Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 071441
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
541 AM AKST Wed Dec 7 2016
.SHORT TERM...Northern half of the panhandle continues to be
buried in snow this morning. Snow fall totals as of Tues evening
ranged as high as 8 inches at Cohen Drive in Juneau, 5.5 inches at
Gustavus, and 10 inches at Pelican. As of 3 am WFO Juneau has 6.7
inches storm total. Lower snowfall amounts have been observed in
the rest of the northern panhandle north and west of Frederick
Sound and southern Chatham Strait. Currently the heaviest band of
snow has set itself up from Baranof Island north to Juneau with
widespread snow showers west of that line. South and east of
Frederick Sound stronger offshore flow is keeping the snow at bay
and is expected to continue to do so through tonight.
Through Wednesday evening snow is expected to continue for the
northern half of the panhandle with terrain and low level
convergence keeping the higher snow rates along cross sound,
northern coast of Icy Strait and into Juneau. Expect another 5 to
8 inches in these areas. Winter Storm Warnings remain up through
9 pm tonight. Elsewhere, Hoonah, Angoon, and Sitka remain under
winter weather Advisories as snow continues to fall at lighter
rates. Some rain may mix in with the snow in Sitka today as
temperatures there will remain a few degrees above freezing
through the day. Haines and Skagway have not seen much in the way
of accumulations as the precip has mostly been blocked by upstream
mountain ranges for this flow direction. This precip shadowing for
Haines and Skagway is expected to continue before the precip stops
Into tonight, increasing easterly flow will finally push the snow
off to the west. Most of the precip should be over for the
northern inner channels by midnight tonight. Only to be replaced
by strengthening outflow winds as Lynn Canal and Taku Inlet see
small craft and even min gale force winds start to develop late
tonight. Temperatures will remain cold with northerly outflow
Farther west, Yakutat has only seen light snow showers most of the
night but that is expected to change as the heavier snow bands
move west Wednesday night. Snow rates will be increasing this
evening and they should have around 5 inches of new snow through
early Thursday morning before the snow moves further west. Decided
to issue another winter weather advisory for the Yakutat area
from 9 pm to 5 am tonight.
Main changes to the forecast were increasing high temperatures by
around 5 degrees in some of the northern panhandle as cloud cover
and some warm air advection raised temps a little overnight.
Otherwise mostly minor changes overall compared to the previous
forecast using Nam for guidance.
.LONG TERM...Cold, dry and locally windy weather pattern for the
extended range forecast. Blocking type high pressure over western
interior AK shifting to the SE over the weekend and upper low
remains over the western gulf through Sunday then shifts south.
For the weekend upper troughs will drop from northern Canada
southward over the panhandle. Between the cold arctic Canadian
high and lows over the western gulf and north Pacific are setting
up strong northerly- easterly gradient. Inner channel winds,
especially the northern channels will have upper level gale force
winds, strong gusts out of E-W orientated channels and potential
for high winds in Skagway and Taku winds in the downtown Juneau
area picking up Thursday and may last through the weekend.
Models in agreement for an even colder air mass to move in for
the weekend and then again mid week. Began the trend to lower
temps for this time. For now staying toward the higher side of
the model temp spectrum. The cold air and increasing winds will
result in freezing spray for some of the inner channels and cold
wind chills, especially at higher elevations.
NAM/ECMWF overall still in line. Latest GFS had bit more
variation with a low in the N pacific for the end of the week.
Main changes were to temps and some adjustments to localized
winds and increase to northern inner channels winds. Potential
for Skagway high wind warning, wind chills advy for white pass and
Taku winds could near warning levels. Forecast confidence is
PUBLIC...Winter Weather Advisory until 4 PM AKST this afternoon for
Winter Storm Warning until 9 PM AKST this evening for AKZ020-022-
Winter Weather Advisory until 9 PM AKST this evening for AKZ021.
Winter Weather Advisory from 9 PM this evening to 5 AM AKST
Thursday for AKZ017.
MARINE...Gale Warning for PKZ012.
Small Craft Advisory for PKZ011-013-021-022-031-033-041>043-051-
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