Small Craft Advisory 97, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
548 AM AKST Thu Feb 8 2018

.SHORT TERM.../Thu to Fri night/ Familiar weather pattern over N
Panhandle on Thur will continue to cause localized very strong
N-NE winds through inner channels and out of bays and inlets. 1050
mb surface high pressure centered over Dawson Yukon Territories
this morning with associated ridge axis extending SE into N
British Columbia. N winds frequently in the 50-60 kt range
throughout Lynn Canal overnight and heavy freezing spray still a
concern in Lynn Canal this morning. Peak instantaneous wind at
Little Island sensor /SW of Berners Bay entrance/ pegged at or
above 90 kts around midnight.

Surface low pressure center that was over Dixon Entrance south of
Ketchikan on Wed has moved quickly east since then to SE BC this
morning. A stationary frontal system lingers in its wake from
roughly Craig/Klawock to Prince Rupert this morning. Temps south
of the front are in the mid 30s. Areas of low clouds and light
rain or rain/snow mixed are exiting the far southern panhandle
this morning.

There is a High Wind Warning (60+ mph) for Skagway zone through 4
pm today as well as Strong Wind (40+ mph) headlines for Haines
and downtown Juneau/Douglas. Winds will diminish later this
afternoon. Highest wind gusts in Skagway overnight were only in
the 40-45 mph range so verifying the wind warning for Skagway
today won't be a slam dunk as it has been recently. However, satellite
water vapor imagery depicts an upper level short wave feature
heading S through the Yukon at a speed that would have it pass
Skagway and N inner channels around 12 noon Thu. This short wave
could enhance the winds closer to 60 mph in the warning area so
reluctant to cancel the warning just yet.

Thu and Fri will be dry days in SE AK. The combination of the
less clouds Thu night and decreasing winds will allow for good
radiational cooling Thur night...especially where there is snow on
the gound. Temps will be on the order of 5 degrees or so cooler
Fri morning than this morning.

Lastly, the current forecast trend shows increasing clouds and
chances of precip spreading into SEAK as early as Sat. Newer model
runs and statistical guidance now indicating that dry weather may
persist into Sun. That time period will be updated later today.

.LONG TERM.../ Saturday to Wednesday / Continuing into Saturday, the
upper level ridge and surface features that had been protecting
Southeast Alaska from the storm track, will start moving away from
the panhandle. Thus the cooler and drier offshore flow over the
panhandle will be coming to an end. The ridge will be weakened
significantly by a low undercutting the gulf aiming mainly for the
British Columbia coast for Sunday.

This feature will suppress the Canadian high pressure while at
the 500 mb level the flow will become more zonal from the
Aleutians towards the panhandle, over a flattened ridge over the
Gulf of Alaska. The zonal flow will lead to wetter pattern from
the early part of the week headed to next weekend, although it
doesn't look like there is a significant storm in the near future.

Forecast in the later time ranges were leaning heavily to the WPC
solution as operational solutions began to going in sufficiently
different patterns, that including much of them wouldn't have
pointed in more concise forecast solution. Forecast confidence is
Moderate into the weekend and lower through the following week.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until 3 PM AKST this afternoon for AKZ019-025.
     High Wind Warning until 4 PM AKST this afternoon for AKZ018.
     Wind Chill Advisory until noon AKST today for AKZ018.
MARINE...Heavy Freezing Spray Warning for PKZ012-013.
     Storm Warning for PKZ012-013.
     Gale Warning for PKZ021-022-031.
     Small Craft Advisory for PKZ011-032>035-043-051-053.

&&

TA/Bezenek

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