Gale Warning 197, NWS Anchorage, AK

396 
FZAK61 PAFC 292347
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
347 PM AKDT WED MAR 29 2017

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

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.

PKZ399-301300-
347 PM AKDT WED MAR 29 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A TROUGH OF LOW PRESSURE ALONG THE NORTH GULF COAST WILL 
DISSIPATE TONIGHT. A FRONT ENTERS THE SOUTHWESTERN GULF OF ALASKA 
THU MORNING AND MOVES TO THE NORTH GULF COAST BY THU EVENING. THE 
FRONT WILL THEN DISSIPATE ALONG THE NORTH GULF COAST THU NIGHT.

$$

PKZ351-301300-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
347 PM AKDT WED MAR 29 2017

...GALE WARNING THURSDAY AND THURSDAY NIGHT...

.TONIGHT...SW WIND 10 TO 20 KT BECOMING SE TOWARDS MORNING. SEAS 6 
TO 9 FT.
.THU...SE WIND 25 TO 40 KT INCREASING TO 35 TO 45 KT IN THE
AFTERNOON. SEAS 6 TO 10 FT BUILDING TO 10 TO 16 FT. RAIN.
.THU NIGHT...S WIND 25 TO 40 KT. SEAS 15 FT. RAIN.
.FRI...SE WIND 25 KT. SEAS 12 TO 15 FT.
.FRI NIGHT...SE WIND 25 KT. SEAS 14 TO 18 FT.
.SAT...S WIND 10 TO 25 KT. SEAS 14 TO 18 FT.
.SUN THROUGH MON...SE WIND 25 KT. SEAS 9 TO 14 FT.

$$

PKZ352-301300-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
347 PM AKDT WED MAR 29 2017

...GALE WARNING THROUGH THURSDAY...

.TONIGHT...SW WIND 15 KT BECOMING SE 20 TO 35 KT AFTER MIDNIGHT.
SEAS 8 FT.
.THU...SE WIND 30 TO 45 KT. SEAS 9 TO 16 FT BUILDING TO 15 FT IN
THE AFTERNOON. RAIN WITH SNOW.
.THU NIGHT...S WIND 30 KT. SEAS 15 FT. RAIN.
.FRI...S WIND 20 TO 30 KT. SEAS 14 TO 19 FT.
.FRI NIGHT...S WIND 10 TO 25 KT. SEAS 17 TO 20 FT.
.SAT...SW WIND 15 TO 30 KT. SEAS 15 TO 22 FT.
.SUN THROUGH MON...SE WIND 10 TO 25 KT. SEAS 9 TO 16 FT.

$$

043 
FZAK61 PAFC 301139
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
339 AM AKDT THU MAR 30 2017

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

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.

PKZ399-310200-
339 AM AKDT THU MAR 30 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A FRONT ENTERS THE SOUTHWESTERN GULF OF ALASKA AND MOVES TO THE
NORTH GULF COAST BY FRI MORNING. A 975 MB LOW NEAR 56N 157W FRI 
AFTERNOON MOVES TO 57N 151W AT 982 MB BY SAT MORNING. A TROUGH
EXTENDS ALONG THE NORTH GULF COAST AND SOUTHEAST ALASKA THROUGH 
SAT MORNING.

$$

PKZ351-310200-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
339 AM AKDT THU MAR 30 2017

...GALE WARNING THROUGH TONIGHT...

.TODAY...SE WIND 25 TO 40 KT INCREASING TO 35 TO 45 KT IN THE
AFTERNOON. SEAS 6 TO 10 FT BUILDING TO 10 TO 16 FT IN THE
AFTERNOON. RAIN AND SNOW.
.TONIGHT...S WIND 25 TO 40 KT. SEAS 15 FT. RAIN.
.FRI...SE WIND 25 KT. SEAS 14 FT.
.FRI NIGHT...SE WIND 25 KT. SEAS 13 TO 19 FT.
.SAT...SW WIND 15 TO 25 KT. SEAS 14 TO 20 FT.
.SUN THROUGH MON...E WIND 15 TO 30 KT. SEAS 8 TO 16 FT.

$$

PKZ352-310200-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
339 AM AKDT THU MAR 30 2017

...GALE WARNING TODAY...

