Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 222358
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
358 PM AKDT SAT OCT 22 2016
.SHORT TERM...Low pressure that has persisted over the eastern
gulf for the past few days is weakening and will shift to the
south tonight. The dominant weather feature for Southeast Alaska
over the next 24 hours will be high pressure building over the
Yukon. This combined with the low sliding to the south will result
in strengthening offshore flow. Therefore, forecast remains on
track with clearing skies and increasing northerly winds. The
usual outflow locations such as Skagway and downtown
Juneau/Douglas will become gusty late tonight and through Sunday.
Did consider issuing a strong wind headline for the downtown
Juneau area Sunday morning and afternoon but limited gusts to 35
mph. There are indications a critical level will develop around
500 mb late in the morning and afternoon, but the inversion will
be weakening during that time. Later shifts will monitor the
potential for higher winds gusts. Northerly winds over the inner
channels will be strongest in Northern Lynn Canal with 30 kt by
late tonight. The northerly winds will spread into the remainder
of the northern and central inner channels overnight and into
Utilized hi-res model guidance for updates to the previous
forecast. Forecast was on track so edits were mainly limited to
wind and low temperature local effects.
.LONG TERM.../ Sunday night to Saturday / Near term part of the
forecast to Wednesday running on the similar track it had been. A
low moving west from Haida Gwaii region Sunday evening with an
associated trough falling apart across the central and southern
panhandle. A weak low in the northern gulf dissipating by Monday
morning as well as high pressure ridge becomes more prevalent from
southwest of Kodiak Island to the McKenzie Delta in Northwest
Canada. A slowly weakening low Monday to Tuesday will drift north
to be south of Haida Gwaii and High pressure over the Yukon
As result there is generally an offshore flow pattern in the
northern panhandle and drying weather for the southern after a
dying trough across the southern panhandle on Sunday evening. As
a strong low moves north to the southern tip of Haida Gwaii
weakening on Tuesday...a chance of rain may spread north across
The set up for Monday to Monday night in the Juneau area is
beginning to look more like a mountain wave event is beginning.
25 to 30 kt cross barrier flow with a critical level setting up
around 600 mb Monday into Monday evening, in Juneau. The clearer
skies should allow the inversion to establish itself Sunday night
heading to Monday which is the last of the mountain wave element.
The only mark against a strong event is the lack of real cold air.
Should be enough for 35 to 40 mph gusts..perhaps more as we
continue to monitor the situation.
The pattern becomes more confused as the model solutions are
trying to come to an agreement about a frontal band from the
strong low that moved across the Bering Sea into the Eastern
Russia on Monday. The fronts eastward movement is stalled by the
upper level ridge and that then gives way to a split flow pattern
for Wednesday/Thursday over the eastern gulf. Used WPC ensemble
for the Wed onward pattern over the gulf and the panhandle.
MARINE...Small Craft Advisory for PKZ012-013-022-036-043-051.
Small Craft Advisory due to Seas for PKZ041-042-052.
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