High Wind in Alaska, November 5 to 6, 2022

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
436 AM AKDT Sat Nov 5 2022

.SHORT TERM...Deeper cold advection is expected to overspread the
panhandle this morning, winds aloft will couple with the already
tight surface pressure gradient to produce storm force northerly
winds in our typical gap/channel areas such as Lynn Canal, Cross
Sound and the NE Gulf waters. One vessel reported 65 kts out of
Dangerous River around 10 pm. Water temps are still warm and thus
a significant vessel icing risk is not expected at this time,
however the combination of strong winds and cold air temperatures
will lead to at least some light freezing spray across the
northern channels through Sunday.

Winds will also be gusty over land areas exposed to NE winds such
as Skagway. For downtown Juneau and Douglas, two out of the
three ingredients necessary for significant Taku winds are
present. Strong cross barrier flow will peak Sunday morning with
significant deep cold advection. Mountain top inversion also looks
to be present though this is harder to determine. The main
feature that is missing will be the col, or weak flow reversal in
the mid levels of the atmosphere to really reflect mtn wave energy
downwards. There will be a brief window for all three ingredients
to be in place this morning and if we can get a mountain wave
established, strong winds may persist with the reverse shear
profile aloft favoring self- induced waves. With the question
marks, kept wind gusts just shy of warning criteria for the Taku
wind areas attm. Even so, deep layer cold advection and strong
winds aloft will still provide impetus for wind gusts in the 50 to
55 mph range through this afternoon and into Sunday.

Temperatures will also be on a downward trend with the coldest
night looking to be Sunday night. Coldest temps will be in wind-
sheltered locations such as Gustavus and the Mendenhall Valley.
Southern Panhandle locations will likely also see numerous daily
record low minimum and maximum temperatures over the weekend.
Preparations should be made now to protect persons and property
vulnerable to cold winter temps.

.LONG TERM...High pressure will continue to build across the
Yukon allowing for cold air to deepen across the area this weekend.
This cold air will move into SE AK bringing unseasonably cold
temperatures to the region. A northerly outflow will advect the
cold airmass into the region. Areas that are prone to NE winds
could see some significant winds in particular, Downtown Juneau,
Cross Sound, and the NE Gulf Coast. Winds in Lynn Canal will be
out of the N during this time creating unfavorable conditions for
mariners. Cloud cover will diminish during this time allowing for
overnight lows to drop down well below freezing except in areas
that will be moderated by the winds. Some areas look to see the
potential for record cold temperatures for this time of year,
especially the southern panhandle. Cold temperatures will persist
into next week with temperatures remaining well below normal.
This airmass will moderate by mid week with a gradual warm up
pushing temps possibly reaching above freezing again for highs by
Thu. Outflow winds will also diminish as the airmass moderates
with most winds dropping below small craft criteria by Tue
evening. Guidance continues to push the upper ridge east by mid
week with a front moving into the central/eastern gulf.

Confidence is growing that this front may at least to some extent
manage to advance into the panhandle through the latter half of
the week, and so have increased chances for PoPs. It is possible
that much of this could initially fall as snowfall should
sufficient cold air remain in place. However, this is still far
set in stone, as operational guidance continues to indicate a
broad spread of possible solutions for this system. Beyond this,
ensembles are hinting that a strong ridge could build over the
area through the weekend, Overall, synoptic pattern continues to
support below normal temps and slightly below normal precip
through the extended.

&&

.AVIATION...Aviation weather is at a transition point this
morning. On one hand we got showers in the southern panhandle that
has produced IFR ceilings at Petersburg, Wrangell, and briefly at
other areas. That should improve to VFR and showers will diminish
through the morning as the remnant low pulls away to the S. On
the other hand is the developing outflow across the north with all
the localized areas of high winds, low level wind shear, and
turbulence from mountain waves that that entails. That outflow is
expected to only strengthen through the day and into tonight as
well as spread S and E through the weekend. Expect the outflow To
persist through the weekend and into early next week before
diminishing Monday or Tuesday.

&&

.MARINE...A Marine Weather Statement is in effect for increasing
northerly outflow winds through Sunday. The winds will peak in
strength this evening with strong gale to storm force winds in
many of our northern channels and gap areas. Water temps are
running warm, but the combination of cold arctic air and strong
winds may possibly lead to some light freezing spray for the
northern channels. See the Marine Weather Statement for more
details.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from 10 AM AKDT this morning through late tonight
     for AKZ318-325.
     Strong Wind from 10 AM AKDT this morning through this evening
     for AKZ319.
     Strong Wind from this evening through late tonight for AKZ322.
MARINE...Storm Warning for PKZ012-013-022-043-051.
     Gale Warning for PKZ011-021-031>034-041-042-052-053.
     Small Craft Advisory for PKZ035-036.

&&

SHORT TERM...DL/CC
LONG TERM....BC/GFS
AVIATION...EAL
MARINE...Fritsch

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