Winter Storm Warning 25, NWS Juneau, AK

769 
WWAK47 PAJK 130241
WSWAJK

URGENT - WINTER WEATHER MESSAGE
National Weather Service Juneau AK
541 PM AKST Fri Nov 12 2021

AKZ019-130345-
/O.EXP.PAJK.WS.W.0025.000000T0000Z-211113T0300Z/
Haines Borough and Lynn Canal-
Including the city of Haines
541 PM AKST Fri Nov 12 2021

...WINTER STORM WARNING WILL EXPIRE AT 6 PM AKST THIS EVENING...

Snowfall is tapering off or ending so additional significant snow
is not expected. Reports of snowfall from event have ranged from 
4 to 8 inches in Haines to 10 inches near the border this 
morning.

$$

AKZ017-131045-
/O.CON.PAJK.WW.Y.0038.211113T0600Z-211114T0000Z/
Cape Fairweather to Cape Suckling Coastal Area-
Including the city of Yakutat
541 PM AKST Fri Nov 12 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 9 PM THIS
EVENING TO 3 PM AKST SATURDAY...

* WHAT...Snow expected. Total snow accumulations of around 4 
  inches. 

* WHERE...Yakutat.

* WHEN...From 9 PM this evening to 3 PM AKST Saturday.

* IMPACTS...Travel could be very difficult.

* ADDITIONAL DETAILS...Snow showers will develop Friday evening 
  and continue through Saturday. Snow showers may be heavy at 
  times with snowfall rates of 1 to 2 inches per hour if showers 
  train over the same area. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

&&

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
636 AM AKST Fri Nov 12 2021

.SHORT TERM.../Through Saturday night/...A warm low level airmass
moved in overnight and completely overwhelmed cold air at the
surface in all locations except for Haines and the Haines Highway.
Consequently, precipitation overnight came as rain everywhere
except Haines. The winter weather advisories for Skagway and
Juneau were cancelled with the morning forecast issuance. The
advisory for Haines remains and that is the only location that
snowed reliably through the night. Temperatures warmed through the
night in most other locations and this is well depicted in 850 mb
charts. With little to no chance for solar insolation today, some
locations may have already seen their max temperature for the day
with highs ranging from the mid 30s over the north to the upper
40s to the south.

The associated low remains on track for a landfall in the
vicinity of Cross Sound, but is showing clear signs of a
weakening trend in both satellite imagery and in observed wind
speeds. As a result, the wind forecast for northern Lynn Canal was
adjusted down significantly for this morning. An abrupt shift in
wind direction over the northern half of the Panhandle is still
expected as the low skips inland and moves northeast into the
Yukon. The potential for high end small craft southerlies over
Lynn Canal as this happens, so the wind forecast for this evening
was not modified.

As the low and associated warm low level air moves off into
Canada, colder air will advect in from the west and produce a
cooling trend for the remainder of this short range forecast
period. Concurrently, PoP will decrease, so accumulating snow at
lower elevations is becoming less and less likely through the
weekend.

.LONG TERM.../ Sunday through Friday as of 10 PM Thursday /
Diminishing precipitation will give way to clearing skies through
Sunday afternoon, at least across the N half of the panhandle. The
cause of the clearing skies will be an outflow event which will
take place as the pressure gradient strengthens between a new low
moving N out of the southern Gulf and a high in the Yukon. Expect
that with this outflow event, it is likely that breezy conditions
will be seen across at least the N half of the panhandle. Lynn
Canal will likely see gale force winds, and have added small
craft winds in through many of the central inner channels. There
may also be an opportunity for a weak to moderate strength
mountain wave event to setup over downtown Juneau, though am not
yet confident in this given the differences in timing of the low
to the south.

The windy conditions will most likely begin to subside Monday
afternoon through Monday night as the low in the south attempts to
advance into the panhandle, before being deflected back to the S
as its associated trough moves out of the area. It still looks
like the southern panhandle will experience the bulk of any
significant precipitation with this system. The far N panhandle
will likely stay fairly dry, with precip chances slowly increasing
through the Icy Strait Corridor on South.

Disagreement among ensembles and operational runs alike rapidly
increases after this time period, but it does look like the low
in the S departs the area by Tuesday. There are increasing
indications that a new wave could impact the area Tuesday or
Wednesday, but forecast uncertainty means this is not yet set in
stone. Looking even further afield, there are hints that
significant cooldown for late next week could be in the works-
something which would likely be joined with a substantial outflow
event. However, confidence in this event remains low at this time.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 6 PM AKST this evening for AKZ027.
     Winter Weather Advisory until noon AKST today for AKZ019.
     Winter Weather Advisory from 6 AM to 3 PM AKST Saturday for
     AKZ017.
MARINE...Gale Warning for PKZ041>043-310.
     Small Craft Advisory for PKZ011>013-021-022-031>034-036-051>053.

&&

Fritsch/GFS

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