Scientific Forecaster Discussion
Southeast Alaska forecast discussion
National Weather Service Juneau Alaska
347 PM akst sun Dec 4 2016
Short term...the weakening low over the east central Gulf will
quickly move southeast out of the area by Monday morning. Strong
high pressure will remain over northwest Canada and be the
dominant weather feature through Monday afternoon. Isolated to
scattered snow showers lingering over the southern Panhandle will
diminish by late this evening. Patchy fog may develop during the
evening hours, but expect this to diminish overnight with the
drier air moving into the area and temperatures dropping into the
20s. Gale force northerlies will persist through the night over
the northern Inner Channels with the usual outflow areas
experiencing gusty conditions. Have included a strong wind
headline for downtown Juneau and Douglas through Monday morning
with cross barrier flow supporting continued strong wind gusts up
to 45 mph. A weak low will begin to move into the northern Gulf
on Monday afternoon which will act to turn the surface pressure
gradient more parallel over the Inner Channels. Therefore, winds
will be on the diminishing trend through the day.
Used the 12z namdng/06z nmm for updates to the previous forecast.
Long term...the large cold high pressure center over northwest
Canada persists even as it continues to expand south in the
Midwest Continental U.S. Over the latter part of the week. So the overall
theme for the Panhandle is a continued offshore outflow with cold
air of varying intensity as the gradient alters intensity.
The weak 1014-1016 mb low moving into the northern Gulf will try
and spread some moisture north onshore and the associated lift
about an old front/trough should spark some showers in the
northern Gulf and Gulf Coast. Ended up with chance showers
Tuesday/Tuesday night in the northeast Gulf Coast, and snow fall
amounts were in the 2 to 5 inch or so, with best accumulations were
west of Yakutat. Will need to watch if they are more prevalent in
later forecast packages that an advisory or more may be needed.
For the present it seems the snow only has a 20 to 30 percent
chance to be measurable at the end of the week.
Minimal changes were done to the longer range portion of the
forecast. Confidence is average through the package.
public...strong wind through Monday morning for akz025.
Wind Chill Advisory until 9 am akst Tuesday for akz018.
Marine...Gale Warning for pkz012-013-022-031-043.
Small Craft Advisory for pkz011-021-032>034-041-042-051.
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