textproduct: Juneau

UPDATE

Update to include 6z TAF issuance and Winter Weather Advisories. A strong front bringing heavy snow with accumulations of 2 to 5 inches is moving north through the panhandle, and is currently sitting over the Icy Strait Corridor. This band is expected to continue to move north overnight, continuing snowfall for the northern panhandle before it dissipates through the next few hours. Behind the front, widespread showers have moved over the southern and central panhandle. Periods of light to moderate snowfall with lowered visibility is expected with these showers, though heavier showers with higher accumulations will be possible overnight.

SYNOPSIS

Key Messages:

- Periods of precipitation and gusty winds across the panhandle through Sunday.

- More snow likely for the southern panhandle Sunday into Sunday night. Winter weather advisories are up for those areas.

LONG TERM.../Monday through Wednesday/

Another shortwave quickly rotating along the upper level trough over the Gulf will push over the area Monday. This will allow for the development of another weak low extending from the multivortex surface low currently in the Gulf, which will bring showers primarily along the southern panhandle and outer coastline through Tuesday morning. By Tuesday much of the northern half of the panhandle will begin to see a break in the precipitation, alongside clearer skies and some cooler temperatures, as a low approaches to the south of the panhandle while a high lingers to the north over Canada.

The current forecast for this low to the south has changed quite a bit since yesterday, as new model runs have shifted towards agreement with the GFS solution of keeping the low further south, in part due to the agreement now on the upper level low finally beginning to push eastward rather than linger just west of the panhandle as it has been. The low itself will move more into the west coast of BC, just east to southeast of Haida Gwaii. After this is where some uncertainty remains, with some models indicating that the quickly weakening low will move north around the southern panhandle, bringing precipitation chances more northward for Wednesday. The other solution keeps the low moving northeast into BC, keeping much of the precipitation southeast of the panhandle with chances mainly for the far southern parts of SE AK. Precipitation amounts look to be on the lower end for this system, and alongside the warm temperatures over the southern panhandle will result in lower snow accumulations even with the solution that brings in more precipitation into the area.

Overall this change has brought down the winds significantly across the southern panhandle with the low being much weaker and staying south for longer, as well as across the rest of the panhandle as the outflow will be much less strong and mainly impact the Lynn Canal area, and off the NE coast with gap winds. These winds now are expected to only get to gale force, largely staying below 40 kt at the peak on Wednesday, before beginning to diminish into Thursday.

AVIATION.../Through 6z Monday/

A strong front is moving through the panhandle Saturday evening, bringing heavy snowfall with gusty winds in its wake. This front is starting to deteriorate as it moves north, currently sitting draped over the Icy Strait Corridor. This front will continue sliding northward, bringing more organized snowfall through the northern panhandle and Yakutat before moving out. Behind this front, widespread light to moderate snow showers are following through the panhandle and lowering VIS to MVFR/IFR conditions with CIGs around 2000 ft. Heavier showers will be possible through the night, which may periodically bring conditions all the way down to LIFR with 1/2 SM of VIS. In between showers, conditions may jump back up to VFR with broken CIGs and light winds.

Widespread showers are expected to continue through Sunday morning before starting to lose steam. Around midday Sunday, the northern panhandle will start to clear out as weak outflow winds develop. From the Icy Strait Corridor north, VFR conditions are expected to prevail through the rest of Sunday and into Monday with potential for gusty winds up to 25 kts. For the rest of the panhandle south of this, expect more persistent IFR snow showers, with a widespread band of IFR snow moving across the southern Panhandle Sunday night (Frederick Sound south to Dixon Entrance). By the very end of the period, the southernmost areas have a chance to break out of the band of snow and for conditions to improve. Gusty winds along the band may take a bit longer to diminish after the front moves out.

MARINE

Inner Channels...Gusty S and E winds of 20 to 30 kt remain the norm this evening for many areas of the inner channels this evening. The exception is Lynn Canal and the northern half of Stephens Passage where N winds are blowing. Those N winds should switch around to a southerly overnight with Lynn Canal possibly seeing a period of 25 kt winds shortly after the switch as the first low in the gulf moves northward and pressure gradients switch. Those southerly winds should persist until Sunday evening when the next short wave approaches the southern panhandle causing winds in the north to turn north once again Sunday night. Seas are generally around 3 to 6 ft and will generally vary between those values as winds increase and decrease with each short wave that passes through the area.

Gulf and Coastal Waters...The broad low in the gulf continues to be rather complex in structure due to several small low centers rotating around the main circulation. The first and strongest one is moving north around 56N 140W and is bringing some min gale force winds near its circulation especially on the south side of it. That low will move N and then W this evening taking its winds with it. The next low will move closer to Prince of Wales island and will be weaker only producing 25 kt winds around it from midday Sunday into Sunday night. Otherwise most areas are around 20 kt or less with variable wind directions as the complex low shifts around. Seas are around 10 to 14 ft. Seas are expected to generally increase overnight (up to 20 ft) as the first strong low moves through before subsiding into Sunday and Sunday night.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Weather Advisory until 4 AM AKDT Sunday for AKZ317-319. Winter Weather Advisory until 1 AM AKDT Sunday for AKZ320>330- 332. Winter Weather Advisory from 10 AM Sunday to 4 AM AKDT Monday for AKZ328. Winter Weather Advisory from 4 PM Sunday to 4 AM AKDT Monday for AKZ330-332. MARINE...Gale Warning for PKZ644-651-652-662>664-671-672. Small Craft Advisory for PKZ011>013-021-022-031>033-035-036- 641>643-661.