Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 232257
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
257 PM AKDT SUN OCT 23 2016
.SHORT TERM...High pressure builds into northwest Canada and
persists though Monday. A weak low over the Haida Gwaii Sunday
afternoon is rotating west and dissipating overnight. A stronger
low will start moving northward and by late Monday afternoon it
will be about 400 nm south of Haida Gwaii.
Associated with the Sunday afternoon low, a weakening trough is
slowly moving northward over the panhandle. Light rainfall
amounts occurred today and will continue into the evening before
the front dissipates across the central panhandle. Clouds
generally limited the southern half to 2/3 of the panhandle.
With the low and high positions there is good pressure gradient in
the north south channels...especially across the northern
panhandle due to the trough over the southern panhandle. Gale
force winds are found and expected to continue over Lynn Canal
and small crafts for Chatham Strait and Stephens Passage. Cross
Sound is seeing and easterly Small Craft at roughly 25 to 30 kt.
The other interesting feature is that a Taku Mountain wave event
will begin to become better organized overnight and Monday.
Looking for the cross barrier flow to increase and the needed
critical level to start forming the mountain wave. The expected
clear skies will aid the low level inversion forming.
With exception of the scattered rain showers over the southern
half of the panhandle, the other weather possible might be just
patchy morning fog in the central inner channels.
.LONG TERM...A shortwave dropping south from the Alcan border into
the Gulf of Alaska Monday evening will help induce the Taku wind
event touched on above. The ingredients look good and the watch
continues for Monday evening into Tuesday afternoon. Downtown
Juneau, West Juneau, and Douglas, gusts of 60 mph plus are
possible during this window. Gusts around 45 mph seem a decent
bet for Skagway as well. We also extended the outflow winds south
into Northern Chatham, and raised them out of Taku Inlet for the
same time period.
Looking beyond a low will sneak into the southeast gulf Tuesday
and potentially spreads rain showers into the far southern Inner
Channels. This low looks to stall or weaken considerably into
Wednesday. Slight rain chances may advance as far north as the
south-central Panhandle, but as this system weakens, we expect
rain chances will remain depressed across the north until late
week. This block of dry weather may all but promise that a few of
our climate sites experience the driest October on record.
Looking at the long range, it becomes all about how the ridge
weakens, gets shoved eastward, or temporarily gets dented. Hence
the reasoning that rainfall peaks back into the forecast next
PUBLIC...High Wind Watch from Monday evening through Tuesday afternoon
STRONG WIND from Monday morning through Tuesday morning for
MARINE...Gale Warning for PKZ012-013.
Small Craft Advisory for PKZ011-021-022-031>033-036-041>043-051.
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