Storm Warning 56, NWS Anchorage, AK

690 
FZAK62 PAFC 112311
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
311 PM AKDT Wed Mar 11 2020

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.

PKZ499-121330-
311 PM AKDT Wed Mar 11 2020
.SYNOPSIS FOR CENTRAL BERING SEA...
A strong front extending from a low over the southern Kamchatka 
Peninsula in an arc to the northwest Bering Sea then south across 
the western Aleutians will move to the Central Bering Sea
extending through Adak Thursday evening. This front will then
remain stationalry and dissipate. 

$$

PKZ411-121330-
Bering Sea Offshore West of 180 and East of the International
Dateline-
311 PM AKDT Wed Mar 11 2020

...STORM WARNING THROUGH THURSDAY...

.TONIGHT...S wind 35 to 50 kt. Seas 11 to 19 ft. Rain.
.THU...S wind 35 to 50 kt. Seas 17 to 25 ft. Rain and snow.
.THU NIGHT...SW wind 20 to 35 kt diminishing to 10 to 25 kt after
midnight. Seas 15 to 23 ft. Snow and rain.
.FRI...W wind up to 20 kt. Seas 11 to 18 ft.
.FRI NIGHT...NE wind up to 15 kt. Seas 7 to 11 ft.
.SAT THROUGH SUN...E wind up to 20 kt. Seas 5 to 10 ft.
.MON...SE wind 15 to 25 kt. Seas 9 to 14 ft.

$$

PKZ412-121330-
Bering Sea Offshore 171W to 180 and North of 56N-
311 PM AKDT Wed Mar 11 2020

...STORM WARNING THURSDAY...

.TONIGHT...S wind 15 to 30 kt increasing to 30 to 45 kt after
midnight. Seas 7 to 12 ft.
.THU...S wind 35 to 50 kt. Seas 11 to 19 ft.
.THU NIGHT...S wind 20 to 35 kt. Seas 12 to 20 ft. Snow and rain.
.FRI...S wind 15 to 30 kt. Seas 11 to 19 ft.
.FRI NIGHT...E wind up to 20 kt. Seas 10 to 13 ft.
.SAT THROUGH MON...SE wind up to 20 kt. Seas 6 to 11 ft.

$$

PKZ413-121330-
Bering Sea Offshore 171W to 180 and South of 56N-
311 PM AKDT Wed Mar 11 2020

...GALE WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...S wind 10 to 25 kt increasing to 25 to 40 kt after
midnight. Seas 5 to 10 ft.
.THU...S wind 25 to 40 kt. Seas 9 to 14 ft.
.THU NIGHT...SE wind 20 to 35 kt becoming S 15 to 25 kt after
midnight. Seas 8 to 16 ft.
.FRI...SE wind 10 to 25 kt. Seas 10 to 16 ft.
.FRI NIGHT...E wind up to 20 kt. Seas 8 to 12 ft.
.SAT THROUGH SUN...E wind up to 20 kt. Seas 6 to 11 ft.
.MON...SE wind 15 kt. Seas 4 to 7 ft.

$$

PKZ414-121330-
Bering Sea Offshore East of 171W-
311 PM AKDT Wed Mar 11 2020

.TONIGHT...SE wind 10 to 20 kt. Seas in ice free waters 1 to 5 ft.
.THU...SE wind 15 to 30 kt. Seas in ice free waters 3 to 7 ft.
.THU NIGHT...SE wind 20 to 30 kt. Seas in ice free waters 3 to 7
ft.
.FRI...SE wind 20 to 30 kt. Seas in ice free waters 4 to 9 ft.
.FRI NIGHT...SE wind 15 to 25 kt. Seas in ice free waters 4 to 9
ft.
.SAT THROUGH MON...SE wind 10 to 25 kt. Seas in ice free waters 3
to 7 ft.

$$

001 
FZAK62 PAFC 121136
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
336 AM AKDT Thu Mar 12 2020

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.

PKZ499-130130-
336 AM AKDT Thu Mar 12 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A strong front over the western Bering and Aleutians Wed morning
will lift into the northern Bering and weaken through Fri morning.
A front developing over the eastern Bering and Alaska Peninsula will
persists through Sat.

$$

PKZ411-130130-
Bering Sea Offshore West of 180 and East of the International
Dateline-
336 AM AKDT Thu Mar 12 2020

...GALE WARNING TODAY...

