Gale Warning 123, NWS Anchorage, AK

886 
FZAK61 PAFC 220025
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
325 PM AKST Wed Feb 21 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.

PKZ399-221330-
325 PM AKST Wed Feb 21 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 1012 mb low will develop near 60N 147 early Thu and move to 59N
140W at 1003 mb Thu evening. High pressure will build across the 
Gulf Fri.

$$

PKZ351-221330-
Gulf of Alaska Offshore North of 57N and West of 144W-
325 PM AKST Wed Feb 21 2018

...GALE WARNING THURSDAY AND THURSDAY NIGHT...

.TONIGHT...SW wind 10 to 20 kt. Seas 5 to 8 ft.
.THU...W wind 25 to 35 kt. Seas 6 to 11 ft.
.THU NIGHT...NW wind 30 to 40 kt. Seas 12 to 20 ft.
.FRI...NW wind 25 to 40 kt. Seas 11 to 19 ft.
.FRI NIGHT...SW wind up to 20 kt. Seas 6 to 11 ft.
.SAT...W wind 20 to 35 kt. Seas 8 to 16 ft.
.SUN THROUGH MON...W wind 20 to 35 kt. Seas 7 to 12 ft.

$$

PKZ352-221330-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
325 PM AKST Wed Feb 21 2018

...GALE WARNING THURSDAY NIGHT...

.TONIGHT...SW wind 25 kt. Seas 8 ft.
.THU...W wind 30 kt. Seas 10 ft.
.THU NIGHT...W wind 25 to 35 kt. Seas 11 to 17 ft.
.FRI...W wind 20 to 35 kt. Seas 9 to 17 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 8 to 13 ft.
.SAT...W wind 25 to 40 kt. Seas 12 to 20 ft.
.SUN THROUGH MON...W wind 25 to 35 kt. Seas 9 to 15 ft.

$$

181 
FZAK61 PAFC 221310
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
410 AM AKST Thu Feb 22 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.

PKZ399-230215-
410 AM AKST Thu Feb 22 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 1008 mb low at 60N 145W this afternoon will move inland near 
59N 137W at 1004 mb by tonight. High pressure will remain over the
Gulf through Sat morning.

$$

PKZ351-230215-
Gulf of Alaska Offshore North of 57N and West of 144W-
410 AM AKST Thu Feb 22 2018

...GALE WARNING THROUGH FRIDAY...

.TODAY...W wind 25 to 35 kt. Seas 6 to 11 ft.
.TONIGHT...NW wind 30 to 40 kt. Seas 12 to 20 ft.
.FRI...NW wind 30 to 40 kt diminishing to 15 to 30 kt in the
afternoon. Seas 11 to 19 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 6 to 11 ft.
.SAT THROUGH SUN...NW wind 25 to 40 kt. Seas 12 to 20 ft.
.MON...W wind 10 to 25 kt. Seas 7 to 12 ft.

$$

PKZ352-230215-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
410 AM AKST Thu Feb 22 2018

...GALE WARNING TONIGHT AND FRIDAY...

.TODAY...W wind 30 kt. Seas 9 to 12 ft.
.TONIGHT...W wind 25 to 35 kt. Seas 11 to 18 ft.
.FRI...W wind 25 to 40 kt diminishing to 15 to 30 kt in the
afternoon. Seas 10 to 18 ft.
.FRI NIGHT...SW wind 15 to 30 kt. Seas 8 to 13 ft.
.SAT THROUGH SUN...NW wind 25 to 40 kt. Seas 14 to 26 ft.
.MON...W wind 25 kt. Seas 9 to 12 ft.

$$

729 
FZAK61 PAFC 230030
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
330 PM AKST Thu Feb 22 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.

