Gale Warning 650, NWS Anchorage, AK

922 
FZAK61 PAFC 251229
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
329 AM AKST Sun Nov 25 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.

PKZ399-260230-
329 AM AKST Sun Nov 25 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 956 mb low at 52N 156W moves to 54N 152W at 959 mb Sun night.
The low then moves to 57N 151W at 971 mb Mon night.

$$

PKZ351-260230-
Gulf of Alaska Offshore North of 57N and West of 144W-
329 AM AKST Sun Nov 25 2018

...GALE WARNING TODAY...

.TODAY...SE wind 30 to 45 kt. Seas 14 to 22 ft. Rain.
.TONIGHT...SE wind 10 to 20 kt. Seas 17 ft.
.MON...SE wind 15 to 25 kt. Seas 16 ft.
.MON NIGHT...SE wind 25 kt. Seas 14 ft.
.TUE THROUGH THU...SE wind 10 to 25 kt. Seas 7 to 12 ft.

$$

PKZ352-260230-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
329 AM AKST Sun Nov 25 2018

...GALE WARNING TODAY...

.TODAY...SE wind 25 to 40 kt becoming S 10 to 25 kt in the
afternoon. Seas 15 to 18 ft. Rain.
.TONIGHT...SE wind 10 to 25 kt increasing to 20 to 30 kt after
midnight. Seas 17 ft.
.MON...SE wind 20 kt becoming 10 to 25 kt in the afternoon. Seas
15 to 18 ft.
.MON NIGHT...S wind 10 to 25 kt. Seas 12 to 17 ft.
.TUE THROUGH WED...SW wind 10 to 25 kt. Seas 8 to 13 ft.
.THU...S wind 15 kt. Seas 6 to 9 ft.

$$

850 
FZAK61 PAFC 260013
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
313 PM AKST Sun Nov 25 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.

PKZ399-261345-
313 PM AKST Sun Nov 25 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 951 mb low at 53N 157W Sun afternoon moves to 55N 150W at 965 mb
by Mon afternoon and then to 59N 150W at 976 mb by Tue afternoon. 

$$

PKZ351-261345-
Gulf of Alaska Offshore North of 57N and West of 144W-
313 PM AKST Sun Nov 25 2018

.TONIGHT...SE wind 10 to 20 kt. Seas 17 ft.
.MON...SE wind 10 to 20 kt increasing to 25 kt in the afternoon.
Seas 16 ft.
.MON NIGHT...SE wind 25 kt. Seas 14 ft.
.TUE...S wind 15 to 25 kt. Seas 9 to 14 ft.
.TUE NIGHT...SW wind 15 to 30 kt. Seas 7 to 12 ft.
.WED THROUGH FRI...SE wind 15 to 30 kt. Seas 6 to 10 ft.

$$

PKZ352-261345-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
313 PM AKST Sun Nov 25 2018

.TONIGHT...SE wind 10 to 25 kt. Seas 17 ft.
.MON...SE wind 15 to 30 kt. Seas 15 to 18 ft.
.MON NIGHT...S wind 15 to 30 kt. Seas 12 to 17 ft.
.TUE...SW wind 15 to 30 kt. Seas 11 to 15 ft.
.TUE NIGHT...W wind 20 to 30 kt. Seas 9 to 14 ft.
.WED THROUGH FRI...S wind 10 to 25 kt. Seas 5 to 10 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
456 AM AKST Sat Nov 24 2018

.ANALYSIS AND UPPER LEVELS...
A low, just south of Adak, is extending an inverted trough over
the Eastern Bering. This low is the parent low for a slowly
weakening front that is moving to the northeast over the mainland.
Precipitation is occurring with this front along the western
mainland which can be observed by radar. A second low in the
southern Gulf is moving northward toward Southcentral AK. This low
is wearing away the ridge that once encompassed the Gulf of AK
and is bringing moisture into the area. This low is also pushing
a front into the northern Gulf of AK coast, bringing precipitation
and strong southeasterly winds to the area. Convective style
showers are occurring on the leading edge of the front while more
stratiform precipitation is occurring along the western Gulf coast.

&&

.MODEL DISCUSSION...
Models continue to perform poorly. Run to run continuity has been
very inconsistent, with models now moving the low moving north
through the Gulf of AK east about 25 miles. While this might not
seem like much, it completely changes the wind forecast for
localized areas along the coast like Turnagain Arm. Therefore, a
complicated forecast where substantial changes had to be made
tonight. Initially, models had starting tracking this system more
westerly and at least had some agreement on this, but shifted it
east again last minute. Models also still disagree on system speed
and timing through the weekend with weather moving into the coast.
Went with the GFS for tonight's forecast package, as that seemed
the most reasonable.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist for most of the
TAF period. Fog has cleared out and is not expected to return.
MVFR ceilings and visibility from light snow will move in tomorrow
night due to a low pressure system moving in from the Gulf of AK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2: Tonight
through Sunday)...

