Gale Warning 643, NWS Anchorage, AK

703 
FZAK61 PAFC 200046
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
346 PM AKST Mon Nov 19 2018

Offshore waters forecast for the Gulf of Alaska West of 144W

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

PKZ399-201400-
346 PM AKST Mon Nov 19 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 989 mb low at 58N 147W Mon afternoon moves to 60N 145W at 988 mb
by Tue afternoon and then moves inland.

$$

PKZ351-201400-
Gulf of Alaska Offshore North of 57N and West of 144W-
346 PM AKST Mon Nov 19 2018

.TONIGHT...W wind 15 to 30 kt. Seas 9 to 12 ft.
.TUE...W wind 10 to 25 kt. Seas 7 to 12 ft.
.TUE NIGHT...W wind up to 20 kt becoming 10 kt after midnight.
Seas 5 to 9 ft.
.WED...NE wind 10 kt. Seas 6 ft.
.WED NIGHT...N wind 15 kt. Seas 4 to 7 ft.
.THU THROUGH SAT...SE wind up to 20 kt. Seas 4 to 9 ft.

$$

PKZ352-201400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
346 PM AKST Mon Nov 19 2018

.TONIGHT...W wind 20 to 30 kt. Seas 11 to 15 ft.
.TUE...W wind 15 to 25 kt diminishing to up to 20 kt in the
afternoon. Seas 8 to 13 ft.
.TUE NIGHT...NW wind 10 to 25 kt. Seas 6 to 9 ft.
.WED...N wind 10 to 25 kt. Seas 6 to 11 ft.
.WED NIGHT...N wind 10 to 25 kt. Seas 7 to 10 ft.
.THU THROUGH SAT...SE wind 10 to 25 kt. Seas 5 to 10 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 PM AKST Sun Nov 18 2018

.ANALYSIS AND UPPER LEVELS...
There is an upper level trough stretching from the eastern tip of
Russia through southwest Alaska into the the southwestern Gulf.
Embedded in this trough are two upper lows, one centered just
southwest of Bethel and the other south of Kodiak Island. The
associated surface lows are centered near Hooper Bay and southeast
of Kodiak. The Kodiak low has two fronts, one over the northern
Gulf and Gulf coast, the other stretching from the surface low
northeast into the upper Kuskokwim valley. Both of these fronts
are producing some precipitation, mostly in the form of rain at
lower elevations. Some freezing rain is still occurring in the
Kuskokwim valley, and some snow is being reported at higher
elevations. There is a flat ridge over the central Bering with a
weak front pushing eastward across the western to central Bering.
A front associated with a surface low southwest of Shemya is just
moving into the western Aleutians.

&&

.MODEL DISCUSSION...
The numerical models are not in very good agreement on a low in
the Gulf right from the beginning of the forecast. The 12z Nam
especially is different, starting the low further north and taking
it into the Kenai Peninsula Monday morning. The other models keep
it south of the Kenai, and then slowly drift it east. Further
west, the models are initially in good agreement on a low moving
rapidly across the Aleutians and southern Bering through Monday
afternoon. By Monday evening the models are still in agreement on
timing, but begin to have differences on how the front and various
lows forming on it are behaving. So confidence on the timing of
the general pattern is good, but on the associated precipitation
and some local winds is not very good.

&&

.AVIATION...
PANC...IFR ceilings should give way to VFR conditions sometime
Monday morning. However, confidence in this is not high and IFR
conditions may linger until around noon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
The next developing wave is currently lifting north into the
southern Gulf while its associated frontal system stretches across
the western and northern Gulf coasts. An additional frontal band
stretches north over Cook Inlet and over the western Susitna
Valley. With the continued warm, southerly flow aloft
precipitation is falling as rain over the majority of the area. In
the Copper River Basin from roughly Gulkana westward, colder air
in the upper 20s lingers at lower elevations. As southeasterly
winds push up the Copper River Valley temperatures should warm
into the lower 30s through this evening in all but the more
western portions of the basin where precipitation associated with
the frontal wave lifting over the basin tonight may fall as a mix
of snow and freezing rain.

The surface low will track north to be located just south of
Seward by Monday afternoon then as it weakens continue slowly
northeast towards Prince William Sound through Tuesday. An upper
level trough reaching Southwest Alaska on Tuesday will dig
southeastward towards the far southwestern Gulf through Wednesday
with precipitation over Southcentral Alaska tapering off in
response and temperatures beginning to gradually cool.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2: Tonight
through Tuesday)...

The primary weather hazards affecting Southwest Alaska have
shifted from freezing rain over to fog this evening. Where
precipitation continues this evening, warm air has been firmly in
place and it is falling as plain rain. These locations primarily
are focused in the eastern part of the area, along the Alaska
Range. To the west, cold air is slowly making its way into
Southwest Alaska from off the Bering. As that cooler air moves in
from off the Bering, it is picking up moisture from off the water
and moving onshore in the form of fog. Thus, it is likely to
persist throughout the overnight and the morning on Monday. There
may be a brief reprieve from the fog Monday afternoon before
redeveloping in some areas again Monday night.

The other weather story will be the intrusion of cold air, which
in turn will end any threat of liquid precipitation. A weak
impulse of moisture is expected to move into Southwest Alaska
from the Bering on Tuesday morning. This may lead to a brief hit
of an inch or two of snow as it quickly tracks eastward. With the
models still struggling with this otherwise weak feature, nothing
special has yet been added to the forecast, but is worth noting
for those who will be out and about on Tuesday. Temperatures are
beginning their cooling trend tonight and by Tuesday, highs will
struggle to reach freezing at the coast and remain in the 20s
inland, with teens expected for lows.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2: Tonight
through Tuesday)...

An area of low pressure currently centered west of Attu will
quickly track eastward as it weakens over the next couple days. As
it moves through, winds to small craft advisory levels (25-35 mph)
are expected, with localized gales possible in the gaps between
islands. It will also bring in some brief light rain as it moves
through, with colder air following behind it. Despite the low
likely opening up into a trough by Tuesday, enough moisture is
with it that it is expected to move into Southwest Alaska Tuesday
morning. Meanwhile, persistent low pressure off the west coast of
Alaska will continually pump colder air in across the northern
Bering. High pressure moves into the western Bering on Tuesday,
which will intensify the northerly winds on Tuesday across the
eastern Bering due to the increasing pressure gradient.

&&

.LONG TERM FORECAST (Days 3 through 7/Wednesday night through
Sunday)...

The extended time frame starts with troughing over southcentral
AK, ridging for the central and eastern Aleutians, and troughing
over the Western Aleutians. This is similar to the solution
yesterday for midweek, so confident in the pattern. This means
active weather for southcentral AK and the western Aleutians.

Models are still showing ridging working its way east later next
week with the ridge moving over southcentral AK. There is some
difference in the strength of this ridge so remains to be seen how
much influence it will have, but generally a cooling and drying
trend can still be anticipated later next week for southcentral AK.
As with the past few days, models diverge significantly going
into next weekend. This means a middle of the road approach in the
forecast until things can get straightened out with model consistency.
The western Aleutians are also a mess by Thursday of this week
with the forecast. With confidence being so low in the long range,
not much point in trying to nail down a solution at this time.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gales...130 155 174 176 177.

&&

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...JR
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JW
LONG TERM...BB