, they will be breezy/gusty out of a southerly to southeasterly direction due to a combination of a tightened pressure gradient & sea breeze influence over the northern Lynn Canal region(PAGY & PAHN) through this evening. The winds will pick-up again, during the day on Sunday for the same reasons. Elsewhere, SFC winds look to stay relatively benign. LLWS values continue to not be a concern through the TAF period, as well.

MARINE

A flat dirty ridge of high pressure has built-in over the eastern Gulf & Inner Channels & will remain into tonight, giving onshore flow & low marine layer stratus clouds for the northern 2/3 of the Outer Coast & into the Icy Strait corridor. Then, another low & associated front approach the Panhandle & dive southeastward while weakening, moving past the Panhandle for the latter half of the weekend, bringing winds & seas up for the southeastern Gulf, Dixon Entrance, & Clarence Strait.

Outside Waters(Eastern Gulf of Alaska): Seas will remain between 5 & 7 ft & winds will remain 20 kt or less until Sunday when sustained winds increase up to around 25 kt with the highest values, particularly over the southeastern Gulf area, & significant wave heights build back to between 7 & 9 feet when another low & associated front approach Southeast Alaska & dive southeastward while weakening, passing by & moving away from the our region early next week. Around the Dixon Entrance of Clarence Strait, the sustained winds may peak out at around 30 kt Sunday afternoon through Sunday night. Southerly swell up to 3 ft is expected through Sunday morning, with the largest swell to the south. The swell will diminish to 1 to 2 feet late Sunday through midweek. Winds will progressively diminish to less than 15 kt & waves will subside to less than 3 ft for the entirety of the eastern Gulf through midweek as that low continues to weaken, move southeastward away from the area, & the pressure gradient further relaxes.

Inside Waters(Southeast Alaskan Inner Channels): Winds over most of the Inner Channels will generally stay around 15 kt or less through early next week with Lynn Canal/Taiya Inlet experiencing a bit breezier conditions due to a periodically tighter pressure gradient. Overall, for areas that get breaks in the cloud cover, winds will generally follow a diurnal sea breeze/land breeze cycle through Saturday night. On Sunday, winds will increase up to around 25 kt for southern Clarence Strait/the Dixon Entrance & seas will build up to around 7 ft, once again, as another low & its associated front approach Southeast Alaska & dive southeastward, bypassing the area through early next week. Around the Dixon Entrance of Clarence Strait, the sustained winds may peak out at around 30 kt Sunday afternoon through Sunday night. Winds will progressively diminish to less than 15 kt & waves will subside to less than 3 ft for the entirety of the Inner Channels through midweek as that low continues to weaken, move southeastward away from the area, & the pressure gradient further relaxes.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-036-641-651-652-661>664-671-672.