Storm Warning 78, NWS Anchorage, AK

744 
FZAK61 PAFC 101150
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
350 AM AKDT Sun Mar 10 2019

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.

PKZ399-110230-
350 AM AKDT Sun Mar 10 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front along the northern Gulf will move inland late Sun morning. A
stationary front associated with a 968 mb low in the eastern Bering 
will persist in the southwestern Gulf through Mon morning. An area of
weak low pressure will develop in the northern Gulf Mon night and 
persist through Tue morning. 

$$

PKZ351-110230-
Gulf of Alaska Offshore North of 57N and West of 144W-
350 AM AKDT Sun Mar 10 2019

.TODAY...SW wind 30 kt. Seas 16 to 21 ft. Rain showers.
.TONIGHT...SW wind 20 to 30 kt. Seas 16 to 21 ft. Rain showers.
.MON...W wind 15 to 30 kt. Seas 13 to 19 ft.
.MON NIGHT...W wind 30 kt. Seas 13 to 17 ft.
.TUE...S wind 25 to 40 kt. Seas 9 to 16 ft.
.WED THROUGH THU...S wind 25 to 40 kt. Seas 15 to 23 ft.

$$

PKZ352-110230-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
350 AM AKDT Sun Mar 10 2019

...GALE WARNING TODAY...

.TODAY...SW wind 35 kt. Seas 19 to 27 ft. Rain showers.
.TONIGHT...SW wind 30 kt. Seas 20 to 26 ft. Rain showers.
.MON...W wind 20 to 30 kt. Seas 18 to 21 ft.
.MON NIGHT...W wind 30 kt. Seas 15 to 20 ft.
.TUE...SE wind 25 to 40 kt. Seas 11 to 17 ft.
.WED THROUGH THU...S wind 25 to 40 kt. Seas 13 to 21 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
456 AM AKST Sat Mar 9 2019

.ANALYSIS AND UPPER LEVELS...

A very strong 180 knot upper-level jet is currently positioned
south of the Aleutians, stretching thousands of miles across the
Pacific to 160E. A much weaker ~100 knot north-south oriented jet
spans the central mainland. An mid-level low is located in the
left exit region of the Aleutian jet continues to strengthen and
is now nearly completely phased with a weaker low that was
spinning in the central Bering for the past few days. The mid-
level ridge axis over eastern Alaska last night has now moved over
Canada and a trough has developed in its wake, currently centered
over the Barren Islands. A weak surface trough slightly
downstream of the mid-level trough is bringing mixed precipitation
to coastal areas along Prince William Sound. A strong ~950mb
surface low is tracking across the central Bering and radar is
indicating associated precipitation along the western mainland
coast. The strong steering winds aloft will cause this front to
move quickly into interior portions of the state.

&&

.MODEL DISCUSSION...

Models remain in good agreement in the near-term. The strong,
broad area of low pressure will continue to track across the
Bering. Its associated front is expected to bring strong winds to
Southcentral beginning this afternoon. As models have indicated
the higher Turnagain Arm winds for several days now, confidence is
high. There remains some uncertainty with how strong the winds
will be in Anchorage proper as well as precipitation types along
coastal areas.

&&

.AVIATION...

PANC...VFR conditions are expected to persist through the forecast
period. The main issue will be gusty southeasterly winds this
afternoon through early Sunday morning. Winds are expected to peak
at approximately 05z, potentially reaching 35-40 kts before
gradually diminishing thereafter. Wind shear is not in the
current TAF, however if surface winds verify lower than our
forecast, speed sheer in particular could be a threat. Winds at
2000 feet are expected at around 45-50 kts.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2: Today and
Sunday)...

A front over the Alaska Peninsula will track to the northeast
today and into Southcentral Alaska this afternoon. This strong
front, that is anchored by a low in the Bering, will bring strong
winds and heavy precipitation to the area. Additionally, it will
pull in warmer air resulting in a change from snow to rain for
many low lying areas and cutting off the possibility for blowing
snow conditions that would drastically reduce visibility. The
majority of the precipitation will be along the north Gulf coast
with the eastern Kenai Peninsula seeing the highest amounts.

