Gale Warning 751, NWS Anchorage, AK

821 
FZAK61 PAFC 260004
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
304 PM AKST Tue Dec 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.

PKZ399-261530-
304 PM AKST Tue Dec 25 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front in the Gulf Tue afternoon will move into the eastern Gulf
by Tue evening. A 993 mb low at 53N 158W Wed afternoon moves to
59N 148W at 994 mb by Thu afternoon.

$$

PKZ351-261530-
Gulf of Alaska Offshore North of 57N and West of 144W-
304 PM AKST Tue Dec 25 2018

.TONIGHT...E wind 15 to 30 kt. Seas 11 to 17 ft. Rain.
.WED...NE wind 10 to 25 kt becoming SE up to 15 kt in the
afternoon. Seas 11 to 18 ft.
.WED NIGHT...S wind up to 15 kt becoming SE 15 to 30 kt after
midnight. Seas 10 ft.
.THU...S wind 25 to 35 kt. Seas 11 to 18 ft.
.THU NIGHT...SW wind 15 to 30 kt. Seas 10 to 16 ft.
.FRI THROUGH SUN...S wind 15 to 30 kt. Seas 7 to 12 ft.

$$

PKZ352-261530-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
304 PM AKST Tue Dec 25 2018

.TONIGHT...NW wind 10 to 25 kt, except NE 10 to 25 kt E of 147W. 
Seas 9 to 15 ft. Rain.
.WED...S wind 10 to 20 kt. Seas 10 to 16 ft.
.WED NIGHT...SE wind 10 to 25 kt becoming S 20 to 30 kt after
midnight. Seas 12 ft. Rain.
.THU...SW wind 20 to 35 kt. Seas 11 to 17 ft.
.THU NIGHT...SW wind 15 to 25 kt. Seas 11 to 15 ft.
.FRI THROUGH SUN...S wind 15 to 30 kt. Seas 8 to 16 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
455 PM AKST Mon Dec 24 2018

.ANALYSIS AND UPPER LEVELS...
Relatively quiet weather, including dry conditions, light and variable
winds, and cold temperatures, remain across Southcentral Alaska this
afternoon. Strong surface inversions were evident by the presence
of a fairly extensive band of stratus and fog extending from Knik
Arm to the western Kenai Peninsula near Kenai/Soldotna. A shortwave
along the northeast Gulf coast has brought precipitation to areas
along coastal regions. Light snow showers were observed at Cordova,
while Middleton Island saw light rain throughout the day. Looking
to the west, a vertically stacked low southeast of Adak seems to
be the major feature of the day. This low is weakening as its
front continues to move eastward over the central Aleutians and
AKPEN towards the North Pacific. Gusty conditions and light snow
showers that were observed this afternoon will continue to be the
main impact from this system.

&&

.MODEL DISCUSSION...
Models are in fairly good synoptic agreement through early Thursday.
They all appear to have a similar handling with the next strong
low heading toward the western Gulf Wednesday/Thursday. They start
to diverge some Thursday afternoon with the GFS being the further
west solution.

&&

.AVIATION...
PANC...With a steep inversion in place, expect fog to continue to
produce mainly IFR to LIFR conditions at the terminal. Increasing
northerly flow (ahead of a frontal boundary moving into the Gulf)
Tuesday morning should be enough to help lift ceilings and improve
visibilities by Tuesday afternoon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Cold temperatures and patchy fog will continue tonight as the weak
upper low remains over the area. There is enough cyclonic flow
with this low to bring some snow showers to the Prince William
Sound area. The pattern will begin to change on Tuesday as a front
approaches the area from the south. Precipitation with this front
will move into Kodiak tonight, then to the Kenai Peninsula and
Gulf coast Tuesday morning. Kodiak may start with snow tonight,
but will transition over to rain Tuesday morning as warm air
surges northward with the front. On Tuesday afternoon the front
will slow down or possibly stall along the Gulf coast as the
upper level energy splits between a low west of Kodiak Island and
another low over the eastern Gulf. Some precipitation is possible
inland, but will be limited by the stalling of the front and some
protection from the coastal mountains. On Tuesday night the low
west of Kodiak will open up into a trough, and begin to slide
northward. This will bring chances of precipitation to the Kenai
and Cook Inlet area, moving north to the Matanuska and Susitna
valleys as the day progresses. This system is also fairly weak
and not a lot of precipitation is expected. On Wednesday night a
stronger system will develop in the southwest Gulf and work its
way northward to Kodiak Island, with the leading frontal
precipitation reaching the Kenai Peninsula and Gulf coast by
Thursday morning.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3/Monday
night through Wednesday night)...
Cold temperatures still linger, especially in low lying interior
locations of southwest Alaska. Areas around Bethel continue to see
some light snow today. The cold air in place will be stubborn and
will hold in place for another day or two, so kept minimum
temperatures in the minus teens for some interior areas. Warming
should finally take over on Wednesday.