.TODAY...SE WIND 30 TO 45 KT. SEAS 9 FT BUILDING TO 15 FT IN THE 
AFTERNOON. RAIN AND SNOW.
.TONIGHT...S WIND 30 KT. SEAS 15 FT. RAIN SHOWERS.
.FRI...S WIND 20 TO 30 KT. SEAS 14 TO 19 FT.
.FRI NIGHT...S WIND 15 TO 30 KT. SEAS 16 TO 22 FT.
.SAT...SW WIND 20 TO 30 KT. SEAS 15 TO 22 FT.
.SUN THROUGH MON...E WIND 15 TO 30 KT. SEAS 9 TO 17 FT.

$$

233 
FZAK61 PAFC 302355
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
355 PM AKDT THU MAR 30 2017

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

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.

PKZ399-311415-
355 PM AKDT THU MAR 30 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A FRONT OVER THE CENTRAL GULF OF ALASKA WILL MOVE TO THE NORTH
GULF COAST TONIGHT. A 978 MB LOW NEAR 55N 155W FRI AFTERNOON WILL
MOVE TO 59N 150W AT 990 MB SAT AFTERNOON.

$$

PKZ351-311415-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
355 PM AKDT THU MAR 30 2017

...GALE WARNING TONIGHT...

.TONIGHT...S WIND 25 TO 40 KT. SEAS 14 TO 17 FT. RAIN.
.FRI...SE WIND 25 KT. SEAS 14 FT. RAIN SHOWERS.
.FRI NIGHT...SE WIND 15 TO 25 KT. SEAS 13 TO 18 FT.
.SAT...S WIND 15 TO 30 KT. SEAS 15 TO 20 FT.
.SAT NIGHT...SW WIND 20 TO 30 KT. SEAS 14 TO 20 FT.
.SUN THROUGH TUE...E WIND 15 TO 30 KT. SEAS 8 TO 16 FT.

$$

PKZ352-311415-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
355 PM AKDT THU MAR 30 2017

.TONIGHT...S WIND 30 KT. SEAS 15 FT. RAIN.
.FRI...S WIND 20 TO 30 KT. SEAS 14 TO 19 FT.
.FRI NIGHT...S WIND 15 TO 30 KT. SEAS 17 TO 23 FT.
.SAT...SW WIND 25 TO 35 KT. SEAS 18 TO 24 FT.
.SAT NIGHT...SW WIND 20 TO 30 KT. SEAS 13 TO 20 FT.
.SUN THROUGH TUE...E WIND 15 TO 30 KT. SEAS 9 TO 17 FT.

$$

508 
FZAK61 PAFC 311126
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
326 AM AKDT FRI MAR 31 2017

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

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.

PKZ399-010130-
326 AM AKDT FRI MAR 31 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 975 MB LOW AT 56N 157W FRI AFTERNOON SWINGS EAST OF KODIAK
ISLAND TO 60N 151W AT 1001 MB BY SUN MORNING. A FRONT SWINGS TO 
THE NORTH GULF COAST FRIDAY NIGHT WHILE THE TRAILING FRONT SWEEPS 
THE GULF OF ALASKA AND TRAILING INTO THE NORTH PACIFIC THROUGH 
SUN MORNING.

$$

PKZ351-010130-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
326 AM AKDT FRI MAR 31 2017

...GALE WARNING SATURDAY...

.TODAY...SE WIND 25 KT. SEAS 14 FT. RAIN SHOWERS.
.TONIGHT...SE WIND 25 KT. SEAS 13 TO 18 FT.
.SAT...SW WIND 20 TO 35 KT. SEAS 16 TO 21 FT. RAIN SHOWERS.
.SAT NIGHT...SW WIND 20 TO 30 KT. SEAS 16 TO 20 FT.
.SUN...S WIND 10 TO 25 KT. SEAS 9 TO 14 FT.
.MON THROUGH TUE...E WIND 15 TO 30 KT. SEAS 6 TO 11 FT.

$$

PKZ352-010130-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
326 AM AKDT FRI MAR 31 2017

...GALE WARNING TONIGHT AND SATURDAY...

.TODAY...S WIND 20 TO 30 KT. SEAS 14 TO 18 FT.
.TONIGHT...S WIND 20 TO 30 KT BECOMING SW 25 TO 40 KT AFTER
MIDNIGHT. SEAS 16 TO 23 FT.
.SAT...SW WIND 30 TO 40 KT. SEAS 20 TO 24 FT.
.SAT NIGHT...SW WIND 20 TO 30 KT. SEAS 14 TO 21 FT.
.SUN...S WIND 10 TO 25 KT. SEAS 8 TO 13 FT.
.MON THROUGH TUE...E WIND 15 TO 30 KT. SEAS 6 TO 11 FT.

$$

185 
FZAK61 PAFC 010001
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
401 PM AKDT FRI MAR 31 2017

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

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.

