Gale Warning 232, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
326 PM AKDT Sat Oct 31 2020

.SHORT TERM.../Through Mon night/ Short range forecast is very
complex and scary today. Several hazards are up across the
panhandle ranging from gales warning for marine hazards, high wind
warnings for the southern panhandle, blizzard warnings for the
northern inner channels, and flood watches for most of the rest of
the area. Most of these are in effect for the stronger second
system that will be entering the panhandle on Sun. There is a
weaker system moving through the panhandle right now, but it is
only really weaker in comparison to the Sun system as we are still
seeing wide spread breezy to windy conditions and periods of
moderate rain across a wide part of the panhandle this evening.

Main forecast challenge in the short range is that second system
with determining where the low center will go, how far into the
panhandle the cold air from the north is going to get, and how
much wind accompanies the system both to the north and south of
it. As far as low track, all guidance takes the low inland between
Cape Edgecombe and Cape Spencer Sun night, they differ on where
they track from there ranging from up to Berners Bay to down to
Angoon and Stephens Passage. Where it goes will determine wind and
precip for various areas Sun night into Mon.

As for the cold air, Haines and Skagway areas still look good for
winter weather conditions on Sun night. It is areas around Juneau,
and Gustavus that bare watching as some guidance wants to bring
freezing temps at low levels into those areas Sun night. This
could mean snow, or, if certain model upper air profiles pan out,
even freezing precipitation for Juneau and Gustavus Sun night
instead of straight rain. There is more confidence for rain to be
the primary ptype so kept that for Sun night, but the rain/snow
line will not be very far away, and if it comes just a little
farther south could make the difference between just getting 2 to
4 inches of rain, or getting several inches of snow.

Winds are the last issue and look to be mainly for the southern
panhandle (due to the low) and the northern inner channels (due to
outflow). High wind warning are now up for the southern panhandle
for Sun night. Confidence is good on this with low level jet
strength reaching 80 kt at 850 mb. As for the north, northerly
pressure gradients are rather strong and cold air will be flowing
across the passes so the wind forecast for the northern inner
channels are rather confident.

Forecast confidence overall is about average.

.LONG TERM.../ Monday to Saturday as of 10 pm Friday/ Long wave
trough is forming over the Gulf of Alaska from Monday to the
Thursday with combination of a low moving south from Alaska to
near Prince William Sound with a short wave driving southward from
northwest of the Arctic Slope over the western part of the state
into the western gulf. By Thursday this short wave is headed
towards the Pacific Northeast and the WA/OR coastlines. A broad
ridge aloft covers the western gulf into the western part of the
state.

Monday will see SEAK dealing with the tail end of potential
Flooding (Central/Southern panhandle) plus Heavy snow and end of
a possible Blizzard (Nrn Lynn Canal) please see short term for
more info on these items. SE should wind down to chance/likely
showers from onshore flow, with a slow spread of snow vs rain as
colder air continues to spill southward. Dry / cool weather from
late Friday into the weekend.

By the End of the week most of the panhandle will be struggling to
have high temperatures top out above freezing, with Prince of
Wales Island having the better bet of that. High pressure with
central pressure in the mid 1040s is possible over NW Canada and
this will likely lead to good outflow winds headed to the weekend
and may need to watch for a potential Taku event. North winds were
increased some to reflect this idea, but will likely need to be
increased more.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch from Sunday morning through Monday morning for
     AKZ020>028.
     High Wind Warning from 6 PM Sunday to 5 AM AKST Monday for
     AKZ027-028.
     Strong Wind until 7 PM AKDT this evening for AKZ025.
     Blizzard Warning from noon Sunday to 4 PM AKST Monday for AKZ018-
     019.
     Strong Wind until 4 PM AKDT this afternoon for AKZ018.
MARINE...Gale Warning for PKZ012-013-022-031-036-041>043-053.
     Small Craft Advisory for PKZ011-021-032>035-051-052.

&&

EAL/Bezenek

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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JUNEAU AK
1208 PM AKDT SAT OCT 31 2020

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

0706 AM     SNOW             WHITE PASS              59.63N 135.16W
10/31/2020  E4.5 INCH                           AK   DEPT OF HIGHWAYS

&&

EAL