Gale Warning 242, NWS Juneau, AK

998 
FZAK67 PAJK 240004
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
304 PM AKST Tue Nov 23 2021

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-241815-
304 PM AKST Tue Nov 23 2021
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A gale-force low pressure system enters the gulf tonight and 
tracks toward the NE gulf coast through Wednesday. The associated 
front passed over the panhandle Wednesday. 

$$

PKZ310-241815-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
304 PM AKST Tue Nov 23 2021

.TONIGHT...S wind 20 kt increasing to 30 kt. Seas 9 ft building
to 12 ft late. Rain showers in the evening. 
.WED...S wind 20 kt becoming W 15 kt in the afternoon. Seas
12 ft. SW swell. 
.WED NIGHT...N wind 20 kt. Seas 12 ft. SW swell. 
.THU...NW wind 20 kt becoming W 30 kt in the afternoon. Seas
13 ft. 
.THU NIGHT...W wind 30 kt. Seas 16 ft. 
.FRI...SW wind 30 kt. Seas 14 ft. 
.SAT...NW wind 20 kt. Seas 8 ft. 
.SUN...S wind 20 kt. Seas 9 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
446 PM AKST Mon Nov 22 2021

.SHORT TERM.../Tonight through Tuesday night/...Overall, the
short term forecast continues the showery pattern tonight and
Tuesday.

A reinforcing front looks to move over the panhandle late
tonight, keeping the showers in SE AK. The southern panhandle has
a chance to see rain showers early tonight, some snow mixing in
late tonight, then switching back to rain in the morning. The
central and northern panhandle would have rain/snow mix showers
early tonight, becoming snow showers late tonight, then becoming
rain and snow showers.

Any snow accumulations tonight and tomorrow look on the smaller
side. The central and northern panhandle could see around 1 to 3
inches through Tuesday. The south could see snow amounts around 1
inch or less through Tuesday. But due to the showery nature of the
pattern, these amounts have high uncertainty.

Temperatures will remain on the colder side with lows tonight in
the mid to upper 30s for the south, low to mid 30s for the central
panhandle, while the Haines/Skagway area and Yakutat look to
bottom out in the 20s. High tomorrow will warm to the 30s for most
of the panhandle. Upper 30s to near 40 could be found in the
south. Tuesday night’s lows look to be around the same, or a
touch warmer, as tonight’s lows.

Winds through Tuesday look to be low impact at around 5-15 mph or
less. Coastal waters and open ocean areas could see some 15-20
mph kts. However, winds will ramp up as the next system
approaches.

.LONG TERM.../Wednesday through Saturday/ Active weather pattern
for the holidays for all of SE Alaska. Heavy precipitation, strong
winds, and warming temperatures which will determine
precipitation type and snow totals all happening from a series of
fronts and lows moving into the region. Unfortunately due to
large model disagreements and spread among ensembles there is
potential for a variations in resulting practical weather. This
will be a rapidly evolving situation so significant changes to
issued forecast are possible. Use caution for any of your holiday
activities.

At mid levels an upper level low drops down from the AK interior
and ridging moves eastward over the panhandle. This low/trough
over the AK Gulf with ridging over western Canada will remain in
place through into the start of the weekend. At the surface, a
low pressure system moves up from the N Pacific into the SE AK
Gulf with the associated gale force front moving in. Behind the
front another low develops late Wednesday into Thursday with
enhanced precipitation and winds for the southern panhandle.

What has changed from last forecast: The position of the low now
looks to move further north and faster. What this will do is bring
in warmer air faster thus changing initial snowfall into rain
sooner, resulting in lower snow totals for the central panhandle.
The 850 temperatures reflect this with ensemble having positive
changes. Getting high QPF values from the long fetch of tropical
moisture and atmospheric river set up (mainly for the southern
panhandle) Rainfall amounts over 48 hours of 3 to 4 inches. Snow
totals for the central areas of 3 to 5 inches before switching to
rain, if the timing is correct. 925 mb winds with selected models
are into the 50 to 55 kt range for the southern panhandle and 30
to 40 kt range to the north. They still look to mix down which
also supports transition from snow to rain. For now keeping
surface winds gusts at 50 mph or less but watching for higher
gusts. Trying to nail down the temperature and a non standard
diurnal trend. Should see warming start Wednesday and continue to
rise into Thursday.

Model agreement was not helping the forecast. Got good line up
between ECMWF, NAM, and Canadian for location of the low center with
GFS as an outlier. NBM was supporting lower confidence on higher
snow amounts. Ensembles overall trended warmer for 850 temps. All
except the GFS. Everything stated above will be changed if the
GFS (which was considered an outlier) turns out to be correct. a)
QPF will be much higher b) winds for the souther panhandle will be
higher c) snow will last longer and thus accumulate more. That
said keeping close watch on new model runs and current conditions
over the next few days. Once again forecast confidence is low and
expecting the forecast to change as new information comes in.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from late Tuesday night through Thursday
     morning for AKZ017>021-025.
MARINE...Small Craft Advisory for PKZ012-021-022-041>043-051>053.

&&

GJS/PRB

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