Gale Warning 172, NWS Anchorage, AK

229 
FZAK52 PAFC 240027
CWFALU

COASTAL WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE ALASKA
327 PM AKST THU FEB 23 2017

COASTAL WATERS FORECAST FOR SOUTHWEST ALASKA+BRISTOL BAY+THE
ALASKA PENINSULA WATERS AND THE ALEUTIAN ISLANDS UP TO 100 NM OUT.

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.

PKZ199-241245-
327 PM AKST THU FEB 23 2017
.SYNOPSIS FOR SOUTHWEST ALASKA+BRISTOL BAY+THE ALASKA
PENINSULA WATERS AND THE ALEUTIAN ISLANDS...
BOGOSLOF VOLCANO 53 NM WEST OF DUTCH HARBOR REMAINS ACTIVE. 
A 977 MB LOW 290 NM NORTH OF SHEMYA MOVES TO THE GULF OF ANADYR
AND WEAKENS TO 1006 MB FRIDAY AFTERNOON. A DEVELOPING NORTH
PACIFIC LOW MOVES TO 270 NM NORTHWEST OF SHEMYA AT 969 MB FRIDAY
AFTERNOON THEN TO 360 NM WEST OF SAINT LAWRENCE ISLAND AT 982 MB
SATURDAY MORNING.

$$

PKZ150-241245-
SOUTH OF THE AK PENINSULA SITKINAK TO CASTLE CAPE-
327 PM AKST THU FEB 23 2017

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS 13 FT.
.FRI...SW WIND 25 KT. FROM CHIRIKOF ISLAND W...SW WIND 25 KT
DIMINISHING TO 15 KT IN THE AFTERNOON. SEAS 13 FT.
.FRI NIGHT...NW WIND 20 KT. SEAS 10 FT.
.SAT...W WIND 20 KT. SEAS 7 FT.
.SAT NIGHT...W WIND 25 KT. SEAS 7 FT.
.SUN...W WIND 25 KT. SEAS 8 FT.
.MON...NW WIND 30 KT. SEAS 8 FT.
.TUE...NW WIND 35 KT. SEAS 9 FT.

$$

PKZ155-241245-
SOUTH OF THE AK PENINSULA CASTLE CAPE TO CAPE SARICHEF-
327 PM AKST THU FEB 23 2017

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S WIND 25 KT. SEAS 20 FT. W OF THE SHUMAGIN
ISLANDS...S WIND 25 KT BECOMING W 15 KT AFTER MIDNIGHT. SEAS 20 FT
SUBSIDING TO 15 FT AFTER MIDNIGHT.
.FRI...W WIND 15 KT. FROM THE SHUMAGIN ISLANDS E... S WIND 20 KT
BECOMING W 15 KT IN THE AFTERNOON. SEAS 14 FT.
.FRI NIGHT...W WIND 15 KT. SEAS 10 FT.
.SAT AND SAT NIGHT...SW WIND 20 KT. SEAS 8 FT.
.SUN...SW WIND 20 KT. SEAS 9 FT.
.MON...NW WIND 20 KT. SEAS 8 FT.
.TUE...N WIND 25 KT. SEAS 7 FT.

$$

PKZ160-241245-
BRISTOL BAY-
327 PM AKST THU FEB 23 2017

...BRISK WIND ADVISORY TONIGHT...

.TONIGHT...S WIND 25 KT DIMINISHING TO 10 KT AFTER MIDNIGHT.
PATCHY FOG.
.FRI...SW WIND 10 KT INCREASING TO 15 KT IN THE AFTERNOON. PATCHY
FOG.
.FRI NIGHT...SW WIND 15 KT. PATCHY FREEZING FOG.
.SAT AND SAT NIGHT...SW WIND 20 KT.
.SUN...SW WIND 20 KT.
.MON THROUGH TUE...NW WIND 25 KT.

