Storm Warning 195, NWS Anchorage, AK

466 
FZAK62 PAFC 090038
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
338 PM AKST Tue Dec 8 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.

PKZ499-091500-
338 PM AKST Tue Dec 8 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 991 mb low at 57N 161W moves into the Alaska Peninsula at 1001 
mb by Wed morning. Its front moves into Southwest Alaska for Wed 
afternoon. A strong 976 mb low near 49N 171E becomes a 971 mb gale 
force low complex at 52N 177E by Thu afternoon. Its front pushes 
across the Aleutians through Thu afternoon.

$$

PKZ411-091500-
Bering Sea Offshore West of 180 and East of the International
Dateline-
338 PM AKST Tue Dec 8 2020

...STORM WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...SE wind 15 to 30 kt becoming E 25 to 40 kt after
midnight. Seas 7 to 12 ft.
.WED...E wind 35 to 50 kt. Seas 13 to 21 ft. Snow and rain showers.
.WED NIGHT...E wind 35 to 50 kt. Seas 19 to 30 ft. Widespread snow
and rain showers.
.THU...E wind 40 to 55 kt. Seas 21 to 36 ft.
.THU NIGHT...E wind 30 to 45 kt. Seas 17 to 32 ft.
.FRI...NE wind 20 to 35 kt. Seas 15 to 23 ft.
.SAT...N wind 10 to 20 kt. Seas 8 to 11 ft.
.SUN...NW wind 10 to 25 kt. Seas 9 to 12 ft.

$$

PKZ412-091500-
Bering Sea Offshore 171W to 180 and North of 56N-
338 PM AKST Tue Dec 8 2020

...STORM WARNING WEDNESDAY NIGHT...

.TONIGHT...NE wind up to 15 kt becoming E 10 to 25 kt after
midnight. Seas 5 to 8 ft.
.WED...E wind 15 to 30 kt increasing to 25 to 40 kt in the
afternoon. Seas 7 to 12 ft.
.WED NIGHT...E wind 30 to 45 kt increasing to 40 to 55 kt after
midnight. Seas 12 to 20 ft building to 15 to 30 ft after midnight.
.THU...E wind 40 to 55 kt. Seas 21 to 34 ft.
.THU NIGHT...E wind 35 to 50 kt. Seas 15 to 30 ft.
.FRI...E wind 15 to 25 kt. Seas 13 to 21 ft.
.SAT...NE wind 10 to 25 kt. Seas 8 to 11 ft.
.SUN...NW wind 10 to 20 kt. Seas 9 ft.

$$

PKZ413-091500-
Bering Sea Offshore 171W to 180 and South of 56N-
338 PM AKST Tue Dec 8 2020

...STORM WARNING WEDNESDAY AND WEDNESDAY NIGHT...

.TONIGHT...E wind 10 to 25 kt increasing to 25 to 40 kt after
midnight. Seas 6 to 9 ft.
.WED...E wind 35 to 50 kt. Seas 11 to 19 ft. Snow and rain.
.WED NIGHT...E wind 40 to 55 kt. Seas 15 to 26 ft building to 23 to 
33 ft after midnight. Snow and rain.
.THU...SE wind 30 to 45 kt. Seas 15 to 30 ft.
.THU NIGHT...SE wind 15 to 25 kt. Seas 11 to 18 ft.
.FRI...SE wind 10 to 25 kt. Seas 8 to 16 ft.
.SAT THROUGH SUN...NW wind 10 to 25 kt. Seas 7 to 11 ft.

$$

PKZ414-091500-
Bering Sea Offshore East of 171W-
338 PM AKST Tue Dec 8 2020

...STORM WARNING WEDNESDAY NIGHT...

.TONIGHT...N wind 15 to 30 kt. Seas 7 to 12 ft. Freezing spray.
.WED...NE wind 10 to 20 kt becoming E 15 to 30 kt in the
afternoon. Seas 6 to 9 ft. Freezing spray.
.WED NIGHT...E wind 35 to 50 kt. Seas 6 to 11 ft building to 9 to
17 ft after midnight. Freezing spray.
.THU...E wind 30 to 45 kt. Seas 12 to 20 ft.
.THU NIGHT...SE wind 30 to 45 kt. Seas 11 to 19 ft.
.FRI THROUGH SAT...SE wind 15 to 30 kt. Seas 8 to 13 ft.
.SUN...NW wind up to 20 kt. Seas 5 to 9 ft.

$$

431 
FZAK62 PAFC 091247
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
347 AM AKST Wed Dec 9 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.

