Storm Warning 28, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
259 PM AKST Thu Dec 26 2019

.SHORT TERM...The formidable front responsible for the most recent
round of high winds, rain, and snow is finally departing the
panhandle. Behind the departing front, showers will linger in some
areas, and a pressure gradient perpendicular to the coast will
provide the impetus to help sustain strong winds and maintain
gusty conditions, but these will diminish through the overnight
hours as the gradient turns increasingly parallel to the coast.
The first half of Friday will continue this trend, with some small
craft advisory level winds lingering in a few inner channels, but
otherwise little more than a chance of rain in some areas serving
as the primary weather concern for Southeast Alaska.

This brief reprieve from busy weather will soon come to an end as
another low begins to wind up in the Gulf. Model guidance is
beginning to come into good agreement that another strong front
takes aim on the region late on Friday. While not quite as intense
as the past event, it will definitely brings its own host of
weather related issues. A round of gales will begin to move in on
the Coastal waters and then into multiple inner channels Friday
afternoon. In some coastal waters, these gales are expected to
further intensify and reach storm force, particularly as the
pressure gradient tightens Friday night. On land, this will likely
translate to several strong wind headlines at various locations,
Also prior to the front moving north, NAEFS ensembles indicates a
decent amount of p-wat setting up for us likely due to previously
mentioned southerly flow. Given this, the potential for some
healthy precip totals looks possible. Because of substantial WAA
associated with this system, snow near sea level in the central
and southern panhandle does not appear likely at this time, but
normal spots like the northern highways and Hyder look like they
could see yet another round of heavy snow.

.LONG TERM.../ Saturday to Thursday as of 9 pm Wednesday / The
parade of lows and frontal bands continue marching across the gulf
and through Southeast Alaska panhandle. A broad flat topped ridge
over the Pacific off the west coast of the CONUS is keeping a
long southwest flow from the central Pacific across the gulf. As
a result all of the trough and front moving along the main Jet
stream, move right through the region.

As it they typically seem to, the models have fairly good
agreement on the major systems, although some of the timing and
strengths and tracks are slightly different. With the smaller wave
caught in the mainstream flow, the timing of those are even more
chaotic comparing model solutions. The stronger systems will have
the much stronger winds with them so there will be a bout or two
of the gusty winds along the frontal boundaries. A quick look at
the mid to long range solutions, shows the stronger front should
be impacting the area late Sunday.

With no really cold air source to bring in cold air to Southeast
Alaska expect temperatures to remain fairly steady in the
highs/lows forecast into the middle of next week. This limits the
possibility of now to near the border on the Haines and Klondike
Highways.

Forecast confidence is average across the extended time range.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Storm Watch from Friday afternoon through Saturday
     morning for AKZ018-019.
     Strong Wind Friday afternoon for AKZ021.
MARINE...Gale Warning for PKZ041>043-051-052.
     Small Craft Advisory for PKZ011>013-021-022-031>036-053.

&&

GFS/Bezenek

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