Small Craft Advisory 25, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
457 AM AKST Sat Jan 14 2017

.SHORT TERM...Satellite imagery this morning showing a closed low
moving from the northeastern gulf into the Yukon with a trough
extending down the central gulf and ridging over the panhandle.
The associated weather front crossing over the panhandle early
Saturday. The front produced temperatures across most of the
panhandle to rise into the upper 30s to low 40s. The exception being
Hyder, which still had some northeasterly flow, and at higher
elevations. Rain across the panhandle was heavy at times and will
continue through the day. Unstable airmass behind the front with rain
changing to showers tonight. As the trough over the gulf moves
east crossing into British Columbia showers will begin to taper
off late tonight. Kept the Winter Storm warning for White Pass
until 9 am and extended the Hyder Winter Weather Advisory until
noon since the position of the ridge axis will keep colder air in
place and add a few more inches of snow before transitioning to
rain.

Winds over the gulf drop from gales to small craft through the
day and continue to subside tonight. Inner channel winds follow a
similar trend but the ridge over the gulf will keep higher winds
over the far northern inner channels. Strong winds occurred over
most of the panhandle overnight will last through the morning then
drop off. Skagway winds expected to remain higher due to presence
of pressure gradient between the panhandle ridge and Yukon low.

Used Hi Res NAM to refresh grids, but overall changes were mostly
with timing of temperatures and a slight increase to panhandle
winds. Forecast confidence is average.

.LONG TERM...Cyclonic jet core aimed at Ketchikan on Sunday
afternoon will help to bring the main event. A negatively tilted
upper trof will support a 961 MB low in the central Gulf on Sunday
evening with a very strong front. This system is strong enough to
drive storm force winds in our outer waters and certainly strong
winds for the land areas with gusts to 55 MPH. Couldn't quite bite
and widespread sustained 60 MPH due to the strong warm advection
with this system. Those of us who are fans of winter weather will
have to look to the northern Lynn Canal area to find significant
snowfall combined with wind. We have to keep a look out if the
system develops deep enough to require warnings for the wind or
wind/snow combo for the roads into BC Sunday night. Look for a
lee side development in the southern Yukon on Monday to keep a lot
of strong wind going and snow north. Seas outside will be
monstrous and look for storm force or whole gales inside.

The next interesting event will be on Thursday as a very cold
upper low sets up over the Seward Peninsula. This will drive a
cold short wave across the Gulf into the Panhandle. This one is
looking more like a widespread snow event but confidence is not
that high on this feature that far out. It will be fun to see if
this one comes true. If so, -40C aloft at 500 HPa will do the
trick. Guidance for this package was mainly staying with the
previous forecasts that agreed with a model blend and yesterday's
WPC guidance. Confidence high on significant wind, moderate on the
northern snow.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until noon AKST today for AKZ022-023-027.
     Strong Wind until 9 AM AKST this morning for AKZ025.
     Winter Weather Advisory until noon AKST today for AKZ029.
     Winter Storm Warning until 9 AM AKST this morning for AKZ018.
     Strong Wind through late tonight for AKZ018.
MARINE...Gale Warning for PKZ012-013-022-031>036-041>043.
     Small Craft Advisory for PKZ011-021-051>053.
&&

PRB/JC

Visit us at http://www.weather.gov/Juneau

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JUNEAU AK
134 PM AKST SAT JAN 14 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1014 AM     NON-TSTM WND GST SKAGWAY                 59.48N 135.33W
01/14/2017  M62 MPH                             AK   ASOS

            SKAGWAY ASOS MEASURED A PEAK WIND GUST OF 62 MPH AT 1014
            AM

&&

DEL