PKZ399-010115-
401 PM AKDT FRI MAR 31 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 977 MB LOW NEAR 55N 155W WILL WEAKEN TO 1005 MB WHILE DRIFTING 
TO 59N 159W BY SUN MORNING..THEN DISSIPATE OVER COOK INLET SUN 
AFTERNOON. A FRONT MOVES TO THE NORTH GULF COAST TONIGHT WHILE THE
TRAILING FRONT CROSSES THE GULF OF ALASKA THROUGH SUN MORNING.

$$

PKZ351-010115-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
401 PM AKDT FRI MAR 31 2017

...GALE WARNING SATURDAY...

.TONIGHT...S WIND 25 KT. SEAS 13 TO 18 FT.
.SAT...SW WIND 20 TO 35 KT. SEAS 16 TO 21 FT.
.SAT NIGHT...SW WIND 30 KT. SEAS 15 TO 19 FT. RAIN SHOWERS.
.SUN...S WIND 10 TO 25 KT. SEAS 9 TO 15 FT.
.SUN NIGHT...SE WIND UP TO 20 KT. SEAS 5 TO 9 FT.
.MON THROUGH WED...E WIND 20 TO 35 KT. SEAS 9 TO 16 FT.

$$

PKZ352-010115-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
401 PM AKDT FRI MAR 31 2017

...GALE WARNING THROUGH SATURDAY...

.TONIGHT...S WIND 20 TO 30 KT BECOMING SW 25 TO 40 KT AFTER
MIDNIGHT. SEAS 16 TO 23 FT.
.SAT...SW WIND 25 TO 40 KT. SEAS 20 TO 23 FT.
.SAT NIGHT...SW WIND 20 TO 30 KT. SEAS 13 TO 21 FT.
.SUN...S WIND UP TO 20 KT. SEAS 9 TO 14 FT.
.SUN NIGHT...SE WIND 10 TO 25 KT. SEAS 5 TO 8 FT.
.MON THROUGH WED...E WIND 15 TO 30 KT. SEAS 9 TO 14 FT.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
445 PM AKDT Tue Mar 28 2017

.ANALYSIS AND UPPER LEVELS...
A high amplitude upper level trough extending across western
Alaska down into the western Gulf of Alaska is slowly becoming
negatively tilted as the southern end of the trough begins to lift
northeast. A low level baroclinic zone sits right on the front
edge of the trough (to the east of Kodiak Island) with a steady
stream of moisture advecting north toward south central Alaska.
Radar imagery shows widespread snow falling along the Gulf coast
and spreading inland across the Kenai Peninsula to Anchorage and
the Mat-Su as a surface low moves onshore near Seward. Another
distinct surface low is tracking north across the Gulf of Alaska
out ahead of the baroclinic zone. This low will become a key
player in producing additional snow across south central Alaska
tonight.

High pressure centered over the central Bering Sea and Aleutians
continues to produce cool and dry conditions across the eastern
half of the Bering Sea and southwest Alaska. Cold air advection
behind the upper trough axis is producing some localized gap winds
on the south side of the Alaska Peninsula. To the west of the
upper high a weak system is lifting north across the far
southwestern Bering Sea, bringing some light rain to the western
Aleutians. To the south, a large deep low over the north Pacific
is tracking east along the subtropical jet stream. This system
will become a major player in the forecast for later this week.

&&

.MODEL DISCUSSION...
Although latest models are in much better agreement with the track
of lows across the Gulf of Alaska, there are subtle but critical
differences with the track of lows inland along with waves moving
along the front edge of the upper trough. This is leading to
significant differences in the precipitation fields. Thus, timing
and location of heaviest snowfall remains the biggest forecast
challenge, especially for the Kenai Peninsula up to Anchorage and
the Mat-Su. Conditions for heavier snow do become much more likely
overnight tonight into Wednesday morning with a more well defined
low backing into western Prince William Sound and a strongly
negatively tilted upper level trough. Thus, feel more confident in
upping snow amounts for this time period.