This warming will be associated with a frontal push into southwest
Alaska, which will bring some moisture with it. Right now, we are
just looking for some light snow with this system, with little
accumulation. Some higher totals, up to 4 inches, are possible
with enhanced snow in the Kuskokwim Mountains. Models are doing a
decent job of picking up on this today and are consistent on
keying in on the upslope flow over the mountains. Therefore, made
sure this stayed in the forecast today. Overall though, not much
expected out of this system before the end of the forecast period.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3/Monday
night through Wednesday night)...
A mature low pressure system is moving southeast on the Pacific
side of the Aleutian Island chain. It is sending a stretched out
occluded front north over the central and eastern Aleutians. This
boundary is bringing light snow with it. There is also a band of
post frontal winds that will produce gale force conditions in the
marine waters on the south side of the islands tonight. Meanwhile,
a shortwave ridge is leading to quiet weather along the western
Aleutians today.

The next low pressure system is on the heels of the one currently
located south of the eastern Aleutians. This quick succession of
lows means a just a short break in the weather for the Aleutians
and the Bering. This next system will enter the western Aleutians
tonight into early tomorrow, bringing more gale force winds with
it. It will weaken as it moves east through the week. It will also
reinvigorate the persistent northerly flow for the Bering Sea
Wednesday night.

&&

.LONG TERM FORECAST (Days 3 through 7...Thu Dec 27 through
Mon Dec 31)... The pattern will become quite a bit more active
during this time period. This is due to a deep cold trough
extending from the Bering Strait to the North Pacific, creating
an active storm track from the north central pacific to the Gulf
of Alaska. (This set up is actually quite a bit like the one we
had in the middle of December where Anchorage had many snow
chances.) The first of these systems approaches the Northern Gulf
of AK on Thu. Model agreement with this system is actually pretty
good at this time. They all paint at least a gale- force low
working from Kodiak Thu morning toward Prince William Sound by
early Fri. This system will certainly bring precipitation to the
Gulf Coast, along with some gusty easterly winds. Precipitation
looks to start out as snow, but could slowly become mixed with
rain during the event. For inland locations (to include Cook
Inlet), this will be the best shot for widespread snow since the
middle of last week. There are still a lot of details to iron out
and this storm track has proven extremely challenging for models
this past month, however, the system does bear watching.

Out west, snow chances will also return for SW AK while a warm
occluded front impinges upon the Aleutians. The cold trough
digging through the Bering Strait looks to bring a couple shots of
light snow across the SW Mainland. As the trough continues to dive
into the weekend, expect another round of gusty winds and snow
showers across parts of the Alaska Peninsula and through bays and
passes on the Pacific side. Out over the Western Aleutians, the
warm occlusion will bring a mix of rain/snow Fri-Sat. This front
will set the stage for next week's weather.

As the front elongates over the Central Aleutians, the models
start to differ. The GFS wants to develop a potent triple-point
low along the boundary. This would serve to cut off the warm air
advection and keep the storm track primarily through (west to
east) the Gulf of AK. However, the European and Canadian models
(and their various ensembles) present a solution with much better
warm air advection moving north. This in turn builds a sharp ridge
over Eastern/SE AK. With the ridge in place, the storm track
starts to become much more SW to NE (picture Alaska Peninsula
towards central AK Range) allowing much warmer air into the
southern mainland. Individual pieces of energy and associated
surface lows are too hard to lock onto at this time. But the main
idea to start 2019 would be a much warmer and somewhat wetter
pattern with the possibility of some rain mixing with snow over
Southern AK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Dense Fog Advisory 101.
MARINE...Gale Warning 130 131 132 138 139 150 155 172.
         Heavy Freezing Spray 181.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...ALH/BC
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...BB
MARINE/LONG TERM...MSO