$$

PKZ165-241245-
PORT HEIDEN TO CAPE SARICHEF-
327 PM AKST THU FEB 23 2017

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...S WIND 25 KT DIMINISHING TO 10 KT AFTER MIDNIGHT.
FROM COLD BAY W...SW WIND 20 KT. SEAS 8 FT.
.FRI...W WIND 15 KT. SEAS 10 FT.
.FRI NIGHT...SW WIND 15 KT BECOMING S 25 KT AFTER MIDNIGHT. E OF
COLD BAY...SW WIND 15 KT BECOMING S AFTER MIDNIGHT. SEAS 10 FT.
.SAT...S WIND 30 KT. SEAS 12 FT.
.SAT NIGHT...SW WIND 25 KT. SEAS 13 FT.
.SUN...SW WIND 20 KT. SEAS 11 FT.
.MON...NW WIND 25 KT. SEAS 6 FT.
.TUE...N WIND 30 KT. SEAS 8 FT.

$$

PKZ170-241245-
CAPE SARICHEF TO NIKOLSKI BERING SIDE-
327 PM AKST THU FEB 23 2017

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...SW WIND 20 KT. SEAS 11 FT.
.FRI...SW WIND 25 KT. SEAS 12 FT.
.FRI NIGHT...S WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT.
SEAS 12 FT.
.SAT...S WIND 35 KT. SEAS 15 FT.
.SAT NIGHT...S WIND 30 KT. SEAS 14 FT.
.SUN...SW WIND 25 KT. SEAS 12 FT.
.MON THROUGH TUE...NE WIND 25 KT. SEAS 7 FT.

$$

PKZ171-241245-
UNALASKA BAY-
327 PM AKST THU FEB 23 2017

.TONIGHT...SW WIND 10 KT. GUSTS TO 20 KT IN THE EVENING. SEAS 2
FT.
.FRI...SW WIND 10 KT INCREASING TO 15 KT IN THE AFTERNOON. SEAS 2
FT.
.FRI NIGHT...S WIND 20 KT. SEAS 3 FT.
.SAT...S WIND 20 KT. SEAS 3 FT.
.SAT NIGHT...S WIND 15 KT. SEAS 2 FT.
.SUN...SW WIND 15 KT. SEAS 2 FT.
.MON...NE WIND 15 KT. SEAS 4 FT.
.TUE...NE WIND 20 KT. SEAS 5 FT.

$$

PKZ172-241245-
CAPE SARICHEF TO NIKOLSKI PACIFIC SIDE-
327 PM AKST THU FEB 23 2017

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...W WIND 15 KT. SEAS 18 FT.
.FRI...SW WIND 20 KT. SEAS 14 FT.
.FRI NIGHT...S WIND 25 KT. SEAS 11 FT.
.SAT...S WIND 25 KT. SEAS 10 FT.
.SAT NIGHT...SW WIND 20 KT. SEAS 11 FT.
.SUN...SW WIND 20 KT. SEAS 11 FT.
.MON...N WIND 25 KT. SEAS 9 FT.
.TUE...NE WIND 30 KT. SEAS 9 FT.

$$

PKZ173-241245-
NIKLOSKI TO SEGUAM ISLAND BERING SIDE-
327 PM AKST THU FEB 23 2017

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...SW WIND 25 KT. SEAS 14 FT.
.FRI...S WIND 30 KT. SEAS 14 FT.
.FRI NIGHT...S WIND 40 KT. SEAS 15 FT.
.SAT...S WIND 35 KT. SEAS 15 FT.
.SAT NIGHT...S WIND 30 KT. SEAS 12 FT.
.SUN...S WIND 25 KT. SEAS 11 FT.
.MON THROUGH TUE...E WIND 30 KT. SEAS 11 FT.

$$

PKZ174-241245-
NIKOLSKI TO SEGUAM ISLAND PACIFIC SIDE-
327 PM AKST THU FEB 23 2017

...SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT...

.TONIGHT...SW WIND 20 KT. SEAS 18 FT.
.FRI...S WIND 15 KT INCREASING TO 25 KT IN THE AFTERNOON.
SEAS 15 FT.
.FRI NIGHT...S WIND 30 KT. SEAS 13 FT.
.SAT...S WIND 30 KT. SEAS 16 FT.
.SAT NIGHT...S WIND 25 KT. SEAS 16 FT.
.SUN...S WIND 25 KT. SEAS 13 FT.
.MON...E WIND 30 KT. SEAS 9 FT.
.TUE...E WIND 30 KT. SEAS 13 FT.