PKZ499-100200-
347 AM AKST Wed Dec 9 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

High pressure over the Central/Eastern Bering through tomorrow
night. A 970 mb storm force low at 49N 172E today moves to 50N 
176E on Thursday. Its front pushes across the Bering through 
Thursday night. 

$$

PKZ411-100200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
347 AM AKST Wed Dec 9 2020

...STORM WARNING THROUGH THURSDAY...

.TODAY...E wind 35 to 50 kt. Seas 14 to 22 ft. Widespread snow and
rain showers.
.TONIGHT...E wind 35 to 50 kt. Seas 20 to 32 ft. Widespread snow
and rain showers.
.THU...E wind 40 to 55 kt. Seas 21 to 36 ft. Snow showers and rain
showers.
.THU NIGHT...E wind 35 to 50 kt. Seas 17 to 32 ft.
.FRI...E wind 15 to 30 kt. Seas 13 to 21 ft.
.SAT THROUGH SUN...N wind 10 to 25 kt. Seas 9 to 14 ft.

$$

PKZ412-100200-
Bering Sea Offshore 171W to 180 and North of 56N-
347 AM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT AND THURSDAY...

.TODAY...E wind 15 to 30 kt increasing to 25 to 40 kt in the
afternoon. Seas 7 to 12 ft.
.TONIGHT...E wind 30 to 45 kt increasing to 40 to 55 kt after
midnight. Seas 12 to 20 ft building to 16 to 31 ft after midnight.
.THU...E wind 45 to 55 kt diminishing to 35 to 50 kt in the
afternoon. Seas 22 to 34 ft. Snow.
.THU NIGHT...E wind 35 to 50 kt. Seas 16 to 31 ft.
.FRI THROUGH SUN...NE wind 10 to 25 kt. Seas 10 to 18 ft.

$$

PKZ413-100200-
Bering Sea Offshore 171W to 180 and South of 56N-
347 AM AKST Wed Dec 9 2020

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 35 to 50 kt. Seas 11 to 19 ft. Snow and rain.
.TONIGHT...E wind 50 kt becoming 40 to 55 kt after midnight. Seas
16 to 31 ft. Snow and rain.
.THU...SE wind 30 to 45 kt diminishing to 10 to 25 kt in the
afternoon. Seas 14 to 29 ft. Rain and snow.
.THU NIGHT...SE wind 10 to 25 kt. Seas 12 to 18 ft.
.FRI...E wind 10 to 25 kt. Seas 8 to 16 ft.
.SAT THROUGH SUN...NW wind up to 20 kt. Seas 7 to 12 ft.

$$

PKZ414-100200-
Bering Sea Offshore East of 171W-
347 AM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TODAY...NE wind 10 to 20 kt becoming E 15 to 30 kt in the
afternoon. Seas 5 to 8 ft. Freezing spray.
.TONIGHT...E wind 35 to 50 kt. Seas 7 to 12 ft building to 10 to
18 ft after midnight. Freezing spray.
.THU...E wind 30 to 45 kt. Seas 12 to 20 ft. Freezing spray. Snow
and rain.
.THU NIGHT...SE wind 30 to 45 kt. Seas 12 to 20 ft.
.FRI THROUGH SAT...NE wind 20 to 35 kt. Seas 8 to 16 ft.
.SUN...N wind 10 to 25 kt. Seas 6 to 11 ft.

$$

493 
FZAK62 PAFC 100041
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
341 PM AKST Wed Dec 9 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.

