Gale Warning 675, NWS Anchorage, AK

074 
FZAK61 PAFC 100056
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
356 PM AKST Sat Dec 9 2017

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.

PKZ399-101400-
356 PM AKST Sat Dec 9 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 986 mb low at 57N 148W will pass over Kodiak Island and move
inland Sun morning. A 962 mb North Pacific low will move to 53N 152W
Sun evening then move inland over the Alaska Peninsula Mon 
afternoon. Another North Pacific low will move into the southwestern 
Gulf at 972 mb Mon evening.

$$

PKZ351-101400-
Gulf of Alaska Offshore North of 57N and West of 144W-
356 PM AKST Sat Dec 9 2017

...STORM WARNING SUNDAY NIGHT...

.TONIGHT...S wind 20 to 35 kt. Seas 12 ft.
.SUN...SE wind 25 kt becoming E 30 to 45 kt in the afternoon. Seas
12 ft building to 13 to 18 ft.
.SUN NIGHT...SE wind 40 to 55 kt. Seas 20 to 31 ft.
.MON...S wind 35 to 50 kt. Seas 22 to 31 ft.
.MON NIGHT...SE wind 25 to 35 kt. Seas 15 to 21 ft.
.TUE THROUGH THU...S wind 20 to 30 kt. Seas 11 to 19 ft.

$$

PKZ352-101400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
356 PM AKST Sat Dec 9 2017

...STORM WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...S wind 20 to 35 kt becoming 30 kt after midnight. Seas
11 ft.
.SUN...SE wind 20 to 30 kt becoming E 35 to 50 kt in the
afternoon. Seas 12 to 20 ft.
.SUN NIGHT...SE wind 35 to 50 kt. Seas 21 to 31 ft.
.MON...S wind 35 to 50 kt. Seas 21 to 30 ft.
.MON NIGHT...S wind 20 to 35 kt. Seas 15 to 20 ft.
.TUE...SE wind 15 to 30 kt. Seas 15 to 21 ft.
.WED THROUGH THU...S wind 15 to 30 kt. Seas 10 to 16 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion...CORRECTED
National Weather Service Anchorage AK
456 PM AKST Fri Dec 8 2017

.ANALYSIS AND UPPER LEVELS...
The flow aloft continues to be highly amplified. There is a large
upper level ridge along the west coast of Canada, a sharp trough
stretching from the eastern Bering south into the Northern
Pacific, and a ridge over the western Bering and western
Aleutians. The upper level flow over the southern Alaska
mainland is from the south. Within the Bering trough there is an
upper level low over the central Bering Sea and another south of
the Alaska Peninsula. Currently southern Alaska is between weather
systems, with an exiting front over the Wrangell Mountains. Weak
ridging is over most of southern Alaska. There is a weak front
stretching south from the Alaska Peninsula, and the main storm
track is pushing into the Panhandle. To the west, there is an
approaching front near the Kamchatka Peninsula.

&&

.MODEL DISCUSSION...
The numerical models are in fairly good agreement through Sunday
afternoon. There are still some differences in timing and strength
of a low moving into the Gulf Sunday, but the models seem to be
coming into better agreement. Precipitation type will continue to
be a challenge to forecast. Forecast confidence is thus near
normal.

&&

.AVIATION...
PANC...Fog and stratus are expected to be in the area through
Saturday morning reducing conditions to LIFR at times. Conditions
are expected to improve to VFR around noon Saturday with the
arrival of high clouds and a northerly surface gradient as a low
approaches from the south.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Benign conditions will prevail across much of Southcentral AK
through Saturday afternoon in a brief break between systems. These
systems continue to be focused along the Gulf coast in this
active southerly flow pattern. Locally dense fog has formed in the
Cook Inlet region as winds subsided and low level moisture
lingers in the wake of the recent precipitation. This fog is
expected to persist over portions of the Anchorage Bowl and Kenai
Peninsula through late Saturday morning in the absence of any
discernible features to scour it out. Therefore, dense fog
advisories have been issued for those locations through noon
Saturday. The next system to impact the area will arrive Saturday
night as another front moves to the Gulf coast. This front is
expected to be weaker than the last system, with precipitation
mainly confined to coastal areas as inland locations stay largely
downsloped. Precipitation type should safely be rain at sea level,
with snow levels hovering around 2000 ft or greater as warm air
remains over the region in deep southerly flow.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Rain and snow showers have tapered off across much of the
southwest Mainland this afternoon as the shortwave tracks further
north and into the interior. With residual moisture trapped in
the lower levels and upper level ridging beginning to nose into
the area this evening, fog has started to develop over parts of
the Kuskokwim Delta and Bristol Bay area. Showery conditions are
expected to pick back up over parts of the Bristol Bay area and
Alaska Peninsula this evening as well, as another trough rotates
across the Alaska Peninsula and an associated front swings across
western parts of the Bristol Bay area and Alaska Peninsula.
Meanwhile, an east-to-west running upper level ridge will amplify
over the lower Kuskokwim Valley and Kuskokwim Delta tonight while
an upper low persists south of the Alaska Peninsula. The next
easterly wave will cross from the western Gulf into Southwest
Alaska Saturday night through Sunday morning with a significantly
stronger frontal system tracking up from the southeast Sunday
afternoon and evening.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Showery precipitation and gusty northwesterly winds along the
east side of an upper level ridge building over the western
Aleutians and Bering, will shift east over the central Aleutians
tonight as the upper level ridge amplifies and slides east. A
strong frontal system bringing storm force southeasterly winds and
mixed precipitation will approach the western Aleutians Saturday.
The front will stall stretched across the western and central
Aleutians Saturday night, and then weaken quickly as it shears
apart and drops back down to the south. A significantly stronger
frontal system will track up from the north Pacific and into the
Alaska Peninsula Sunday evening. This system will tighten the
gradient between a ridge over the Bering, creating some gusty
northerly flow and showery conditions over the central and eastern
Bering/Aleutians Monday.

&&

.LONG TERM FORECAST (Days 3 through 7)...

The barrage of low pressure systems will continue for the next
week. This means warm air, multiple rounds of heavy precipitation
along the Gulf Coast, and occasional high wind events will remain
the threat across much of southern Alaska during the extended
forecast period. The good news is that there are increasing signs
that the big ridge over western North America that has created
this persistent weather pattern will be breaking down by next
weekend. Thus, while there will be at least 3 significant storms
that affect southern Alaska over the next 7 days, the direction of
movement of these storms will be slowly changing.

The first storm, on Monday, will come in from the southeast and
hammer the north Gulf Coast again and also potentially create
strong chinook winds in inland areas like Anchorage. This bears
watching over the next day or two to begin to fine-tune the
details. The second storm comes through around the middle of next
week from a more southern direction (rather than southeast). By
Friday, a 3rd storm moves into the area, but this time it will be
from the southwest (tracking first through the Bering Sea and then
impacting Southwest and Southcentral Alaska with rain and wind).
Although all of these storms will continue to resupply the warm
air in place around the region, they will be slowly but surely
paving the way for a return to cooler weather by next weekend.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Dense Fog Advisory 101 121.
MARINE...Gale 119 130 131 138 139 172-177.
		 Storm 178.

&&

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...AMD