$$

PKZ175-241245-
SEGUAM ISLAND TO ADAK BERING SIDE-
327 PM AKST THU FEB 23 2017

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

.TONIGHT...SW WIND 30 KT. SEAS 15 FT.
.FRI...S WIND 35 KT INCREASING TO 45 KT IN THE AFTERNOON. SEAS
16 FT.
.FRI NIGHT...S WIND 45 KT. SEAS 18 FT.
.SAT...S WIND 35 KT. SEAS 15 FT.
.SAT NIGHT...S WIND 25 KT. SEAS 10 FT.
.SUN...NE WIND 25 KT. SEAS 9 FT.
.MON...E WIND 30 KT. SEAS 11 FT.
.TUE...E WIND 35 KT. SEAS 13 FT.

$$

PKZ176-241245-
SEGUAM ISLAND TO ADAK PACIFIC SIDE-
327 PM AKST THU FEB 23 2017

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

.TONIGHT...SW WIND 25 KT. SEAS 19 FT.
.FRI...S WIND 25 KT INCREASING TO 35 KT IN THE AFTERNOON.
SEAS 16 FT.
.FRI NIGHT...S WIND 40 KT. SEAS 20 FT.
.SAT...S WIND 35 KT. SEAS 21 FT.
.SAT NIGHT...S WIND 30 KT. SEAS 17 FT.
.SUN...S WIND 25 KT. SEAS 14 FT.
.MON...E WIND 30 KT. SEAS 11 FT.
.TUE...E WIND 35 KT. SEAS 15 FT.

$$

PKZ177-241245-
ADAK TO KISKA-
327 PM AKST THU FEB 23 2017

...STORM WARNING FRIDAY...

.TONIGHT...SW WIND 35 KT BECOMING S AFTER MIDNIGHT. SEAS 21 FT.
.FRI...S WIND 40 KT INCREASING TO 50 KT BY LATE MORNING. SEAS 21
FT BUILDING TO 27 KT BY LATE MORNING.
.FRI NIGHT...S WIND 45 KT BECOMING SW 30 KT AFTER MIDNIGHT. SEAS
27 FT SUBSIDING TO 22 FT AFTER MIDNIGHT. RAIN.
.SAT...SW WIND 25 KT. SEAS 20 FT.
.SAT NIGHT...W WIND 15 KT. SEAS 16 FT.
.SUN...NE WIND 25 KT. SEAS 12 FT.
.MON...E WIND 35 KT. SEAS 13 FT.
.TUE...E WIND 35 KT. SEAS 17 FT.

$$

PKZ178-241245-
KISKA TO ATTU-
327 PM AKST THU FEB 23 2017

...STORM WARNING FRIDAY AND FRIDAY NIGHT...

.TONIGHT...SW WIND 30 KT BECOMING S 45 KT AFTER MIDNIGHT. SEAS
20 FT. RAIN.
.FRI...S WIND 50 KT. SEAS 23 FT BUILDING TO 30 FT IN THE AFTERNOON.
RAIN.
.FRI NIGHT...SW WIND 50 KT DIMINISHING TO 40 KT AFTER MIDNIGHT.
SEAS 32 FT SUBSIDING TO 24 FT AFTER MIDNIGHT.
.SAT...SW WIND 30 KT. SEAS 21 FT.
.SAT NIGHT...W WIND 20 KT. SEAS 16 FT.
.SUN...NE WIND 25 KT. SEAS 12 FT.
.MON THROUGH TUE...E WIND 35 KT. SEAS 17 FT.

$$

PKZ179-241245-
PRIBILOF ISLANDS NEAR SHORE WATERS-
327 PM AKST THU FEB 23 2017

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...SW WIND 25 KT. SEAS 16 FT.
.FRI...S WIND 30 KT. SEAS 16 FT.
.FRI NIGHT...S WIND 30 KT INCREASING TO 40 KT IN THE EVENING.
SEAS 19 FT.
.SAT...SW WIND 35 KT. SEAS 21 FT.
.SAT NIGHT...SW WIND 25 KT. SEAS 16 FT.
.SUN...W WIND 20 KT. SEAS 12 FT.
.MON...N WIND 15 KT. SEAS 7 FT.
.TUE...NE WIND 20 KT. SEAS 5 FT.

$$

PKZ180-241245-
KUSKOKWIM DELTA AND ETOLIN STRAIT-
327 PM AKST THU FEB 23 2017

...BRISK WIND ADVISORY TONIGHT AND FRIDAY NIGHT...

