textproduct: Juneau

SYNOPSIS

Key Messages:

- Moderate to heavy snow continues over the Icy Strait Corridor and will continue to spread southward into central and southern panhandle as temperatures decrease. - Cold temperatures moving into SEAK to start the week, with some areas seeing single digits or sub zero temperatures. Apparent temperature along White pass dipping below -20.

LONG TERM

/Monday night through Saturday/ Arctic boundary continues to move southward over the southern panhandle at the start of the mid range and will likely move south of the panhandle by mid week. Building high pressure in NW Canada and Alaska Interior is creating offshore flow and ushering colder air through the northern panhandle. This air is very cold with 850 mb temps plummeting into the -15 to -25 C range by mid week across the northern panhandle and near -10 C over the south. At sea level this is translating to overnight lows reaching single digits above or below zero for the north and teens and 20s for the south. Daytime highs will struggle to get into the 20s for the north and into the 30s for the south. Coldest temperatures look to occur Monday night into Wednesday night, but sub freezing temperatures are likely to stick around into next weekend as well. Northern panhandle will be watched as many locations will be approaching their criteria for cold weather advisories or extreme cold warnings (especially the haines and Klondike Highways) early to mid week.

In addition to the cold, strong outflow winds are also expected with many northern panhandle channels seeing gale force outflow through most of the week. A strong 1035 mb high in the Yukon is the main driver of that outflow and it will just persist and strengthen to 1045 mb by late next week. Expect gusty winds out of many of the outflow areas in the northern panhandle to start with, but expect outflow out of areas farther south through the week as the Yukon high spreads into northern British Columbia by late week. With these winds and the cold air that it is bringing, a few secondary effects will be noticeable. First, wind chills will be rather frigid reaching into the negative teens and possibly colder in the north most of the week. Second, is that freezing spray will become a more widespread problem for many marine areas in the inner channels and along the NE gulf coast. The freezing spray could become heavy at times in Lynn Canal, Near Taku Inlet, and northern parts of Glacier Bay throughout the week.

Otherwise, most of the panhandle will be dry through the mid and long range except for possibly the south. A series of lows will be moving into the BC coast and could send some of their precip into the southern panhandle throughout the week. Given how cold the atmosphere is expected to be the precip, when it does fall, will mostly be in the form of snow. Highest accumulations possible early Tuesday, but additional accumulations will likely be low for the mid week period. There is the possibility of a another snow event for the south next Friday into Saturday with a couple inches of accumulation possible but storm track is uncertain at this time for that system.

AVIATION.../through Sunday night/

Improving flight conditions across the north today as snow tapers off, with generally VFR flight conditions for PAGY and PAYA. MVFR flight conditions for PAJN, PAHN and PAGS as snow lingers a bit longer. Further south, MVFR to at times IFR VIS and CIGs for the period as rain will mix with and eventually change over to snow, first for PASI this afternoon and then PAPG and PAWG this evening. PAKT and PAKW look to remain rain through tonight, with generally MVFR flight conditions expected.

Winds will continue to increase for Skagway becoming 25-35G40-50kts today and continuing tonight. For Haines, winds will be 18-22G28-32kts for the period. Blowing snow will be possible, mainly for Skagway. Elsewhere, winds becoming 10 to 15 kts with gusts up to 25 kts. These stronger winds continue well into next week with strong northerly outflow. LLWS concerns continue as winds 2kft aloft remain 25-35kts across much of the panhandle.

MARINE

Outside (Gulf and Coastal Waters): A low pressure continues to sit in the western Gulf this morning bringing southerly fresh to strong breezes to the outer coast and offshore waters. These conditions are expected to persist while gales continue to strengthen in areas that are favored by outflow winds. In particular, areas between Cape Spencer and Yakutat Bay could see high end gales, and even near storm force winds in favorable outflow channels. As the low remains over the western Gulf, these strong outflow winds look set to continue through at least the first half of the upcoming week, and potentially even through the second half. With the low remaining in the Gulf, wave heights are expected to remain elevated with 10-15 ft seas and a SW swell component.

Inside (Inner Channels): The Arctic boundary continues to push southward this morning with the boundary around Grave Point for the Stephens Passage area and somewhere between Point Couverden and Tenakee Springs. As the boundary continues its trek southward, winds will continue to shift to north while wind speeds are expected to increase for the Lynn Canal area. To the south, winds are expected to remain out of the south before switching to either more of a northerly or easterly wind as the pressure gradient increases. Headed into the start of the week, a low is expected to move across the southern panhandle which should allow for winds to diminish for the southern Inner Channels. Meanwhile, winds and cold temperatures across the northern Inner Channels will likely see an increasing potential for freezing spray, especially as the air temperature continues to drop with the Arctic air mass.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Strong Wind until 6 AM AKST early this morning for AKZ317. Winter Storm Warning until 3 PM AKST this afternoon for AKZ319. Cold Weather Advisory from 3 PM this afternoon to 6 PM AKST Monday for AKZ318. Extreme Cold Watch from Monday evening through Tuesday afternoon for AKZ318. Winter Storm Warning until midnight AKST tonight for AKZ320-321- 325. Winter Weather Advisory until midnight AKST tonight for AKZ322. Winter Storm Watch from Monday afternoon through late Monday night for AKZ326-329. Winter Weather Advisory from 5 PM this afternoon to 6 AM AKST Monday for AKZ327. Winter Storm Warning from 7 AM this morning to 9 PM AKST Monday for AKZ331. MARINE...Storm Warning for PKZ651. Gale Warning for PKZ011>013-022-031-053-643-644-652-663-664-671- 672. Small Craft Advisory for PKZ021-032>036-641-642-661-662.