PKZ499-101500-
341 PM AKST Wed Dec 9 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 971 mb low at 50N 174E moves to 52N 178E Thu afternoon then 
shifts to 56N 174E at 981 mb Fri afternoon. Its front sweeps over 
the Aleutians and Bering to stall in the Eastern Aleutians for Thu
afternoon. A strong North Pacific low moves along the front to 
51N 161W at 964 mb by Fri afternoon.

$$

PKZ411-101500-
Bering Sea Offshore West of 180 and East of the International
Dateline-
341 PM AKST Wed Dec 9 2020

...STORM WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...E wind 40 to 55 kt. Gusts to 70 kt. Seas 21 to 34 ft. 
Widespread snow and rain showers.
.THU...E wind 40 to 55 kt. Gusts to 70 kt. Seas 22 to 37 ft. 
Widespread snow and rain showers.
.THU NIGHT...E wind 35 to 50 kt with gusts to 65 kt diminishing to 
25 to 40 kt after midnight. Seas 17 to 32 ft.
.FRI...E wind 15 to 30 kt. Seas 13 to 21 ft.
.FRI NIGHT...E wind 10 to 25 kt. Seas 9 to 17 ft.
.SAT THROUGH MON...NE wind up to 20 kt. Seas 9 to 14 ft.

$$

PKZ412-101500-
Bering Sea Offshore 171W to 180 and North of 56N-
341 PM AKST Wed Dec 9 2020

...STORM WARNING THROUGH THURSDAY NIGHT...

.TONIGHT...E wind 35 to 50 kt increasing to 45 to 60 kt after
midnight. Gusts to 75 kt. Seas 13 to 21 ft building to 17 to 32 ft 
after midnight.
.THU...E wind 45 to 60 kt. Gusts to 75 kt. Seas 23 to 35 ft. Snow 
and widespread rain showers.
.THU NIGHT...E wind 40 to 55 kt with gusts to 65 kt becoming SE 30 
to 45 kt after midnight. Seas 17 to 32 ft. Snow.
.FRI...E wind 20 to 30 kt. Seas 11 to 19 ft.
.FRI NIGHT...E wind 15 to 25 kt. Seas 10 to 15 ft.
.SAT THROUGH MON...N wind 10 to 25 kt. Seas 10 to 16 ft.

$$

PKZ413-101500-
Bering Sea Offshore 171W to 180 and South of 56N-
341 PM AKST Wed Dec 9 2020

...STORM WARNING TONIGHT...

.TONIGHT...E wind 45 to 60 kt. Gusts to 75 kt. Seas 17 to 32 ft. 
Snow and rain.
.THU...SE wind 30 to 45 kt diminishing to 10 to 25 kt in the 
afternoon. Seas 14 to 29 ft. Rain.
.THU NIGHT...SE wind 10 to 25 kt. Seas 12 to 18 ft.
.FRI...SE wind 10 to 25 kt. Seas 9 to 16 ft.
.FRI NIGHT...E wind up to 20 kt. Seas 7 to 12 ft.
.SAT THROUGH MON...N wind up to 20 kt. Seas 8 to 13 ft.

$$

PKZ414-101500-
Bering Sea Offshore East of 171W-
341 PM AKST Wed Dec 9 2020

...STORM WARNING THROUGH THURSDAY...

.TONIGHT...E wind 35 to 50 kt. Gusts to 65 kt S of the Pribilofs
late. Seas 7 to 12 ft building to 10 to 18 ft after midnight. 
Freezing spray.
.THU...E wind 35 to 50 kt. with gusts to 65 kt W of 168W. Seas 12 to
20 ft. Freezing spray.
.THU NIGHT...E wind 30 to 45 kt becoming SE 20 to 35 kt after
midnight. Seas 12 to 20 ft. Rain and snow.
.FRI...E wind 15 to 30 kt. Seas 8 to 13 ft.
.FRI NIGHT...NE wind 20 to 35 kt. Seas 9 to 14 ft.
.SAT THROUGH SUN...N wind 20 to 35 kt. Seas 8 to 13 ft.
.MON...NW wind up to 20 kt. Seas 5 to 10 ft.

$$

351 
FZAK62 PAFC 101216
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
316 AM AKST Thu Dec 10 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.

