Heavy Freezing Spray Warning 8, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
311 PM AKST Mon Feb 8 2021

.SHORT TERM.../Tonight through Wednesday/...For starters, a low
pressure has been tracking along the coast and while QPF amounts
have been light, the liquid to snow ratio has been high. So the
final result is impressive snowfall on Eastern Baranof Island,
Kuiu Island, and Prince of Wales Island. A Winter Storm Warning
has been issued for those areas until 10 PM AKST this evening. The
rest of the short term forecast is calling for diminishing
chances for precip and increasing sunshine. Most areas along the
panhandle should see mostly clear skies beginning late tonight and
lasting well into Wednesday.

The catch is, the clearer skies are due to expected strong
outflow in the wind pattern. Many regions in the northern
panhandle will be under a Strong Wind headline through Tuesday
morning. Sustained wind speeds will be easily over 20 mph for the
more open areas and areas that are more tucked away should still
see 10 to 20 mph winds. Wind gusts near 30 to 40 mph are likely
with some gusts nearing 50 mph possible. Because of these
forecasted winds, Gale Warning and Small Craft Advisory headlines
have been posted for many marine areas.

Those strong winds will also drive in some very cold air. Air
temperatures tonight will dip into the single digits above and
below zero for the northern and central regions, with higher
elevations getting to the teens and 20s below zero. Lows in the
teens are expected for the southern areas. And due to the cold air and
strong wind, there are Heavy Freezing Spray Warnings posted for
several marine zones and the Haines and Klondike highways are
under Wind Chill Warning and Wind Chill Advisory headlines through
tonight due to wind chills nearing 30 to 60 below.

The overall pattern of a strong high in Canada and a quiet
atmosphere over the gulf, remains relatively unchanged going into
Tuesday and Wednesday. Because of this, Tuesday is looking sunny
and cold with highs only in the single digits and teens above
zero. And with the still strong outflow, wind chills during the
day will still be cold, ranging a few degrees either side of zero
during the day. The highways will be colder with wind chills
still in the teens below zero or colder.

Tuesday night is still looking cold with lows mostly in the single
digits or teens. Wednesday looks maybe a touch warmer...but still cold.
Expected highs are in the teens to lower 20s. Skies will still be
sunny to mostly sunny.

.LONG TERM.../Wednesday through Monday night/...It looks like a
relatively tranquil long-term is in store for us through the end
of the forecast period in terms of precipitation. Weather-wise,
the only two real issues that we face through the period are the
cold temperatures, which are already settled in across the
Panhandle and dangerously low windchills from a sharp pressure
gradient from a deep persistent high poised to our northeast in
northwestern Canada. The outflow winds from the high will
continue, but progressively and gradually weaken throughout the
long- term forecast period. The high could exceed 1060mb in
strength, which is quite impressive. Taku winds are possible for
downtown Juneau/Douglas according to guidance, but they should be
easing around the beginning of the long-term period. As long as
we don't keep a persistent inversion over Juneau, the winds
should have little trouble making it down to the surface. Gusty
conditions will be present across the remainder of the Panhandle,
as well, but the northeastern half of the Panhandle will be
impacted with the strongest winds as they are poised nearer to the
tightest gradient. The models are in good agreement in the long-
term period about the strong persistent high bringing strong
winds, dangerously low windchills, and much drier weather than we
have experienced in quite some time. Temperatures will gradually
warm slightly throughout the rest of the period while the outflow
winds, while still gusty, look to gradually decrease. There are
greatly reduced chances of precipitation throughout the period. In
fact, the PoPs are near zero until near the end of the long-term
period when relatively low chances for precipitation begin to
creep in. Generally, the models are in relatively good agreement
in the long-term. Additionally, the decreased cloudiness will be
better for radiational cooling than what we have been experiencing
most of the time over the Panhandle over the past year. This
radiational cooling would be dampened a bit by vertical mixing
caused by any strong outflow winds making it down to the surface.
Due to the very cold air and dangerously low windchills being in
place, it is very important to dress warmly in layers, & prepare
accordingly. Mariners should be prepared for enhanced seas and
freezing spray from the very cold temperatures and strong gusty
winds if they must venture out. Use extra caution.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning until 10 PM AKST this evening for AKZ023-
     026>028.
     Strong Wind through Tuesday morning for AKZ019-025.
     Wind Chill Advisory from 9 PM this evening to noon AKST Tuesday
     for AKZ019.
     Wind Chill Warning from midnight tonight to 9 AM AKST Tuesday
     for AKZ018.
     Wind Chill Advisory until midnight AKST tonight for AKZ018.
MARINE...Heavy Freezing Spray Warning for PKZ053.
     Heavy Freezing Spray Warning for PKZ032-051.
     Heavy Freezing Spray Warning for PKZ011-031.
     Heavy Freezing Spray Warning for PKZ013.
     Heavy Freezing Spray Warning for PKZ035-043.
     Heavy Freezing Spray Warning for PKZ012.
     Gale Warning for PKZ012-013-022-043-051-053.
     Small Craft Advisory for PKZ011-021-031>035-041-042-052.

&&

GJS/JLC

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