Gale Warning 544, NWS Anchorage, AK

860 
FZAK61 PAFC 222256
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
256 PM AKDT Mon Oct 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.

PKZ399-231330-
256 PM AKDT Mon Oct 22 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 973 mb North Pacific low will move into the eastern Gulf Tue 
morning then it will move to 58N 146W at 968 mb Tue afternoon. 
The low will then move inland over Anchorage Tue night. A front 
will move into the southern Gulf Wed morning. 

$$

PKZ351-231330-
Gulf of Alaska Offshore North of 57N and West of 144W-
256 PM AKDT Mon Oct 22 2018

...GALE WARNING THROUGH TUESDAY...

.TONIGHT...NE wind 15 to 25 kt increasing to 20 to 35 kt after
midnight. Seas 8 to 12 ft. Rain.
.TUE...NW wind 20 to 35 kt becoming SW 25 to 40 kt in the
afternoon. Seas 10 to 18 ft. Rain.
.TUE NIGHT...S wind 15 to 25 kt. Seas 8 to 13 ft.
.WED...E wind 15 to 30 kt. Seas 8 ft.
.WED NIGHT...NE wind 25 to 40 kt. Seas 10 to 18 ft.
.THU...SE wind 20 to 35 kt. Seas 13 to 21 ft.
.FRI THROUGH SAT...E wind 15 to 30 kt. Seas 8 to 13 ft.

$$

PKZ352-231330-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
256 PM AKDT Mon Oct 22 2018

...GALE WARNING TUESDAY...

.TONIGHT...N wind 10 to 20 kt. Seas 9 ft.
.TUE...W wind 20 to 35 kt. Seas 9 to 14 ft.
.TUE NIGHT...SW wind 10 to 20 kt. Seas 8 to 12 ft.
.WED...E wind 15 to 30 kt. Seas 6 to 10 ft.
.WED NIGHT...NE wind 20 to 35 kt. Seas 8 to 16 ft.
.THU THROUGH SAT...SE wind 20 to 35 kt. Seas 9 to 17 ft.

$$

828 
FZAK61 PAFC 231144
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
344 AM AKDT Tue Oct 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.

PKZ399-240045-
344 AM AKDT Tue Oct 23 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 973 mb low at 58N 144W moves inland Tue afternoon at 967 mb. A 972
mb North Pacific low moves to 57N 142W at 966 mb Wed night.

$$

PKZ351-240045-
Gulf of Alaska Offshore North of 57N and West of 144W-
344 AM AKDT Tue Oct 23 2018

...GALE WARNING TODAY...

.TODAY...S wind 25 to 40 kt. Seas 12 to 20 ft. Rain showers.
.TONIGHT...S wind 15 to 25 kt. Seas 12 to 16 ft subsiding to 10 ft
after midnight.
.WED...SE wind 10 to 20 kt becoming E 15 to 30 kt in the afternoon. 
Seas 7 to 10 ft. Rain.
.WED NIGHT...NE wind 25 to 40 kt. Seas 11 to 19 ft.
.THU...N wind 25 to 40 kt. Seas 13 to 21 ft.
.FRI THROUGH SAT...E wind 15 to 25 kt. Seas 8 to 13 ft.

$$

PKZ352-240045-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
344 AM AKDT Tue Oct 23 2018

.TODAY...W wind 15 to 30 kt. Seas 9 to 14 ft.
.TONIGHT...SW wind 10 to 20 kt. Seas 8 to 11 ft.
.WED...E wind up to 20 kt becoming N 15 to 30 kt in the afternoon.
Seas 6 to 9 ft. Rain.
.WED NIGHT...NW wind 25 to 40 kt. Seas 9 to 14 ft.
.THU...W wind 30 to 45 kt. Seas 13 to 21 ft.
.FRI THROUGH SAT...E wind 15 to 30 kt. Seas 8 to 13 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
434 PM AKDT Sun Oct 21 2018

.ANALYSIS AND UPPER LEVELS...
A mature vertically stacked low is moving from the western Gulf
of Alaska to Bristol Bay. Cold air aloft wrapping around this
center has increased the atmospheric lapse rates and destabilized
the atmosphere over the Gulf and Southcentral. This is evident on
recent satellite and radar imagery which should a broad band of
showers and isolated thunderstorms under the dry slot. Several
lightning strikes have occurred over the Gulf waters and along the
coast. In addition to instability, strong pressure gradients
continued brisk southerly winds over the Gulf in addition to
locally strong gap flows inland.

Out west, rain is increasing over the AKPEN and southwest Alaska. For
the first time in several days, weather has become more active
over the eastern Bering and visible satellite imagery shows
stratus clouds in the area of the low. In juxtaposition, the Gulf
of Alaska and western Bering are experiencing more banded,
convective style cloud cover with scattered skies. With the low
spinning over Bristol Bay, gusty conditions prevail over much of
the western mainland.

&&

.MODEL DISCUSSION...
Models are in fairly good agreement overall in the upper levels
and to a lesser degree the surface synoptic pattern. The main
differences come in the speed and intensification of a developing
frontal wave along a broad baroclinic zone over the northeast
Pacific. What is certain is that there will Gale to Storm force
low over the Gulf Tuesday. Again the track and timing of this
center is still in question. So for now will perform some model
blends and hand edits as a best first guess.

