textproduct: Juneau

SYNOPSIS

Key Messages:

- Bands of showers moving through the southern half of the panhandle through Friday. Winter Weather Advisories have been added for Prince of Wales Island and the Southern Inner channels due to anticipated appreciable snow accumulations.

LONG TERM

A return to the active weather pattern looms on the horizon, as a strong system advances into the panhandle on Sunday. Driven northward as it rides along the eastern flank of a deepening positively tilted trough located over the western Gulf, ensemble guidance has locked into the potential for a ~980 decameter low to make landfall somewhere along the Gulf Coast; though the exact location is still not yet set in stone.

The big stories for the panhandle with this system will be the snow and wind. The strongest winds will be across the southern half of SE AK, and gusts of up to 35 kt or higher may be possible for for these areas, along with parts of the Outer Gulf Coast. Snow will be more widespread, with anywhere from 3-12 inches possible for areas near sea level through Monday. Snow totals will be generally higher further south, but this will need to be watched closely, as the final track of the low will have significant impacts on the snow totals. A changeover to rain or a rain snow mix is possible for the southern panhandle Sunday afternoon onwards as warm air advection attempts to push north, but expect cooler conditions will prevail over the northern half of SE AK.

Beyond this, we enter back into a pattern favorable for convective showers will looks set to last through the remainder of the week, as a low spins up over the northern Gulf. These showers will bring accumulating snow at times, with potential impacts to maritime and aviation concerns. The southern panhandle concurrently looks set to receive stronger surges of moisture, as systems racing along the flank of the southern stream jet are able to side-swipe the area.

AVIATION

Panhandle remains split between VFR conditions and clearer skies across the northern panhandle, and lingering showers and intermittent drops to MVFR/IFR across the southern panhandle. The meso low continues to linger off the coast of Baranof Island just south of Sitka, keeping the snow showers moving into the southern panhandle. This will begin slowly drifting southeastward today into tonight, and with it the area of showers and subsequent drops to CIGs and VIS will also push southeastward through the day. This will allow for Sitka and the more central parts of the panhandle to begin to clear from the morning hours through midday as the showers begin to diminish, while areas further south will keep seeing some intermittent drops from VFR down to MVFR/IFR as showers last into tonight. Expecting these showers to bring CIGs to 1500- 2000 ft and VIS to 2-4SM as they push through. Klawock and Ketchikan will see some higher potential for some brief drops down to IFR/LIFR with CIGs 500-800 ft and periods of VIS of 1SM or less during the heaviest snow showers from the bands this morning and midday. The snow showers will diminish across the far southern panhandle this evening into tonight, with a return to VFR conditions after around 4 to 6z, clearing earlier around PoW and lasting longer around Ketchikan and Metlakatla.

Skagway and Haines will continue to see some outflow during the morning and through the day, with Haines expecting winds of 10 to 20 kt and gusts of 20 to 30 kt now through the afternoon, and Skagway expecting to see sustained winds of 15 to 25 kt with gusts of 25 to 35 kt. The outflow will begin to slowly diminish midday into the evening, bringing down the surface winds by tonight. Continuing to see no LLWS concerns for this TAF period. Overall improving conditions for both the outflow and the showers / VIS and CIG restrictions this afternoon through tonight across the panhandle.

MARINE

Inside Waters(Inner Channels): Enhanced northerly outflow sustained winds will subside from between 25 & 30 kt, with gusts up to around 40 to 45 kt mainly around Point Couverden, down to sustained winds between 10 & 15 kt as the pressure gradient relaxes through this evening for the northern north-south oriented Inner Channels, specifically Lynn Canal, Stephens Passage, & extreme northern Chatham Strait, near Point Couverden. Fully developed seas up to around 8 to 10 ft will remain today before the northerly outflow fully tapers down. 10 to 20 kt sustained winds early today will diminish to around 10 kt or less by Saturday morning. Winds will pick back up, peaking out at around 20 to 30 knots on Sunday as a more substantial area of low pressure approaches & pushes into the Panhandle. Waves will generally pick-up to around 4 to 10 ft with that weather system. Waves will ne higher near ocean entrances.

Outside Waters(Eastern Gulf & Outer Coastal Waters): The generally benign pattern will continue through the first part of the weekend with a relatively relaxed pressure gradient in place keeping winds mainly between 10 & 25 kt with seas around 3 to 6 ft for that timeframe. The only exception will be some residual gap winds over the extreme northeastern gulf waters of up to around 25 knot small craft advisory values from the diminishing northerly outflow today. Winds over the eastern gulf will increase up to between 25 kt small craft & 40 kt gale force from the aforementioned more significant approaching low pressure system on Sunday. The highest winds will be over the southeastern gulf waters to the right of the low track. We currently expect the low to track northward, approaching the central outer coast of the panhandle late Friday evening. Seas are expected to build up to between 8 & 14 ft with the highest values in the southeastern Gulf by Sunday night.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Weather Advisory until 10 AM AKDT this morning for AKZ328. Winter Weather Advisory until 4 PM AKDT this afternoon for AKZ330. MARINE...Small Craft Advisory for PKZ012-013-031-643.