.TODAY...S wind 30 to 45 kt. Seas 17 to 25 ft. Rain and snow.
.TONIGHT...SW wind 15 to 30 kt diminishing to up to 20 kt after
midnight. Seas 14 to 22 ft. Snow.
.FRI...N wind 10 to 15 kt. Seas 11 to 18 ft. Snow.
.FRI NIGHT...NE wind up to 15 kt. Seas 7 to 12 ft.
.SAT...W wind up to 15 kt. Seas 6 to 9 ft.
.SUN...E wind 10 to 25 kt. Seas 5 to 10 ft.
.MON...SE wind 25 kt. Seas 13 to 21 ft.

$$

PKZ412-130130-
Bering Sea Offshore 171W to 180 and North of 56N-
336 AM AKDT Thu Mar 12 2020

...GALE WARNING THROUGH TONIGHT...

.TODAY...S wind 30 to 45 kt. Seas 11 to 19 ft.
.TONIGHT...S wind 20 to 35 kt. Seas 12 to 20 ft. Snow.
.FRI...SE wind 10 to 20 kt. Seas 11 to 17 ft. Rain and snow.
.FRI NIGHT...E wind up to 15 kt. Seas 8 to 13 ft.
.SAT...S wind up to 20 kt. Seas 5 to 10 ft.
.SUN...NE wind up to 10 kt. Seas 3 to 7 ft.
.MON...SE wind 20 kt. Seas 6 to 11 ft.

$$

PKZ413-130130-
Bering Sea Offshore 171W to 180 and South of 56N-
336 AM AKDT Thu Mar 12 2020

...GALE WARNING TODAY...

.TODAY...SE wind 25 to 40 kt. Seas 8 to 13 ft.
.TONIGHT...SE wind 20 to 30 kt diminishing to 10 to 25 kt 
after midnight. Seas 9 to 15 ft. Rain.
.FRI...SE wind 10 to 20 kt. Seas 9 to 14 ft. Rain.
.FRI NIGHT...E wind up to 20 kt. Seas 7 to 12 ft.
.SAT THROUGH SUN...NE wind up to 20 kt. Seas 6 to 11 ft.
.MON...SE wind 10 to 20 kt. Seas 6 to 11 ft.

$$

PKZ414-130130-
Bering Sea Offshore East of 171W-
336 AM AKDT Thu Mar 12 2020

.TODAY...SE wind 10 to 25 kt. Seas in ice free waters 3 to 7 ft.
Freezing spray.
.TONIGHT...SE wind 25 kt. Seas in ice free waters 3 to 8 ft. Rain.
.FRI...SE wind 30 kt. Seas in ice free waters 4 to 9 ft. Rain.
.FRI NIGHT...SE wind 15 to 25 kt. Seas in ice free waters 4 to 9
ft.
.SAT THROUGH MON...SE wind 15 to 30 kt. Seas in ice free waters 3
to 7 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
433 PM AKDT Tue Mar 10 2020

.ANALYSIS AND UPPER LEVELS...
There is an upper level trough axis just west of the Alaska/Canada
border moving slowly eastward. There are some lingering showers
along and east of this axis. Clear skies are over most of the
southern Alaska Mainland to the west of this trough as high
pressure builds in. There is an upper level trough and associated
surface low over the Bering Sea to the north of the western and
central Aleutians. This low is producing some precipitation over
that area, and is moving to the southeast and weakening. High
pressure is building in to the west of this feature.

&&

.MODEL DISCUSSION...
The numerical models are in very good agreement. The high
resolution models are preferred due to the better handling of gap
winds. Forecast confidence is above normal.