Gaps and passes with an east/west orientation will see strong
winds with this system that will increase throughout the morning
and peak this afternoon/evening. One of the locations that will
see the strongest winds will be along Turnagain Arm where a High
Wind Warning has been issued for winds gusting to 80 MPH. Winds
and precipitation will begin to diminish Sunday morning after the
front passes, but will linger, to a lesser extent, around the same
locations through Sunday night.

&&

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

A strong front associated with a low in the eastern Bering will
push across Southwest today. Winds along the front will be strong
particularly along the coast in the lee of gaps and passes in the
Alaska and Aleutian Ranges. Winds along the coast are currently
gusting to around 40 mph and expect coast winds to peak around
mid-morning, while farther inland gusts could reach 70 mph by
early afternoon from Kamishak Bay to the Nushagak Hills.
Persistent southeast flow with a deep fetch of moisture will bring
temperatures to the upper 30s to low 40s for most of Southwest
this afternoon. Accordingly, other than along the ridges
precipitation will be rain. Downslope winds will limit
precipitation amounts for areas in the lee of the Aleutian/Alaska
Ranges and the Kilbuck/Ahklun Mountains, and increase highs to
the mid 40s. The front will clear the region tonight, and a
showery pattern with diminished winds is expected in its wake. As
the low shifts inland, cold air from eastern Siberia will wrap
around and winds will shift to onshore and temperatures will
decrease Sunday into Monday.

&&

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

A vertically stacked low in the central Bering will continue to
bring a swath of storm force winds south of the Aleutians and rain
showers to much of the Bering, Aleutians and Pribilofs into this
afternoon. Cold air advection around the west side of the low will
support a large area of gales in the western/central Bering.
Precipitation will changeover to snow from west to east into
Sunday, but with a much drier air mass, snow amounts will be
light. Winds will diminish substantially Sunday. The next North
Pacific low will approach the western Aleutians Sunday afternoon,
but does not look very impactful with winds likely only small
craft advisory level. That said, it may be a bit early to
completely rule out gales.

&&

.MARINE (Days 3 through 5)...

Beginning the day 3 period on Monday, confidence is high that the
overall storm track will be shifting east into the Gulf of
Alaska. There is a high likelihood of a strong gale force to low
end storm force low moving into the Gulf of AK Tue night and
Wednesday. The large size of this low means it will impact all of
the Gulf waters as the low deepens then stalls with gale force
winds likely lasting through Thursday.

Over the Bering Sea, broad cyclonic flow with 20-30 knot winds
will gradually weaken through Tuesday night as the storm track
shifts eastward. This will bring a break to what has been a very
stormy Bering Sea of late as no strong lows are expected through
Thursday (likely remaining at or below gale force through that
period).

&&

.LONG TERM FORECAST (Days 3 through 7: Sunday evening through
Friday)...

Beginning the long term forecast Sunday evening, there will be an
upper level low centered over Southwest Alaska with that cyclonic
flow extending over the Bering Sea. Colder air will be filtering
into Southcentral on Monday as the trough shifts east. Rain and
snow will gradually become all snow Monday evening across all of
Southcentral, but no significant accumulations are expected inland
given the relative warm temps in place and the showery nature of
the precipitation.

As the mainland trough moves east into Canada, another shortwave
trough trailing over the Bering Sea will dig south and amplify the
flow. This will make the pattern become more meridional Tuesday
with increasing chances for coastal rain/snow and inland areas of
mostly snow. On Wednesday a deep Gulf low will develop and bring
storminess to the Gulf region with more chances for heavier
coastal precipitation into the late week. Conversely, rather
strong downslope flow will generally keep Southcentral inland
areas drier. For Southwest, it looks like the region west of the
AK Range will stay on the colder side of the cyclonic flow with
increasing chances for accumulating snow Tuesday into Friday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...

PUBLIC...High Wind Warning 101.
MARINE...Storm Warning 155 172 174 176.
 Gale Warning 119 120 125 129 130-132 136-139 141 150 160 165 170
171 173 175 177-181 185 351 352 411-413.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...AP/JW
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MM
MARINE/LONG TERM...JA