Storm Warning 99, NWS Anchorage, AK

324 
FZAK61 PAFC 052322
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
322 PM AKDT Wed Oct 5 2022

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.

PKZ399-061400-
322 PM AKDT Wed Oct 5 2022
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A trough across the Northern Gulf sweeps West by Thu afternoon. A
1002 mb North Pacific low extends a second trough over the Gulf 
through Fri afternoon.

$$

PKZ351-061400-
Gulf of Alaska Offshore North of 57N and West of 144W-
322 PM AKDT Wed Oct 5 2022

...GALE WARNING TONIGHT...

.TONIGHT...S wind 25 to 40 kt becoming SE 15 to 25 kt after
midnight. Seas 10 ft.
.THU...SE wind 20 kt. Seas 7 ft.
.THU NIGHT...SE wind 20 kt. Seas 7 ft.
.FRI...SE wind 10 to 20 kt. Seas 7 ft.
.FRI NIGHT...S wind 15 to 25 kt. Seas 6 to 11 ft.
.SAT THROUGH MON...W wind 20 to 35 kt. Seas 6 to 11 ft.

$$

PKZ352-061400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
322 PM AKDT Wed Oct 5 2022

.TONIGHT...SE wind 25 kt. Seas 9 ft.
.THU...E wind 15 to 25 kt. Seas 7 to 10 ft.
.THU NIGHT...E wind 10 to 20 kt. Seas 9 ft.
.FRI...SE wind 10 to 20 kt. Seas 6 to 10 ft.
.FRI NIGHT...S wind 10 to 25 kt. Seas 6 to 10 ft.
.SAT THROUGH MON...SW wind 15 to 30 kt. Seas 6 to 11 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
540 AM AKDT Wed Oct 5 2022

.ANALYSIS AND UPPER LEVELS...

The upper-level pattern is defined by a large, cut-off upper low
over the North Pacific centered south of the AKPEN. On either side
of the low, two ridges extend northward. To the west, a North
Pacific ridge extends across the Bering Sea ahead of a large
developing low over Far Eastern Russia. To the east, another ridge
extends along the length of the western coast of North America and
meets the first over southern mainland Alaska. Riding up on the
relatively warm, moist flow out ahead of the cut-off low is the
main shortwave trough of interest for the short term, entering
the southern Gulf this morning. This shortwave is aiding
development of a surface trough along a cold front. Stronger
convective activity is occurring along this front in association
with the wave, with even some lightning detected during the
overnight hours. Just to the north, a warm front extends across
the Gulf, contributing to widespread cloudy and wet conditions,
with numerous rain showers detectable on radar this morning in the
northern Gulf. Rainfall extends toward Kodiak Island, where
Kodiak City has received some 2.5 inches of rain in the past 24
hours. Much lighter rainfall is also making its way into the Cook
Inlet region, where cross-barrier flow is a more significant
factor limiting accumulations.

Underneath the ridge out west, surface high pressure prevails
with some clearing. However, a stream of low stratus is filling in
over the Kuskokwim Delta and the eastern Bering. A colder airmass
also continues to press southward across the eastern Aleutians,
contributing to winds gusting to around 40 mph through gaps and
passes. Further west, a plume of warm, moist air is being drawn up
ahead of the large, strong low over Far Eastern Russia, leading
to a blanket of low stratus for the western Aleutians/Bering. The
plume is bounded to its east by a warm front sweeping eastward
across the central Aleutians, and to its west by a cold front in
the far western Bering approaching Attu Island. Both fronts are
producing rainfall for these regions.

&&

.MODEL DISCUSSION...

Synoptic-scale agreement is good through the short term forecast
period. While details have come into better alignment with a
strong shortwave rotating around the upper-level low over the
North Pacific, there are still slight track and timing differences
as the feature moves inland through Wednesday night. Otherwise,
model agreement is good with a strong cold front pushing east
across southern mainland Alaska into the weekend.

&&

.AVIATION...
PANC...VFR conditions and light northerly winds will persist
through Wednesday evening, with a stray rain shower or two
possible. This evening, rain chances increase and a gusty
southeasterly wind is expected to develop. Ceilings will hover
near 5000 ft but may drop lower with heavier rain showers. By
early Thursday morning, southeasterly Turnagain Arm winds are
expected to intensify, with gusts likely reaching 35 mph. Gusty
winds continue through at least the morning hours on Thursday.

&&

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

A front currently extending along the Gulf coast is bringing rain
and gusty easterly winds to Kodiak and areas near Prince William
Sound. As warm air aloft pushes northward, high temperatures
across Anchorage and the Mat-Su today could possibly reach the mid
60s. An upper low will pivot northward this afternoon leading to
the development of stronger Turnagain Arm winds this evening.
These will persist through Thursday. Mid-level winds will gradually
shift southerly, however areas in the lee of the Chugach should
remain mostly downsloped and precipitation-free. Although
uncertainty remains, another front will enter the Gulf on Friday
and likely bring widespread rain into Southcentral into the
weekend.