.TONIGHT...S WIND 30 KT DIMINISHING TO 20 KT AFTER MIDNIGHT.
.FRI...SW WIND 20 KT.
.FRI NIGHT...S WIND 30 KT. PATCHY FREEZING FOG.
.SAT...S WIND 30 KT.
.SAT NIGHT...SW WIND 25 KT.
.SUN...SW WIND 20 KT.
.MON...NW WIND 25 KT.
.TUE...N WIND 30 KT.

$$

PKZ181-241245-
NORTH AND WEST OF NUNIVAK ISLAND-
327 PM AKST THU FEB 23 2017

...GALE WARNING FRIDAY NIGHT...

.TONIGHT...S WIND 25 KT.
.FRI...S WIND 25 KT.
.FRI NIGHT...S WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT.
SNOW AND RAIN.
.SAT...SW WIND 35 KT.
.SAT NIGHT...SW WIND 25 KT.
.SUN...W WIND 20 KT.
.MON THROUGH TUE...N WIND 20 KT.

$$

PKZ185-241245-
SAINT MATTHEW ISLAND WATERS-
327 PM AKST THU FEB 23 2017

...GALE WARNING THROUGH FRIDAY NIGHT...

.TONIGHT...S WIND 20 KT INCREASING TO 30 KT IN THE EVENING E OF
SAINT MATTHEW ISLAND...S 35 KT W OF SAINT MATTHEW ISLAND. SEAS IN
ICE FREE WATERS 21 FT.
.FRI...SW WIND 35 KT BECOMING S IN THE AFTERNOON. E OF SAINT
MATTHEW ISLAND...S WIND 25 KT. SEAS IN ICE FREE WATERS 21 FT.
.FRI NIGHT...S WIND 35 KT INCREASING TO 45 KT AFTER MIDNIGHT. FROM
SAINT MATTHEW E...S WIND 25 KT INCREASING TO 35 KT AFTER MIDNIGHT.
SEAS IN ICE FREE WATERS 24 FT. RAIN AND SNOW.
.SAT...SW WIND 50 KT. SEAS IN ICE FREE WATERS 31 FT.
.SAT NIGHT...SW WIND 40 KT. SEAS IN ICE FREE WATERS 26 FT.
.SUN...W WIND 30 KT. SEAS IN ICE FREE WATERS 17 FT.
.MON...NW WIND 25 KT. SEAS IN ICE FREE WATERS 10 FT.
.TUE...E WIND 20 KT. SEAS IN ICE FREE WATERS 5 FT.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
357 PM AKST Wed Feb 22 2017

.ANALYSIS AND UPPER LEVELS...
Satellite water vapor imagery shows the upper trough moving east
into Canada. The surface low over the northern Gulf continues to
move east-southeast and weaken. Radar imagery showed snow
diminishing across much of the northern Gulf.

A strong vertically stacked low over the western Bering Sea produced
storm force southwesterly winds across the western Aleutians and
gales across much of the Bering Sea and the remainder of the
Aleutians and western AK Pen. The frontal boundary continued
south to near 30n with satellite imagery showing a deep moisture
fetch associated with a strong southerly subtropical jet. Some
areas of light snow were evident across the southern mainland
with locally gusty winds along the coasts.

&&

.MODEL DISCUSSION/Uncertainty...
Models are in fairly good agreement. However, there are some
differences in 850 mb temperatures, especially on Friday across
the Anchorage Bowl/Mat Valley. The NAM is the cooler of the models
and would suggest any precipitation across the above areas would
remain as snow. For now will continue to lean that way.
Otherwise, the NAM will be used through the short term (through
Friday afternoon) in the east and the GFS in the west.