PKZ399-231400-
330 PM AKST Thu Feb 22 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 1006 mb low at 60N 145W this afternoon moves ashore near Yakutat
tonight. A ridge of high pressure then builds across the central 
Gulf for Friday afternoon. An Aleutian low moves to 59N 139W 
Saturday afternoon while strengthening to 986 mb.

$$

PKZ351-231400-
Gulf of Alaska Offshore North of 57N and West of 144W-
330 PM AKST Thu Feb 22 2018

...GALE WARNING THROUGH FRIDAY...

.TONIGHT...NW wind 30 to 40 kt. Seas 12 to 20 ft.
.FRI...NW wind 30 to 40 kt diminishing to 20 to 30 kt in the
afternoon. Seas 12 to 20 ft.
.FRI NIGHT...W wind 10 to 20 kt becoming SW 15 to 30 kt after
midnight. Seas 6 to 11 ft. Rain.
.SAT...W wind 25 to 40 kt. Seas 10 to 18 ft.
.SAT NIGHT...W wind 20 to 35 kt. Seas 15 to 21 ft.
.SUN...NW wind 20 to 35 kt. Seas 12 to 20 ft.
.MON THROUGH TUE...W wind 10 to 25 kt. Seas 8 to 13 ft.

$$

PKZ352-231400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
330 PM AKST Thu Feb 22 2018

...GALE WARNING THROUGH FRIDAY...

.TONIGHT...NW wind 25 to 40 kt. Seas 12 to 19 ft.
.FRI...W wind 25 to 40 kt. Seas 11 to 19 ft.
.FRI NIGHT...SW wind 15 to 30 kt. Seas 9 to 14 ft. Rain.
.SAT...W wind 30 to 40 kt. Seas 15 to 22 ft.
.SAT NIGHT...W wind 30 to 40 kt. Seas 18 to 24 ft.
.SUN...NW wind 25 to 40 kt. Seas 14 to 22 ft.
.MON THROUGH TUE...W wind 25 kt. Seas 8 to 12 ft.

$$

397 
FZAK61 PAFC 231259
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
359 AM AKST Fri Feb 23 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.

PKZ399-240130-
359 AM AKST Fri Feb 23 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
High pressure remains in the Gulf through this afternoon. A 1006 
mb low at 58N 152W tonight moves to 58N 148W at 996 mb by Sat 
morning and then moves inland near 57N 136W at 984 mb by Sat 
night.

$$

PKZ351-240130-
Gulf of Alaska Offshore North of 57N and West of 144W-
359 AM AKST Fri Feb 23 2018

...GALE WARNING THROUGH SATURDAY...

.TODAY...NW wind 25 to 40 kt. Seas 12 to 20 ft.
.TONIGHT...SW wind 10 to 20 kt increasing to 25 to 40 kt after
midnight. Seas 7 to 12 ft. Snow and rain.
.SAT...W wind 30 to 45 kt. Seas 13 to 21 ft. Snow and rain showers.
.SAT NIGHT...W wind 30 to 45 kt. Seas 17 to 24 ft.
.SUN...W wind 25 to 40 kt. Seas 10 to 18 ft.
.MON...SW wind 15 to 25 kt. Seas 9 to 14 ft.
.TUE...W wind 15 to 30 kt. Seas 14 to 19 ft.

$$

PKZ352-240130-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
359 AM AKST Fri Feb 23 2018

...GALE WARNING THROUGH SATURDAY...

.TODAY...W wind 25 to 40 kt. Seas 11 to 19 ft.
.TONIGHT...W wind 25 to 40 kt. Seas 9 to 16 ft. Rain and snow.
.SAT...W wind 35 to 45 kt. Seas 17 to 25 ft. Snow showers.
.SAT NIGHT...W wind 35 to 45 kt. Seas 18 to 25 ft.
.SUN THROUGH TUE...W wind 25 to 40 kt. Seas 12 to 20 ft.

$$

425 
FZAK61 PAFC 240042
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
342 PM AKST Fri Feb 23 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.