PKZ499-110145-
316 AM AKST Thu Dec 10 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 971 mb storm force low at 50N 175E on Thursday becomes 977 mb at
53N 176E on Friday. Its front moves across the Bering through 
Friday.

$$

PKZ411-110145-
Bering Sea Offshore West of 180 and East of the International
Dateline-
316 AM AKST Thu Dec 10 2020

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 40 to 55 kt. Seas 22 to 37 ft. Rain and snow showers.
.TONIGHT...E wind 35 to 50 kt diminishing to 15 to 30 kt after
midnight. Seas 16 to 31 ft.
.FRI...E wind 15 to 30 kt. Seas 13 to 21 ft.
.FRI NIGHT...E wind 10 to 25 kt. Seas 9 to 16 ft.
.SAT THROUGH SUN...NW wind 15 to 30 kt. Seas 9 to 13 ft.
.MON...NE wind 15 to 30 kt. Seas 8 to 16 ft.

$$

PKZ412-110145-
Bering Sea Offshore 171W to 180 and North of 56N-
316 AM AKST Thu Dec 10 2020

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 45 to 60 kt. Seas 23 to 36 ft. Rain and snow.
.TONIGHT...E wind 35 to 50 kt becoming SE 20 to 35 kt after
midnight. Seas 16 to 31 ft. Rain and snow.
.FRI...E wind 15 to 30 kt. Seas 12 to 19 ft. Snow.
.FRI NIGHT...E wind 15 to 30 kt. Seas 10 to 15 ft.
.SAT THROUGH SUN...N wind 15 to 30 kt. Seas 9 to 13 ft.
.MON...E wind 15 to 30 kt. Seas 8 to 13 ft.

$$

PKZ413-110145-
Bering Sea Offshore 171W to 180 and South of 56N-
316 AM AKST Thu Dec 10 2020

...STORM WARNING TODAY...

.TODAY...SE wind 35 to 50 kt diminishing to 15 to 30 kt in the
afternoon. Seas 15 to 30 ft.
.TONIGHT...SE wind 15 to 30 kt. Seas 12 to 18 ft.
.FRI...SE wind 15 to 30 kt. Seas 9 to 16 ft.
.FRI NIGHT...E wind up to 20 kt. Seas 7 to 12 ft.
.SAT THROUGH SUN...NW wind 15 to 30 kt. Seas 9 to 15 ft.
.MON...SW wind up to 20 kt. Seas 6 to 11 ft.

$$

PKZ414-110145-
Bering Sea Offshore East of 171W-
316 AM AKST Thu Dec 10 2020

...STORM WARNING TODAY...

.TODAY...E wind 35 to 50 kt. Seas 13 to 21 ft. Freezing spray.
Rain and snow.
.TONIGHT...SE wind 30 to 45 kt diminishing to 20 to 35 kt after
midnight. Seas 12 to 20 ft.
.FRI...E wind 20 to 35 kt. Seas 9 to 14 ft.
.FRI NIGHT...NE wind 25 to 40 kt. Seas 9 to 17 ft.
.SAT...E wind 25 to 40 kt. Seas 8 to 16 ft.
.SUN THROUGH MON...S wind 10 to 25 kt. Seas 5 to 10 ft.

$$

988 
FZAK62 PAFC 110028
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
328 PM AKST Thu Dec 10 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.

PKZ499-111400-
328 PM AKST Thu Dec 10 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 972 mb low at 51N 177E will move to 55N 175E Fri afternoon then
dissipates Sat. Its front moves across the northern Bering through 
Sat. A 975 mb low at 50N 159W on Fri will move to 59N 169W Sat. Its
front moves across the Bering through Sat.

$$

PKZ411-111400-
Bering Sea Offshore West of 180 and East of the International
Dateline-
328 PM AKST Thu Dec 10 2020

...STORM WARNING TONIGHT...

.TONIGHT...E wind 35 to 50 kt diminishing to 15 to 30 kt after
midnight. Seas 16 to 31 ft.
.FRI...SE wind 15 to 30 kt. Seas 13 to 21 ft.
.FRI NIGHT...SE wind 10 to 25 kt. Seas 9 to 16 ft.
.SAT...NW wind 10 to 25 kt. Seas 9 to 13 ft.
.SAT NIGHT...NW wind 15 to 30 kt. Seas 9 to 15 ft.
.SUN...NW wind 10 to 25 kt. Seas 9 to 13 ft.
.MON THROUGH TUE...E wind 15 to 30 kt. Seas 8 to 16 ft.

$$

PKZ412-111400-
Bering Sea Offshore 171W to 180 and North of 56N-
328 PM AKST Thu Dec 10 2020

...STORM WARNING TONIGHT...

