Small Craft Advisory 554, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
259 PM AKST Tue Nov 7 2017

.SHORT TERM...A tail of two trofs. The current chapter is coming
to a close with the weather front near Haida Gwaii continuing to
move south and out of our area. The new chapter begins as a trof
of low pressure sets up near Dixon Entrance while the second
forms and deepens along the outer coastal waters tonight through
Wednesday. Strong high pressure will continue to sit over NW
Canada.

Cold air persists for the northern half of the Panhandle, while
warmer temperatures occupy the south. The central Panhandle will
have mixed bag with colder temperatures in wind sheltered areas
while windier areas will be warmer. Temperatures are expected to
stay near or below freezing in the northern areas. Yakutat is the
except with temperatures today reaching the upper 40s. Raised
daytime temperatures and lowered the overnight temperatures there
using the GFS but did moderate it with the NAM.

These cold temperatures are not associated with any moisture and
precipitation is not expected. To the south there are some
lingering chances of rain tonight. Dry pattern will set up briefly
on Wednesday and then by early Thursday night some slight chances
move in along the outer coastal areas spreading inland overnight.

Winds have been on the diminishing trend today, although holding
on a bit longer in areas of Lynn Canal and Cross Sound this
afternoon with continued gales early this evening. By midnight
tonight the last gale will be found in area 41, elsewhere on the
outside waters SCA will prevail. Along with a few lingering SCA
on the inside waters.

Model agreement between models and model runs are very good.
Confidence is good for the major features the next couple of days.
The details in the wind grids are, as always, tricky, but overall
is of average confidence. The GFS was the favored models with a
slower movement of the precipitation to the south this afternoon
and evening. The AKHIRESWarw has a good representation of the
winds and the affects of the stronger winds out of interior passes
and other local influences.

.LONG TERM.../Thursday through Tuesday/ Upper ridge will build
over the Bering Sea during late week and generally stay there
through early next week. This will amplify an upper trof over the
gulf for late week, and this trof will remain in that area into
early next week. This will lead to a colder pattern along with
periodic rain and snow as shortwaves move SE into the gulf
through the long range period. Models in good agreement on the
larger scale pattern with some differences in the smaller scale
details.

First shot of colder air will move into the area as shortwave trof
digs SSE into the gulf and a low forms in the NE gulf Thu night
into Fri. This system may bring some rain or snow to the area as
well, with best threat for snow over the more northern areas.
Looks like this system will move SE out of most of the area by
Sat night, but may get hung up over the S area.

Another cold airmass will likely move in for late Sun into early
next week as another shortwave trof dives SE into the gulf. This
will be similar to previous system with a low moving SE across the
E gulf. More precip is possible during early next week, but model
timing differs some on this. Since the colder airmass from
previous system will still be in place, it is more likely that a
larger part of the area would see some snow, especially over the
inner channels.

Moderate to strong outflow winds will be likely as Arctic high
pressure builds over the Yukon and low pressure areas move SE
across the E gulf. Fri-Sat and Sun night into early next week
appear to be the windiest time frames.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until 3 PM AKST this afternoon for AKZ025.
     Strong Wind until 6 PM AKST this evening for AKZ018.
MARINE...Gale Warning for PKZ012-022-031-041>043.
     Small Craft Advisory for PKZ011-013-021-032>036-051.
     Small Craft Advisory due to Seas for PKZ052.

&&

KV/Bezenek

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