Gale Warning 103, NWS Anchorage, AK

439 
FZAK62 PAFC 031257
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
357 AM AKST Sat Feb 3 2018

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-040200-
357 AM AKST Sat Feb 3 2018
.SYNOPSIS FOR CENTRAL BERING SEA...

A 982 mb low at 50N 172W will dissipate Sun morning near 48N 180E.
A 986 mb North Pacific low will move to 49N 178W Sun evening and
then it will move to 51N 179W at 989 mb Mon morning. A North 
Pacific low approaches the Eastern Aleutians Mon morning. 

$$

PKZ411-040200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
357 AM AKST Sat Feb 3 2018

.TODAY...NE wind 20 to 30 kt. Seas 12 to 15 ft. Freezing spray.
.TONIGHT...NE wind 20 to 30 kt. Seas 13 to 16 ft. Freezing spray.
Snow.
.SUN...E wind 15 to 25 kt. Seas 10 to 15 ft. Freezing spray. Snow
showers.
.SUN NIGHT...E wind 15 to 25 kt. Seas 9 to 12 ft.
.MON THROUGH WED...NE wind 10 to 25 kt. Seas 6 to 11 ft.

$$

PKZ412-040200-
Bering Sea Offshore 171W to 180 and North of 56N-
357 AM AKST Sat Feb 3 2018

.TODAY...NE wind 30 kt. Seas 12 to 17 ft. Freezing spray. Snow.
.TONIGHT...E wind 20 to 30 kt. Seas 13 to 17 ft. Freezing spray.
Snow.
.SUN...E wind 15 to 30 kt. Seas 9 to 14 ft. Freezing spray.
.SUN NIGHT...E wind 25 kt. Seas 9 ft.
.MON THROUGH WED...E wind 15 to 30 kt. Seas 6 to 11 ft.

$$

PKZ413-040200-
Bering Sea Offshore 171W to 180 and South of 56N-
357 AM AKST Sat Feb 3 2018

...GALE WARNING TODAY...

.TODAY...NE wind 35 kt. Seas 17 ft. Rain and snow.
.TONIGHT...E wind 15 to 30 kt. Seas 10 to 16 ft.
.SUN...E wind 25 kt. Seas 9 to 13 ft.
.SUN NIGHT...E wind 15 to 25 kt. Seas 10 ft.
.MON THROUGH WED...E wind 15 to 30 kt. Seas 7 to 12 ft.

$$

PKZ414-040200-
Bering Sea Offshore East of 171W-
357 AM AKST Sat Feb 3 2018

...GALE WARNING TODAY...
...HEAVY FREEZING SPRAY TODAY...

.TODAY...E wind 35 kt. Seas 11 to 16 ft. Heavy Freezing spray along
the ice edge. Snow.
.TONIGHT...E wind 15 to 30 kt. Seas 9 to 14 ft. Freezing spray.
Snow.
.SUN...E wind 15 to 25 kt. Seas 6 to 11 ft. Freezing spray.
.SUN NIGHT...E wind 20 to 30 kt. Seas 6 to 9 ft.
.MON...E wind 15 to 30 kt. Seas 5 to 10 ft.
.TUE THROUGH WED...SE wind 15 to 30 kt. Seas 6 to 11 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
519 AM AKST Fri Feb 2 2018

.ANALYSIS AND UPPER LEVELS...

A weak col in the upper levels has developed with ridging over
northwest Alaska, ridging over the far southern Gulf, and weak
remnant troughing along the Gulf Coast and the southern Bering.
The two aforementioned ridges are dominating the general flow
elsewhere, but they oppose one another as far as upper level winds
are concerned. Thus, northerly flow over Alaska is running into
southerly flow over the Pacific and shearing apart to the east and
west. In other words, very little is happening in the upper levels
to change the ongoing weather pattern over Southern Alaska. Low
level moisture on easterly flow is largely confined to the
southern Gulf and the Kodiak area, which then continues westward
into the southern Alaska Peninsula. Being ill-supported, any
associated precipitation is light.

So for nearly all of southern mainland Alaska, the primary weather
story remains the winds, as high pressure over mainland Alaska
pushes the cold air over the state southward and out into the Gulf
towards the low pressure there. In the locations that are
windiest, generally temperatures remain warmer. In the calm
locations, temperatures are in free-fall once again due to optimal
radiational cooling conditions with clear skies and a deep, well-
established snow pack.

&&

.MODEL DISCUSSION...

