Marine Weather and Tide Forecast for Hobart Bay, AK

PREV DISCUSSION
ISSUED AT 401 pm Thursday...

SYNOPSIS...

Key Messages:

- Cold temperatures continue, with many areas seeing single digits to teens for overnight lows. Northern Lynn Canal is still expected to dip below zero. Dangerously cold wind chills continue along White Pass.

- Continued strong outflow winds will keep the cold air in place through the weekend for the northern panhandle. Marginally warmer air moves into the southern panhandle this weekend with snow becoming likely.

- A point of uncertainty in the weekend snow forecast is how far north the moisture will be able to push. The farther the moisture travels, the more colder and drier air it has to contend with. But if the moisture is able to push through, significant snowfall is possible as far north as the Icy Strait corridor.

- Farther south, there is a possibility that enough warmer air could push far enough north that the snow could switch to rain for areas south of Sumner Strait.

SHORT TERM
/through Friday night/
The weather remains more- or-less unchanged through the short term. Continue dry skies for most of the area.

A weak area of low pressure in the gulf has been tracking southward and it has brought some light snow for folks near Sitka.
This low will keep moving south so the snow will diminish this evening.

Overnight lows will, again, be well below normal with the coldest temps in the far north where cold temps products are in effect.

LONG TERM
/Saturday through Tuesday/
Cold and windy weather continues through the long term. The arctic boundary is sitting just south of the panhandle, keeping below freezing temperatures through much of the extended forecast.
A low jumping into the southern gulf Saturday is expected to send a high precipitation- producing front into the southern panhandle this weekend. This front will steadily climb northward through the weekend, starting to pull back through early next week. Cold temperatures combined with the ample moisture being carried in with this system should result in widespread snowfall spreading up the panhandle through the period.

Strong outflow winds begin picking back up Saturday, persisting through next week reaching at least gale force through the northern inner channels and out of Cross Sound. Gaps and drainage channels along the gulf coast will serve as outlets for strong winds to funnel through, with pockets of storm force sustained winds looking possible Sunday into Monday. Freezing spray will remain an issue in the inner channels and along the NE gulf coast with these elevated winds, which could become heavy at times.
These outflow winds pose a challenge for the forecast, as the strong northerly flow will attempt to force the front to stay more south and keep higher snow accumulations confined to the southern panhandle. Another uncertainty in the forecast is the temperatures in the southern panhandle Sunday and Monday, as models are starting to depict the arctic boundary shifting just north of this area allowing the front to bring temperatures in the mid to upper 30s to some southern locations. This would halt snow accumulations down south, impacting totals and increasing icy conditions.

If things play out as currently intended, the front will move into the southern and parts of the interior central panhandle Saturday night when temperatures are still below freezing, bringing snow accumulations of 6 to 12 inches into Sunday morning.
The front will continue to shift northward through early Sunday morning, spreading snow accumulations to the rest of the central panhandle and into the Icy Strait Corridor, which includes Juneau, by midday. Totals still widely vary this far out, though moderate to heavy rates still remain possible. Confidence largely decreases on the front reaching further north than that, though the possibility still remains of communities in northern Lynn Canal receiving very light snow accumulations from this system.

Hyder is the odd one out with this system, as the location may allow for cold air to stick around longer. A weak atmospheric river directed into BC south of the panhandle may hook up along the southern parts of the coastal range, drastically increasing QPF amounts for Hyder in particular. If they are able to hold onto their cold temperatures in combination with such increased moisture making it that far inland, total snow accumulations between 20 and 30 inches through Saturday and Sunday may be possible.

Precipitation chances currently last for Monday at similar rates, though are expected to quickly diminish into Tuesday with a lack of available moisture. Though final snowfall totals may widely vary from place to place, the longer duration of this event could lead to impactful accumulations by the beginning of next week.
Another system looks to queue up behind this one, and combined with the arctic boundary shifting back southward, may keep active winter weather in the forecast through next week.

AVIATION...Outflow continues to be the main concern for aviation this evening with ground level gusts to 40 to 50 kt in the outflow areas of the north. These winds are expected to start diminishing mid day Friday as pressure gradients relax a bit, but it will only be a temporary reprieve as the outflow is expected to come back just as strong by Saturday. Some wind sheltered areas may see low level wind shear or turbulence while the outflow is strong as some of that wind will be blowing over ridge lines as well.
Farther south, a weak convergence zone has been bringing clouds and some snow showers to the central panhandle all evening. Sitka in particular has been impacted with vis and ceilings down to IFR or lower this evening. The snow is expected to persist into late tonight before diminishing early Friday. Expect conditions to become VFR after that for most areas.

MARINE...
Outside Waters: Northeasterly outflow wind speeds decrease tonight.
Then, outflow gap winds increase again, up to around 35-45 kt, for the same areas for the weekend. Significant wave heights increase to around 22 ft for the weekend. Some freezing spray is possible for the northeastern gulf.

Inside Waters: The outflow pattern continues through tonight with an overall weakening trend. The tighter pressure gradient in the north will keep wind speeds up to 30 to 35 kt for most of Lynn Canal. Near the Icy Strait area and south, wind speeds will decrease tonight and Friday as the gradient weakens. Friday night into Saturday, wind speeds pick back up to 25 to 35 kts, with near 35 to 40 kts back in Lynn Canal as a low pressure system tracks northward, tightening the pressure gradient over SE AK. Wind directions will, more-or-less, go unchanged through this time frame. These winds will also be accompanied by fully-developed seas up to 15 ft subsiding as the winds weaken.

AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...Extreme Cold Warning until 9 AM AKST Friday for AKZ318.
Cold Weather Advisory until 9 AM AKST Friday for AKZ319.
Winter Weather Advisory until 3 AM AKST Friday for AKZ323.
Winter Storm Watch from Saturday morning through Sunday morning for AKZ326>330-332.
Winter Storm Watch from Saturday morning through Monday morning for AKZ331.
MARINE...Heavy Freezing Spray Warning for PKZ012.
Heavy Freezing Spray Warning for PKZ031.
Gale Warning for PKZ012-013-021-651.
Small Craft Advisory for PKZ011-022-031>034-053-641>644-652- 661>664-671-672.