Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 272355
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
355 PM AKDT Thu Oct 27 2016
.SHORT TERM...Today we feel as if we are contestants on a
familiar game show with a large wheel spinning around and
Ketchikan, Wrangell, Sitka, Petersburg, and Juneau and all points
across Southeast are wondering where the ticker will land. This
weather pattern feels very similar, only we deal with short-waves
spinning around Southeast Alaska around a largescale low over the
gulf. And of course, all of us, as our own ticker, wonders which
wave will strike at whichever time. Models...just like
people...struggle to know when/where the ticker will land at any
given time or place. Because with every shortwave...showers or
sprinkles follow. The wheel is currently spinning some of the
weaker variety shortwaves, but sprinkles of rain have been felt as
far north as Skagway, Hoonah and Juneau this afternoon.
A more robust short-wave will spread across the Panhandle
starting this evening over the southern Panhandle and expand
northward into the central Panhandle overnight. However, the
parent largescale low is at the same time sinking south-
southeastward from the central gulf into the North Pacific. This
should in theory help weaken this wave as it slides northwest such
that Juneau, Gustavus, Skagway should be not be concerned with
anything other than possible sprinkles tomorrow. Elsewhere,
scattered showers will be in the forecast...although we are
confident enough to consider they will be more numerous this
evening for Prince of Wales Island. We have left an isolated
shower over the northeast gulf to cover any apparent build-ups
with some convergence in the area between a system arriving from
the west and the ones noted above from the southeast.
With warm air advecting even across western Canada and a low
pulling away well to the south, gradients will weaken across the
board tonight into tomorrow. Therefore, winds will be a good deal
lighter. Some small craft winds over the gulf tonight will quickly
disappear this evening as a gulf front pulls away and weakens.
The most impactful weather occurring today was the dense fog that
formed in Petersburg early this morning. Despite a convective
pattern aloft and no classic ridge overhead, the warm air aloft
coupled with the light but recent rains across the area have made
for a very damp air mass. Thus we think areas of fog will develop
across many central and southern Panhandle zones relatively early
overnight and last well into the morning tomorrow. Some of it
could be dense, but given shower activity passing overhead we
would not say very low visibilities are likely. Yet it happened
Forecast confidence is average but impacts are low.
.LONG TERM...Isolated showers will remain possible along the
northern gulf coast Friday night into Saturday, but expect amounts
to be light, similarly to the sprinkles that have occurred over
the central panhandle the last couple days. Overall pressure
pattern and flow aloft will become very weak over the weekend.
Expect that if there are winds they will be somewhat variable and
10kt or less.
Sunday and Monday showers assoc with a diminishing front will move
across the gulf. At this time amounts look to be light but there
are still enough difference among models in timing to cause lower
confidence. Thus have continued with a chance of precip in the
forecast for Monday. Some interior valley locations like the
Mendenhall and Chilkat Valleys could see some snow to start or
mixed in. Precip becomes more likely Tues and Wed as models are
hold the next front together.
MARINE...Small Craft Advisory for PKZ022-042-043-051-052.
Small Craft Advisory due to Seas for PKZ041.
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