.TONIGHT...SE wind 35 to 50 kt diminishing to 15 to 30 kt after
midnight. Seas 16 to 31 ft. Snow.
.FRI...E wind 15 to 30 kt. Seas 11 to 18 ft. Rain and snow.
.FRI NIGHT...E wind 15 to 30 kt. Seas 9 to 14 ft. Snow showers and
rain.
.SAT...NE wind up to 20 kt. Seas 10 ft.
.SAT NIGHT...NW wind up to 15 kt. Seas 8 to 11 ft.
.SUN...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.MON THROUGH TUE...E wind 15 to 30 kt. Seas 9 to 14 ft.

$$

PKZ413-111400-
Bering Sea Offshore 171W to 180 and South of 56N-
328 PM AKST Thu Dec 10 2020

.TONIGHT...SE wind 15 to 30 kt. Seas 11 to 17 ft.
.FRI...SE wind 10 to 25 kt. Seas 9 to 15 ft.
.FRI NIGHT...SE wind 10 to 15 kt. Seas 8 to 11 ft. Rain and snow.
.SAT...W wind up to 20 kt. Seas 8 ft.
.SAT NIGHT...W wind 15 to 30 kt. Seas 9 to 14 ft.
.SUN...W wind 15 to 30 kt. Seas 10 to 15 ft.
.MON...SW wind up to 20 kt. Seas 6 to 11 ft.
.TUE...E wind 15 to 25 kt. Seas 10 to 15 ft.

$$

PKZ414-111400-
Bering Sea Offshore East of 171W-
328 PM AKST Thu Dec 10 2020

...GALE WARNING TONIGHT AND FRIDAY NIGHT...

.TONIGHT...SE wind 30 to 45 kt diminishing to 20 to 35 kt after
midnight. Seas 11 to 19 ft. Snow.
.FRI...E wind 15 to 30 kt. Seas 9 to 14 ft.
.FRI NIGHT...NE wind 30 to 45 kt. Seas 9 to 17 ft. Snow and rain
showers.
.SAT...NE wind 25 to 40 kt. Seas 9 to 16 ft.
.SAT NIGHT...S wind 10 to 25 kt. Seas 5 to 10 ft.
.SUN...SW wind 10 to 25 kt. Seas 4 to 9 ft.
.MON...S wind up to 20 kt. Seas 4 to 7 ft.
.TUE...SE wind up to 20 kt. Seas 4 to 9 ft.

$$

054 
FZAK62 PAFC 111203
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
303 AM AKST Fri Dec 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.

PKZ499-120200-
303 AM AKST Fri Dec 11 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 977 mb low at 53N 176E on Friday moves to 55N 174E at 988 mb on
Saturday. A 970 mb low at 49N 157W on Friday moves to 56N 163W at
977 mb on Saturday.

$$

PKZ411-120200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
303 AM AKST Fri Dec 11 2020

.TODAY...SE wind 15 to 30 kt. Seas 13 to 21 ft.
.TONIGHT...SE wind 10 to 25 kt. Seas 8 to 16 ft.
.SAT...SE wind up to 20 kt becoming NW 10 to 25 kt in the
afternoon. Seas 8 to 13 ft.
.SAT NIGHT...NW wind 15 to 30 kt. Seas 9 to 13 ft.
.SUN...NW wind 10 to 25 kt. Seas 8 to 13 ft.
.MON THROUGH TUE...SE wind 10 to 20 kt. Seas 9 to 17 ft.

$$

PKZ412-120200-
Bering Sea Offshore 171W to 180 and North of 56N-
303 AM AKST Fri Dec 11 2020

.TODAY...E wind 15 to 30 kt. Seas 11 to 18 ft. Rain.
.TONIGHT...E wind 15 to 30 kt. Seas 9 to 14 ft. Rain and snow showers.
.SAT...NE wind 10 to 20 kt. Seas 9 to 12 ft.
.SAT NIGHT...NW wind up to 15 kt. Seas 7 to 12 ft.
.SUN...NW wind up to 20 kt. Seas 7 to 12 ft.
.MON...SE wind up to 15 kt. Seas 4 to 8 ft.
.TUE...E wind 10 to 20 kt. Seas 9 to 14 ft.

$$

PKZ413-120200-
Bering Sea Offshore 171W to 180 and South of 56N-
303 AM AKST Fri Dec 11 2020