PKZ399-241400-
342 PM AKST Fri Feb 23 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 1001 mb low will form at 58N 150W then it will move to 59N 144W
at 988 mb Sat morning. It will then move into the eastern Gulf 
Sat night at 986 mb. 

$$

PKZ351-241400-
Gulf of Alaska Offshore North of 57N and West of 144W-
342 PM AKST Fri Feb 23 2018

...STORM WARNING SATURDAY...

.TONIGHT...SW wind 10 to 25 kt increasing to 25 to 40 kt after
midnight. Seas 8 to 13 ft. Rain and snow.
.SAT...W wind 40 to 55 kt. Seas 15 to 23 ft. Rain showers changing to
snow showers. 
.SAT NIGHT...NW wind 30 to 45 kt. Seas 18 to 25 ft.
.SUN...NW wind 25 to 40 kt. Seas 13 to 21 ft.
.SUN NIGHT...SW wind 15 to 30 kt. Seas 8 to 13 ft.
.MON THROUGH WED...NW wind 25 to 40 kt. Seas 11 to 19 ft.

$$

PKZ352-241400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
342 PM AKST Fri Feb 23 2018

...STORM WARNING SATURDAY...

.TONIGHT...SW wind 20 to 35 kt becoming W 30 to 45 kt after
midnight. Seas 9 to 17 ft. Rain.
.SAT...W wind 40 to 50 kt. Seas 18 to 27 ft. Rain showers changing to
snow showers. 
.SAT NIGHT...W wind 45 kt. Seas 18 to 27 ft.
.SUN...W wind 25 to 40 kt. Seas 14 to 22 ft.
.SUN NIGHT...W wind 25 to 40 kt. Seas 9 to 17 ft.
.MON...W wind 25 to 40 kt. Seas 15 to 29 ft.
.TUE THROUGH WED...NW wind 25 to 40 kt. Seas 11 to 19 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
442 PM AKST Tue Feb 20 2018

.ANALYSIS AND UPPER LEVELS...

A look at the weather map shows a low pressure system moving near
the Bering Strait and into the Arctic Ocean. An associated
weather front extends southeastward from the low and has plowed
across virtually all of mainland Alaska in the last 24 hours.
While this storm has brought major impacts to the interior
portions of the state, our forecast area has had much lighter
impacts. In fact, as the front went through this morning, it
couldn't even produce enough vertical mixing in the atmosphere to
churn up and get rid of the low clouds and fog stuck around upper
Cook Inlet and parts of the Bristol Bay zone and Upper Kuskokwim
Valley. With the leftovers of the front now moving away from us.
Low clouds and fog are likely to persist tonight as warm
advection overspreads the area once again from the southwest.

Over the Bering Sea and Aleutians, thick clouds and widespread
precip has already moved into the western 2/3 of the area as the
next low center is just about to cross over the western Aleutians
and into the Bering Sea. This storm will follow a similar track to
the last one and track northeastward toward the Bering Strait.

&&

.MODEL DISCUSSION...

The available models are in reasonably good agreement on the
overall path of the next storm through our AOR (the storm
currently moving into the western Aleutians). All solutions depict
a large and deep pocket of warm air moving into Southwest and then
Southcentral Alaska in the next 12-36 hours. As this warm sector
continues off to the east on Wednesday night/Thursday, a cold
front will surge eastward through Southwest and then Southcentral
Alaska. This cold front is the focus of most of our effort today,
and represents the forecast challenge of the day. The problem is
not with the surface features as much as the upper level
trough/dynamics associated with the storm. As the supporting upper
trough passes through southern Alaska, there is disagreement on
the overall orientation of the feature. The NAM/GFS bring the
trough through with a neutral or even slightly positive tilt,
which would push the whole thing through fairly quickly and with
fairly minor amounts of precipitation in most areas. Meanwhile,
the Canadian and European models have tried to go neutral and then
even negatively tilted with the trough. This would result in much
heavier and more widespread precipitation across Southcentral on
Thursday morning than the NAM/GFS models. Forecast experience and
pattern recognition would support the NAM/GFS solutions, so that
is what the forecast is largely based on today, and some movement
toward this solution was noted in the 12z GEM/Canadian model run
this morning.