&&

.AVIATION...
PANC...A building ridge and warm advection will likely keep the
threat of MVFR and possibly IFR conditions across Anchorage
through Thursday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
As the low in the Gulf weakens and moves away from the area most
areas will see some degree of clearing skies tonight as shortwave
ridging moves quickly into the area. The one exception will likely
be locations around Cook Inlet where persistent temperature
inversions and mountain barriers could result in low
clouds/stratus hanging around most of the night and perhaps may
even see some localized fog development. Places that do clear out,
though, will cool off fairly substantially, although even this
will be limited by the approach of clouds ahead of the next Bering
Sea storm that is heading our way. Clouds from this storm are
already thickening near Kodiak Island as of early Wednesday
afternoon.

The next storm coming into the area Thursday night and Friday will
bring a surge of warmer temperatures and good chances for
widespread precipitation to most areas. At this point it looks
like the cold air will hang on just long enough to keep things
mostly snow from Anchorage northward, with a mix of rain and snow
on the Kenai Peninsula and rain along the Gulf Coast. One fly in
the ointment is the potential for light freezing rain to fall out
of the low clouds stuck in Cook Inlet between now and Friday
morning (which is when the stronger precipitation should be able
to tap into some colder temperatures higher in the atmosphere to
produce snowflakes). With warm and moist air beginning to surge
straight up Cook Inlet only a few thousand feet aloft, most places
from Kenai north to the Anchorage area are at risk for this light
freezing rain, though confidence in timing or location are low.
Have opted to include some mention of this in the afternoon
forecast, and future upper air soundings will need to be closely
studied to diagnose risk.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The trough has moved across southwest Alaska and we are now
seeing the next front move across the Bering Sea through the
Pribilof Islands toward the Bering Sea coast. This will push
moisture and a warm tongue aloft over southwest Alaska by
Thursday morning. This introduces a challenge to the precipitation
type for the Kuskokwim Delta and Bristol Bay regions as the warm
air aloft initially spreads over the region. However, it does look
as though the warm air will rapidly mix to the surface bringing
the temperatures above freezing. Any freezing rain will be light
and short lived overnight and toward the morning over southwest
Alaska. South to southwest flow into the southwest mainland will
allow for more widespread rain and snow over the Kuskokwim Delta
and northern Bristol Bay Thursday. The rain and snow will spread
east to the Iliamna area to the upslope regions of the Aleutian
Mountains and Alaska Range late Thursday into Friday. Colder air
wraps back into the southwest mainland by Friday, thus the
precipitation type will return to snow. At this point, a broad
southwest flow is established from the Bering Sea into southwest
Alaska, therefore expect a continuation of cloudy conditions with
periods of precipitation.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The parent low of the gale to storm force front sweeping across
the Aleutians and Bering Sea to the southwest mainland will move
to the Bering strait as it dissipates through Friday afternoon. On
the heels of this storm is another vigorous storm that is moving
into the extreme western Bering Sea Friday afternoon. This will
push a gale to storm force front across the western Aleutians
Friday to the Pribilofs by Saturday.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The active weather pattern over the Bering Sea will begin to move
into the Mainland this weekend as high pressure slides southward
into the North Pacific. This will allow for a gale force front
over the Bering Sea to spread gusty winds and rain/snow into the
Southwest Mainland with deep onshore flow for much of the weekend.
Then by early next week the models continue to be in good
agreement that an arctic trough will deepen over the Mainland Mon-
Tue, ushering in colder air and gusty offshore flow to much of the
Gulf Coast. What is still unclear however is the exact track that
this trough will take through the Mainland, which is having a
significant impact in the possibility of snow to the South
Mainland into the middle of next week. The EC and GEM are more
aggressive in bringing Bering Sea moisture into the Mainland ahead
of the arctic trough, and a result are more aggressive in the
potential for a snow event Mon-Tue. The GFS on the other hand has
been very consistently more aggressive in bringing cold/dry
interior air, leaving most of the South Mainland dry into the
middle of next week. For now the forecast favors the drier GFS
solution as it has been much more consistent. Forecast confidence
is below average.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storm Warning 178.
         Gale Warning 155 165 170 172>175 177 179 185.

&&

SYNOPSIS AND MODEL DISCUSSION...RMC
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...SA
LONG TERM...DEK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1005 PM AKST WED FEB 22 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0945 PM     SNOW             4 ENE BIG LAKE          61.54N 149.83W
02/22/2017  M5.0 INCH                           AK   PUBLIC

            PAST 24HRS

&&

MOTTENWE