&&

.AVIATION...
PANC...VFR conditions and light winds are expected.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
An unstable airmass combined with deep southerly flow between the
upper level low/trough centered over the Alaska Peninsula and the
upper level ridge over western Canada will continue to stream
showers as well as some isolated thunderstorm across the western
Gulf and Kenai Peninsula through tonight. As the southern portion
of the upper level trough swings east Monday and breaks off into a
separate low south of the central Gulf Monday night, the frontal
system stretched across the Kenai Peninsula and western Gulf will
slowly rotate and sink to the southwest as it shears apart. The
orographically enhanced precipitation along the east and
southeastern Kenai Peninsula and mountains to the west of Cook
Inlet will start tapering off Monday morning while precipitation
over Kodiak Island and the east slopes of the Aleutian range will
persist the longest, tapering off Monday evening.

The next potentially rather strong low will spin up Monday night
as the upper low coming in from the west interacts with the front
stalled over the southeastern Gulf. The resulting rapidly
deepening surface low will track into the Central Gulf Tuesday
morning tightening the northerly offshore pressure gradient across
the northern Gulf Coast. While there will not be much in the way
of cold air inland to support winter level out flow, the low
should still be deep enough to generate fairly strong northerly
gap winds all by itself. Additionally, upslope north to
northeasterly flow at low levels (with associated upslope cooling)
and strong east to southeasterly flow aloft will likely bring a
period of moderate to briefly heavy snow to Thompson Pass midday
Tuesday.

The low will continue to the northwest Tuesday, making landfall
and swinging inland over the Kenai Peninsula Tuesday evening.
While plenty of model uncertainty remains regarding the precise
strength and track of this low, an area of storm force winds over
the northern Gulf waters looks likely with strong Gales elsewhere.
Additionally, the orientation of the winds aloft look favorable
for the strong Gales to push into Prince William Sound Tuesday
afternoon/evening as well as favorably oriented terrain gaps such
as Turnagain Arm. In Cook Inlet, northerly winds will likely
increase to Gales out ahead of the low with northwesterly Gales
through the Barrens. The pressure rises behind the low, once it
makes landfall will also bear close watching for a strong push of
southerly winds Tuesday night. However with the track and timing
of landfall still somewhat uncertain have not yet tried to pin
those down too precisely.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
There is an occluded boundary that spans from Southcentral to the
AKPEN. The current pressure on the surface low over Bristol Bay is
approximately 980mb. This low has already maxed out and is
steadily on decline this period. The radars at King Salmon (PAKC)
and Bethel (PABC) both have showers on them. Expect more
wraparound moisture this evening across portions of Southwest. The
surface low that is driving the pattern will drift off to the
northwest and then re-curve south on Tuesday. With warm
temperatures in the boundary layer, expecting rain and rain
showers in the low elevations and the higher elevations will get a
fresh blanket of of snow. Unsettled weather will remain over the
area to start the week as a weakening low drifts into Bristol Bay
and wobbles around.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
There is a mature low over Bristol Bay which has already reached
its maximum intensity. This storm will continue to be the main
event for this time period. The surface low will drift off to the
northwest and then re-curve and head south on Tuesday over
Unalaska. The pressure gradient will remain tight on the back side
of the low through Wednesday. Expect more small craft winds. Cold
air aloft will be ushered into the Bering which will result in
convective conditions.

&&

.LONG TERM FORECAST (Days 4 through 7: Wednesday Night through
Sunday)...

There have been a few changes to the long-term forecast regarding
the low expected to impact the Gulf on Thursday. The model trends
now are suggesting a slower forward speed of the low across the
Gulf. Thus, while the fastest models had the low making landfall
Thursday evening in yesterday's forecast, now the fastest ones
have it moving in on Friday morning. The GFS remains the slow
outlier, not moving the center inland into the Kenai Peninsula
until late Friday night. Secondly, the models are now showing a
steady weakening trend in the low. Thus, its strongest point as
far as lowest central pressure goes is when it enters the Gulf
Wednesday night. The steady weakening should keep winds down
somewhat, especially considering the slowing forward speed of the
low. However, since the low will be starting off in the mid-960s
when it enters the Gulf, it will still take some time for the
winds to appreciably diminish, and as such widespread gales are
still expected over a large area of real estate over the Gulf
waters. Since the center of the low is tracking on more of a
southeast to northwest direction, that should diminish the barrier
jet strength along the north Gulf Coast Thursday into Thursday
night.

The downside to these changes, primarily with the slowing speed of
the low, is that will allow for a more prolonged period of rain
associated with the low along the North Gulf Coast, particularly
along the coastal Kenai Peninsula. The rain will begin sometime
late Wednesday night/early Thursday morning, and continue into
Saturday morning. Depending on the track and intensity of a front
that is not well agreed upon in the models, its moving through
Saturday may cause the rain to resume Saturday afternoon and
continue into Saturday night. The good news once again is the
weakening low should prevent anyone from getting any heavy rain,
but rather a light to moderate rain. It remains unchanged that the
heaviest rain along the Kenai Peninsula into Seward will be after
the low center passes south of Seward on Friday morning. After
that point, the winds will turn out of the south and draw Gulf
moisture into the Kenai Mountains and Seward for the rest of the
day.

As regards the colder air across the Bering, that aspect of the
forecast remains on track early in the period. The core of the
coldest air will be over the western Bering Wednesday night. It
will move over the Pribilofs and the central Bering Friday
morning. The Canadian model stops the eastward advance there.
However, both the GFS and EC continue it into the Kuskokwim Delta
by Saturday morning. Those two models begin to diverge greatly
after that, with the GFS taking the core of the cold air mass well
north after that, leaving the rest of the cold air to warm up pretty
quickly, while the EC leaves the cold air in place over much of
Southwest Alaska through Sunday. Even with this most aggressive
solution, the EC still does not bring much, if any, of that cold
air into Southcentral. Stay tuned.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning 119.

&&

SYNOPSIS AND MODEL DISCUSSION...RA/RC
SOUTHCENTRAL ALASKA...JR
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PJS
LONG TERM...JW