&&

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

Quieter weather will gradually take hold through the day as a
ridge continues moving inland from the Bering Sea. For now, the
day will dawn with a blanket of stratus over the Kuskokwim Delta
and the tip of the Alaska Peninsula. Higher clouds are present
over the remainder of Southwest Alaska, courtesy of a low near
Kodiak Island in the Gulf of Alaska. This low will also keep winds
northerly and elevated over Southwest through this evening, with
the strongest winds expected through channeled terrain in the
Alaska Peninsula. As we head through the day, winds should slowly
diminish and the stratus should gradually burn off, allowing for
clearer skies and calmer conditions.

More active weather returns late tonight through early Thursday
morning as a low in the Chukchi Sea pushes its front into the
Kuskokwim Delta. The front is expected to weaken as it pushes
onshore Thursday morning. However, precipitation is expected to
reintensify by Thursday afternoon and evening as a low pivots
from the Gulf of Alaska into Bristol Bay, colliding its front with
the existing front in Southwest Alaska. At the same time,
southeasterly winds will channel through Kamishak Gap and into
interior Bristol Bay. Some model differences with this Gulf low
mean that the finer details with expected wind speeds and
precipitation timing and amounts are still somewhat uncertain at
this time. For now, the front is expected to slowly move eastward,
weakening as it runs up against the Alaska Range Friday evening.
Meanwhile, a trough will move towards the Kuskokwim Delta by
Friday evening, bringing another round of light rain. Temperatures
are expected to drop into the 30s as we head into the night on
Friday, with 850 mb temperatures ranging from -3 to -7 degrees
Celsius. Snow is a possibility, but much uncertainty remains with
whether the surge of cold air will coincide with falling
precipitation.

&&

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

A front is currently located in the Western Bering, with
southerly winds up to gale force expected along the front. As the
parent low moves north into the Chukchi Sea through today, expect
the core of strongest winds to follow. Gales will be limited to
the Northern Bering by this afternoon, with winds dropping to
small craft speeds or lower by early Thursday morning. Meanwhile,
in the Eastern Bering, expect northerly small craft winds this
morning to slowly diminish as a low in the North Pacific Ocean
weakens.

By Thursday, winds will begin to shift southwesterly as the cold
front pushes across the region, reaching Western Alaska by Friday
afternoon. Winds are expected to peak at around small craft
speeds, with lighter winds in the Southern Bering and along the
Aleutian Islands. Overall, while winds will be elevated and rain
chances will increase, no major impacts are expected with this
feature. By Friday evening, an upper level trough will begin to
dig southward, bringing a surge of colder air.

&&

.LONG TERM FORECAST (Days 4 through 7: Saturday through
Tuesday)...

The synoptic pattern through the long term period shows upper
level ridging over Western North America with primarily upper
level troughing over east Russia and the northwest coast of
Alaska. In between these main features will be transient upper
level ridges and troughs which vary from model to model. Some are
deeper with the trough moving across southern Alaska Sunday while
others keep a more zonal flow. A stalled front remains across
Southwest heading into Saturday keeping the region unsettled.
Another stronger upper level shortwave is expected to traverse the
northern Bering and barrel its way into Southwest Friday night
through Saturday. This will act to reinforce the front especially
across the Middle Kuskokwim Valley and Bristol Bay leading to
upslope in these areas, especially the Lake Clark National Park
and Reserve. This will lead to enhanced precipitation rates in
this area. Further east, southwesterly flow will be aimed north
through Cook Inlet Saturday and then Prince William Sound for
Saturday/Saturday night leading to heavier precipitation.

Behind this first system, much colder air will filter in behind it
especially across Southwest/northern Bering Sea where 850 mb
temperatures may fall to as low as -8 to -9 degrees Celsius. Some
of this cold air will get funneled through the Kamishak Gap
leading to increased winds through the Barren Islands area
potentially to gale force. Enough of this cold air may filter into
the northern areas of Southcentral namely Broad Pass area from
Chulitna on north towards Cantwell and across the northern Copper
River Basin (Paxson area). The main issue here though will be if
the cold air can move into the area before the precipitation ends
to bring some snowfall. There is the potential that snow may fall
on the road system in these areas. Also, this could potentially
lead to the first widespread freeze of the season for Southcentral
but will be highly dependent on if it can clear out or not. If it
stays cloudy it most likely would stay in the mid to upper 30s.

Sunday looks to be a transition day where heights may rise some
behind the departing upper level trough. However, another system
looms right on the heels of this first one leading to another
round of unsettled weather for much of southern Alaska, the
Bering Sea/Aleutian Chain Monday/Tuesday. Depending on the exact
track and intensity of this low some warmer air may be brought
northward into Southcentral raising snow levels some. Southwest
Alaska where the deeper cold air will be may have the potential to
see the first accumulating snow of the season especially across
the Kilbuck/Kuskokwim/Ahklun Mountains. Some of the villages also
might have the potential at seeing the first snowfall but too
uncertain to pinpoint which ones yet. Most likely it would be
either the Kuskokwim Delta, western Middle Kuskokwim Valley and
western Bristol Bay.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 119 120 125 131 138 150 185 351 411 412.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CQ
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KC
LONG TERM...MV