Gale Warning 581, NWS Anchorage, AK

640 
FZAK61 PAFC 150015
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
315 PM AKST Thu Nov 14 2019

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.

PKZ399-151315-
315 PM AKST Thu Nov 14 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 969 mb low near 54N 151W this afternoon will move northward into
the central Gulf at 981 mb early Fri morning. The low will then 
become absorbed Fri afternoon by a complex 980 mb low over Bristol
Bay. The complex low will then move over the northern AKPEN at 989
mb Sat afternoon. 

$$

PKZ351-151315-
Gulf of Alaska Offshore North of 57N and West of 144W-
315 PM AKST Thu Nov 14 2019

...GALE WARNING FRIDAY...

.TONIGHT...SE wind 15 to 25 kt. Seas 14 ft. Rain showers.
.FRI...S wind 20 to 35 kt becoming SW in the afternoon. Seas 12 to
20 ft.
.FRI NIGHT...SW wind 15 to 25 kt becoming S up to 15 kt after
midnight. Seas 9 to 17 ft subsiding to 8 to 11 ft after midnight.
.SAT...SW wind up to 15 kt. Seas 6 to 11 ft.
.SAT NIGHT...NW wind 10 to 25 kt. Seas 7 to 12 ft.
.SUN THROUGH TUE...SW wind 15 to 25 kt. Seas 7 to 12 ft.

$$

PKZ352-151315-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
315 PM AKST Thu Nov 14 2019

...GALE WARNING FRIDAY...

.TONIGHT...S wind 15 to 30 kt. Seas 12 to 19 ft.
.FRI...SW wind 25 to 35 kt diminishing to 15 to 25 kt in the
afternoon. Seas 12 to 20 ft.
.FRI NIGHT...SW wind 10 to 25 kt becoming S up to 15 kt after
midnight. Seas 9 to 16 ft subsiding to 7 to 10 ft after midnight.
.SAT...W wind up to 15 kt. Seas 6 to 11 ft.
.SAT NIGHT...W wind 15 to 30 kt. Seas 7 to 12 ft.
.SUN THROUGH TUE...SW wind 20 to 30 kt. Seas 9 to 16 ft.

$$

744 
FZAK61 PAFC 151215
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
315 AM AKST Fri Nov 15 2019

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.

PKZ399-160230-
315 AM AKST Fri Nov 15 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 977 mb low at 57N 147W will move to 60N 145W Fri afternoon at 
986 mb and then become absorbed by a complex 980 mb low over 
Bristol Bay. The complex low will then move over the northern 
AKPEN at 989 mb Sat afternoon. A 991 mb low will develop near 57N 
147W Sat morning and move to 60N 147W at 989 mb by Sun morning.

$$

PKZ351-160230-
Gulf of Alaska Offshore North of 57N and West of 144W-
315 AM AKST Fri Nov 15 2019

...GALE WARNING TODAY...

.TODAY...SE wind 20 to 35 kt becoming SW 10 to 25 kt in the
afternoon. Seas 10 to 18 ft.
.TONIGHT...SW wind 15 to 25 kt becoming S up to 15 kt after
midnight. Seas 8 to 13 ft.
.SAT...W wind up to 15 kt. Seas 6 to 11 ft.
.SAT NIGHT...NW wind 10 to 25 kt. Seas 7 to 12 ft.
.SUN THROUGH MON...W wind 10 to 25 kt. Seas 6 to 11 ft.
.TUE...S wind 25 to 35 kt. Seas 11 to 19 ft.

$$

PKZ352-160230-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
315 AM AKST Fri Nov 15 2019

...GALE WARNING TODAY...

.TODAY...SW wind 25 to 35 kt diminishing to 15 to 25 kt in the
afternoon. Seas 11 to 19 ft.
.TONIGHT...SW wind 10 to 20 kt. Seas 8 to 13 ft.
.SAT...W wind 10 to 15 kt. Seas 6 to 11 ft.
.SAT NIGHT...W wind 15 to 30 kt. Seas 7 to 12 ft.
.SUN THROUGH MON...SW wind 15 to 25 kt. Seas 8 to 11 ft.
.TUE...S wind 25 to 40 kt. Seas 14 to 22 ft.

$$

872 
FZAK61 PAFC 160033
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
333 PM AKST Fri Nov 15 2019

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.

