FXAK67 PAJK 222338
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
238 PM AKST Fri Feb 22 2019

.SHORT TERM...The active winter weather pattern has shifted to a
northerly outflow pattern. This has ushered storm force winds 
into portions of Lynn Canal and gales over most of the N-S 
orientated inner channels. This weather pattern will also support
high winds near downtown Juneau and Douglas through Saturday 
morning. As of writing, wind gusts up to 69 mph have been detected
by the marine exchange sensor on top of the downtown Juneau 
Library. Winds are expected to continue to increase through this 
evening peaking sometime later tonight or early Saturday morning 
before starting a gradual decline through the rest of of weekend. 
As a whole, expect cooler overnight lows as clear skies persist 
through the weekend.

Overall the existing forecast was well representative of expected
conditions so minimal change was made. One change was to increase
winds in southern Lynn Canal to storm force through early Saturday
morning. Forecast confidence is high through the weekend.

.LONG TERM.../Sunday through Friday/...An extremely large upper
level blocking ridge will dominate the central gulf, nearly all of
the interior, and extend well north into the Beaufort Sea by the 
start of this extended range forecast period. The descending 
branch of the jet stream will draw cold upper level air from the 
Northwest Territories across the Yukon & northern British 
Columbia, and across Southeast Alaska. This branch of the jet will
shift south and east as the ridge develops a closed high over the
north gulf coast and re-orients slightly by Monday morning. As is
often the case with such large blocking features, it is highly 
likely that this pattern will persist through the upcoming week. 
With all meaningful jet energy being deflected around the 
high/ridge and no surface lows in sight, the remainder of February
will almost certainly remain dry. In addition to the dry weather,
lower level offshore flow will clear out clouds and provide for 
an extended period of sunny days and clear but cold nights. 

The late winter fair weather will not be without some 
inconvenience. Very strong surface high pressure over western 
Canada will sag south as the low that brought the latest round of 
rain and snow exists the area to the southeast. The result will be
a resumption of strong outflow winds over the inner channels 
closest to the coast mountains. A surface reflection of the upper 
high that will form over the northern gulf coast will aide the 
large scale offshore flow. As a result, winds over Lynn canal have
been increased for Sunday and Sunday night. Outflow detail has 
been increased in and around Taku Inlet, Tracy Arm, Port 
Snettisham, and Endicott Arm as well. If the surface pressure 
forecast remains consistent, additional increases to inner channel
winds Sunday through Monday night may be necessary. 

Previous pressure forecast remains on track, with aforementioned
increases to wind speeds. Prior temperature forecast reasoning
seems solid, so only minor changes to temperatures were made.
Above average confidence in a dry, sunny week with temperatures 
trending below normal. 

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Warning until noon AKST Saturday for AKZ025.
     Strong Wind through Saturday afternoon for AKZ018.
MARINE...Storm Warning for PKZ013. 
     Gale Warning for PKZ012-022-031>034-043. 
     Small Craft Advisory for PKZ011-021-041-042-051-053. 
     Small Craft Advisory due to Seas for PKZ052. 

&&

$$

JB/Fritsch

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