&&

.AVIATION...
PANC...Periods of snow will continue through at least midday
Wednesday with MVFR conditions prevailing. The challenge is
determining the timing of heavier snowfall at which time
conditions will drop to IFR or possible even briefly LIFR. Right
now there is quite a bit of uncertainty in snow intensity for
late this afternoon through evening. Confidence is higher for a
period of heavier snow overnight tonight through early Wednesday
morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Snow will increase in intensity through this evening from
Anchorage north into the Mat-Su region as the upper level trough
becomes more negatively tilted and begins to lift north into the
Cook Inlet region. This will coincide with a fast moving surface
low tracking into western Prince William Sound and spreading ample
moisture into the region. The heaviest snow will occur during the
overnight hours into mid Wednesday morning, with the dynamic
setup appearing to favor the highest accumulations across the
Anchorage Bowl as mid level deformation develops overhead.
Therefore, we have issued a Winter Weather Advisory for the
Anchorage Bowl. The Mat-Su region is expected to remain below
advisory criteria, although several inches of snow is likely to
fall along the Parks Highway corridor from Wasilla to Willow, with
slightly lower amounts toward Palmer. Elsewhere, occasionally
heavy precipitation will continue to fall through Wednesday
afternoon along the gulf coast, with snow continuing to pile up
from Whittier to Valdez and through Thompson/Turnagain passes.
Snow will quickly diminish area-wide on Wednesday afternoon as the
trough lifts through south central Alaska.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The high pressure and northerly flow that had persisted over the
southwest Mainland over the past few weeks has given way to a
slightly more active pattern as an upper level trough has set up
over the western interior. This trough is however, very dry
throughout the atmosphere, so anything that does develop should be
light and limited to the Alaska Range. As a result we will remain
generally dry with seasonable temperatures through Wednesday.
Starting Thursday the incoming pattern change will become much
more apparent as a gale force front approaches from the south.
This will spread gusty easterly winds along with rain and snow
throughout the area for Thursday and Friday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
Weakening high pressure will keep much of the Bering Sea region
quiet for one more night before the next storm force low moves in
beginning on Wednesday. This system is currently well south of the
Aleutians, but will quickly track towards the eastern Aleutians
and Alaska Peninsula as it strengthens to storm force on
Wednesday. With this track, the worst conditions should occur over
the Alaska Peninsula on Thursday with snow mixed with rain and
gale force easterly winds. Depending on how much snowfall reaches
of Bering side of the Alaska Peninsula this may produce some
areas of blowing snow. This was however left out of the forecast
as there is currently no transportable snow in the area with
uncertainty in how much snow will fall on the Bering coast. This
low will then move over southwest Alaska on Friday, leaving
widespread northerly winds and a chance of showers in its wake.

&&

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

Thursday will be the day that the upcoming pattern change will
begin to be felt across much of southern Alaska. An upper level
trough is still expected to amplify in the coming days as strong
jet support traverses the western periphery of the trough. This
will help to advect a warmer and wetter air mass up towards
Alaska. On Thursday, a surface low pressure south of Dutch Harbor
will begin to weaken. However, the frontal boundary associated
with this low and a surplus of upper level energy will help a
triple point low to develop south of the Alaska Peninsula. This
low is expected to move inland sometime late Friday morning into
Friday afternoon but a a bit of model divergence has made it quite
difficult to pinpoint all of the big details at this time.

With certainty, southern Alaska will see a pattern shift that
will entail temperatures warming a good bit above normal and
periods of rain and snow that will largely be confined to the
northern Gulf Coast. As it appears now, Anchorage and other areas
on the lee side of the Chugach Mountains will be downsloped from
any precipitation with impressive cross barrier flow developing.
Confidence is increasing that a chinook type pattern will set up
over the Anchorage bowl on Thursday and/or Friday which could
allow temperatures to warm into the lower to mid 40s. The
temperature forecast is heavily dependent on the amount of wind
that makes it into town but a warm up is nevertheless inevitable.
A mix of snow and rain will likely be seen along the coast
Thursday afternoon ahead of the frontal boundary but precipitation
across most of south central Alaska will quickly change to all
rain as 850 temperatures warm to near zero degrees Celsius and sfc
to 850 mb thicknesses rise quickly. Any precipitation from Friday
morning onward across south central Alaska will likely be rain,
except for portions of the Talkeetna Mountains, the Alaska Range
and the Aleutian Range where some minor snow accumulations could
be seen.

Heading into the weekend, chances for rainfall and possibly a mix
of snow at times cannot be ruled out thanks to an active synoptic
pattern. A series of lows will pass through the Gulf of Alaska
heading into next week but trying to come up with any low position
is near impossible this far out as the models are quite volatile
past 4 or 5 days. The weekend looks warm as temperatures will
likely remain above normal and no reprieve is seen through the
first half of next week.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storm 172. Gale 130 150 155 165 170 173 175 175 176.
Heavy Freezing Spray 179.

&&

SYNOPSIS AND MODEL DISCUSSION...SB
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PS/DEK
LONG TERM...MC