PKZ399-161415-
333 PM AKST Fri Nov 15 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A complex 982 mb low over Southwest Alaska this afternoon will move
over Southcentral at 987 mb Sat afternoon. The low will remain 
over Southcentral through Sun afternoon at 995 mb. 

$$

PKZ351-161415-
Gulf of Alaska Offshore North of 57N and West of 144W-
333 PM AKST Fri Nov 15 2019

.TONIGHT...SW wind 15 to 25 kt becoming S up to 15 kt after
midnight. Seas 8 to 13 ft.
.SAT...W wind up to 15 kt. Seas 5 to 8 ft.
.SAT NIGHT...W wind up to 15 kt increasing to 20 kt after
midnight. Seas 5 to 8 ft.
.SUN...W wind 20 kt. Seas 7 to 11 ft.
.SUN NIGHT...W wind 20 kt. Seas 9 ft.
.MON...SW wind 10 to 20 kt. Seas 6 to 9 ft.
.TUE THROUGH WED...S wind 20 to 35 kt. Seas 12 to 20 ft.

$$

PKZ352-161415-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
333 PM AKST Fri Nov 15 2019

.TONIGHT...SW wind 10 to 20 kt. Seas 8 to 13 ft.
.SAT...W wind up to 15 kt. Seas 7 ft.
.SAT NIGHT...W wind 20 kt. Seas 6 to 9 ft.
.SUN...W wind 25 kt. Seas 8 to 11 ft.
.SUN NIGHT...W wind 15 to 25 kt. Seas 9 ft.
.MON...SW wind 15 to 25 kt. Seas 7 to 10 ft.
.TUE THROUGH WED...S wind 25 to 40 kt. Seas 14 to 22 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
459 PM AKST Wed Nov 13 2019

.ANALYSIS AND UPPER LEVELS...
A strong mid-level disturbance was located over central Alaska,
with another strong low located at the surface and aloft south of
the Alaska Peninsula. Surface observations show large dewpoint
depressions of 10 degrees or more persist across much of
Southcentral, with the trend over the last few hours showing a
gradual moistening occurring. Further east across the Copper
Basin, widespread snowfall is being observed.

&&

.MODEL DISCUSSION...

The latest hi-res models show a more ominous picture regarding
the winter weather impacting most of Southcentral, as a more
prolonged precipitation event with resultant higher totals
indicated. However, some of the other models still indicate lower
totals. That said, the hi-res guidance nailed the initial wave of
precipitation that moved through the region this afternoon, and
the forecast for this region trended heavily towards them.

Otherwise, the numerical guidance is in good agreement through the
next few days, before model continuity rapidly diminishes, leading
to less confidence in the details. In general, the pattern looks
to become more active with several rounds of precipitation
possible.

&&

.AVIATION...
PANC...Freezing rain will be the main weather concern for the
airport, as the hi-resolution latest numerical models are showing
a prolonged freezing rain event, with coverage and intensity
increasing after 06z. Otherwise, ceilings will lower into the 1500
to 2500 foot range with light winds persisting.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Day 1: Tonight through
Thursday)...

The first major winter weather event of the season has begun
across much of Southcentral. There are numerous warnings and
advisories in effect for the area in association with this storm
system, which will be addressed regionally with a summary of the
overall weather as it looks right now.

Cook Inlet Region:

A relative break in the precipitation is over the Cook Inlet
region as an upper level jet streak moves overhead. Thus, the
precipitation has become more scattered in nature. This evening,
colder air will continue to gradually drain into the area from the
Susitna Valley and Copper River Basin. Meanwhile two lobes of
energy that make up extensions of the upper level trough,
associated with the vertically stacked low well south of Kodiak,
and a strengthening upper low moving into Southwest Alaska, will
make the upper level flow become more cyclonic as it approaches
the area. This will reinvigorate the precipitation activity as the
upper level jet re-orients itself to put much of Southcentral in
its left exit region initially, which is an area favorable for
lift and enhanced precipitation activity. As cold air moves in
near the surface, the moisture will also contain warmer, above-
freezing air mass in the mid-levels of the atmosphere. This is a
setup favorable for mixed precipitation, including freezing rain
and sleet.

By Thursday morning, while the primary upper level jet
streak gets shunted off to the east, a weakening secondary jet
streak will persist for the first part of the day over the Alaska
Range, keeping Southcentral in its right entrance region, another
area favorable for precipitation. Thus, expect steady precipitation
to persist into the daylight hours Thursday morning, until the
jet streak dissipates Thursday afternoon.

Precipitation is expected to be at its heaviest intensity from
late tonight through Thursday morning. Dynamic cooling, which is
snow aloft melting as it falls through the warm mid-atmosphere,
will work to cool the warm layer with time. This will result in
the precipitation changing over to snow all the way down to sea
level. The changeover will come more quickly in the areas where
precipitation intensity is the greatest. This process is expected
to take several hours to succeed in most areas. Between that and
the warm ground, only up to an inch of accumulation is expected by
the end of the event Thursday afternoon.

Precipitation types will largely stay all snow across the Susitna
Valley north and west of Talkeetna, and will persist into Thursday
evening along the Parks Highway through Broad Pass. Three to six
inches of snow accumulation with locally higher amounts are
expected in these areas. From Talkeetna south along the Parks
Highway, some warmer air may keep the precipitation mixed. A
Winter Storm Warning is in effect through 1pm Thursday. Colder air
moving over the Palmer area and eastern Matanuska Valley from the
Copper River Basin will help keep precipitation more on the
frozen side as well, but it will also be drier, which will limit
overall precipitation totals. Meanwhile, from Wasilla south
through Anchorage and the Kenai Peninsula, warm air in the mid-
levels may help keep the precipitation liquid for longer. Surface
temperatures will determine if the precipitation type is a plain
rain or freezing rain. Sometime Thursday morning, most of these
areas will see precipitation change over to snow before ending.
Winter Storm Warnings are in effect for Anchorage, the Matanuska
Valley, the Susitna Valley, and the Kenai Peninsula north of
Anchor Point until 1 PM Thursday.