.TODAY...SE wind 10 to 25 kt. Seas 9 to 15 ft.
.TONIGHT...SE wind 10 to 15 kt. Seas 6 to 10 ft.
.SAT...W wind 10 to 20 kt. Seas 6 to 9 ft.
.SAT NIGHT...W wind 15 to 30 kt. Seas 8 to 13 ft.
.SUN...W wind 15 to 30 kt. Seas 9 to 14 ft.
.MON THROUGH TUE...SE wind up to 20 kt. Seas 7 to 12 ft.

$$

PKZ414-120200-
Bering Sea Offshore East of 171W-
303 AM AKST Fri Dec 11 2020

...GALE WARNING TONIGHT AND SATURDAY...

.TODAY...E wind 15 to 30 kt. Seas 9 to 14 ft. Rain and snow showers.
.TONIGHT...NE wind 30 to 45 kt. Seas 9 to 17 ft. Rain and snow. 
.SAT...NE wind 25 to 40 kt becoming SW 15 to 30 kt in the
afternoon. Seas 9 to 16 ft.
.SAT NIGHT...S wind 10 to 25 kt. Seas 5 to 10 ft.
.SUN THROUGH MON...W wind up to 15 kt. Seas 4 to 9 ft.
.TUE...S wind up to 15 kt. Seas 4 to 9 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
600 PM AKST Mon Dec 7 2020

.ANALYSIS AND UPPER LEVELS...

A broad longwave trough remains centered over most of Alaska with
two dominant embedded low centers evident on IR this afternoon.
The first of these consists of a rapidly weakening and vertically
stacked low drifting towards the northern Gulf Coast. A nose of
warm air most prominent near 900 mb has advected into much of
Southcentral with the southeast flow near and to the north of the
low center. The cold air in place at the surface (underneath the
warm layer) resulted in numerous precip type issues this morning
along the Kenai Peninsula, including a disruptive period of
freezing rain in the Homer area before temperatures rose above 32F
by around 9 AM AKST. While temps remain sub-freezing in the
Anchorage vicinity with profiles again supportive of freezing rain
or drizzle, downslope warming/drying has overall prevented precip
streaming in from the PWS from making it into town thus far.

Elsewhere, conditions are deteriorating across the Y-K Delta off
to the north of a second upper level low situated just downstream
of an omega block ridge that continues to spill polar air into
the lion's share of the Bering. Strong northeast winds are
yielding areas of blowing snow combining with a broad band of
falling snow over much of the Y-K Delta and Kuskokwim Bay. Surface
obs from Toksook Bay and Bethel have already indicated winds
gusting to around 35 kts with visibility below 1 statute mile at
times, and blizzard conditions are possible for mainly coastal
sections of the delta region throughout the afternoon and
evening. For the remainder of the Bering, AKPEN and the Aleutians,
areas of convective snow showers rooted in an unstable marine
layer are racing south in the cold advection to the west side of
the low along with plenty of gusty north to northwest winds.

&&

.MODEL DISCUSSION...

Models are in excellent agreement for most synoptic features
through midweek, however, mesoscale details continue to prove
elusive in terms of fully resolving issues with precip type and
location/timing in parts of the Mat-Su Valleys in particular.
Gradual cooling of the overrunning warm layer across Southcentral
is clearly depicted by all reliable models through Tuesday, and
this should result in a changeover from any light freezing
rain/drizzle persisting in the Anchorage Bowl to all snow some
time between tonight and early Tuesday morning. Timing out this
transition may prove a challenge in the immediate term.

In addition to the short term precip type problems, determining
the placement and timing of potentially two rounds of snow between
Tuesday and Wednesday night for parts of the Kenai Peninsula to
Susitna Valley remains difficult. Models show a push of southwest
flow into the area behind the dissipating low as it drifts
inland, likely resulting in a band of snow enhanced by upslope
along and west of the Talkeetna and Chugach Mountains with some
minor model discrepancies persisting for exact locations of higher
amounts. Models differ significantly more with the possible
second round late on Wednesday with the upper low in the Southwest
projected to become part of a very sharp, negatively-tilted
trough that sweeps across the northern Gulf and southern mainland.
The NAM/GFS are currently most optimistic for snowfall for
Wednesday to Thursday with the EC/Canadian more pessimistic
despite what appears to be a favorable setup for a quick but
potentially intense round of snowfall as the trough passes.

