Gale Warning 198, NWS Anchorage, AK

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...CORRECTED
National Weather Service Anchorage AK
516 PM AKDT Thu Mar 30 2017

Corrected for marine warnings.

.ANALYSIS AND UPPER LEVELS...

A broad upper level low is currently centered south of the Alaska
Peninsula with an associated 968 mb low at the surface. An
impressive baroclinic zone stretches from the low northwards
along the north gulf coast, with much warmer air to the south. It
is supporting a low level jet along the coast and will be the
main weather driver across the region over the next several days.
Radar imagery is showing widespread showers across the eastern
Kenai Peninsula and Prince William Sound which are supported by
the baroclinic zone. Along the northwest side of this low, broad
northwesterly flow is supporting generally sunny skies and colder
temperatures across the Kuskokwim Delta with broad areas of light
showers across the Bering Sea.

&&

.MODEL DISCUSSION...
Models are in generally good agreement synoptically. However there
is a wide range of solutions for precipitation type across the
Alaska Peninsula. The Canadian models are the most aggressive in
bringing warm air towards Dillingham overnight, which would
drastically limit snow amounts. Meanwhile the NAM retains the cold
air longer resulting in greater snow amounts. Currently the middle
ground GFS is the model of choice.

&&

.AVIATION...
PANC...Strong cross-barrier flow will keep ceilings at or near VFR
conditions into tomorrow morning due to downsloping. Some low
level wind shear is possible as northerly winds increase near the
surface, but southeasterly winds remain above the surface.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A front is tracking north through the Gulf that will push into
coastal locations tonight. It will bring snow along the north Gulf
coast that will transition to rain with the strong push of warm
air associated with the front. Some higher elevations will stay
with snow but there should be enough low level warm air to bring
rain to low lying areas. The southerly flow behind the front will
continue through Saturday which will keep bringing precip to
coastal locations. Inland locations will be protected from most of
the precip by the coastal ranges, but some showers may sneak
through. Temperatures throughout Southcentral Alaska look to
increase due to the front with afternoon temperatures around much
of Southcentral rising into the 40s for Friday and Saturday
afternoons.

&&

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

Enhanced southeast flow ahead of an occluded front will continue
to steer moisture into the region. However, as time elapses the
surface low will begin to fill and the moisture flux will nose its
way into the southwest...bringing the threat of snow north of
Dillingham. As mentioned above, models are differing in how much
warm air moves up from the north Pacific, decreasing confidence in
forecast snow amounts. Additional adjustments to snow amounts are
possible...at this time no headlines were issued for winter
weather products.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

The latest ASCAT pass shows gale force winds over portions of the
eastern Aleutians. The low continues on track. Expecting moisture
to wrap into the Eastern Aleutians this forecast period and
bumped up POPs and QPF this package. A tight pressure gradient
associated with this feature will persist into Saturday. Cold air
advection will follow in the wake of the low.

&&

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

Continued upper level support upstream of an upper level trough
anchored across the Bering Sea and northern Pacific Ocean will
help amplify the through much of next week. As this happens, a
surplus of jet energy will help wrap up a series of upper level
waves into fairly strong closed upper level lows. The most
noticeable of these lows will be one that develops somewhere near
42N to 44N and 164W to 159W on Tuesday. As this low develops, a
very strong surface low will develop in response and quickly push
into the Gulf of Alaska. Another low is expected to develop
Thursday or Friday but will likely be deflected further east
toward the Alaska Panhandle as the upper level trough shifts
eastwards. However, the low on Tuesday which moves into the
central Gulf of Alaska on Wednesday will bring some strong winds
to the offshore and coastal waters while another round of moderate
rain (and snow at higher elevations) to the Gulf coast. Inland
locations once again look to remain dry as the low position will
likely keep many locations downsloped. Temperatures across
Southcentral Alaska will likely remain a good bit above normal as
warmer air continues to get advected northward due in large part
to the amplified trough across the region. Southwest Alaska will
not be as warm or as wet as Southcentral Alaska as the orientation
of the upper level trough will keep much of the warmer and wetter
air east of the area.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storm warning 119 130 131 138 139.
Gale warning 120 125 140 150 155 160 165 170 171 172 174 180 351
414.
Heavy Freezing Spray Warning 179 414.

&&

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