&&

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

&&

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

An upper trough continues its track east over mainland Alaska. A
steep pressure gradient between the accompanying surface ridge
over northern/interior Alaska and lower pressure/warmer air over
the Gulf will continue to drive gusty offshore winds through the
usual gaps and passes, including Resurrection Bay, Passage Canal,
the Valdez waterways, through Thompson Pass and out of the Copper
River Delta. Otherwise, clear skies prevail as expected with
general offshore flow. Winds should diminish from west to east
tonight and tomorrow. Arctic air will continue to spread
southward, and temperatures should drop substantially tonight...
likely a good 20 degrees colder than Monday night in most of
Southcentral. A ridge building over the Bering will push eastward
Wednesday. Cold air will recede towards the Alcan and conditions
will trend warmer by Thursday. Of note, a shortwave is expected to
track across the top of the ridge Wednesday night, bringing
another period of gusty offshore winds to Whittier, Valdez waters,
Thompson Pass and the Copper River Delta late Wednesday night
into Thursday. The ridge axis will become centered over mainland
Alaska by Friday and clear, dry weather will persist.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
Dry and cold conditions are expected to continue across Southwest
Alaska tonight through Wednesday. There remains the chance for
snow showers across the Hooper Bay area overnight Wednesday into
Thursday as an upper level wave moves through. Behind this upper
level wave, a strong upper level ridge will build into the region
bringing a significant moderation in temperatures for the
second half of the week.

&&

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

Cold northerly flow will continue through the gaps of the Alaska
Peninsula through Wednesday keeping heavy freezing spray in the
forecast along with the gusty winds. While winds will diminish
tonight as the pressure gradient weakens, a front associated with
a low over the Pacific will slowly move north allowing the gap
winds between Dutch Harbor and Cold Bay to increase to small craft
advisory criteria winds once again tomorrow morning into tomorrow
night.

Currently, a mix of rain and snow is falling in Adak as a storm
system moves through. This storm system will continue to weaken as
it tracks southward due to a strong upper level ridge building
into the western Bering and western Aleutians. This upper level
ridge will aid in the weakening of the upper level wave associated
with the storm system moving through Adak shearing and stretching
the energy apart.

The focus then shifts to a storm force low moving northward in the
North Pacific towards Russia. The front is expected to begin
impacting the western side of the Aleutian Chain and western
Bering Wednesday night into Thursday with widespread
precipitation. This precipitation will mainly be in the form of
rain as a strong southerly push of warm air at 850 mb helps to
warm the air at the surface well above freezing. Strong southerly
winds are also expected due to the tight pressure gradient between
the low pressure over the North Pacific and the high to the east.
As a result, gale to storm force winds are expected across a wide
swath of the western Bering and western Aleutians. Due to the
strength of the upper level ridge to the east, this front will
stall across the central Bering with a weakening precipitation
shield as the front becomes elongated.

The aforementioned front lifting toward the Alaska Peninsula on
Wednesday will continue northward into the Bering Sea Thursday
night through Friday. This will bring widespread precipitation
and small craft advisory winds to the eastern Aleutians, southern
Alaska Peninsula and on northward into the eastern Bering.

&&

.MARINE (Days 3 through 5)...

Thursday and Friday, the offshore and enhanced gap winds will
continue across the Barren Islands and the Copper River Delta.
These winds will slack off late Friday.

A storm force system over the northern Bering will keep an area
of storm force to high end gale force winds west of St Matthew
Island and north of 56N on Thursday. By Friday, this system will
have lost its gusto but enhanced winds and rough seas still
anticipated into Saturday. Shifting to the North Pacific, a low
will approach the central and eastern Aleutians Thursday night,
bringing the next round of precipitation to the eastern Aleutians,
including Dutch Harbor, through Friday night. A ridge will set up
over the Gulf Of Alaska and mainland. Once this ridge gets
established, the active corridor for low tracks will be the NW
Pacific to the Western Bering. This ridge is expected through
Tuesday March 18th.

&&

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

Both the GFS and ECMWF ping into an "Omega Block" setting up over
the Gulf of Alaska. This will keep clear skies and dry weather
over most of Southcentral Alaska. Temperatures will continue to
run slightly below normal. However, the weather will be active
over the Western Aleutians and Western Bering. But at this time,
none of these systems look particularly ominous. The ridge remains
steadfast the entire forecast period.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gales 127 128 130-132 138 150 155 172 178.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...MM
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...SEB/MV
MARINE/LONG TERM...PS