The forecast this weekend remains challenging as two low pressure
systems rapidly develop over the North Pacific and move to the
southern mainland. Winds remain the biggest challenge as models
struggle with the track of the low centers. The precipitation for
the first system will primarily be snow for inland locations with
a change over to rain for all coastal areas and locations just
inland. With a cold pool remaining across much of the Copper River
on Sunday, there could be some freezing rain potential.

The first front pushes across the Kenai Peninsula and northern
Gulf waters this morning with light rain expected across the
southern and eastern Peninsula and snow for areas north and west
of Seward. The front pushes across Prince William Sound and along
the Northeast Gulf by late morning. A wintry mix is expected along
the western sound as low level flow remains from the northeast,
with snow expected to change over to rain for coastal locations to
the east. The front pull inland this evening bringing light snow
as it continues across the interior.

The focus for the strongest wind gusts today and tonight are
expected mainly along the northern Gulf as the surface low
increases the coastal pressure gradient due to a ridge holding
over the Alcan Border. Winds across the region generally increase
out of the north and east as the boundary pushes through. Expect
gusts to develop today and persist through the weekend as a second
North Pacific system ushers the next front to the coast by mid day
Sunday.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
A front associated with a strong low in the southern Gulf
currently stretches across Southwest Alaska bringing snow and
breezy east to northeasterly winds to the area. Precipitation will
taper off this afternoon and evening as the parent low tracks
further to the north into the Gulf and shears apart the portion of
the front stretched over Southwest Alaska. The next frontal
system tracking towards the southwestern Gulf will rotate across
Southwest Alaska from the east Sunday and Sunday night, bringing
in warmer air aloft. With the surface winds persisting out of the
northeast and reinforcing the cold low level air there is some
concern that the overrunning precipitation could bring a variety
of precipitation types including a chance of freezing rain mixed
with snow. A surface low will track north into Southwest Alaska
Monday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A vertically stacked low to the south of the central Aleutians
will weaken as it tracks south today while a developing frontal
wave to its south strengthens and swings northeastward to replace
it as the dominant low. A frontal system associated with this low
will lift north to be located south of the Alaska Peninsula
Saturday night as the low becomes vertically stacked further to
the south. The low will then continue to the northeast towards the
southwestern Gulf swinging its frontal system over the Alaska
Peninsula Sunday afternoon through Sunday night while
northwesterly flow increases across the Bering. The next low
pressure system coming in from the west will reach the western
Aleutians Monday night.

&&

.LONG TERM FORECAST (Days 3 through 7: Monday Nov 26th through
Friday Nov 30th)...

The forecast period commences with the longwave trough across the
Bering and the North Pacific with a ridge axis over the Western
Aleutians. At the onset of the forecast period, the models
generally ping into the same features however, there are some
timing and tracking issues. The most glaring difference is with
the low entering the Gulf Of Alaska on Monday. The GFS and ECMWF
are about 350 NM apart with the placement of the surface low south
of Kodiak and the ECMWF being the most southerly solution for
this storm. Overall, it looks like an unsettled pattern for both
the Bering and the Gulf Of Alaska. Also noteworthy is the
emergence of the "Atmospheric River" in the Gulf Of Alaska. The
current thinking is that the bulk of the "Atmospheric River" will
move into Southeast Alaska, and Southcentral will only get a
portion of the moisture plume. The pops were bumped up again this
forecast package for the Prince William Sound Region. In addition
to the moisture, this system has a tight pressure gradient
associated with it, gusty winds expected in some inland locations
as well as over the water.

All the while, an assembly of lows from the Sea Of Okhotsk and
Bering are depicted in the operational runs of the global models.
The first is anticipated late Monday and Tuesday. The GFS is a
skosh quicker bringing this low eastward but both the GFS and the
ECMWF place the track directly over the Chain. In its wake a weak
ridge axis will push across the Aleutians. Last but not least, a
cyclone will move out of the Sea Of Okhotsk and into the Western
Bering late in the period. But given the run to run consistency
issues only minor adjustments for the later portion of this
forecast package, as we all wait for the details of these cyclones
to flesh out.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 161.
MARINE...Storm Warning 119 120 125 351 352
 Gale Warning 121 127 128 130 131 132 137 138 139 140 150 155 177
411 412 413

&&

SYNOPSIS AND MODEL DISCUSSION...RA/BJB
SOUTHCENTRAL ALASKA...KH
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...PS