&&

.AVIATION...

PANC...VFR conditions are hanging on due to some very dry air in
the low levels and light northerly winds. The thermal profile
still supports the possibility of freezing rain, but there is
little to no precipitation reaching the ground. That will change
later tonight (~10z) when enough precipitation moves in to
saturate the column. This should allow for precipitation to fall,
but exactly what type remains uncertain. There should be a brief
period where a wintry mix reaches the airfield, but that will give
way to all snow. As the snow starts in earnest, expect vis and
cigs to drop into IFR and possibly LIFR range.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

A very complex weather pattern is expected for Southcentral Alaska
over the next 3 days. The first low that is currently weakening
south of the central Kenai Peninsula is moving northeastward
towards the eastern Kenai Peninsula/western Prince William Sound
will bring a wintry mix of snow with a slight chance of light
freezing rain this evening, turning to all snow overnight. Chances
of precipitation will increase after midnight tonight and
precipitation will become more widespread as the southeasterly
cross-barrier flow across the Chugach Mountains will weaken. This
is important as it will help minimize the amount of downsloping
on the leeward side of the Chugach and thus increase the chance
for precipitation. The combination of cold air advection across
Southcentral and wet bulbing when precipitation becomes more steady
will decrease the temperatures at both the surface and in the
upper levels and thus change any remaining wintry mix to all snow.
Snowfall amounts will generally be 1-3" across the Anchorage Bowl
and across the Mat-Su (including Palmer and Wasilla). However,
locally higher amounts of 2-4" are expected along the Upper
Hillside.

Conditions will become drier late Tuesday morning into Tuesday
afternoon as the first low dissipates. Pressure gradients will be
favorable for a Turnagain Arm wind Tuesday night, though
northeasterly down-inlet flow will keep these Turnagain Arm winds
out of Anchorage which will help keep temperatures cold for the
Anchorage Bowl.

Wednesday will become more active again as the energy from the
aforementioned dissipating low will become absorbed into a
developing low over the AKPEN Tuesday afternoon. This low will
move northeastward into Southcentral for Wednesday. This storm has
the potential to bring another couple inches of snow to the
Anchorage Bowl and the Mat-Su Valley from Wednesday morning
through Thursday morning. The ingredients needed for Anchorage
snow were seen in the past few model runs. The vorticity maxima
(center of counterclockwise circulation) is expected to move
northeastward through Cook Inlet. Meanwhile, the cross-barrier
flow along the Chugach Mountains will remain very weak. All of
guidance shows very weak pressure gradients between Whittier and
Anchorage which will help keep this southeasterly cross-barrier
flow weak. As stated above, weak cross-barrier flow is essential
for precipitation in the Anchorage Bowl because it will help
inhibit the downslope effect in the lee of the Chugach Mountains.
Precipitation type will be less of a concern for the Anchorage
Bowl and Mat-Su Valley with this storm as temperatures will be
cold throughout the duration of the storm. Thus the expected
precipitation type is snow. The biggest area of uncertainty with
this storm is precipitation/snowfall amounts along the southern
Kenai Peninsula as there was significant model disagreement on
precipitation amounts in this area.

With regards to model guidance, the NAM was heavily weighted for
this forecast package for Southcentral Alaska as it had the best
initialization on both the synoptic and thermodynamic situation.
When comparing the GOES-17 water vapor imagery overlaid with MSLP
plots, the NAM had the low center directly over the center of the
low center on satellite. The 12z initialization of the NAM and
NAMNest had very similar vertical profiles with the 12z PANC
sounding. Likewise the 00z frame of the 18z NAM and NAMNest had
the most congruence with the 00z PANC sounding. For the second
storm system on Wednesday, a NAM/GFS blend was used with the NAM
weighted heavier. The biggest disagreement was with the
precipitation amounts, thus that is the area with the most
uncertainty and lowest confidence in this forecast package.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Monday
afternoon through Thursday afternoon)...