Thompson Pass and the Copper River Basin:

These areas are likely to stay in the left exit region of the
upper level jet for far longer than points farther west. With a
steady flow of moisture into the area from off the Gulf, there
will be significantly more total precipitation in these areas. For
Thompson Pass, cold air building to the north across the Copper
River Basin combined with strong moisture advection from the Gulf
will produce significant amounts of snow and wind, leading to
prolonged blizzard conditions from now through Thursday morning.
There is considerable uncertainty as to whether the city of Valdez
stays rain, or mixes with and changes over to snow. Regardless,
temperatures will remain above freezing the entire time, so even a
changeover to snow will not result in significant accumulations
in town. A Blizzard Warning remains in effect through Thompson
Pass through 3pm Thursday afternoon.

The Copper River Basin will be one of the few areas of Southcentral
where precipitation type will not be a problem; snow is expected
from beginning to end. This is the result of well-below-freezing
air building into the area throughout the snowfall event. A strong
jet streak currently approaching the region will gradually shift
eastward with time. This will keep the Copper Basin in a very
favorable left exit region of the jet. Thus, with plenty of lift
expected, the primary limiting factor for snow will be the amount
of moisture that can make it into the area from over the Chugach
Mountains. Since the moisture fetch from off the Gulf will be
substantial, there should be plenty of snow that successfully
moves into the area. A Winter Weather Advisory for 6 to 10 inches
of snow with higher amounts up to 15 inches south of Tonsina
remains in effect through 3pm Thursday afternoon.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

Bands of precipitation are pushing northward into Southwest
Alaska and the Kuskokwim Delta on the north side of a low in the
north Pacific. An area of split flow exists in the Kuskokwim
Valley that is providing some upper level support for the pulses
of energy moving through the mean flow on the north side of the
low south of the Alaska Peninsula. Some of these waves will
interact with another upper low tracking from the north overnight
Wednesday into Thursday morning and spark some snow for the
Kuskokwim Valley. As the northern low tracks south on Thursday,
expect areas of snow and rain for southwest Alaska, Bristol Bay
and the AKPEN. Areas of snow showers in the Kuskokwim Valley will
continue as the low tracks ashore Saturday morning and into
Saturday afternoon while rain and snow showers in Southwest Alaska
will change over to all snow.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

The upper low tracking from northwest Alaska into Southwest
Alaska will bring some showers to the western Bering on its
backside. High pressure will build in behind the low briefly
Friday night into Saturday. Another frontal boundary enters the
western Bering and Aleutians on Saturday afternoon.

&&

.MARINE (Days 3 through 5/Saturday through Monday)...
A series of gale to storm force lows will affect the Aleutians
and Bering Sea Saturday through Monday. There is quite a bit of
uncertainty in the track of individual systems, so it's hard to
say where the worst conditions will be located. The Gulf of Alaska
looks quieter through this period.

&&

.LONG TERM FORECAST (Days 4 through 7/Sunday through Wednesday)...
Beginning on Sunday, an upper level low will approach Southcentral
from the west. Model guidance from previous days has differed on
the ultimate track of this low, but the latest solutions all
depict the same general idea, though there are differences in
timing. They also all show a trailing upper wave immediately
following the low. With arctic air spreading across Southcentral,
this set-up is favorable for snow across most of the region,
sometime in the Sunday through Monday time frame.

Meanwhile, a strong jet stream will drive a long-wave trough
eastward across the North Pacific. Expect numerous fast moving
deep storm systems to rapidly form and move through the trough,
affecting the Bering Sea/Aleutians through at least the middle of
next week. Model guidance is all over the place with depictions
of individual storm systems, but in general agreement on the storm
track which will be close the Aleutian chain. The first of these
storms will begin to impact the southern mainland of Alaska next
Monday or Tuesday. Expect high winds/seas and heavy precipitation
with each storm. It looks like there will be enough arctic air
over the southern mainland to support mostly snow inland, with
rain likely along the coast. Of course, individual storm tracks
will greatly affect this. Bottom line, the extended forecast
period will be characterized by an active storm pattern with
widespread weather impacts likely across the entire region.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning 101, 111, 121, 145.
 		 Blizzard Warning 131.
		 Winter Weather Advisory 141.
MARINE...Gale 119 130 180 181 182.
		 Heavy Freezing Spray 180.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...PD
SOUTHCENTRAL ALASKA...JW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...LB/JR
MARINE/LONG TERM...SEB