The models remain in excellent agreement overall over the next
couple days across most of Southern Alaska. This agreement lends
to higher overall forecast confidence. The winds through the gaps
remain the primary forecast challenge through the weekend,
followed by watching a series of low pressure systems move
northward and gradually erode the protective dome of high pressure
such that more active weather can make it into southern Mainland
Alaska by the start of the upcoming workweek. As regards those
lows, the models don't yet have a good handle on those, and it's
there that there is much more disagreement and uncertainty in the
forecast. This still is very common, given the lows are weak and
over the very data-sparse North Pacific.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Little overall change has occurred in the weather pattern as high
pressure continues to bring clear skies and gap winds to Mainland
with a nearly stationary weak front and rain/snow towards Kodiak
Island. A shortwave that moved over the Mainland overnight and
caused an increase in many of the gap winds has mostly moved south
of the North Gulf Coast, which should allow these winds to slowly
weaken over the course of this morning, then fall below strong
wind criteria (45 mph) throughout the area by this evening. This
should allow for temperatures tonight in areas like west Anchorage
and the Matanuska Valley that have stayed much warmer over the
past few nights to be much colder tonight, potentially cold enough
to bring the first official below zero temperature at the
Anchorage Airport of the season tonight. Gap winds will then
reform again Friday evening in advance of a weak front that will
clip the southern gulf, but with a much weaker pressure gradient
and no upper level support these should remain much weaker than
the winds that blew earlier this week. This front will bring
rain/snow back into Kodiak into this weekend, with continued
outflow winds generally under gale force along the North Gulf.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
(Today through Monday)

A slow moderating trend is in store for the region, as high
pressure which has dominated our weather for the past week
continues to slowly loose its grip. This is large due to the flat
ridge re-centering over the Yukon and British Columbia, while a
series of lows and their associated surface fronts push northward
into the region. The first warm front attached to a west central
Aleutians low will stall just south of the peninsula, but it'll be
close enough for over-running precipitation to affect parts of
the region, mainly south of Bristol Bay and the AKpen for Friday
evening, lifting northward some through the weekend, with
precipitation potential spreading north as well. Another benefit
of the approaching front is winds will gradually veer from a
northeasterly to southeasterly direction, especially as one heads
down the AKpen. This will allow for some down-slope warming to help
moderate the airmass. However, it'll also allow precipitation to be
more spotty west of the Alaska Range.

Heading into the start of the work week, another low will develop
and move from the North Pacific to the AKpen for Monday, dragging
a warm front into the area as well. Increased lift aloft and
surface convergence will allow for precipitation to become more
widespread, with a continued slight moderating trend in
temperatures, especially for southern parts of the mainland.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
(Today through Monday)

Increasing precipitation potential and wind speeds is in our
future, especially for areas along and south of the Aleutians. A
pair of low pressure systems will send an occluded front northward
today, while the lows spin around each other in a Fujiwhara-like
fashion. Increased surface convergence and ascent aloft will
allow a fairly widespread showery pattern to develop. Initially,
snow showers will be the predominant precipitation type. However,
warm advection in the lower levels of the atmosphere will allow
any frozen precipitation to switch over the the liquid variety by
Saturday morning. Although the lows really never get north of
Shemya, disturbances aloft rotating around the low will allow the
showers to spread northward through much of the Bering Sea through
the weekend.

As for winds, an increasing pressure gradient ahead of the
incoming front will mean an uptick in the winds, as they
strengthen to gales from south to north through Saturday evening,
before subsiding in the Sunday through Monday time frame as the
front weakens.

&&

.LONG TERM FORECAST (Days 3 through 7)...

Beginning the long term forecast period Saturday night, the
strong omega blocking high will still be in place over Eastern
Siberia and northwest Alaska. There will be a weakening upper
trough (deforming and stretching) over Southern Alaska with a
strong arctic surface high over the interior. A relatively stationary
front will stretch from the western Bering Sea to Kodiak Island
and then to the Eastern Gulf of Alaska. Energetic shortwave
troughs will slowly but surely push the front farther north toward
the Gulf Coast, slowly eroding the arctic high in place Sunday.
However, with the stout blocking high in place, it now seems
quite likely that fronts moving up toward the coast will stretch
and deform, keeping most if not all of Southern Alaska dry (with
the exception of the immediate coastline and Kodiak Island).
Eventually, troughing will re-establish itself over the western
Bering Sea, keeping the low track to the west of the mainland.
Temperatures should moderate back to near normal next week as the
arctic high slowly weakens.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning 127 128 130 131 132 138 165 170 172-176 179
                     180 351 352 413 414.
         Heavy Freezing Spray 121 126-129 139 150 155 160 180 185
                              414.

&&

SYNOPSIS AND MODEL DISCUSSION...JPW
SOUTHCENTRAL ALASKA...DEK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD
LONG TERM...JA