Gale Warning 224, NWS Anchorage, AK

763 
FZAK62 PAFC 071301
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
401 AM AKST Sat Mar 7 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.

PKZ499-080200-
401 AM AKST Sat Mar 7 2020
.SYNOPSIS FOR CENTRAL BERING SEA...

A 991 mb low at 55N 174E will move to 57N 176W Sun morning. The 
low then moves eastward into the Gulf Mon morning.

$$

PKZ411-080200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
401 AM AKST Sat Mar 7 2020

.TODAY...NE wind 15 to 30 kt. Seas 7 to 11 ft. Snow and rain.
.TONIGHT...N wind 15 to 30 kt becoming 25 kt after midnight. Seas
9 to 13 ft.
.SUN...N wind 15 to 25 kt. Seas 11 ft.
.SUN NIGHT...NW wind 10 to 25 kt. Seas 6 to 10 ft.
.MON...SW wind 10 to 25 kt. Seas 5 to 10 ft.
.TUE...S wind 25 kt. Seas 6 to 11 ft.
.WED...SE wind 25 to 40 kt. Seas 12 to 20 ft.

$$

PKZ412-080200-
Bering Sea Offshore 171W to 180 and North of 56N-
401 AM AKST Sat Mar 7 2020

.TODAY...E wind 15 to 30 kt. Seas 4 to 8 ft. Snow and rain.
.TONIGHT...E wind 15 to 30 kt. Seas 6 to 11 ft. Freezing spray.
Snow and rain.
.SUN...NE wind 15 to 30 kt. Seas 7 to 11 ft. Freezing spray.
.SUN NIGHT...NE wind 15 to 30 kt. Seas 6 to 11 ft.
.MON...W wind up to 20 kt. Seas 3 to 8 ft.
.TUE...S wind 10 to 20 kt. Seas 3 to 7 ft.
.WED...S wind 15 to 30 kt. Seas 10 to 14 ft.

$$

PKZ413-080200-
Bering Sea Offshore 171W to 180 and South of 56N-
401 AM AKST Sat Mar 7 2020

.TODAY...S wind 15 to 30 kt. Seas 5 to 10 ft. Rain and snow.
.TONIGHT...SW wind 15 to 30 kt. Seas 7 to 10 ft.
.SUN...W wind 10 to 25 kt. Seas 8 to 11 ft.
.SUN NIGHT...NW wind 15 to 30 kt. Seas 7 to 12 ft.
.MON...W wind 10 to 25 kt. Seas 5 to 10 ft.
.TUE...S wind 15 to 25 kt. Seas 4 to 9 ft.
.WED...S wind 20 to 30 kt. Seas 13 ft.

$$

PKZ414-080200-
Bering Sea Offshore East of 171W-
401 AM AKST Sat Mar 7 2020

.TODAY...SE wind 10 to 20 kt. Seas in ice free waters 3 to 6 ft.
.TONIGHT...SE wind 15 to 30 kt. Seas in ice free waters 3 to 7 ft.
Snow.
.SUN...NW wind 10 to 25 kt. Seas in ice free waters 3 to 7 ft.
.SUN NIGHT...NE wind 10 to 25 kt. Seas in ice free waters 3 to 7
ft.
.MON...NW wind 10 to 25 kt. Seas in ice free waters 3 to 7 ft.
.TUE THROUGH WED...SW wind 10 to 20 kt. Seas in ice free waters 3
to 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
412 AM AKST Fri Mar 6 2020

.ANALYSIS AND UPPER LEVELS...

A highly amplified upper level pattern is currently over Southern
Alaska and the Bering/Aleutians. Upper level ridging continues to
dominate over the Alaskan mainland as a positively-tilted upper
level trough currently extends southwestward from northern British
Columbia to the subtropical Pacific. A negatively-tilted trough
currently extends southeastward from the central Bering into the
North Pacific. Teleconnections support a strengthening jet-stream
across the North Pacific as the Arctic Oscillation (AO) continues
to shift into a stronger positive phase and thus increasing the
pressure gradient between the North Pole and mid-latitudes and
thus increasing the wind speed inside of the jet-stream. At the same
time, the Pacific/North American Pattern (PNA) and Eastern Pacific
Oscillation (EPO) are trending towards the neutral phase which will help
the upper-level synoptic flow become more zonal. The jet-stream is
currently oriented from southeast to northwest extending from 45N
150W to the northern Bering Sea. The right-exit region is
currently over the central interior of Alaska, thus skies will be
relatively clear due to confluent flow aloft. The left-exit
region of the jet is over the northern Bering which means a higher
probability of clouds and snow showers as a result of diffluent
flow aloft.

