textproduct: Juneau

SYNOPSIS

Key Messages:

-Showers continuing south of Sumner Strait with snow accumulation expected late tonight into early Thursday.

-Northerly outflow continuing and strengthening across the north through the next few days with freezing spray becoming more widespread and temperatures becoming colder.

-Temperatures gradually cooling through late week across the panhandle.

LONG TERM.../Friday through Sunday/

Overall outflow conditions and colder temperatures are the main impacts the end of the week through the weekend, as an upper level trough sets up over the panhandle and a series of lows pass to the south into the west coast of British Columbia. This will allow some slight chances of precipitation to remain in the far southern panhandle, but the low being situated to the south with a surface high over the Yukon by Saturday and Sunday will allow for strong northerly outflow across the northern panhandle and making its way into the central panhandle through N/S channels. A stronger gradient also sets up along the coastal mountain area to the NE into Saturday morning, bringing stronger winds coming out of Taku Inlet and the mouth of the Stikine River with the gradient remaining strong into Monday morning. This stronger gradient for this weekend will allow for some stronger NE 925 mb winds, which have already been showing through the long range models around the Juneau area. This strong cross barrier flow expected Friday evening through Saturday and into Sunday is also expected alongside weak 500 mb winds over the panhandle as the trough sets up over the area, creating a good critical level from this no flow area just over Juneau. The last ingredient is the inversion expected over Juneau between 900-800 mb, and all together these all being expected for the Juneau area this weekend bring confidence at a Taku Wind event. At this time, uncertainty still remains at exactly how strong these wind gusts will be and the exact timing of it during the weekend, but confidence is high for over 60 mph gusts Saturday and potentially lingering longer into Sunday if these favorable conditions stay in place for longer.

Along with this outflow and stronger northerly winds pushing down through the panhandle this weekend brings colder temperatures into the weekend, with the decreasing temperature trend this week lasting well into Saturday and Sunday. This will bring surface temperatures to just around 0 degrees F and down into the negatives as the minimum temperatures this weekend for the northern panhandle at sea level down to parts of Icy Strait Corridor, and with the wind chill temperatures the northern panhandle from Skagway and Haines down to Gustavus and Juneau have a Cold Weather Advisory in effect Thursday through Sunday for Juneau and Gustavus, starting tonight for Skagway and Haines and lasting into Sunday as well. The highways will see even lower temperatures at elevation, alongside dangerous wind chill temperatures. This brings Skagway up to an Extreme Cold Warning lasting Thurday Heavy freezing spray will also continue to be a hazard into the weekend due to the cold temperatures and strong outflow conditions. These cold, dry, and windier outflow conditions are to continue into early next week, however the coldest temperatures at this time are expected Saturday and Sunday.

AVIATION

The northern and central panhandle continues to see overall VFR conditions with strong outflow winds, mainly over Skagway and Haines. Skagway is likely to see wind gusts up to 35 to 40 kts, increasing Thursday. Yakutat could see some increased wind shear as outflow continues to increase. This brings areas of increased winds around 2000 ft up to 30 kts, slightly south of the Yakutat airport. Juneau is also likely to see continued wind shear around 25 kts at 2000 ft, lasting throughout the TAF period.

Snow showers have reached areas around the south central panhandle, Sitka, Petersburg, and Wrangell airports. This snow has reduced flying conditions at times to MVFR and even IFR with visibilities as low as 1 SM. Snow showers are going to continue through late tonight with a few short breaks. Then conditions will start to improve late tonight into early Thursday morning with a few light lingering showers. By tomorrow late morning/afternoon, ceiling and visibilities improve to VFR.

The southern panhandle will have the most impacts throughout the TAF period as snow showers continue over the area and then more organized bands of snow move over the area this evening into tonight. There have already been times of lowered visibilities and ceilings due to snow, reducing flying conditions to primarily IFR with times improved conditions to MVFR and on the flip side, times of reduced visibilities to LIFR. This story will continue into late tonight for the southern panhandle with times of MVFR with lighter snow and IFR when snow becomes moderate to heavy allowing for visibilities to decrease. We will start to see conditions improve for the southern panhandle Thursday morning as the low pressure system moves east and the organized precipitation bands diminish.

MARINE

Outside (Gulf of Alaska/Coastal Waters): Easterly outflow winds continue to scream out of Cross Sound, with Sumner/Chatham ocean entrances reporting near-gale force conditions. Coastal buoys are reporting southerly swell at 7 to 10ft and a period of 10 to 12 seconds. This swell, combined with outflow winds, are creating large and confused seas, especially near Cross Sound and the Fairweather grounds. This trend will continue through Friday before winds slightly weaken. This break will be short lived; strong gales will be felt at Cross Sound and the Fairweather grounds by late Saturday. Moderate freezing spray is likely near major bays and river outlets along the northern coast, with the 45F ocean temperatures being the limiting factor.

Inside (Inner Channels): Strong gale force outflow winds continue to pummel the inner channels, with the most danger in areas along and north of the Icy Strait Corridor (Cross Sound east to Taku Inlet) and Stephens Passage. Expect winds to continue and/or increase Thursday as the pressure gradient tightens between the Gulf of Alaska and Canada; however, sustained winds should remain within strong-gale force, with gusts to storm force. Seas of 12 to 17 ft will continue to impact Lynn Canal and northern Chatham. Heavy freezing spray is expected with higher confidence the closer you are to Canada. Mariners should heed caution with these dangerous conditions. Outflow winds will persist through the weekend.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Cold Weather Advisory until 6 PM AKST Thursday for AKZ318. Strong Wind through Thursday afternoon for AKZ318-325. Extreme Cold Warning from 6 PM Thursday to noon AKST Sunday for AKZ318. Cold Weather Advisory from 6 PM this evening to noon AKST Sunday for AKZ319. Cold Weather Advisory from 6 PM Thursday to noon AKST Sunday for AKZ320-325. High Wind Watch from Saturday morning through Sunday morning for AKZ325. Winter Weather Advisory until noon AKST Thursday for AKZ328. Winter Weather Advisory from 9 PM this evening to 3 PM AKST Thursday for AKZ330-332. MARINE...Heavy Freezing Spray Warning for PKZ012. Storm Warning for PKZ012. Gale Warning for PKZ011-013-022-031-032-053-642-643-651-663-671. Small Craft Advisory for PKZ021-033>035-641-644-652-661-662-664- 672.