&&

.AVIATION...
PANC...IFR cig/vis will likely persist as warm air moving up Cook
Inlet tonight helps strengthen the temperature inversion.
Therefore the low clouds and/or fog will continue through the
Wednesday morning period with increasing mid level clouds
improving the situation by afternoon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Areas of low stratus and fog will linger across portions of
Southcentral and particularly the Cook Inlet region through
Wednesday morning as weak outflow winds quickly diminish and
upper level ridging is re-established over the mainland. This
will yield generally quiet conditions Wednesday into Wednesday
night before the next trough approaches from the west. This
feature will bring another round of winter precipitation to much
of the area early Thursday morning into Thursday afternoon,
although many of the details are still uncertain. A favorable
southwest flow pattern aloft yields the greatest forecast
confidence from Hatcher Pass into the northern Susitna Valley,
with a quick 6-12 inches possible in Hatcher Pass by Thursday
morning. Accumulations are expected to be more limited over the
Susitna Valley as the system looks to move through pretty quickly
given the progressive nature of the synoptic pattern. The
situation is a bit more muddled for Anchorage, as the presence of
southeasterly winds at the surface and temperatures hovering near
freezing will introduce precipitation type concerns. This lends
lower confidence to the forecast, with a rain/snow mix possibly
helping to limit accumulations to around one inch or less within
the Bowl. The trough will then swing east to Prince William Sound
and the Copper River Basin by Thursday afternoon, bringing snow to
these locations before departing to the east Thursday evening and
paving the way for another round of outflow winds to begin the mid
term part of the forecast.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Light southerly flow along with low stratus and fog will persist
over much of the southwestern Mainland this evening through
Wednesday morning. A weak upper level wave tonight will preface a
larger wave moving into the southwest Mainland Wednesday evening,
both of which will bring some precipitation and gusty onshore
winds to the area tonight through Thursday night. Precipitation
will likely start off as a mixture of snow and rain across the
southern mainland tonight, transitioning to mostly rain overnight
tonight into tomorrow morning. Snow will begin mixing back in with
rain through the remainder of the day Wednesday, and eventually
transition back to predominantly snow by Thursday morning as
colder air aloft begins to filter back into the area from the
west.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A stacked gale force low over the western Aleutians will slowly
track northward tonight. The associated front will continue to
track northeastward from the central Aleutians/Bering through the
eastern Aleutians/Bering tonight through Wednesday morning.
This system will not be nearly as strong as the previous, but it
will last longer since it is slower moving, so expect gale force
winds over parts of the Bering Sea through Wednesday before the
low weakens and moves toward the Southwest coast Wednesday night.
The next system enters the western waters Thursday morning,
bringing another round of precipitation and gusty winds to the
area.

&&

.LONG TERM FORECAST (Thursday evening through Tuesday)...
Expect the active pattern to continue with near to above normal
temperatures, periodic clouds/snow with dry and colder periods
between.

A short-lived dry outflow pattern is on tap for Thursday night as
the previous upper-level trough exits to the east. Dry, clear,
and cold conditions will prevail everywhere, as well as gusty gap
winds along the north gulf coast. These conditions will hold on
Friday, slowly weakening, as the next system pushes into the area
from the southwest overnight Friday into Saturday. Guidance is
struggling with how to track the triple point low as the front
moves into the Gulf, and hence how far north to track to frontal
boundary. The front should make it to the coast and the southern
Kenai Peninsula, bringing snow to these areas. A return to short-
lived outflow conditions comes late weekend when that system
exits.

Into the extended forecast, the upper-level southwesterly flow
remains. The progressive nature of the pattern will continue
through next week, with front and lows rolling into the region
every 1-2 days. At this point, the low amplitude pattern should
stop any big warm-up from happening, any warmer air associated
with the fronts should slide to the east with the triple-point
lows.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale 173 175-179.

&&

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