At the surface, a 992 mb low is currently over the central Bering
south of the aforementioned left-exit region and is moving
eastward. A 1033 mb ridge of high pressure is centered over
northern Yukon Territory. A weakening 1006 mb low currently
centered in the southeastern Gulf of Alaska remains nearly
stationary. Radar imagery and observations shows bands of light
snow beginning to move into Southwestern Alaska ahead of the
approaching surface low.

&&

.MODEL DISCUSSION...

Models are in good agreement with respect to the overall synoptic
pattern through Sunday morning and then are in fair agreement on
Sunday as differences arise in the placement of a surface low in
the Bering. Despite the placement of the low center being slightly
off between guidance, the overall general track of this low is
fairly consistent. Guidance also remains in good agreement with
respect to the upper level pattern as all models show a strong
zonal jet developing this weekend as teleconnections support this
synoptic setup. However significant differences arise in the
placement of surface lows Monday afternoon, thus our forecast
confidence remains low thereafter.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist for this TAF
package. Ceilings will gradually fall after 07th/0900z as a
shortwave trough moves in from the west. Light snow will develop
around 07th/1500z as the trough moves through, however conditions
will remain VFR.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (through Saturday)...

Pressure gradients and upper support for gap and outflow winds
continue to weaken this morning, thus expect much calmer winds. A
series of upper short waves head east across Southcentral through
Saturday night. The first wave moves in tonight and brings in
moisture associated with a weakening frontal boundary currently
over the eastern Bering Sea. It looks like the chance for
precipitation tonight will be generally low as it will take some
time to overcome the dry air in place across Southcentral. The
flow aloft becomes progressively more southwesterly with the next
wave Saturday and Saturday night. So the region will experience
increasing chances of snow especially in upslope areas in the MAT-
SU Valleys and across the Anchorage Bowl. Increasing cloud cover
with these systems will warm up temperatures some, but they should
stay safely below freezing in many areas through Saturday night.

&&

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

The front that was over the Bering Sea is moving across the
coast. Snowfall has started and has been verified with
observations on the Kuskokwim Delta coast into Bristol Bay. This
front is weakening as upper level flow forces the low southeast,
shearing it apart. This means that instead of a normal closed off
low, the low has a more elongated appearance. Due to this,
precipitation will not be able to propagate very far inland.
Behind this system, we see zonal flow which is latitudinal in
nature versus the longitudinal flow pattern we have been in. This
will continue to bring moisture and warm temperatures inland from
the Bering Sea with widespread light snowfall expected throughout
the weekend.

&&

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

The front over the eastern Bering has brought warmer temperatures
to the central Aleutians and the Pribilofs. Snow has transitioned
to rain a few hours ago and has been verified with observations.
Areas like Cold Bay and Sand Point are still currently snowing,
however, temperatures are at or slightly above 32 degrees. Expect
a wintry mix of precipitation with a possibility for rain as the
low continues to propagate southeast through Saturday morning.

Following this, things will calm for most of the day Friday, as
the Bering Sea sits between the low exiting the region and a new
low coming across the western Bering. This second low will enter
the western Aleutians late Friday. Due to the latitudinal (zonal)
flow aloft, this low will become elongated across the Bering
similar to the one before it. It also looks to rapidly weaken as
it propagates into the central and eastern Bering Saturday into
Sunday.

&&

.MARINE (Days 3 through 5 Sun through Tue)...
Gulf of Alaska: A low pressure systems moves Northeast through
the Gulf of Alaska Monday into Tuesday. Both will induce
southerly winds ahead of it that are expected to max out at small
craft advisory at most. The backside of the low will pull northwest
winds and cold air through gaps in the Alaska Range, creating gale
force winds in the Western Gulf Tuesday. We are confident in this
forecast, though winds through bays and passes may need to be
adjusted as the system gets closer in time.

Bering Sea: Weak low pressure works its way through the Bering Sea
through Sunday night. It is expected to be largely a small craft
advisory low, with some isolated gale force winds. Behind this
system, northerly flow develops for the entire Bering through
Monday. We are confident in the forecast. Tuesday will see the
beginning of the next low pressure system move into the Western
Bering, while the eastern Bering maintains northerly flow. We are
confident in the forecast, though timing to the low pressure
systems may need to be adjusted.

&&

.LONG TERM FORECAST (Days 4 through 7: Monday through Thursday)...
A progressive pattern is expected next week as a broad upper
level ridge over the Bering pushes a deep upper level trough in
place over Mainland Alaska to the east. By the middle of the week,
a strong upper level trough on the heels of the ridge moves
eastward into the Bering, forcing the ridge to amplify as it moves
over the Mainland. By the end of the week, model solutions are
hinting at a strong system impacting much of the Bering as the
actual low center lifts northward and exits the Bering into next
weekend.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Heavy Freezing Spray Warning 127 128 130 139.
         Gale Warning 178.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...ED
SOUTHCENTRAL ALASKA...RMC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CK
MARINE/LONG TERM...BB/KO