A surface low over Bristol Bay is continuing to develop this
evening underneath a now well defined upper level trough. The
heaviest snow and strongest winds will be underneath the occluded
front to the north of the low center. Blizzard conditions have
been observed this afternoon over the coastal areas of the
Kuskokwim Delta and will continue through 5am Tuesday morning.
Snow and blowing snow are also expected for interior areas of the
Kuskokwim Delta with snow accumulations up to 6 inches. Bristol
Bay and the Lower Kuskokwim can expect some snow overnight tonight
and into Tuesday but accumulations should stay below 3 inches.

By Tuesday afternoon the pressure gradient will relax as the low
fills in and begins to move slowly east. This should abate blowing
snow potential as the winds subside. On Wednesday snow is likely
near the western Alaska Range and Lower Kuskokwim Valley as the
upper level low departs to the west. Snow accumulations on
Wednesday should remain below 3 inches with the higher amounts
near the mountains. By Thursday the upper level shortwave will be
to the east with high pressure building in from the west. This
will return clear skies and cold temperatures to the region.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: Monday
afternoon through Thursday afternoon)...

An area of low pressure is developing this evening over the
eastern Bering. This will continue the pattern of gale force
winds moving south over the eastern Bering. A Winter Weather
Advisory remains in effect for the Alaska Peninsula from 9pm
tonight to 3pm Tuesday. The wrap around flow to the west of the
low center is expected to bring persistent snow, gusty winds and
blowing snow to the AKPen. Snow accumulations up to 5 inches are
possible with visibilities reduced to one half mile at times. This
upper level wave is expected to move off to the east Tuesday
evening, which will abate the threat of blowing snow.

The hazardous weather threat will then shift to the western Bering
where a storm force low is expected to develop. There is still
some uncertainty on Wednesday with the finer details of this
storm, particularly along the front. A few models have meso-lows
developing and circulating around the primary low. This could
cause localized areas of storm force winds to develop along the
front. On Thursday confidence is moderate and a storm force front
will move across the Bering; however, there is still considerable
model discrepancy in regards to the finer details.

&&

.MARINE (Days 3 through 5 - Thursday through Saturday)...

Bering: A well-developed Western Bering low merges with a North
Pacific low, forming a new low that moves to the Central Bering
by Sat. Its front sweeps to the Northeastern Bering by Sat. While
model track and development are mixed, widespread high-end gale
force winds and waves wrap the low and front through Sat. The
rear flank winds over the Western and Central Aleutians moves
South and dissipate Sat as the low weakens.

Gulf of Alaska: A weakening low moves across the Northern Gulf
through Thu night. Model track and development vary, but lingering
gap winds bring northwesterly small craft winds and waves over the
Barren Islands into the Western Gulf diminishing Thu. A front
extending across the Alaska Peninsula into the North Pacific moves
into the Gulf through Sat. A well-developed North Pacific low
moves along the front to the extreme southwest corner of the Gulf.
Widespread high-end southeast gale force winds move into the Gulf
becoming easterly across Kodiak Island and the Gulf by Sat.

&&

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

Models are in decent agreement on a broad vertically stacked low
near the western Aleutians early on Friday with a weakening front
draped across the central/eastern Bering and Aleutians.

On Saturday the Aleutians/Bering storm continues to gradually
weaken, with a new storm system lifting out of the North Pacific
towards the Alaska Peninsula. There is significant disagreement as
to whether this low will bring a front towards the Northern Gulf
Coast, or keeps its impacts primarily just limited to Kodiak and
the AKPEN.

On Sunday this new low looks to retrograde and merge with the
broader low centered in the Bering, with a fairly quiet pattern
setting up for Southcentral which will persist into Monday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Blizzard Warning: 155.
Winter Weather Advisory: 181.
MARINE...Gale Warning: 155 175-178 180-185 411 414.
Heavy Freezing Spray Warning: 160 180.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...ED
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CJ
MARINE/LONG TERM...KZ/BG

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
1243 AM AKST Tue Dec 8 2020

AKZ101-111-081700-
Anchorage-Matanuska Valley-
Including the cities of Anchorage, Eagle River, Indian, Eklutna,
Palmer, Wasilla, Sutton, and Chickaloon
1243 AM AKST Tue Dec 8 2020

Periods of light to moderate snow are expected for the morning
commute continuing into the early afternoon hours. That said,
there is still a chance of isolated pockets of light freezing rain
during the early morning hours. Motorists should allow extra time
for their morning commute and use caution while driving.